​After 22 months, well over fifteen thousand kilometres and zero love, the modified Sturmey Archer hub on my commuter bike finally decided that enough was enough. I first wrote about the bike when I’d finished building it back in April 2016 and then provided a bit of an updated on how everything had been performing in May 2017. I wanted to see just how far the hub could go, and after the last two weeks of some terrible noises I got my answer. For someone who considers themselves to normally be a pretty mechanically sympathetic person, this was an unpleasant experience.
 
In the end it was, perhaps unsurprisingly, the driveside axle cartridge bearing that proved to be the weakest link. In fact, it was the weakest link by quite some margin as the other two bearings are rotating as smoothly as the day I fitted them, while the rest of the hub was functioning well. All that was needed now was to replace the one cartridge bearing followed by a good clean and re-build.
 
The hardest part of stripping the hub down was trying to unscrew the ball ring from the hub shell, which had seized after nearly two years of being covered in salt and muck – I ended up soaking it in GT85 and providing the necessary encouragement with a hammer and blunt punch. Unfortunately, there doesn’t seem to be a subtler way of doing it (I’ve bought the Sturmey Archer tool, supposedly designed for the job, but I find it hopelessly inadequate).

The hub internals greased up and ready to get pressed back into service

​Once inside the hub I was pleasantly surprised by what I found. As I mentioned, the other two cartridge bearings are still spinning smoothly and so these have gone straight back into the hub for some more punishment, while the grease at the non-driveside end of the hub shell still looked like new. After the liberal application of some degreaser followed by some fresh grease, the hub has been rebuilt and is as good as new. The driverside cartridge bearing has been replaced. The original was a budget, non-branded item, so this time I’ve splashed out on an SKF number to see what sort of difference this might make. This way I’ll hopefully get even longer service out of the hub before it requires its next overhaul.

All back together again and ready for the commute

It’s too early to draw any definitive conclusions, but after a first ride that consisted of four hours and over 44 miles in the Surrey Hills and North Downs I thought that I would note down my first impressions. Up until this point I had only ridden the bike around the block twice. So, considering that I built the frame and wheels myself, had the hub modified, bled the brakes and screwed the whole lot together, I was slightly amazed that the whole thing didn’t just fall apart like a clown car. The truth is the bike didn’t miss a beat the whole ride. The only thing that needed some adjustment was the belt tension after it started to ratchet over the rear sprocket on the first steep climb. But seeing as I had purposefully set this up to be relatively loose (at least in belt-terms) to minimise the load on the bottom bracket and hub bearings, this was entirely expected. With the belt tweaked the bike simply got on with the job.
 
With any concerns about the relatively fundamental issue of the bike falling apart allayed, I was left to concentrate on judging whether all of my past thoughts about geometry had been inspired or a waste of time. But honestly, the bike was simply fantastic. It just did everything that I wanted it to. My position on the bike felt incredibly natural, to the point where getting on to my dropped handlebar commuter bike the following morning (the bike that I easily spend the most time on) suddenly felt incredibly contrived and contorted.

​I wasn’t sure that it was necessarily going to work-out this way, and I had a number of doubts before this first ride. None of them materialised, but I thought that it would be interesting to discuss them below. The first of these was the handlebar. Despite it being an obvious visual departure from the norm, I was actually halfway through the ride before I had to consciously think to myself ‘what do I think of it’. It had gone completely unnoticed, feeling perfectly natural. I suppose this should hardly come as a surprise given that my position on the bike closely resembles that of a Motocross bike, but their shape, in combination with the bikes geometry, was spot-on.
 
Another concern I had with the handlebar was that I might end up hitting my knees on it when climbing out of the saddle, due to the bikes short reach (on other bikes I can brush them a couple of times during a ride). But with the extra stack height this was never an issue. In general, climbing felt surprisingly efficient, despite the bikes relatively short reach and slack seat angle. I suspect that the longer than average chainstays play their part in this, but so must the 3.0 inch tyres, which always seemed to find traction. In fact, the relatively slack seat angle didn’t seem to have any negative side effects, certainly nothing that worried my knees.

For about the last eight years I have used Ergon grips on all of my mountain bikes, as this has been the only way to stop may hands from tingling or going numb after a couple of hours of riding. Despite forgoing these in favour of a set of ODI Longnecks, there was no such problem with this bike. I put this down to the reduced load on my hands as a result of the more upright geometry. 
 
The saddle was another area of concern before riding the bike – with less weight through my hands it could only mean more weight through my backside and I was worried that the saddle might end up slicing me in two! But the Charge Scoop went perfectly unnoticed, as any good saddle should.
​
The only real issue I had with the bike was its weight. At 14.5kg (32lb) it could definitely do with going on a diet. There are a few obvious culprits that are mainly a result of my limited funds. The chromoly Identiti fork is a prime example – weighing in at just over 1.6kg, a switch to something like a carbon Kinesis Maxlight would instantly drop 0.9kg.
 
The wheels are another area where weight could be lost. At 1.2kg each, the 3.0 inch WTB Bridger tyres could be swapped for a set of the latest crop of ‘in-between’ 2.6 inch tyres that are now starting to appear. These could then be fitted to narrower rims, such as Stan’s Sentry MK3 (521kg each) instead of the Easton Arc 45 rims (650g each). But the really big saving would be the loss of the inner tubes that I am currently running. I know that it’s incredibly unfashionable not to have gone tubeless, but with a young family I often can’t get out on my bike as much as I’d like and could do without the need to be topping up sealant every 3 months (when there’s an outside chance that I might only get out on the bike 3 times). This is hopefully something that will change in the future and would help towards saving a couple of kilograms in total from the wheelset.
 
But despite the cuddly physique, the bike was awesome. It definitely has limits - in the really rough and rocky stuff you are left in no doubt that this is still a rigid mountain bike, but everywhere else it was a joy. I set-out to build a bike that maximised the number of visceral, exciting moments where you have that feeling of being up on your toes and dancing between the trees. I wanted a bike that helped me to earn my speed, extracting it from the trail by drifting, accelerating, pumping and getting loose, totally immersed in the experience. This bike does that. The higher handlebars and shorter reach mean that I’m far more stable on the bike. Perhaps counterintuitively, this actually makes weighting the front wheel easier, because my arms aren’t also having to fight to support my own weight – I am able to respond more quickly and with more purpose to what is coming towards me. On flowing singletrack, such as the lower sections of Summer Lightning, the bike (and rider!) was in its element.

​I suppose you could argue that there was always a good chance that the bike would work-out this way as that’s the way I’d designed it. I’ve been fortunate enough to start with a blank sheet of paper in order to create a bike that fits my proportions perfectly and handles the way I wanted. Plus, given that I’ve sunk a not-insignificant amount of time, effort and money into the bike, it would be difficult to admit to myself, let alone anyone else, that it had been a folly. But this simply isn’t the case, and I’m both incredibly relieved and excited to be able to say that! So now I can look forward to a summer of getting to know the bike even better, full of flowing singletrack, fun and big smiles.

After so long thinking, planning, designing, discussing and building the bike, it’s actually a little bit weird that it’s now finished. In fact, I can’t stop looking at it – just standing and staring. While I’m incredibly excited to find out how it rides, I’m also pretty anxious. I should know more in a couple of months, but for now I’m just really pleased with how it’s turned out.

I should probably briefly describe the thinking behind the bike, which is explained in more detail on the website here as well as in a number of my previous blog posts. Essentially, the geometry of the bike deviates from the norm for two key reasons. The first, and least exciting, is because of my lanky proportions. With a saddle height of approximately 825mm, both the saddle and handle bars are around 80mm higher than they would be for someone of the same height (I'm 184cm / 6'1'' tall), but with average proportions.
​
Once you’ve seen past that you get to the second and more interesting part of the bikes geometry – a desire to achieve greater rider stability to create a bike that maximises rider involvement, control and, ultimately, fun. This thinking has led to a frame that has gone in the opposite direction to the current trend for ever longer front ends and steeper seat angles, tipping a rider forwards onto their hands. Instead it places the riders weight squarely through their feet in something akin to an Athletic Stance. As I say, there’s loads more on this topic to be found elsewhere on the website, so I won’t repeat myself any further here.

The upshot of this geometry is that the relationship between the bottom bracket and the handlebars is almost identical to that of a Motocross bikes between the pegs and handlebars (hence the Full-Moto name). Knowing this, I was originally searching for a set of mountain bike handlebars with similar geometry to a Motocross 'bar. Having scoured the internet, I came up with nothing until it dawned on me to just simply use a set of 7/8'' Renthals. At the other end of the bike I'm running an existing belt drive set-up that I've robbed from another of my bikes. This turns a Sturmey Archer 3 speed hub which has been modified to accept cartridge bearings in place of the standard cup and cone ball bearings for added durability.

Following on from the course at The Bicycle Academy, the first job was to get the frame painted. I decided to leave the frame just as it was, with the only exception being an obligatory sand blasting. So the brass fillets have been left exactly as I laid them. As Tom Sturdy mentioned during the course, if a custom framebuilder sanded down their TIG welds then it would beg the question ‘what are you trying to hide?’ For reasons mainly of aesthetics, brazing seems to be viewed a bit differently, but I think that there’s an honesty to leaving the fillets as they are. This extends to a rather large blob of silver on the down tube, which I could have sanded away to nothing and it would have disappeared forever. But, instead, this will be a little reminder of the rush that I was in while trying to get the cable-guides finished late on the last Friday of the course, getting the middle guide too hot and applying too much silver. All part of the bikes story and a lesson learnt for future frames (hopefully!).
 
I had always planned to get the bike powder coated at Armourtex in London as they had done a decent job with another of my frames several years ago. But a friend asked why I wanted to drag the frame, forks and stem all the way into London when there are plenty of places locally that can do powder coating. This seemed logical, so I found someone based just a couple of miles away who appeared to know his stuff. He said that he’d done a number bike frames in the past and his prices seemed reasonable. However, when I picked the frame up it was clear that, although I don’t doubt that he’d painted frames in the past, he didn’t understand bikes. It looked suspiciously like a Victorian radiator, mainly because this is what I suspect he is used to doing. The masking on the rear dropout sliders is far from perfect while a couple of the bottle bosses and a cable guide haven't been properly coated.
 
Being very British about the whole thing, I simply collected the frame, paid my money and said thank you. I spent the next couple of days being incredibly grumpy thinking that I’d effectively wasted a whole bunch of money and a load of time, but, most importantly, I was angry with myself for not sticking with my Plan A. I was all set to get the frame repainted, but the owner of my local bike shop doubled as my shrink, listened to me moan for 15 minutes and talked some sense into me. His advice was to ride the bike for six months as it is and if I was still unhappy then I could always get it repainted. Sage and timely advice that I’ve chosen to follow.

​The truth is, now that the bike is fully built up, the paint job isn’t half as bad as I first thought. There are bits that are far from perfect, which always seem to grab my attention, but really the paint is more than adequate for my needs. Because the paint is also pretty thick in places, it's caused a few problems. For example, the seat clamp was meant to be 32.0mm in diameter, but now measures 33.4mm. No one makes a clamp in this size, so the bike has ended up with a 35.0mm clamp together with a home-made shim. Again, if I’d taken it to a painter who understood bikes then this would have been avoided. You live and learn.
 
As I already had all of the components (except for the aforementioned seat clamp) the rest of the build has simply meant a couple of nights with the Allen keys whilst listening to early nineties dance music in my shed. I can think of worse ways to spend my time! Putting my grumbles about the paint to one side, I’m really pleased with how the bike has turned out. Sitting on it in the shed, it seems to put me in exactly the position that I was after and one that I’ve never been able to achieve with stock frames. Holding on to those handlebars is simply awesome!

Something else that I'm pleased with is how 'right' the bike looks. This is definitely not something that I've been able to say about many of my previous bikes once they've been adapted to fit me. I don't know if it's just because I've been staring at it for so long that I've just got used to it, but, considering the bike has some pretty unconventional geometry (resulting in a 190mm headtube!), I don't think that it jars or looks too ungainly.
 
With the first glimpses of Spring starting to appear and the clocks having just gone forwards for some extra daylight in the evenings, I’m hoping for a long and enjoyable few months of putting the bike through its paces. And once I’ve gathered my thoughts I’ll be back with an update on how the bike rides.
 
As a bit of an aside, if you’ve stuck with the blog since the early days, then I just wanted to say thank you. This feels like a bit of a watershed moment and a timely point at which to show my appreciation. Hopefully you’ve enjoyed the journey so far?

What an amazing place – somewhere dedicated to helping people create bicycles of all shapes and sizes. It feels so incredibly immersive, almost glutinous, as I’ve never been able to chat so much about bicycles and riding. And the real clincher is the calibre of the people that you are talking with. When Robin Mather casually walked over and asked how I was getting on I honestly had to tell myself not to hug him immediately. You’ve got Paul Burford from BTR Fabrications ambling through the building with his Springer Spaniel, on his way to their workshop next door. While Tom Sturdy orders the next batch of tubing to maintain the healthy stock levels. And just the general air of quiet, considered knowledge is palpable. But, and this is the trick, it’s all so humble. We all eat lunch together, which the staff take in turns to make, and we eat it while chatting about everyday stuff. But there is always this under-lying collective appreciation and desire for knowledge associated with the humble bicycle.
 
The next thing to strike me is just the sheer quality of what’s being taught. Not just because of the experience and clarity of those teaching it, but also the thought that has gone into how you get a novice like me to absorb all of this information. I’m in the fortunate position to have done another frame building course at another venue about eight years ago. But the difference in what and how I’m learning is like night and day. The Bicycle Academy seems like a very appropriate name.
​
If I’m honest, I was incredibly disappointed with that first frame building course I did – it all felt way too rushed, I’m truly embarrassed to show people the frame that I built, and I certainly didn’t leave with the knowledge to build another one. So, I then decided to sign myself on to a night-course in welding at Hammersmith and Fulham College in the hope of gaining a better understanding of brazing. But this was primarily aimed at people from the automotive industry and didn’t really help a great deal. Finally, I bought a Jiggernaught (an MDF frame jig) in the hope that if I could at least get some tubes mitred and held in the correct position then I would be heading in the right direction. But I ended up just sort of running out of steam and eventually gave up on the idea in about 2014. However, the itch has slowly returned, this time with the added impetus of wanting to put my thinking on mountain bike geometry into practice. And so, I now find myself at The Bicycle Academy on their seven-day frame building course.
 
Day one and we spent the morning going through some theory on bike geometry as well as some structural considerations. Then, after lunch, we finalised the geometry of the frames that we will build, and I began to work out how I might get my chainstays to work. These are probably the most complicated part of my frame, having to accommodate a three-inch tyre, clearance for the front sprocket, a relatively wide belt, tensioning of the aforementioned belt as well as a 180mm disc rotor.

Chainstay layout

I’m on the course with two others. I know that I’m a bit weird to have spent the best part of the last two-years developing my thoughts about what I wanted to make. But one student’s only criteria was that he wanted a 27.5+ mountain bike while the other, when asked what he might want to make, literally said ‘I don’t really know’. Clearly, I’m even more of an oddball than I had thought!

Today started with the selection of our tubeset. It reminded me of buying pick’n’mix from our local Post Office when I was a kid – you were given a plastic tub to fill up with your choice of Fruit Salad’s, fizzy cola bottles and coconut mushrooms. Only this time I had a long wooden box and a pile of metal tubes. Columbus Zona seemed to cover most of my needs, but my chosen dropouts needed something special made-up to help strengthen their connection to the chainstays. Twenty minutes later Robin Mather had turned some steel bar into two beautiful, custom plugged lugs. Amazing.

Pick'n'mix tubeset

​This was followed by some brazing theory. It probably goes without saying, but these guys really know their stuff. Not just how to lay perfect fillets, but how to explain the process to others in a way that lets you understand exactly what’s happening. If this course stands apart from the one that I did before, it’s in the clarity of the instruction when it comes to brazing. Previously, I felt that I had never properly got to grips with brazing because I never really understood the process and so I was still nervous about putting my newly learned theory into practice, even after such expert tuition.
 
I needn’t have worried. The first time we started brazing was along a simple piece of flat metal with our teacher, Tom Sturdy, guiding our hands like we were playing pool on a first date. This complimented the earlier teaching perfectly, so that even if things didn’t go to plan, you knew why things had gone wrong and how to correct it. Essentially, it puts you in a position of control, allowing you to immediately focus on perfecting your technique, rather than trying to second guess what’s going on.
 
Initially, it felt a bit like the first time that I rode a motorbike – there seemed to be so many things to do all at the same time that it all feels very daunting. But, firstly, Tom explains the things that are most important to focus on and, secondly, many of these things soon become semi-sub-conscious actions. Amazingly, my first attempt at brazing two tubes together was a reasonable effort. In fact, it was probably better than anything that I had ever done before, and this was all thanks to Tom’s instruction. Just keep thinking: rate of travel (torch), dwell time (filler) and orientation (work). Then all that is left to do is focus on toes, foot and throat (the brazing equivalent of head, shoulders, knees and toes!).
 
Easily the worst thing about the whole day is that I know that I now have to wait an entire weekend before I can get back to it!

My first tube-to-tube fillet braze

​Today was pretty frustrating and so a little disappointing. Having already picked out my tubeset, today was meant to be all about starting the process of mitring their ends and fitting them in the jig. The morning was spent practicing the required skills on some test pieces and I’d forgotten just how pleasing it can be when you achieve a really tight mitre between two tubes. My miniature downtube felt beautifully snug, nestling between the headtube and bottom bracket shell – it almost seems a shame to cover it in brass!

Miniature practice pieces

​After some lunch we turned to the actual tubes that we will be using to build our frames. I already knew that I was missing my headtube – it’s on order and will hopefully turn-up tomorrow. But this wasn’t an issue as the plan was to start with the mitre at the bottom of the seat tube where it meets the bottom bracket. However, when I checked the seat tube it turned out that it was not the one that we had previously thought it was and so was unsuitable for my purposes. An alternative was found, but we later discovered that this had been ovalised (thankfully we didn’t discover this too late!)
 
Not perturbed, we decided that I would set about mitring the downtube instead. However, this had some very odd butting (down to 0.5mm at one end), which didn’t tally with any spec sheet. A second down tube was located, but this suffered from exactly the same issue. Much head scratching ensued. Right at the end of the day a third, suitable down tube was found, but by this stage it was all a bit too late to start anything meaningful.
 
So, I seemed to spend a lot of the day looking at tubes that weren’t any good to me and waiting for something more appropriate to be found. As I say, pretty frustrating. In the end I spent the final hour practicing a bit more brazing, so the day was far from a complete waste of time, but disappointing after a weekend of anticipation. Hopefully, I can get properly stuck-in to the tubing tomorrow.

​What a difference a day makes! My headtube arrived in the post, while a suitable seat tube (which apparently doesn’t appear in the official Columbus catalogue) and the monster of all down tubes were both located within 15 minutes of arriving this morning. This turn around in fortunes was orchestrated by Tom Sturdy, who had returned to the workshop after a day away, bringing with him an unflappable calm that seems to put everyone at ease. I think I’m in danger of having a man-crush!
 
So, the day was spent almost entirely on fabricating the front triangle. Seat tube, down tube and then top tube have all been mitred and are now in the jig. I was working flat-out all day, thinking that I’d done loads. Then I stepped back and realised just how far I still needed to go with only three days left. Still, if you squint then it’s almost starting to look like a bicycle.

The front triangle mitred and in the jig

​The only let-up in the measuring, cutting and filing was another short bit of brazing practice. This little-and-often approach is really working (and I’m sure that’s not by chance!) You do a bit, pause, think about what didn’t work so well, have another go and then move on to something else entirely different. It stops you from getting bogged down or too tired (and trust me, concentrating that hard is tiring!) and, again, the quality of the teaching is just fantastic. 

​Today was all about the chainstays. It’s amazing that these two relatively skinny tubes at the back of the bike require so much attention, taking as long to prepare as the entire front triangle. In my case, they were further complicated by my choice of dropouts – Paragon Machine Works’ sliding dropouts. Tom suggested that the connection to the chainstays needs to be beefed up, which is where the plugged lugs that Robin made for me on Day 2 came into effect. These actually needed tig welding to the (stainless steel) dropouts before being brazed to the chainstays. Tom quickly did this for me while I observed (my face guard even had flames painted on it!) and I realised just how difficult this type of welding is – it requires surgical levels of steadiness and precision.
 
This is also where my 1:1 chainstay drawing came into its own (again from Day 2), helping to ensure the stays successfully thread their way from bottom bracket to dropout while avoiding the front sprocket and tyre. This is what led us to choose the double-bend stays that I’ve ended up with – easily my favourite tubes on the whole bike (you’ve got to have a favourite tube after all).
 
Right at the end of the day there was just time to start considering the seat stays. The pre-bent items that I was hoping to use were soon found to be lacking when it came to providing the required tyre clearance. In their stead we are going to create our own from standard 18mm tubing. Some judicious use of a bar-bender and these are now ready to start mitring.

Chainstays done!

​With the front triangle and chainstays in the jig it’s now possible to get a really good sense of what the frame will end up looking like. The 44mm headtube, massive downtube and tall chainstays contrast brilliantly with the relatively skinny top tube and constant-diameter seat stays. I’m absolutely buzzing about the next couple of days – getting the rest of the fabricating finished and brazing it all together.

​The day started with two new students arriving for their 7-day framebuilding course. It seems like both a life-time ago and like it was only yesterday that I was in the same position. And also a stark reminder, if one were needed, that I don’t have long left to complete my frame.
 
My morning was spent trying to get my head around the seat stay mitres, at the point where they join the seat tube. This is not a job to undertake lightly, requiring all of my spatial awareness in combination with a good deal of frustrated muttering to eventually end up with two identical and tight mitres. Once these were complete I attempted to silver braze the plugged lugs to the dropout-end of each stay (that Robin had made for me on Day 2 and which were now attached to the dropouts). The first stay worked perfectly, but for whatever reason the silver refused to flow properly on the second stay, despite Robins expert guidance. So, we took the decision to stop, pull it all apart, clean it up and start again later on once it had all cooled down.
 
In the meantime I cleaned up the rest of the frame tubes, drilled holes in my down tube and seat tube for my bottle bosses, and created an elliptical hole (also in the seat post) for my internal dropper post cable routing. Everything then went back into the jig, measurements were double checked and I made sure that the bottom bracket was the right way around before tacking everything together. The only exception was the aforementioned seat stay. On the second attempt the silver brazing worked as expected and so this joint has been left to soak overnight, wrapped in a damp rag, which should hopefully make it easier to clean tomorrow.
 
Most importantly, when I stepped back from the jig at the end of the day there was definitely no denying that what it was holding was very frame-like. 

Tacked and ready for some fillet brazing

​The final day and still a lot to do. It started by cleaning up the seat stay that had been left to soak overnight. Then this was tacked into place. Next-up, it was time for the sharp-end of the course – brazing the frame together. The decision had been taken the night before that the three of us on the course would each be assigned our own teacher to take us through this final day. I was honoured to have Robin Mather watching over my every move and calmly steering me back on course, often before I’d even realised things were starting to run away from me.
 
If the fillets on my frame look in anyway half decent then it is down to Tom Sturdy’s excellent teaching at the very beginning of the course, the ‘little-and-often’ daily brazing practice and, most importantly, Robin’s wise words on this final day. By the end of the frame brazing I really felt like I was in control of what was going on with the ability to identify issues and take action with confidence. If it isn’t already apparent, this is a massive endorsement for the effectiveness of the course.
 
At this point, I stood back with a sense of massive relief that I hadn’t done anything catastrophically stupid, and euphoric at the object that I had just created. I even let myself think that the end was now in sight. That was until Robin wrote down a long tick list of everything that we still needed to do. First on the list was to dimple the chainstays before reaming the seat post. This latter task felt like an unusually physical thing to do after the relative finesse of the last few days. Then I prepared the seat stay and chain stay bridges while Robin tig welded the non-drive-side seat stay to the stainless dropout. These bridges were then brazed into place after a quick alignment check (before the rear triangle became even more rigid) that showed nothing untoward. At this point Robin noticed an almost invisible line in the tig weld. It might have been nothing or it might have been a crack that could have propagated over time. Either way, better to be safe than sorry, so it would need to be tig welded again – another task to be added to our list.
 
Now it was time for a couple of fiddly tasks that seemed to involve me cutting and filling in some very tight spaces. All of which seemed to use exactly the same muscle groups as when pumping up a tyre at the side of the trail with a mini-pump. First was the seat clamp slot, which I decided to make extra difficult by having it facing forward. This makes it tough to cut without catching either the back of the seat tube or the top tube. Then I had to fill and file the breather holes, before Robin worked his magic with the tig welder on the aforementioned stay.
 
All of a sudden, time was starting to run away with us. I hadn’t even started to silver braze the numerous cable guides and bottle bosses, and we still needed to tap, ream and face the bottom bracket and the head tube (minus the tapping) as well as do the final alignment check. It was time to get my head down.
 
After a busy couple of hours, the frame was eventually finished around 7.30pm. Robin, Tom, Jake and Andrew had all stayed to help me through this final push and I felt that they were genuinely pleased to see the results of my efforts. With the bikes rear wheel and front end to hand I couldn’t help but loosely slot them into place. If it isn't obvious already, then I’ll just make it absolutely clear that I’m over-the-moon with the frame. 

Ecstatic with the final frame

​I decided to go on the course for two primary reasons. First to learn how to make a bicycle frame, with the dream that one day I might start making a few more. And secondly, to build a frame that would allow me to put my theories on frame geometry to the test. While I can say with confidence that I feel like I have achieved the first, only after some time, a lick of paint and a few evenings with the allen keys will I be in a position to test the latter.
 
But the last word must go to The Bicycle Academy. If you have even the slightest inkling that you might want to make a frame, then just do it. It’s a fantastic experience. Once you’ve made this decision, I would suggest that, for those in the UK at least, The Bicycle Academy should be top of your list. The level of thought that has gone into what and how the process is taught, combined with fantastic facilities is, to my knowledge, simply unparalleled. But what makes this course really stand out is the calibre of those teaching it.
 
Andrew Denham is one of the most principled people that I have ever met, whose sole mission with the Bicycle Academy is to enable more people to get into frame building. This may sound overly gushing, but the proof is in what he has created. For this, he is most definitely to be applauded. While the rest of the teaching staff – Tom, Robin and Jake – manage to mix that rarest of combinations: complete mastery of their subject and the ability to convey their knowledge to a desk jockey such as me in a compelling and effective way.
 
A massive thank you to The Bicycle Academy.

Firstly, apologies to those of you who’s interest in my blog was first piqued by the 3 speed hubs that I posted about – it’s been a long while since I’ve had anything tangible to write about. Unfortunately, I’ve struggled to find someone to do the machining work for me, but now that’s sorted I have a new, shiny hub to play with.
 
If you’re a regular reader of the blog then you can probably guess that this new hub is destined for the Full-Moto frame that I will be building later this month. I’m hoping that bike will also be running a belt drive and plus-sized tyres, so the big challenge with this hub was to ensure that I could achieve sufficient clearance past the rear tyre while maintaining a straight belt-line. This is something that the 44-ish millimetre chainline of my current hubs would struggle to achieve.
 
The answer to this little conundrum has come in the form of a CS-RK3. Yet another snappy hub name from Sturmey Archer, but this time it comes complete with an 8/9/10 speed cassette freehub body on one end. I’m guessing that Sturmey Archer’s intention is that this hub will be used in combination with a rear derailleur, with the hubs three internal gears being used to replace a front derailleur. However, with the use of a single speed spacer kit I can instead enjoy a whole heap of chainline adjustment to accommodate my belt drive and plus-sized tyres.
 
Having now rummaged around inside an S-RK3, an RS-RF3 and now a CS-RK3 hub, it’s interesting and heartening to see that Sturmey Archer are continuing to refine their hubs rather than rest on their laurels. Whereas the former two hubs contained a couple of plastic spacers and dust covers, this latest version is an all metal affair. They’ve even found a way to replace the fiddly thrust plate that used to rotate on the end of the driver assembly with a new mechanism that appears to be much more robust. The result of all these small improvements is that this latest hub easily feels the most solid and high quality Sturmey Archer hub that I have worked on.
 
The modifications that I have made to the hub are very similar to those that I have made to previous iterations. The two cup-and-cone axle bearings have been replaced with SKF cartridge bearings, while the larger ball-cage bearing that sits between the driver assembly and the ball ring has been replaced with an Enduro number (SKF don’t make a cartridge bearing in the right size). This modified hub is now silky smooth, something that I’m really pleased about.

As well as the higher quality internals, Sturmey Archer also import this hub into Europe in the 32 spoke hole version (unlike the other hubs that I have, which have always been limited to 36 holes). This opens up rim choice massively – something that was particularly important in this application given my desire for plus-sized tyres.

Because this particular hub is designed to run with a cassette, rear derailleur and associated shifter, Sturmey Archer have changed the cable pull of the hub so that it works with a Shimano front derailleur Rapidfire shifter. So, while this means that I am going to have to run the shifter on the ‘wrong’ / left side of the handlebars, it does mean that I can use a rather nice SLX i-Spec shifter that I can mount to my brake levers. With this shifter located where I would normally place my dropper post remote, I will also need to switch this to the other side of the ‘bars.

While my other hubs are all still running smoothly, I’ve got particularly high hopes for this latest iteration based on what I’ve seen so far. I can’t wait to get it slotted into my new frame to see how it performs. Hopefully I’ll be back in six months or so with an update on my initial thoughts.

​Following on from my November blog post, where I set-out my plans to make a full-size model of a mountain bike girder / linkage suspension fork as well as listing some of the supposed benefits of this design, I’ve been spending a number of long nights in the shed trying to turn my CAD plan into a reality. Well, I've now finished it and thought that I'd present the results of my labour.
 
To try to help explain how the fork works I have colour coded the drawing below. Those parts shaded blue would be attached to the frame (steerer tube as well as top and bottom fork crowns), those in green are the girders that move with the front wheel, while those in orange are the linkages that control the movement of the green elements relative to the blue elements as well as drive the shock.

After trying to make the fork out of plywood (which kept ‘chipping’ around the pivots) I ended up making it out of MDF. My coping saw skills leave a lot to be desired, but this was never meant to be a thing of beauty. Rather, a practical test of an idea. For that it has been really helpful.

The fork is designed to work specifically with the headtube length of the Full-Moto frame that I will be making in February, but with some relatively simple alterations to the top shock mount and the girders / fork legs the fork can be adjusted relatively easily to fit any frame with a headtube length down to 125mm. Start playing around with the linkages and/or shock length and this could be reduced further. So, this general layout can be made to work with a wide range of frames, but, unlike a more conventional single crown telescopic fork, it will always need to be tailored for a bikes headtube length. There is some wiggle room if you are happy to accept a slightly altered axle path, but I suspect that this is a big reason why this type of fork has not had the commercial success of its telescopic cousins. Essentially, if you wanted one then it would need to be customised (to a greater or lesser extent) to your specific frame.
 
My fork pivots on four 12mm axles that rotate within eight nylon bushings. It has been made to accommodate a 110mm Boost front hub with a 15mm axle and uses a 28mm diameter wooden dowel as a proxy for a steerer tube (the closest that I could get to a 1-1/8’’ steerer). The nature of a linkage fork means that its offset varies through its travel with a minimum of 38mm and a maximum of 50mm. It has a little over 100mm of travel controlled by a 200 x 51mm RockShox Monarch RT air shock (that I bought second hand). 
 
Just like many single pivot rear suspension layouts, the forks leverage ratio starts off being progressive (rising rate) for around the first two thirds of its travel, before going regressive (falling rate) at the end. Given the inherent tune-ability of an air shocks spring rate and the fact that they naturally ramp up towards the end of their travel I’m fairly confident that the fork and shock can perform happily together after some tuning to give a decent wheel rate.
 
Although I have no immediate plans to make a fully functioning version of the fork, I’m hoping that the brazing and fabricating skills that I will gain on my frame building course in February will at least make it a possibility. While I’m not aware of any other steel mountain bike full suspension fork, I still think that it can be made to work without being too heavy – think of a Jeff Jones truss fork with some pivots, linkages and a shock thrown in! Alternatively, I could try to find a friendly CNC machinist who can convert my CAD files into shiny pieces of aluminium. Or maybe even try to make the girders out of carbon fibre…

Anyhow, really I just wanted to prove to myself that it could be done and that there wasn't some practical reason (other than the aforementioned adjustments required to accommodate different headtube lengths) why this style of fork hasn't ever really challenged telescopics for sales. Plus it was pretty good fun making it! Let me know what you think.

​To recap, I want to build a bike for having a blast in the woods. For relatively short, fast rides primarily along the North Downs and in the Surrey Hills. To achieve this, I want a bike whose limits are easy to approach and fun to reach. So, I’ve come up with a geometry for the frame with this in mind, something that I have discussed in previous blog posts. However, just as important are all of the components that will hang off it, so I thought that I’d explain some of the key choices that I’ve made (so far).
 
One of the most prominent selections is probably the handlebar. I spent a long time searching for the right one. I knew that my position on the bike would closely resemble that of a Motocross bike, so I was looking for a mountain bike handlebar with a similar shape to that of a Motocross ‘bar. Nothing seemed to fit the bill, and then it dawned on me – stop searching and just use a stock Motocross ‘bar. So, I did the decent thing and ordered a set of Renthal’s!
 
The next challenge was to workout how to connect the ‘bars to the bike. They have a constant diameter along their entire length of 22.2mm. So, fine for bolting on my shifter and brakes, but slightly less straight-forward when it comes to the stem. While a 22.2mm stem clamp may not sound familiar to many mountain bikers, it’s actually one of a few standard sizes for BMX ‘bars. But I wanted something that was just 35mm in length and I could only find one stem that fitted the bill – a Colony Exon Flatland. (I’ve actually had one on back order since March and it only turned up in November, so it doesn’t even appear to be particularly popular with the BMX crowd!)
 
Another important item is the fork. I wanted something relatively long to help me achieve the necessary stack height, something torsionally stiff for decent steering precision, but with a bit of fore-and-aft flex for some comfort. As it seems to have been with many of my component choices, the options available to me were pretty limited. I could only find one fork with a tapered steerer tube, 15mm axle and boost spacing, that was at least 480mm long and all for a decent price – an Identiti XCT ticked these boxes.
 
With the handlebars set much higher than normal there will be much more weight on my backside when seated than on a bike with more traditional geometry. As anyone who has ridden a Dutch-style town bike will know, this means that the Selle Italia Flight Titanium that I wanted so badly for my 1993 Diamondback Apex would probably just slice me in two on this bike. So something with a bit more width and padding is likely to be the order of the day. I’ve got a few options – a Fabric Scoop Radius and a Charge Spoon are both current favourites, but I don’t think I’ll really know what’s going to work until I’ve actually ridden the bike.
 
Tyres are the other big decision. To help achieve the type of bike that I want these need to provide consistent handling above all else. So, I wanted something with a repetitive tread pattern that extends from one side to the other, rather than something that’s lower profile in the centre with more aggressive shoulders. While this might blunt my straight-line speed and cornering grip respectively, it will hopefully mean a more predictable transition from grip to slip as I lean the bike into a turn. The tyre that I’ve gone for is a WTB Bridger.
 
The rest of the build will be pretty straight forward. In my opinion, a bicycle should be both elegant and economical. If people want to spend £8,000 on a bike then I won’t stand in their way, but when those new to the world of mountain biking are given the impression that they couldn’t possibly have anything other than a miserable time unless they spend upwards of £2,500 on a bike my heart sinks. So, some of the components will be bits that I have hanging around the shed after two and half decades of riding, together with some new stuff to plug the gaps. It should all be pretty workman like, but that’s no excuse for it looking like a dog’s dinner – who doesn’t love a bit of colour-coordinated anodizing!

I know that I’m getting way ahead of myself here and that it’s incredibly self-obsessed, but I’ve wanted to do this ever since I first thought about making my own bike. Yep, I’ve only gone and had some clothes made with the Davey Push Bikes logo emblazoned across them!
 
I’d had it all set-up on the printer’s website ages ago, but recently I had an e-mail from them telling me that they were doing some super-duper discount in an attempt to encourage people to place their orders before the Christmas rush. This was all the nudge that I needed. Next thing I know I’ve got a short sleeve and a long sleeve T-shirt, as well as a hoodie, winging their way over to me. This way I figure that I’ve got something to wear on the bike (either T-shirt depending on the weather) and something to throw on afterwards.
 
Watch this space for the Davey Push Bikes dressing gown and baby grow!

With the exception of a small minority of mountain bike suspension forks (Lauf being an obvious example), nearly everything on sale today relies on telescopic legs to enable the front wheel to travel up and down. But it hasn’t always been this way. One such alternative, known as a Girder Fork in the world of motorbikes, takes its name from the classic structural shape of the girder truss used primarily in bridge or roof construction, which was commonly used to create the fork legs. Back in the 1930s this was a popular choice for motorbike manufacturers, with some still continuing to develop variants of this approach, such as BMW's Duolever arrangement.
 
When adapted for use with mountain bikes these forks are more commonly referred to as linkage forks, which is probably a more useful description. The most famous example that I’m aware of was seen gracing the front of many Proflex bikes back in the 90’s, going under various names that included Noleen, Girvin and K2. This probably goes a long way to help explain my subsequent fascination with their design, having lusted after them as a teenager. But other examples have been produced by the likes of Amp Research, Look and Leonardi Racing.
 
Linkage forks have come in various different arrangements over the years. Some have both linkages below the head tube and the shock mounted somewhere between them (such as the Amp Research fork). While this arrangement improves frame compatibility (as the fork isn’t limited to a minimum headtube length), this layout generally has to rely on pretty high shock leverage ratios to achieve anything approaching a useful amount of travel on a mountain bike. However, forks like the Leonardi Racing Alike partly get around this by placing the shock above the linkages. Even so, having both upper and lower linkages below the head tube also limits the forks structural efficiency. For this reason, designs like those found gracing Proflexes all those years ago have the potential to be much stiffer (stiffer even than conventional, single crown telescopic suspension forks) by being supported both below and above the headtube.
 
Furthermore, linkage forks can be designed in such a way that dive under breaking is significantly reduced, enabling them to use their travel far more efficiently. This has further benefits, such as reducing the need for as much low speed compression damping, enhancing the forks potential sensitivity. Linkage forks also side step the issue of binding, something that becomes increasingly important for telescopic forks as head angles get slacker. This occurs when the entire fork tends to flex along its length rather compress due to friction between the forks lower and upper stanchions.
 
It is because a linkage fork pivots on bearings that they can be designed to be much more sensitive than a telescopic fork. As a slight segue, my perception is that most mountain bikers who have an opinion on the matter, would always view cartridge bearings as superior to bushings, regardless of the application on their bike. Somehow, cartridge bearings have simply become known as ‘the best’ with bushings normally thought of as something seen on cheaper bikes. But this over-simplifies the situation. While cartridge bearings have a number of positive attributes, these tend to only apply when they spin through full rotations, something that, for example, rear suspension pivots just don’t do. Instead, some rear suspension pivots would be lucky to rotate through just a handful of degrees under normal operation. It is not uncommon for the balls within a cartridge bearing to slide momentarily before they start to rotate within their races. In something like a hub this isn’t an issue, but in a rear suspension pivot these balls may never do anything other than slide backwards and forwards. Not only will this result in the balls ending up with flattened surfaces resulting in premature wear, they also introduce undue friction making suspension less sensitive. Bushings avoid these issues, but the mountain bikers blind lust for cartridge bearings seems unassailable.
 
Anyhow, given that I’m building my own frame in the New Year, I thought that it might be fun to see if I could design a linkage fork to fit it. Now, this is just me humouring myself at this stage – the bike will be fully rigid, but I like to have something to play around with in my head. I’ve designed the fork around a standard rear shock (200 x 51mm) to produce just over 100mm of travel. The drawing below illustrates what it might look like. My plan is to utilise the long, damp autumn evenings to build a full-size mock-up of the fork out of wood to see if it will actually fit the bike and cycle through its travel in reality. It’ll be pretty rough, but enough to hopefully prove that the idea is viable. Fingers crossed I’ll have something tangible to show for my efforts in the not-too-distant future.