BUSTED!

Here's the bike fully built:

This pics is after returning from a circuit of Richmond Park where the frame worked flawlessly. Not a creak, not a wobble. It was fast. It was fun. It gripped well and rolled fast. And with the lockout on the forks engaged it accelerated like a whippet.

It also felt a bit short in the top tube. I assume my mistake in the geometry was that I hadn't accounted for the extra-low bottom bracket and high head tube when setting the length of the top-tube. With the seat back as far as possible on it's rails the bike feels ok but this is something I'd change if re-making it.

Then disaster. 

After a successful 1st ride I started commuting on the bike. The 1st day was fine. The second day was fine until I was half-way home. After pulling away from some traffic lights the bike started wobbling when pedaling. It felt like a loose crank arm so I pulled over. It wasn't loose cranks. A weld had failed and the bottom bracket was only loosely attached. 

The problem with breaking down with a bike in London is that at rush hour you cannot take a bike on the tube or train so your only option is to push the whole way back! At first I tried to pedal on, very gently - this worked for maybe 100 meters or so before the rear wheel suddenly started to rub the inside of the left chainstay. Stopping again I discovered that another weld had gone, this time it was the chainstay-rear dropout.

It was a long walk home.

A few more pics

Here's the 29er hardtail (now named the "Stealth" - hopefully with a singlespeed or geared hub and it's black paint this will be a very stealthy bike) painted, stickered and partially built...

Another change of plans

So having spent all my recent riding time on a 29er hardtail I've renewed my love of simple bikes and have re-learned just how much fun mountain biking is without any rear suspension.

A trip to Swinley forest on my cheap and cheerful Diamondback 29er showed me several things:

• 29er wheels grip like mad - up several different loose climbs I ended up just powering straight up when previously I would have slid out and ended up walking - the difference was dramatic despite the fact I was riding a semi-slick rear tyre
• A 29er hardtail was just as ridable over the rough stuff as a 26" wheeled full-suspension trail bike.
• The hardtail was a lot of fun over the jumps and around the twisty singletrack - at no point did I feel like the big wheels were holding me back.
• I did NOT feel fully "in" the bike; the relatively high bottom bracket and long chainstays didn't allow me to really get down into the heavily bermed corners in The Labyrinth, something about the riding position didn't feel right.

I started looking around at hardtail 29er frames and came seriously close to buying a couple of different frames; the most appealing options being the Kona Honzo and the On-One Lurcher. The Kona offered super-short chainstays and a bomb-proof build but with the weight you'd expect from a hardcore steel frame. The On-One offered the feather-weight you'd expect with carbon but long chainstays and you'd need to fit a angle-adjust headset if you wanted anything other than XC style handling. Both frames were £500 plus extras.

So I made my own 29er hardtail: a 69deg head angle, 23.5" top tube, 17" chainstays, an eccentric bottom bracket to allow a single-speed set (or a hub-gear), room for big 2.4 tyres, a 2.5" BB drop (at the centre of the BB shell) and a head-tube long enough to fit my nice Maverick DUC32 forks!

A nice tube-set from Nova with pre-bent tubes, a Bushnell eccentric bottom bracket set-up from Ceeway and Surly drop-outs with disk-mounts built in results in this:</p>

It's worth noting that my welding still leave a lot to be desired but I'm really happy so far with the frame - it looks straight and solid; I can't wait to paint, build and ride it!

The welding course and the new direction

I attended the Welding and Light Metalwork course at the Hammersmith learning centre in late 2011; I can highly recommend this to anyone who has an interest in getting started with welding. I had been using a MIG welder for my previous projects since that was what was available to me, and because it's so easy to use; this course allowed me to experiment and learn a number of other welding techniques. It also allowed me the opportunity to start a new project; it had to be another bike frame really, didn't it?

At this point I had ended up buying a 29er hardtail frame; this was proving to be an excellent commute and XC bike and I decided that what I needed was a general "play bike" to suppliment this - something to take to the occasional DH course, something to hit the bigger trails on. An all-mountain bike, or maybe an "Enduro" bike, possibly a "Super D" bike, or if you're still in the last decade, a freeride bike.

With more than a little inspiration from the Orange bikes website (here) I resolved to make myself a version of the new Patriot bike that, at the time, was only a rumour. I have owned a couple of Orange Patriots in the past (one of the original 5" travel bikes, and one of the 7+ freeride bikes) and they always were great to ride - a wonderful balance of simplicity, great geometry, relative light weight, and effective suspension.

The design design I settled on was:
 - 7" travel using the 222mm shock from the DH frames
 - 65deg head angle with 7" travel forks
 - 23" top tube (going with the trend for longer top tubes and shorter stems)
 - clearance for a 3" tyre on a 26" wheel (outside diameter of 28")
 - an eccentric bottom bracket to allow the BB height to be adjusted allowing the use of a wide tyre range without adversely affecting the ride height (also because I had an eccentric BB shell spare)

Unfortunately I only got time on the welding course to get part of the front-end of the frame constructed; this project is currently in limbo but certainly not forgotten. It is my intention to resurrect this frame design in the very near future as a 650b bike.

Why 650b?

Well I'm a sucker for trends! But also because the 650b wheel size will fit my existing design with almost no change (I might adjust the position of the rear drop-outs but it's not actually necessary since I designed the frame to fit huge tyres) and the 27.5" wheel size is perfect for what I want out of this bike - I want the grip, stability and confidence of larger wheels but this bike is all about having silly fun (something that feels a bit lost sometimes when riding 29" wheels).

29er trail bike

So I had made a rather sweet but flawed 29er downhill bike, and a very functional but less plush trail bike. The next step was to attempt to take the best of both worlds and create The One Bike.

Of course it's impossible for even the biggest, best and most innovative bike companies to make a bike that is perfect for everything.

But what do they know?

I decided that the solution to all my bike desires would be a 29er trail bike with 5" travel. With 5" travel my high-pivot design would require no chain routing so would hopefully be as reliable as my previous trail frame, and with the 29er wheels we'd hopefully have some of that amazing plushness that big wheels are famous for.

I invested in some proper chromoly bike tubing this time and set about making what I hoped would be a master-piece:

Again, I couldn't help but do a bit of colour coordination with the build:

Unfortunately I just didn't get this bike right. The rear drop-outs were not aligned well, the weight was still above what you would really want to drag around all day and the fit was wrong - the main problem being that the top-tube length was too short. This bike works but just was not the dream-bike that I had hoped it would be. It also seemed to be the wrong combination of the previous 2 builds - rather than having the solid build of the trail bike and the confidence inspiring feel of the 29er DH what it really felt like was numb, boring, not-that-plush, unmanouverable AND unstable. I simply hadn't designed or built this very well.

In order to address this I started reading every article about 29er design that I could find, and signed up for a welding course...

Trail bike

Annoyed with the constant series of chain problems on my designs so far I resoved to do my next frame with no fancy chain routing. Still sticking to the high-as-practical pivot point design with a simple swingarm I started work on a 26" wheeled trail bike with 5" travel:

I was pretty happy with how this frame came together, particularly the swingarm:

I don't think this bike looked quite as impressive as the 29er DH prototype but it wasn't a bad machine:

More to the point, this was my first build that really worked. I rode this at Cwm Carn (it survived the red DH course), at Swinley forrest (it was pretty handy over the jumps) and I even commuted on it. It pedalled well, it wasn't exactly light but was a perfectly usable weight and it was totally reliable; and with a short chainstay length and sensible head angle it was even quite fun to ride. The suspension action was pretty unimpressive but that probably had something to do with the £30 rear shock that I had fitted.

Not quite the perfect bike, but getting closer?

The 29er downhill bike

After getting mixed-but-encouraging results with the attempt at making a downhill frame I was puzzling over where to take the design next.

And then I saw the Intense 2951 downhill 29er - it just looked so "right". At this point 29ers were just taking off in the US, virtually non-existant in the UK, and entirely dedicated to XC - the Intense 2951 might just have been a joke or mad experiment but the idea had me hooked. I had to try out the 29er idea on my next build.

In combination with the alterations to my DH frame design to route the chain just underneath the swingarm and pivot I got hold of some more cheap mild-steel tubing and set to work again:

Rather proud of my handiwork I couldn't help but paint up the bike and kit it out with colour-coordinated components; it wasn't as pretty as the Intense but to this day I'm still pretty happy with the way this came out:

I was a bit disappointed to find I still had problems with the chain - while I could pedal slightly further than the previous attempt this frame still had a habit of killing whatever was routing the chain. The bike also felt very weird under pedalling, the chain tension pulls the wheel down which is very efficient but does mean the rear feels like it's bobbing about all over the place. This chain tension also meant the suspension didn't feel as plush as the Tank however this bike did actually work - for breif periods of time anyway.

This bike, as pictured above saw a good day of uplift-assisted downhilling at Cwm Carn - it performed admirably. It ironed out the trail bumps like no other bike I've ridden, it gripped like crazy, it felt amazingly stable but also cornered just fine. It even jumped pretty well. What really impressed me was just how much confidence the bike gave me - when I rode the same tracks on a 26er I was all over the place, the 29er DH made the difficult track easy - I could focus entirely on carrying speed, what line I wanted to take and generally just enjoying the trail; on the 26er I spent the entire time hanging on for dear life, struggling to make the next corner. Despire the chain troubles it seemed like I was on to something here.