Folly or phenomenon?
Making a fixed MTB
by Phil Chadwick


Phil Chadwick's converted Evans MTB

Someone on the UK Cycling Plus forum recently described the idea of fixed mountain biking as "strangely compelling... but that way madness lies".

I acquired a mountain bike in 1989, secondhand from a friend-of-a-friend. It wasn't new by any means, and these days we'd probably call it a hybrid rather than a true mountain bike. I had some good times on that bike. I rode it just enough to know that I couldn't justify anything more sophisticated. As I concentrated on road riding I fitted it with mudguards, a rack and a dynamo and used it as a winter commuting/Audax bike.

After a few years the components were pretty much worn out and I hung the frame up in my garage. And then, this year, I came across which set me thinking. A fixed MTB ? Maybe. The clincher was the offer of a pair of decent 26" wheels with a fixed rear hub from UK S/S-specialist On-One at under £100. Couldn't resist that, and then I was committed. The plan was to put something together mainly from low-cost parts, or parts I already had. If I didn't get on with fixed offroading, I would put skinny tyres on and use it for commuting again.

The frame is an FW Evans made from Reynolds 531 ATB -- standard diameter tubing developed specifically for hand-built mountain bikes back in the day. At some point it had come off worse in an argument with a 4x4, acquiring a bent gear hanger. As a result, the gears never worked well and perhaps its destiny was always to end up as fix. The wheels are On-One Inbred hubs (same as Kogswell, except they're sexy black) on Reet'Ard rims and 2.1 inch tyres.The stem is a beautiful 1980s Cinelli road. I can't remember where the Marin saddle came from. Which leaves the important stuff: transmission and brakes.

My off-road technical skills are slim to non-existent, and I was a bit worried about hitting the pedals on rocks and other bits of terrain. So I fancied some short cranks. 160s? Nope, still way too long! 150s? Maybe, but then I came across a cheap 1/8" 44t chainset with 140mm cranks intended for a child's bike. That would do nicely. I figured that those 140s wouldn't give a lot of leverage, and a low gear was going to be more appropriate. Good old Will Meister supplied an outrageous 26t 1/8" cog which gave me around a 44" gear -- equivalent to 53" if you take the crank length into account.

Transmission on Phil Chadwick's converted MTB showing 26t cog and 140mm cranks

I'd intended to use the original Suntour XCD cantis, but after a whole afternoon spent trying to make them work effectively, I gave in and fitted some Vs in about 10 minutes. Which led to another problem: I'd fitted a 2.3" tyre on the front, 2.1 on the back because that's what I had lying about, and because I figured this would give me maximum traction and control as well as a reasonable degree of suspension. I decided against a suspension fork because I was keen to stick with the 'elegant simplicity' ethos, because the bike has a 1" steerer and because, frankly, I didn't want to spend too much money on something I might not actually be able to ride. But now there wasn't enough clearance between the front V-brake cable and the fat tyre. A quick trip to the LBS resulted in a kevlar-reinforced 2.1" tyre for £4.75. Not bad. Now I just had to ride it.

I spent a few hours on a Sunday afternoon trying it out on the road alongside our house, and it felt OK. A bit weird with the short cranks, rather like riding a bike 3cm too small. But the gearing felt OK and I managed to track-stand after a bit of practice. Progress! Spoiled only by falling off when I tried to jump a kerb. Oh well.

The next weekend the sun was shining and the time had come. I still wasn't entirely sure that I would be able to ride it, given those short cranks and my lack of technical skill, but if I didn't give it a proper try offroad then I might as well not have bothered building it.

We are very fortunate to live where we do. There's a fine network of tracks and bridleways accessible directly from the centre of the village and it is possible to link up with long-distance green roads such as the Ridgeway and Icknield Way. I climbed up out of the village on Folly Road (appropriate ?) which soon becomes a wide and well-surfaced track. So far so good. The tarmac climb up Folly Road was OK, but the lack of crank leverage made it tougher than it should have been. Once I hit the gravel/chalk track, I felt distinctly uncomfortable and on the first descent the bike was all over the place. Not good -- I just didn't feel confident. Why should that be ? I'd ridden the same bike with gears on the same tracks some years ago and I didn't recall it being this bouncy. Then it occurred to me that I'd inflated the tyres to road pressures. D'oh.

After I'd reduced the pressure to about 40 psi the bike came into its own. It stuck to the track on the descents, soaked up the rocky bumps and climbed easily over ruts. I even managed to jump a couple of pot-holes. This was fun ! After a few miles I dropped down into a valley along a farm track. The going was muddy, with deep ruts and a central grassy ridge. As the ruts got deeper I began to think that those 140 cranks were a Good Thing. I climbed a couple of steep hills, hills I have struggled with on gears. I got that feeling: ah, THIS is why I ride fixed! Just like the first time on road. I was really beginning to enjoy this. After a while I returned to the chalk track and let the bike fly. Better and better.

I don't yet have the skills for the technical stuff, but then, that would be the case if I used gears. For me, riding fixed offroad is quite different from riding gears. It's even more fun.

Phil Chadwick's rides on home ground

POSTSCRIPT: A week or so later I posted this to the UK Cycling Plus fixie community forum:

"OK, I've now used the MTB (FGG 1143) properly. I went out yesterday afernoon for an hour or so, ended up out there 4 1/2 hours, til it got dark. I'd have stayed longer if I could !

"Cycling on the road was really tough with the 44" gear and 140mm cranks - legs were burning after about a minute - but as soon as I was off-road it came into its own and I ended up riding things I would have found difficult with gears (the emphasis being on 'I' - I was never any sort of technical rider).

"The only real problem was on steep uphills, when it was very difficult to pull up the front wheel to get out of ruts. And I only fell off once, when I tried to climb up out of a muddy hole and the front wheel slid out. Climbing sideways isn't easy. Only one bruise, but it covers all my left thigh.... There's over 200 miles of cycleable tracks within a few miles of my house (the highest density of such in the UK according to the guide to local MTBing) and I managed to get completely lost with 20 minutes in an area that I've lived in for 10 years... excellent!

"On the rutted, bumpy and muddy stuff it was great fun - found myself laughing out loud a couple of times - only a bit undergeared on fast smooth descents on the Ridgeway, which in late summer is so easily rideable that it almost doesn't count as off-road.

"The transmission was a bit graunchy by the end, but there was so much mud around that you can't tell what colour the bike was originally, and Mrs Phil made me take off all my clothes in the kitchen and run naked to the bathroom. OTOH she may have just decided to humiliate me...quite rightly."


Phil Chadwick has been active on the UK Audax scene for some years.

v1.0 written November 2004

Phil wrote for us a feew issues back about the joys of audax. He also has his own site where you can learn more about his brevets and his bikes.
If you're interested in assaying the effects of crank length changes on your riding, you should read Sheldon on gain ratio.

Will doesn't promise to always have 26t cogs in stock, but Hubjub is a better bet than most if you're looking for exotic fixer parts.

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