Saturday, June 6, 2009

A better mountain bike

When I'm out on the trails a lot of people ask me about my bike. Do the bigger 29" wheels really make that much difference? How do I manage without gears? How do I manage without suspension?

They seem to think I'm trying to make some kind of statement or getting on a "bandwagon", and while I'm fine with the idea of the bike having a certain "coolness factor", I actually made the choice more for practical reasons.

When I first started mountain biking I bought a fairly entry level, alloy framed, 24 speed, hard tail Giant (which I still ride occasionally). It featured a Dart 1 front fork which is supposed to have 80mm travel but with my weight on it is more like 30mm. The only adjustment is preload but having tried it at both extremes I can't notice any real difference. I think it really needs a stiffer spring for me but it still does a reasonable job of taking out a lot of the harshness of the bumps.

It was a great bike to start out on but after about 18 months of riding I'd broken & replaced almost everything on it at least once, including the frame. Dirt, water and lots of bumps take a serious toll on moving metal parts. Stuff just doesn't seem to last long. I'd replace the chain, chainrings and cassette only to start experiencing chainsuck again in less than a month. I was well and truly over it so I started wondering about a better compromise.

It was around that time that I saw my first single speed 29er in the flesh, and I also broke the frame on my Giant so I needed another bike.

I was struck at first by the clean look without the derailleurs and cables and the general stance of the bike. I was also impressed by the cost saving by not having gears and expensive suspension so I thought it was definitely worth a closer look.

I learned that 29" wheels:

  • have a longer contact patch than 26" wheels so they have more traction
  • the larger diameter wheels roll over obstacles easier
  • the longer spokes flex more, taking more shock out of bumps
  • the larger tyres have more air volume which takes more shock out of bumps

I also learned that:

  • steel frames & forks have a springier feel than alloy so they take more shock out of bumps
  • steel has a higher tensile strength than alloy
  • steel has a much longer fatigue life than alloy

I also noticed that in the places I ride I spend more than 90% of my time in the same 3 gears (middle ring and 3rd - 5th cog on the back).

Putting all that together I considered that with a steel framed 29er I could pretty much get away without gears or suspension and in practice it works as well as I hoped. Yes, I have to walk up the occasional hill and I might occasionally run out of legs on a long, decending fireroad but I generally don't have trouble staying with a group (being overweight slows me down far more than the bike does), I never get chainsuck and I don't have expensive suspension and gearsets that need constant maintenance and repairs.

For the day to day training rides of 1 - 2 hours I can't think of a better bike.

However, I'm thinking of something (when funds allow) a bit softer for hillier areas, bigger drops & jumps, all day riding and possibly entering an endurance event like the annual 24hr Insomnia (when fitness allows). I can't decide at this stage whether I just grab an over the counter 5" dual suspension rig like the Giant Trance X series, or I stick with the steel 29er theme and customise it with a quality Reba or Fox fork and a Rohloff hub.

At around $2000.00 just for the Rohloff, the over-the-counter duallie's looking pretty good but when I think about how fast I'm going to wear out a standard derailleur setup and that damn chainsuck, maybe the extra dollars for the Rohloff is the cheapest option in the long run...

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