Monday, January 22, 2007

29er updates

After five offroad rides on the 9r, I feel like I'm starting get the hang of it.
Sunday's outing at Woodhill, with Gaz and Chris & Sam Money, was the first that did not include a crash or near-miss. You could put this down to a more relaxed atmosphere without the sibling rivalry of our Wednesday evening rides, but I reckon that the changes I've made to the 9r have also made it easier to ride:

Cranks: the Q factor on the standard Truvativ Blaze cranks is 180mm, about 35mm wider than most of my road bikes. I don't think this is big deal when you are twiddling low gears on a multispeed MTB, but on singlespeed I want to keep my hips, knees and feet in line.
I fitted a set of 180mm Ritchey Logic cranks on a 118mm Kajita bottom bracket for a 155mm Q factor. The extra leverage of the 180mm crankarms is no bad thing either.

Gearing: standard gearing is 32 x 18, or 51.5"in trackiespeak, equivalent to a 2:1 ratio on a 26 wheel.
After a couple of rides I changed to 36 x 21 or 49.7", which gives better acceleration on moderate climbs. I've got a 35t ring on backorder which will give 48.3"

Handlebar stem: the standard 10.5cm stem gave 62cm reach from seat nose to handlebar, which felt comfortable, but put too much weight on the front tyre. After a couple of understeer induced crashes, I fitted a 9cm stem.

Ergon E1L* grips are the only truly comfortable grip I have ever used on a mountain bike.

The Cane Creek* Thudbuster seatpost is good for my back.
I found a 25.4mm Thudbuster on Trademe for $60, and used a Cane Creek shim to fit it to the 9r's 26.8mm seat tube.

*Disclaimer- I am deeply implicated in the importation and distribution of GT, Ergon & Cane Creek in New Zealand.
Nothing that I write about them can be believed.

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