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Toast
6th March 2007, 11:08
I need to down-gear my bike. This became apparent at the Kiwitrackday on Friday when I was hitting 245 in 5th with some left to go in that gear.

The largest rear that I can find which is readily available is a 46 tooth (currently 43).

I'll put that on, but I think I'll need a bit more, so I'll likely put a smaller front on too (haven't had time to check what's actuall on there, yet).

I've been told that going down at the front can increase chain wear because the chain has to form a tighter curl around the front sprocket. How bad is the effect of this? It's not a major concern as it's only a race bike, but are there and other adverse effects like power reduction?

Advice appreciated.

bistard
6th March 2007, 11:13
Be carefull,changing both the front & rear sprockets at the same time
Rule of thumb is the front sprocket is the same as three rear teeth,so if you are going up three on the rear & down one on the front,thats a big change
What track are you going to ride at normally??
The other thing to watch,is if you gear the bike down that much,be weary of getting hard on the gas,it will rev alot quicker & possibly bit you!!

Toast
6th March 2007, 11:18
Sorry, should have been more clear: I'm thinking mostly about the upcoming PMCC round on the Taupo track 2 (2.2km), which is pretty tight.

bistard
6th March 2007, 11:20
yeah,if thats the case,change just one,take the other with you & try them,just make sure they both fit without having to swap chains before going to the track

texmo
6th March 2007, 19:05
Why dont you save your money and worry about the things that count like going faster around the corners? (and maby getting a set of tyre warmers of your own?)

Toast
6th March 2007, 20:22
Why dont you save your money and worry about the things that count like going faster around the corners? (and maby getting a set of tyre warmers of your own?)

Mate, lower gearing will help me on the 'out' part of the corner...as for the warmers, they're coming in to the country soon, I'm told (for the meantime I'm content with kidnapping yours *bow*).

steveyb
6th March 2007, 20:32
Tyrewarmers are available RIGHT NOW at www.tyrewarmers.co.nz
These are made in the UK with 12 month factory warranty, not made in Taiwan with no back up.

emaN
8th March 2007, 17:35
i went from 15 on front to 14,no probs,no noise,no 'undue' wear. wouldn't go any lower on front tho.

a 'guru of all things two wheeled' told me; "to get (many) bikes back to where the engineers originally wanted them, drop one on the front, and add one on the rear."

they come out 'over-geared' to pass emission tests bla bla bla