gear change 13 xm 163

[butthead]

has any one changed the top gear down to a 17 tooth.
box stock sled, stock clutching does have the thing can.
wondering if any ones gone down that low.
iam not a speed freek so loosing a couple mph isnt a problem
any input

 

[BBP]

I ran an 18 tooth top gear back in the day, but not very many teeth were engaged in the chain & a pretty tight radius on that small of a gear. I only ran it in a 15 wide setup. I don't think I'd be comfortable running a 17 tooth, especially with a 13 wide setup.

 

[Dynamo^Joe]

I have seen with my own eyes an 18 tooth, its teeth sheared right off on a 2008 x 163 in Revelstoke back in 2009. Buddy comes off a bench, lands tail down and stripped the teeth off. If you look at the amount of circumference [root circle] of even an 18 tooth gear vs a 19 tooth gear, there's just no meat there, and then want to go 17 top? UGH...
There's only a few teeth propelling the sled forward and then to have a shock applied to it?.... 19 is the smallest top gear i'd go.

Your sled should have 19-51 in it. A 53 fits in the case but with the chain on, the cover wont go on, no-room between chain and case.
19-51 BRP gears [64mph] is still lower than the lowest ratio available on the aftermarket (24-63) [65mph]

You would be safer with a 7 tooth 2.86 Avid with stock 19-51 gears [56mph] and be 1mph slower than stock 8 tooth 2.86 BRP driver @ 17-51[57mph]

 

[butthead]

ok guys thanks for the good info

 

[bnorth]

Personally I think 17 is too low for the reasons mentioned above re lack of chain engagement and also how hard the chain has to wrap around it. An 18 has largely the same reputation until you start reading some threads about turbo Yamaha guys loving the 18's back 5-10 years ago. The problem with the driver change Joe recommends is A) it makes worse the already bad XM approach angle B) it sucks to do the wrench work on a driver change compared to gears. I thought the 53 bottom fit but maybe that was only in the T3's. I am considering gearing down my Cat by running 18/52.

That said gearing doesn't matter if your clutching isn't right so at least make sure everything is healthy in your primary and secondary. My TRA primaries needed love every 1000km.

 

[butthead]

not really into the speed thing and guys i ride with like the trees.
buddy dropped a couple teeth and its like riding a modded sled.
was thinking about doing the same thing with mine.

 

[Dynamo^Joe]

not really into the speed thing and guys i ride with like the trees.
buddy dropped a couple teeth and its like riding a modded sled.
was thinking about doing the same thing with mine.

What sled does your buddy have and what are his gears? What sled/model/year are you comparing to?

 

[butthead]

2019 175 g4
droped the top gear 3 teeth from stock
mine 13 163 xm

 

[bnorth]

His sled is going to feel like a mod sled compared to yours. Just the nature of how fast the technology in these things is evolving.

His sled also had a stock 21 top gear vs your 19.

 

[butthead]

very good point there bnorth