Yamaha TRX850 Enthusiasts Forum

my bike is running 17/39 i have a 16 in the shed would this be better dont have much cash so cant go out and buy new chain might be able to run to a sprocket any simple advice appreciated cheers and merry xmas all

I personally would never run a 16t front ad would recommend 17/42 but it's pretty much the same thing.

Peps up the acceleration and makes town work more manageable

thats what i am after it feels like it doesnt want to pull away as if i was in second also would this affect my dyno i had done

I've been running a 16t front and standard rear for ages and never had any problems. I know people get concerned that the small front sprocket could be a problem but 16T (even 15T) is common enough on bikes and 16 is standard on the TDM anyway so it should not be an issue.

I am running a 16T front - easy swap and very noticable increase in grunt, but does reduce top end quite significantly.

If you want drive rather than top speed it's all good.


As someone said, mayb bikes have 15T front sprockets as standard. The difference between a 16T and 17T is what, 6%. I would think that there should be very little noticable difference in wear on the sprockets based on that.


yet strangely my chain disagrees, it tends to get stretched a bit

will be putting 16t on today

... and I'll put money (if I had any) on the fact that you'll like the difference it makes with the low speed / around town gearing. 5K rpm in 5th = 80mph which is good for 'sensible' riding on British roads too. (Especially for old farts like me !!)

I quite like the standard gearing, am I odd? I was going to try one more tooth on the rear when they're due for changing though (1000 miles ago )

am I odd?

...
Dunno. You're a woman, so that MAY explain it ?...

dillthedog wrote
"i have a 16 in the shed"

Won't make any difference I would have though.

ekoja wrote:dillthedog wrote
"i have a 16 in the shed"

Won't make any difference I would have though.

Can i have one to??

dillthedog wrote:thats what i am after it feels like it doesnt want to pull away as if i was in second also would this affect my dyno i had done

Dil, if you look online for a gearing calculator, there's one in excel format (.xls) that will give you all the in-gear speeds if you put in the primary gearing and then your final drive ratio.

I've just switched to 16/39 (ally rear sprocket) from 17/43 (steel rear) to save some drivetrain weight. 16/39 worked out at 135mph at peak power in 5th, so it's only maybe a 5 mph drop in top from standard 17/39 gearing. Not a really radical change. In fact, if you want maximum thrust and don't want to cruise at 100 everywhere, try 16/41. My 17/43 gearing gave 80mph at 5,000, which was perfectly comfortable.

No need to worry about chain wrap issues - as I said, I ran 17t/43t without any issues, so if a 43 doesn't cause problems, the higher gearing on 16/39 certainly won't.

Can imagine what happened when I put the chain round my 16 in the shed.. and can imagine why kayla likes the 17 with the 40..mmm..Being a woman.. ..hope she wasnt talkin inches

maybee 17cm x 40mm = approx 6 3/4" x 1 1/2"