39t rear sprocket


Has anybody run a 14 or 15 front and 39 rear on a sm. i currently have 14 on the front for s wheels and wondered what it would be like on the sm wheels

mine was 15 39 when i got it pretty much stock engine wise & tbh it wasn't bad for road riding it was just no good if u wanna do wheelies. I changed to to 14 41 & thats much better apart from its high in the revs when goin over 60 70 mph. I'm gonna put my 15 front back on soon but probably keep 41 on the rear, I reckon it'll be better now its got more power after engine mods. (I'm pretty sure my head gaskets gone though so thats main concern atm) :banghead: but I seen ur other post & spotted an FCR carb amongst ur new goodies so I reckon you'll be right with the higher gearing once you put that on :ride: where abouts in UK are you?? I'm north west near preston & manchester

Edited by carlspeaky


Has anybody run a 14 or 15 front and 39 rear on a sm. i currently have 14 on the front for s wheels and wondered what it would be like on the sm wheels

Depending on tyre size 14/39 on 18" wheels would be very similar to 15/39 on 17" wheels in speed comparison @ the same rpm...

Mate I run a 15/39 combo on stock SM rims and I find it great on the freeway and around town. It will cruise 100+ kmh all day if you wanted it to. Depends what you want out of it but I think it's a great alround set up. I don't do the wheelie thing so if that's what your after then maybe this isn't for you.

I have been happy with 15-38 on my SM.

I'm running 15/39, love it. Can do 85mph all day. 2nd gear wheelies are still possible.

I am near chesterfield j29 M1

i just ordered 16/39. ill report back after i get them on :)

I run 16/39 on my SM. I bought a new 14t cs that would put me close to the original 15/41 with the 39t but I found I really like the 16/39 combo on the street. Pulls like a mofo and gives me decent top end without having to redline the engine to go 80-85 mph. 5th gear is almost like an overdrive. Not sure I would run it with a stock engine though, may not have enough huevos to pull it. I'm using FCR/3X3/KN/Pro circuit slip on with no worries, topped out at 109 once. Going to install some HotCams soon and may drop to a 38t after that.

I just tried a 15/39 with a new VX2 chain on my SM, the only mods to my bike are a Yoshimura RS2, 3x3 air box, and a Dynojet stage 2 kit. I love this gearing, at first I was worried weelies would be much harder, but their not. in fact it seems to weelie better now as second gear is alitttle bit longer now, highway riding is now acceptable, also I'm still able to do light trial riding just as good. I really cant see any area's that this gearing adversely affected, it's only positives, for me anyways.

All in all I'm completely happy with my 15/39 setup.

Edited by Run-Forest-Run

I run 15/48 on my E. Haha flat out at 95mph. Does good wheelies though! It is good to hear all these opinions for when i get my SM wheels :thumbsup:

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