Sprocket down in front or up in back?

[dxh24]

Hey guys i've hear lot's of theory's on how sprockets affect accelration top speed etc... i've only ever used them on dirtbikes for more a torque-ier feel...but never really became an expert, i always fiddled with the rear sprocket not the front... but i've hear 1 down in the front is about equivelent to 3 up in the back? any help? i also hear rumor that on some bikes if you go down 1 in the front it messes with your rpm's more than down 3 in the back, although that theory doesn't make much sense to me...and most people on the V forum say go up 2 or 3 in the back instead of down one in the front...So what have you guys done if anything, to the sprocket sizes on your bikes? anybody tried either and had a preference? Any input is greatly appreciated :thumbup:

 

[FB400]

I went with -1 in front. Some guys do both -1 and +2. Simple reason for doing front is you won't have to worry about the length of the chain and front sprocket costs less to swap than the rear does. When you start adding teeth to the rear sprocket the stock chain will no longer fit. Your speedo is going to be off no matter what sprocket change you do so you would probably want to get a speedo correction device.

The -1 sprocket up front costs me about $20
speedodrd correction device was $70. (speedohealer costs around $115)

All in all a cheap way to boost acceleration.

 

[iSteve]

I'm guessing that going up in the back gives you some advantage. If you were to spin your back tire with your hand on the tire it would be easier then spinning it from the brake disk.

The usual sprocket ratio for motorcycles is about 1:3 so 15 front to 45 rear.

 

[Willard]

Front sprocket is a lot cheaper than the rear. I went -1 on the front and it changed the bike dramatically - a great improvement from the stock gearing. Try the -1 route first, if you don't like it for some reason you're not out much money and if you want even lower gearing go up a tooth or two on the back.

 

[TampaFZ6]

I did the front sprocket with a 15T and I don't feel any acceleration difference. Maybe I was thinking it would be something one could feel. I am going to switch back to the standard front sprocket so I'll have a more accurate speedometer and to keep RPMs down when I cruise the interstate.

At some point I'll purchase a Yamaha VMAX if I want serious low end torque.

 

[DownrangeFuture]

If you're only doing one, go in the rear. It's less wear on the chain and assuming you still have 0.280" clearance to move the rear tire forward it'll fit just fine.

That being said, you won't notice much difference. And if cost is the factor, you can find the OEM brand +1 and +2 for around $30. Or spend up to $200 on a vortex sprocket. Your choice.

Personally I'd do -1/+1 it actually moves it back about 0.08" and takes your realistic top speed to about 115, gives a huge ratio boost for the torque, and only adds about 1080 RPMS to any given speed. IE 70mph in 6th is around 6100. It would then be about 7200. I wouldn't mourn the loss of 30mph realistically on the top end. You'll never see a two mile straight on any racetrack to hit that speed. It'd probably go quick until around 110 or so, then slowly creep through the rest of 6th gear.

That's my 2 cents anyway. I've been looking into this alot recently. The PO never oiled the chain I don't think. So both my sprockets are cupped badly, the front is hooked a little even. And since the only track in driving distance has a record of 92mph avg speed, I won't even miss the top end anywhere.