Smaller sprocket in the front or Bigger sprocket in the back?

[Timex]

I am what some would consider a man of larger stature.  I have an 07 R1 and I'm looking to get more torque and a better start off the line.   Which is better...Small in the front or Bigger in the back?

[MotoPutz]

Some people do both. 1 down in the front is about the same as 3 up in the rear.

[n10sive]

oh...there's a joke in there but I'll refrain LOL

[Nesquik]

oh...there's a joke in there but I'll refrain LOL

hahaha i see it  lolol

[99 900ss duc]

oh...there's a joke in there but I'll refrain LOL

thats just wrong

[Justin]

I just learned the following.
A smaller sprocket in the front the cheaper mod.  I have a friend who is doing this to improve the handling by lengthening the wheelbase.

[jlavallee]

Well, there are a couple of things to take into account when doing this. Most bikes have enough adjustment to allow a tooth smaller front and this is the cheapest route. If you're stock now then this is probably the way to go.

Usually it is close to a 3:1 ratio, meaning that stock might be a 16/45 or for every turn of the rear, you get 2.8 turns of the front. Easy enough to do the math on that. Changing to a 15 tooth front in this example nets you a 3:1 exactly which, represents a change of nearly 7% in this example.

Things to keep in mind include:

- Your wheelbase changes with drive gearing changes
- If you go too small on the countershaft sproket you could have swingarm rubbing and extreme wear
- Your speedo will be off by the percentage of change. In the above example, you would be showing 107 mph when doing only 100 mph (if your speedo is currently correct)
- At the track this changing gearing might mean you need to run certian corners in different gears and that could be a plus or a drawback.
- You might end up in a "buzz" zone of engine speed at the cruising speed you normally cruise.

Long and short of it is that if you're stock now and you have a desire for just a little more torque then a front is probably a cheap, easy way to get it.  If you need more than that you will want to adjust both sprockets. Also remember that most bikes don't have enough adjustment for more than 1-2 teeth in the rear so if you need more it is usually a 1 down in front, 2 up in rear situation.

To answer your question about which is better, a bigger rear is generally thought to be better (from an engineering point of view) because it does not have the driveline clearance issue or the increased wear issue. Because you must often change chain legnth to do this and because of wheelbase changes, it is not a matter of one being better than the other but rather, what works given your conditions. This is why most racers have a couple of countershaft and drive sprockets to adjust for the ratio/wheelbase they want. Hope that helps.

[Justin]

i got smarter.  Thanks, J!

[youngster775]

good educational post, thank you!

[n10sive]

had to scratch my head there...threw me off when you tossed 'wheel base' into the equation. Now i get it...but never thought of it. Could you take a link out if you wanted to keep the wheelbase shorter?

[Adiggity]

  Could you take a link out if you wanted to keep the wheelbase shorter?

Yes. You can do any combo (sprockets or wheel base) you want if you are willing to change the chain or chain length.

Another "engineering" reason for it being better to go up the rear...oops, I mean up IN the rear is because you are adding tooth contact. When you go down in the front you are taking that away which in turn makes it weaker. But going up in the rear also adds weight......

I just wanted to chime in and make myself feel smart too. Did it work?? 

[jlavallee]

Yep, as Andy said you can shorten the chain if you like although it might end up being too short so you have to measure first. As I said earlier, you are now spreading the load over fewer teeth so wear increases but it won't likely be significant.

As long as you have room to make proper adjustments I'd guess that unless you are a racer you won't notice the wheelbase change. Also, when you break your OEM chain you should really rivit a new link on and that requires a tool and another link unless you use a clip link which, I wouldn't personally do on a big bike.

If you get the sprocket at SPL or something they can look and tell if you have the adjustment room to put a -1 front on. It wouldn't take them long to swap it out, easy as pie. If it's not for you, you just go back to OEM.

[Adiggity]

Good point J. I do not recommend the clip type master links on any bike. I have a chain break tool if anyone needs to use it.

[Timex]

Wow..That's some great information.  Thank you very much..all of you.  I'm thinking I might go down one and see if I like it.  If I don't feel like thats enough, then I'll go to a new rear sprocket and chain.  I've done some research and have heard alot of good things about Sidewinder sprockets.  Has anybody heard anything about these, good or bad?  And, if I go down one in the front, do you think I'll be able to tell the difference?

[MotoPutz]

if I go down one in the front, do you think I'll be able to tell the difference?

Definitely