Gearing and wheel base

darth nater

darth nater

Staff member
Control Rider
N2
I was looking for information on recommended bike gearing here on the forum and found a thread talking about how a 15/45 and 16/48 gearing achieved the same power/gearing but affected wheel base. I am not all that great with anything motorcycle tech, but could someone fill me in on gearing, wheelbase, how they are affected, and anything else that would be good to know?

If context helps any, interested in gearing for 2009 R6. I understand that gearing changes for each track, but I am looking for a common middle of the road setup since I don't have the money to buy a bunch of different sprocket sets to swap in and out.
 
noobinacan

noobinacan

Member
usually, down one in front means +3 in rear. that's why you have two gearing combinations that will deliver approx same power.
Generally speaking...

increase the wheel base and bike will be more stable through faster high speed turns and sweepers. also will soak up bumps better. wheelie less. more stable on the brakes.

decrease the wheel base and bike will be more stable through slower turns, allow quick direction changes. wheelie everywhere you go. twitchy on the brakes.




increase wheel base by (longer chain) or raising the front.
decrease wheel base by dropping the front or shorter chain/rear wheel.

or you can keep going and do swingarm/ rear linkage changes, which then affect; tire life, rear grip, shock valving...spring rate. it goes on.




few mm (even 1 or 2) can make a massive difference in how the bike feels at pace.
Also, you have to take into consideration your suspension setup.

Don't mess with geometry changes unless you know what you're doing...is rule of thumb.
Also, you're right on the ball with sticking with one gearing, it will work on most tracks.

do -1 in front
then have a rear sprocket for track and one for street. you want to gear lower for the street cause otherwise you'll be tachin 10k...just cruising. haha.

15/47 is last I heard was good for 07 R6 on the track.
 
darth nater

darth nater

Staff member
Control Rider
N2
Thanks for the info. This will be track only. I have heard 15/46 is a good middle ground for the R6, so it seems -1 in the front and stock to -2 in the rear.
 
sobottka

sobottka

New Member
generally speaking a shorter wheelbase sacrfices stability for lighter, quicker turn in and a longer wheelbase is more stable with heavier, slower turn in.
 
Lonewrench

Lonewrench

New Member
Ok
I have a bit of experience with this bike. Get a 520 x114 link chain of your choice. get size 15-16 countershaft sprockets and 41-44 rear sprockets and you can race anywhere in the country. If you race at Sears Point in CA you will need a 14 tooth countershaft spkt:). This wheelbase is perfect. For more set up info just let me know or PM me.
 
snikwad

snikwad

New Member
dark nater;221092 wrote: Thanks for the info. This will be track only. I have heard 15/46 is a good middle ground for the R6, so it seems -1 in the front and stock to -2 in the rear.
Click to expand...
i have 16/47 on mine and its perfect, doesnt top out on VIR, and i will JUST hit the limiter in 6th at summit main, if i get T10 right, which doesnt happen often.

You can also use a speedo healer to correct, and reclaim lost top speed if you go with an aggressive gearing like -1/+2
 
physicistkev

physicistkev

Control Rider
I don't know if anyone outright answered the second part of Nate's question. So, here goes. When you use a different sprocket the wheel base is affected by having to move the rear wheel forward or backward to put the proper amount of slack in the chain. If you just replace a rear sprocket with one that is 1 tooth larger, the rear axle will need to be moved forward so the proper slack in the chain can be maintained. When you do this you are effectively changing the wheelbase (shorter) of the bike.

Kevin
 
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