It seems like the gears on sportbikes are much closer than they need to be, and from what i've read, they are getting closer. I've read that the new r1 and zx10 go over 100 in first gear. So, I was wondering if it is possible, or if anyone has successfully installed a shorter first gear and/or taller 6th gear. This way the bike could be good for slow stuff, and also good for cruising and running from cops.

 

100 in 1st gear? thats REDICULOUS!!

 

We've talked about this a few times. It would be nice to have a bike that was able to do EVERYTHING. Unfortunately none of us know enough or are brave enough to tear our trannys apart.

I'd like to see it done or hear if any of you motor heads out there think it is possible and some ideas of HOW it could be done

good topic

 

racers do it. all you need is the parts and know how. where to find the parts i wouldn't know. probably won't be cheap either.

 

Like in cars, such as offroad trucks, rock crawlers to be specific, you'll have a really low first gear, usually called granny low, its so low that its only good for crawling and when your on the street you usually start in 2nd gear. Now, if you had this in a streetbike, w/ a granny low gear, but still have your other gears for bouncin from tha popo's. But then, who's gonna be tha one to try to build this. I know I prob. could, but wouldnt wanna throw the money out for it, someone wanna sponsor me?

 

Definately could be done. One of our lazy asses just needs to figure it all out!

 

ive had this discussion before too. if you wanted a mad overdrive or even a mad underdrive for sixth or first the only problem i can think of would be crankcase clearance. i cant imagine there being too much room in there to stuff a bigger gear to get the disired results.

 

true dat

 

All right, i busted out the service manual and the calculater and did some figuring. It looks like there's enough room for gear changes. I'll see if i can explain this in a way that makes sense. On the cbr600f4, the 1st gear (on the mainshaft) is part of the mainshaft, and doesn't look like it could be any smaller. So there would be no gearing 1st down. On the other hand, 6th gear on the countershaft looks like it could be made remarkably smaller. While first gear on the main shaft has only has 12 teeth (and 34 teeth on the countershaft), 6th gear on the countershaft has 26 teeth. "IF" 6th gear on the counter shaft could be reduced to 12 teeth (and 6th gear on the main shaft increased to 34 teeth), then the bike would have the potential top speed of 528.5 mph (with stock sprockets). This would allow you to put a 144 tooth rear sprocket ( ) on and maintain the top speed of 165mph.

edit: corrected a mathmatical mistake

 

you may have it backwards. 1st gear should be the largest gear and 6th the smallest. just my from building a few tranys

 

1st gear is the largest and 6th gear is the smallest on the countershaft, and vise versa on the mainshaft.

 

this is true. my stock 03 gsxr1000 does about 93 in 1st. bikes are starting to get a very tall 1st gear. just think of them as smaller indy cars. an indy car will do 150 in 1st gear and rest are so close. a 50 mph gain in 5 gears just don't seem right does it.

 

true, my bad. sounds tough i wouldn't *** with it.

 

Did some more calculations. With a +15 (57) tooth rear sprocket, it would only take the exchange of 3 teeth from the 6th gear on the countershaft to the 6th gear on the mainshaft, to keep the stock top speed.

 

props to you for figuring that out. but will the gears fit in the cases? increasing the 6th gear on the mainshaft by gaining 12 teeth, would it physically fit?

 

that sounds a bit more possible. and the ultimate compromise.

 

Looks like there is plenty of room from what they show in the pictures.

 

they make different gears for the gearbox. the factory teams change up the gear boxes when needed. i know its possinble as to which gears you can change and whether they are obtainable parts is the real question

 

I couldn't find any useful information doing a google search

 

So....when does the building begin??