Just a note on people who like to change your gear ratio's.

It is common for a lot of ppl to go down 1 tooth on the front. On the CBR's this is not a good idea. because of the smaller physicall size of the sprocket compared to the chain and the weight of the bike it puts a lot of pressure on the shaft and sprocket. It also changes the angle of the chain too much and it can slap against the swingarm whuch at the very least robs power and at the worst eats a hole in your swingarm.

If you want to gear it down then go up on the rear instead.

(I got this info from a Engineer and they are never wrong! :P )

I have a gearing program I can email ppl if you want to calculate things. (Excell spreadsheet)

Cheers
Rob

(Go hard or go home)

 

You must be God sent. I was just about to post up asking about what size and what experiences in power and ride change some of you guys have had doing this very thing. I was thinking on going down one in the front. I'll go up one in the rear now instead. I do have one question...with my old bike, I changed the down one in the front, up 3 in the rear and changed the chain to some high performance chain my mechanic advised me of. The power difference was amazing. What about doing something like that with the CBR? Can you punch numbers for me or just send me the spreadsheet? Thanks in advance. (2001 Honda CBR 929 RR)

 

I just put a 16 tooth sprocket on front (-1) and a 44 tooth out back (+2) and I have had no problems at all. The pull from down low is amazing enough on these bikes, but now............WOW!!! Swingarm clearance is NO problem at all...

 

if you go up 2 in the back it the same as going
down 1 in the front if you go 2 up in the rear you will be
running a gear ratio of 2.647


greymustang

 

Yeah but how much clearance is there at the very front of the swingarm where the chain crosses. Remember your chains flaps around quite a bit on downchanges.

 

If you sned me your email I'll send it to ya.

I don't suppose anyknow knows somwhere I can host the file for everyone to get at?

 

Seems to have way more than enough at the front. Without putting a tape on it I would say....almost on inch or so.....Allowable chain sag from factory is 1/2 inch so I have more than enough room I would say, right???

 

I`ve been using a 15tooth front sprocket for the last 8000 miles with no problems,this was recommended to me by TTS performance in the UK,who also carry out big bore conversions for our bike.

Heres a link http://www.tts-performance.co.uk/

 

Going down 1 up front is closer to going 3 up at the rear.

My 2 cents; When you go down up front the chain will wear quicker when passing a smaller radius. When you add the extra tourque by droping down in front or going up in the rear, the chain will wear quicker. Depending on how you ride and how active the right wrist is will also be a major factor.

 

You are right the chain will wear faster, but not from the extra torque. The torque stays the same according to engine rpm. What changes is the road speed where the torque is delivered. With the gearing changes, the engine rpm will be about 10 percent higher at a given road speed than normal. So the chain will be moving 10 percent faster than normal, and should wear out 10 percent faster. Also the indicated road speed will be 10 percent higher (since the speed reads off the front sprocket and it's has to turn faster), the mileage will be 10 percent lower (because of the higher rpm/road speed), but the acceleration should be 10 perent faster. I also read somewhere that if front sprockets have an odd number of teeth, they wear the chain slower than even number teeth.