gear & trans ratio

[paper racer]

I am going to race in the spring and I wanted to have similar gear ratios to a new bike.( I have a 91 YZ250) A new honda 250 has 13FR 48 RR. I have a 14FR so a 51RR would put me pretty close. Then I thought what if the tranny gear ratios are different? That would mess my whole overall ratio up. Is there much difference in tranny gear ratios between bikes of different years and makes. Thanks.

 

[marcusgunby]

Yep there can be-cant really compare them without knowing all the other variables.

 

[paper racer]

My bike originaly had a 14fr and 49 rr so I think i'll just go with that.

 

[stx]

Hey kiddo! I see your still out here trying to get some answers. Well hopefully this will help a 14/[email protected] and a 13/[email protected] final drives, both will pull the same bike totally different. First and most important forget all the MONKEY SEE MONKEY DO You need to figure out what works best for you and the machine your on. The easiest and least expensive thing for you to try is pick yourself up a 13 & 12 frt. sproket you should be able to get both for less than one rear or maybe a buddy might have one. Changing the frt. by one tooth is about the same as 3 teeth in the rear. Running these can help give an idea of how you want the bike to pull. Also pick yourself up a 50&51 rear, if your going to race sprokets are a necessity! There are lots of things that influnce gearing rider wieght-track conditions-riding style even air density although you would first tweak the carb but a slight gear could also benifet,so see it all goes back to what and how you ride and what works for you! Also keep a record book of your bike track conditions air temp humidity ect. the book will become very usefull,write what works and what doesn`t Do pay attention to what the other guys run,it is usefull information but not gospel

 

[limitless]

whats the difference between 3.64 & 3.69 final drive? what is the effect of each?