Originally Posted by bobby01:
Example
53 rear tooth 13 front tooth 04 thru 06 r1 transmission ratio in 3rd gear is 2.66
53 divided by 13 equals 4.0769 multiplied by 2.66 equals 10.8445 witch is the final ratio.
What I have done when I go to a track that I haven't ran before is ask someone (that you trust) that races a UMP or IMCA mod what gear ratio they run then add 4.4 to that. It seems to work really close.
Mod gear 5.83 add 4.4 is 10.23
Almost forgot do not round your numbers very far.
Bobby Layne
2011 MLS Champion
That's right cross multiply and devide.
ump modified 6800 rpm's................ump best gear 5.83 to 1 gear
____________________................ _________________________
12000 rpm desired .......................Unknow mini sprint gear
Take 12000 x 5.83(cross multiply) = 69960 then divide by 6800 = 10.28 to 1
I usually use midget gear ratios but if you know the race car their desired peak rpm and their gear ratio you can take it from there with this formula.
Thank you Mrs Jansen my 4th grade school teacher for this bit of racing know-how. Kids pay attention in school sometime they teach good stuff in school, it's you and your teacher might be just to dumb to see where it's going to help you in the future.
Honest Dad himself
