Tutor me in gearing please! (mini sprint)
 

Unfortunately when I should have been learning how to gear a chain driven race car back in my QM days I played more of the get in the car, drive, tell dad what was wrong and let him fix it role. It made him happy, but leaves me at a disadvantage now. More or less everything I know are bits and pieces picked up over the past year, but I only ran 1 track and I ran the gears I was told were right. Now the minis are coming to Eldora and I am lost since no one knows what gears will be right and it is a good chance for me to learn WHY and HOW not just "put these gears on". The extent of my "knowledge" can be summarized as this: I have a fancy gearing chart for my 2006 R1 with lots of cool numbers. I have a list of front and rear sprockets to run at known tracks. I know that smaller sprocket = smaller track. Rear gear divided by front gear I think gives me a "true" gear ratio without factoring in the tranny gearing on the engine. Pretty sure I remember that adding a tooth on the front (counter) sprocket is the same as adding 3 in the rear (or was that taking off 1 in the front?). Anyways, that is about it. I am about as ignorant as can be on how to go from here to truly UNDERSTANDING gearing and why doing "X" yields "Y" so I am going to sit back and hope that all the fine IOW folks will flood me with their knowledge and help me understand not only the what but the why. And if anyone can use some math magic and come up with a magic guess on gearing for Eldora I would be thrilled as I currently have about a week and a half to find\beg\borrow\buy gears to make this happen and the $1500 clutch my tow vehicle and unplanned engine freshen up kinda ate into my racing money I had built up. Thanks guys!

Re: Tutor me in gearing please! (mini sprint)
 

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

Re: Tutor me in gearing please! (mini sprint)
 

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:6::6: