driver gear

it will be in the 60's what helps more on starts 13 or 14
Todds books are awesome, he has much experience and is so willing to help , He can help you much better if you can give him the nearest exact gear combos, driver and sproket, with sproket variations on back that your considering to run and track size and whether having to lift or flat foot. We have found one tooth even on the rear, can change times drastically even though many say the rule of thumb is approx. 100 RPMs per back tooth, causing us to go up or down on a front and finding a similar ratio to increase lap times.
 

sandhillbandit

New member
Nogoats Web page has a great gear ratio chart along with some great set up info. I never go to the track without it. It would probably help if we also knew the size of the track, not just the shape. Also weight class and what engine you are running would also be a big help. Not trying to be a smart butt, just trying to help you help us to help you lol
 

Jackson

New member
Do you know the name of the track, or the size? Im sure someone would be able to chime in if they knew either of those.
 

W5R

New member
if the track has turns where you need to be out of the gas more often, use the smaller driver, if it has wide turns and you dont have to lift, use the biggest driver you can get away with using. Im usually on a driver that is one tooth bigger or one tooth smaller than what everyone else at the track is on, rarely am i on the same gearing as everyone else. I just like to try new things, and by doing that i found what works best for me at certain tracks, and what line i need to be running at those tracks. It takes time to really figure out the right gearing for a track. With that said, i am usually on a 14 thru 16 driver for the tracks i race at, one is a 1/5 mile oval with sort of wide turns and banking, the other is a flat track and also around 1/5 mile but with tight turns and long straits. For the track that is banked with wider turns, im usually on the 16, and for the one with tighter turns, im on a 14 or 15. i keep my rear gear between 59-68 and adjust the front according to how tight the turns are and how quick i wanna get off the corners. People have said it looks like im cheating because i can pull good speed off the turns and carry that speed down the straits, its all in the gearing you choose and how good your kart is set up. A kart that is set up poorly and not getting thru the corners good would need more gearing to keep the speed and momentum going, while a kart that is properly set up and has the right tires will make alot more speed and wont need as much gear. I have ran as low as 15-58 on the 1/5 mile banked track in box stock class, turning about 6000 rpm along with 11.8-12 sec laps on a good night.
 
6,000 RPM 34” tires
15/58 = 3.87 49.92 MPH
14/54 = 3.86 50.02 MPH
16/62 = 3.88 49.79 MPH
This shows that with a change of one tooth on the engine, the axle gear has to change 4 teeth. At least in that ratio range.
6093 RPM
16/63 = 3.94 49.79 MPH
So, roughly, if you add 1 tooth to the axle, you need to gain 93 RPM to be going the same speed. Someone said 100 RPM and that’s close enough. Just remember that the RPM gain or lose depends on the overall ratio. With a 9/72 gear set, if you add a tooth to the axle, you need to gain right at 200 RPM to be going the same speed.
I have a spreadsheet that does all this math so it’s very little trouble to put it out there.
 

Ltg

New member
What Weddle said is what I typically go by:
- if I'm off the gas a lot and then back on it I'll tend to run the smaller clutch with a smaller sprocket
- if I'm carrying a lot of momentum through the corners and not lifting I'll tend to run larger drivers and larger sprockets
- sometimes, if the track really lugs the motor I'll go with a smaller driver/sprocket combo even if I don't have to lift
- I typically try to keep the sprocket between 61 and 66 or so

Todd
www.dynamicsofspeed.com
 
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