The Perpetual "What Gearing Do I Run at This Track?" Thread

[Jeffreysully]

Looking for recommended gears for Gingerman for FF with Honda power. Hoosier R60 22.7 diameter.

[racersonly]

Formula Ford on Hoosier vintage tires for Blackhawk Farms?

[fzfpxm40]

Looking for gearing for VIR long course with a 10-31 rear axle.

[Messenger Racing]

Deleted - no longer needed.

[Garey Guzman]

...

[Chris Robson]

Looking for gearing for Thompson with 10/31 R&P, Kent engine, Formula F Hoosier spec tires.

[Messenger Racing]

I am helping out a new driver in FF and would like to know current thinking on Homestead gearing. I found this one post from many years ago:

Thanks in advance!

Jay M

10-31
17-34
20-31
22-28
25-27

John

[Larry H]

Curious as to what is the recommended minimum RPM for a Kent Engine?

[TimH]

Typically not much HP below around 4700, motor comes alive around 5200. However, some builds have enough low-end torque to let you pull from a little lower. YMMV.

[Art Smith]

I've looked, but after sifting through pages of info can't really find anything approaching definitive for a 10:31 Kent at Road America. would greatly appreciate local thoughts for an average/above average Kent; it's a bucket list question. track time would be much better spent learning the track versus working gearing........

Art
artesmith@earthlink.net

[jrh3]

Any suggestions, 9:31, CFF, Kent? Thanks!!

[halcyon]

Does any one have suggestions for a Club Ford on R60 Hoosier bias ply slicks for NHMS (New Hampshire Motor Speedway) road course?

Final drive 9:31 for me, but I can do the math if only 10:31 suggestions are available.

[HazelNut]

looking for gearing suggestions for a Thomson, vintage FF, kent, treaded hoosier vintage tires, MK9 box so i believe 8/31 r&p

thanks!

[ric baribeault]

9/31. I’m checking

[Andrew Stein]

looking for gearing suggestions for a Thomson, vintage FF, kent, treaded hoosier vintage tires, MK9 box so i believe 8/31 r&p

thanks!

9/31 for me is 19:32, 21:30, 23:28, 24:26
equivalent for 8:31 is 20:30, 23:29, 24:26, 26:25

[Hawke]

For reasons I won’t bore you with, one of the two proper race tracks near Sydney is closed. So one of our local clubs is going to hold a championship round at the local drag strip. Any suggestions for gearing for a FF1600, with a 9:31 diff?

[DaveW]

For reasons I won’t bore you with, one of the two proper race tracks near Sydney is closed. So one of our local clubs is going to hold a championship round at the local drag strip. Any suggestions for gearing for a FF1600, with a 9:31 diff?

No gearing suggestions, but get some small diameter hard compound narrow tires so they will spin and not destroy your CV joints, clutch, etc.

[Hawke]

No gearing suggestions, but get some small diameter hard compound narrow tires so they will spin and not destroy your CV joints, clutch, etc.

Dave, thanks for that, but in this part of the world, we have standing starts in all of our races, which normally involve reving to 6,000 and almost just drop the clutch. Its rare that you will light up the rear tyres or break anything, you just go.

[Jim Edmonds]

For 10/31 and Hoosier FF tires, I've used 17/33, 17/28, 18/25, and 24/28. Those are not optimized for track direction.

This month they are extending the curbing on most corners, using curb profiles and tractive paints that will allow the motorcycles to run on the curbs as part of their race lines. This will change the lines a bit and will increase the straight speeds a little. It will be interesting re-learning the track.

The West-bound line onto the main straight is being extended past the top of the hill. That plus longer curbs on the right prior to the hill may make more difference than we think in straight line speed.

YMMV

Jim Edmonds
Phoenix, AZ

[Garey Guzman]

For reasons I won’t bore you with, one of the two proper race tracks near Sydney is closed. So one of our local clubs is going to hold a championship round at the local drag strip. Any suggestions for gearing for a FF1600, with a 9:31 diff?

Hi Grahame,
First off, I've never done this. Second, I'm probably just going to say what you were already thinking but wanting confirmation. Nevertheless, opinion follows...
Most of the time is gained from the launch so probably the best gearing would be using lowest 1st gear, hopefully a fixed 1st gear.
Then, assume you'll hit about 100 mph in 4th, which would be 22/29 for my Vintage tire on my March FF at 6800.
Spacing 2nd and 3rd based on my gearing norms gives me this:

14	36	RPM at shift:
17	34	5289
20	32	5440
22	29	5602

[Lotus7]

looking for gearing suggestions for a Thomson, vintage FF, kent, treaded hoosier vintage tires, MK9 box so i believe 8/31 r&p

thanks!

"MK9" doesn't necessarily mean an 8:31 by default.
Pretty easy to check without pulling the side cover using the "how far do the tires roll for one rev of the flywheel" method and some simple math with a known gear ratio in the box.
The difference between an 8;31 and 9;31 is 12%, so accuracy doesn't have to be crazy.

[halcyon]

Suggestions for Pitt International Raceway please. Thank you.

[Bob Wright]

Umm... what kind of car, what dif ratio would be a good start.

[apalvee]

I did this exceice a few years ago
Regards
Etienne