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

[DaveW]

I have an Excel spreadsheet that I likely got from ApexSpeed several years ago that makes the calculations easy for almost any combination. PM with your email address if you want it. You do need to have Excel on your computer to open it. This is what it looks like:

[TimH]

I like this one, also from ApexSpeed some years ago.

[fshort]

Hi all:

2nd try to attach Excel F/F gear spreadsheet (from 2020) to a post...

No joy!

It sez "Invalid file" w/ either an .xls or .xlsx files.

Anyone have a clue?

Regards,
James

[DaveW]

Back a ways Excel files were known for hiding viruses, so they were banned from this site.

[Lee Johnson]

I like this one, also from ApexSpeed some years ago.

Very helpful one. It doesn't take a lot of "Xcel-foo" to expand it to a 5 (or more) speed gear box.

Lee J

[JLuxon]

Looking for road America gearing

kent with 10:31 R&P
hoosier radials

thanks in advance

[TimH]

Here are some recommendations for a 9:31, and you can calculate your own ratios from there:

Lamont 19:32 22:30 24:27 26:25 presumably for slicks
Steve Beeler (local RA guy with Lola 540) 20:32 22:29 24:27 25:25
I was mid-pack in my Crossle' on Toyos with 19:32 21:29 23:27 25:25

Fantastic track. Enjoy!

[rdomeck]

Hello, I have used the search function in this thread to try and find a gear chart for Ozark International Raceway. Any help would be appreciated.

[isagoodday]

I searched this thread and only found one reference for RRR going back to 06. Post 46, but did not reference FD and if it was 10/31 that would put car topping out at 146 so not sure if those were for a FC.

Will be running RRR in end of Oct. Two days of open track. My son is just building seat time in a new car to him and we do this event with friends. Config will be WITHOUT the chicane, but may have a chance to throw it in if I am spotting him and there no fast traffic coming up on him. (typically only 2-3 cars out on track at a time, but out there with things that will hit 170 so have to be very careful).

So does anyone have any ideas on gearing? For reference RRR is almost as fast on the straight as the back straight at VIR. Also no real low speed corners. (unless you take the chicane and I have never done it so I dont know the speeds through there).

I searched youtube and cant find any good AIM or speed overlay

Maybe someone with more experience can draw some guesses from an SRF. (guessing FF should be some margin faster but we are new to FF so I dont know how to guess top speeds...etc) This was from April at same friends event. He was running old tires. Somewhere north of 15 heat cycles so there was probably a little more time in the car with fresh tires. The SRF was 1:15. Top speed 131. Min corner speed 72

https://youtu.be/AGanOO8TFD0

Probably a harder car to 'cross reference' I dug out an old lap from him running our 211 driving it but hard to correlate it's performance to a F1600. On Full course VIR (another high speed course to compare) the 211 is under 2:00 (with my son in it...not with me )

That car hits 140 top speed min speed 66. Ran 114.8

https://youtu.be/QZreqs3QxU4

Any ideas or experience there would be great! Thanks

[isagoodday]

Just updating the Roebling Road Gear selection question. Thanks to those that gave me ideas. In the end, I just went with my gut. Ran two days there and had lots of fun.

for FF Spectrum w/ Honda power
10:31 rear
17:35 1st 70.2mph
18:28 2nd 93mph
22:28 3rd 113.6 mph
19:21 4th 130.8 mph

Spreadsheet says this will get him 130.8 top speed, and looks like that nailed it. Mind you this was only a track day. No drafts so if race conditions, assuming one would need a little more top speed. Just able to hit the 130 at end of straight before the lift and light brake to turn one, lifting at the 1.5 marker.

Race conditions would be different of course and not sure how much a draft would be good for there. One good thing is RRR is if you are going just for fun/test you can run old tires and not fall off that bad. We were running 30+ cycled tires and he still was running in the low 113's. We ran them until they just started to show cords. Amazing how little fall off there is at RRR with roached tires. Seen it with our other cars as well there. So if you ever get the change to go just for fun, no need to bring out good tires. Good tires are good for about a second it seems but we only ran one session saving our good tires for another day.