Hoosier TD-R sizes Options

[twin356]

I will be rolling out my 914-6 2.0 vintage car this spring. Looking to understand what size rear tires to run on 8" rims. I basically geared for 24", as that is size of most 225/50/15 radials. However, in vintage (SVRA/VRG) is preferred. So, run the 24x8.5-15, or the 25x8.5-15.
What is being run by others?
Thanks
Scott

[Racer]

While I don't know what is preferred, perhaps some of the choice is dictated by the circuit run?Since this is effectively a gearing change, you might want different sizes for different tracks, unless you are also able to swap boxes/gearsets for the tracks you run.

[GregAmy]

Scott, check the regs of the groups you're running with. I run with HRG (HRG3) and VRG (DPh) up here in the northeast, and they require DOT-rated tires. Are TD-R DOT-rated? I don't think so, as all DOT-rated tires use the standard size nomenclature of XXX/YY-ZZ

I run 100TW Nitto NT-01, 205/50-15 all four corners. VRG doesn't "like" those, but it meets their reg requirements.

[GregAmy]

Just did a quick check on Hoosier's site. As best I can tell...

- TD is bias-ply and not DOT-approved.
- TD-R is bias-ply and not DOT-approved.
- TD-S is bias-ply and not DOT-approved and has been renamed HOTD-R.
- The new DOT-approved radial vintage tire is called the Speedster.
- VRG specifically allows the TD and Speedster.
- Speedster is available in 205/50-15 and 225/50-15.

If you're stuck on Hoosier, Speedsters is probably the way to go.

Then again, it's historic racing, and at ~$225/tire your tire budget will be "interesting." I paid like $800 shipped for 6 tires, and ran just four of them for 6 events in 218. The otehr two are still on the tire rack in the trailer, and the four on the car aren't showing significant wear...

And this is coming from a guy that is supported by Hoosier for my main Super Touring efforts...

[wndsrfr]

Hi Scott...I've been racing with SVRA/VDCA/VRG/HSR for the past year and am on the Hoosier's with Kermee--2.7/6 weighing 1950#, 215rwhp and stock gearing. I'm on TDR's, 23x7.5 15 front and 24x8.5 15 rear. The car likes that setup as it's faster than the driver....Lap times at Summit Point are 1:28's mostly, one or two at 1:26 & change. Curiously, at VIR & Watkins Glen the lap times are almost identical at around 2:20 with a few at VIR at 2:18 or 2:17& change, Road Atlanta at 1:45's....
If you're any lower on power, don't go with the 25 diameter as you'll be better geared with a stock box on the 24's.....I can just barely hit my rev limiter (conservatively set at 7400) at Daytona crossing the tri-oval at about 153mph...
The Hoosiers start out at 17psi cold, finish at 22psi hot in a 30 minute session and start to fall off after 16-18 heat cycles with my level of talent.
If you're considering radials, the groups may "frown" on them unless they've got full tread--you might get by with Toyo RA1's shaved to 4/16's--I really liked them when doing DE events but am drinking the koolade with the racing groups and using Hoosiers.

[twin356]

Hi Scott...I've been racing with SVRA/VDCA/VRG/HSR for the past year and am on the Hoosier's with Kermee--2.7/6 weighing 1950#, 215rwhp and stock gearing. I'm on TDR's, 23x7.5 15 front and 24x8.5 15 rear. The car likes that setup as it's faster than the driver....Lap times at Summit Point are 1:28's mostly, one or two at 1:26 & change. Curiously, at VIR & Watkins Glen the lap times are almost identical at around 2:20 with a few at VIR at 2:18 or 2:17& change, Road Atlanta at 1:45's....
If you're any lower on power, don't go with the 25 diameter as you'll be better geared with a stock box on the 24's.....I can just barely hit my rev limiter (conservatively set at 7400) at Daytona crossing the tri-oval at about 153mph...
The Hoosiers start out at 17psi cold, finish at 22psi hot in a 30 minute session and start to fall off after 16-18 heat cycles with my level of talent.
If you're considering radials, the groups may "frown" on them unless they've got full tread--you might get by with Toyo RA1's shaved to 4/16's--I really liked them when doing DE events but am drinking the koolade with the racing groups and using Hoosiers.

Thanks for feedback. I geared car, for 24" (A,GQ,KA,Q,U). I will start with the 24's.
Power should be good. full blown 906 build. I use to race 356's , go out of Porsches for a number of years. Now ready to start again.

[wndsrfr]

Hi Scott...I've been racing with SVRA/VDCA/VRG/HSR for the past year and am on the Hoosier's with Kermee--2.7/6 weighing 1950#, 215rwhp and stock gearing. I'm on TDR's, 23x7.5 15 front and 24x8.5 15 rear. The car likes that setup as it's faster than the driver....Lap times at Summit Point are 1:28's mostly, one or two at 1:26 & change. Curiously, at VIR & Watkins Glen the lap times are almost identical at around 2:20 with a few at VIR at 2:18 or 2:17& change, Road Atlanta at 1:45's....
If you're any lower on power, don't go with the 25 diameter as you'll be better geared with a stock box on the 24's.....I can just barely hit my rev limiter (conservatively set at 7400) at Daytona crossing the tri-oval at about 153mph...
The Hoosiers start out at 17psi cold, finish at 22psi hot in a 30 minute session and start to fall off after 16-18 heat cycles with my level of talent.
If you're considering radials, the groups may "frown" on them unless they've got full tread--you might get by with Toyo RA1's shaved to 4/16's--I really liked them when doing DE events but am drinking the koolade with the racing groups and using Hoosiers.

Thanks for feedback. I geared car, for 24" (A,GQ,KA,Q,U). I will start with the 24's.
Power should be good. full blown 906 build. I use to race 356's , go out of Porsches for a number of years. Now ready to start again.

Oh yeah with that gearing you'll want the 24's for sure....looking forward to seeing you on the track....my next sessions are Zone 2 at VIR for shakedown then VDCA Wild Hare run...

[campbellcj]

I'm in the same situation now as well, looking into vintage track and streetable (DOT-R) tires in 15". I normally run 245 in back though on 9's and that is proving to be tough to find. I'm thinking I may need to drop back to 225/50 all around and I do have 8's as well.

Anyone running or looking at the Michelin TB-5, and are there viable Goodyear or Avon options? I'm interested in radials only.

[brant]

Local club finally outlawed my hoosier A7's
so last year I switched over to the treaded speedster
actually have 1 of the first 4 sets made in the country


a really nice tire
not much grip reduction from an A7
I'll see how they hold up into this 2nd season
but I'm pretty happy so far and spent a ton of time talking to the engineers at Hoosier (they were still in prototype when I placed to order)

its a radial, so obviously won't help Scott