Hoosier radials

Aaron Johnson

Aaron Johnson

Well-known member
Ok. I'm tired if tearing the rear tires up on the spitfire so I'm looking to change from the Hoosier bias ply to the radial. After some discussion with htmw I'm going with the 190/530-13.

I'm going to start the fronts at -2.5 deg on camber and work from there. Any of you who have been running have any input on the pressures. I target 25 hot on the bias ply and would think the radial would want slightly more.

Also, what are you doing about rains? Is there a radial rain tire that works or are we having to make due with the bias rains. If we have to keep the bias rains are any of you switching setups to use them?
 
Aaron Johnson":8u8ffkcq said:
Ok. I'm tired if tearing the rear tires up on the spitfire so I'm looking to change from the Hoosier bias ply to the radial. After some discussion with htmw I'm going with the 190/530-13.

I'm going to start the fronts at -2.5 deg on camber and work from there. Any of you who have been running have any input on the pressures. I target 25 hot on the bias ply and would think the radial would want slightly more.

Also, what are you doing about rains? Is there a radial rain tire that works or are we having to make due with the bias rains. If we have to keep the bias rains are any of you switching setups to use them?
Click to expand...

Aaron, from what I hear the new Hoosier H2O is now available in a 185. I think that Ron Bartell may have run them last weekend at Mid-Ohio.

I have been running the 13" Formula 2000 pro series front in the wet. However, it's a 215 and it may be too wide for a 6" wheel. As soon as the wider 13" H2O is out, it has been recommended by Hoosier that I switch to that as it's built for the heavier cars.
 
Aaron Johnson":c3sa45fj said:
Any of you who have been running have any input on the pressures. I target 25 hot on the bias ply and would think the radial would want slightly more.
Click to expand...

Aaron I just talked with Jeff Speer at Hoosier this week about this topic. They're recommending 27-28 for me (2179 GCR weight) and 30lbs for heavier cars.

I've come in at 26 and not been much off the pace - coming in at 30 the car is much slower.
 
The new Hoosier radial rains for my car weren't ready for M.O. so I used the F2000 front tire rain radial. They are 20.5" x 7.0" and are narrower and taller than the bias ply tires but fit fine on my 6" rims.

On the dry tires I look for 26 to 27 lbs hot. Good luck with them.
 
Ron Bartell":1v19cetx said:
The new Hoosier radial rains for my car weren't ready for M.O. so I used the F2000 front tire rain radial. They are 20.5" x 7.0" and are narrower and taller than the bias ply tires but fit fine on my 6" rims.

On the dry tires I look for 26 to 27 lbs hot. Good luck with them.
Click to expand...

Sorry bout that Ron. I misunderstood when Tim was asking me about wet tire pressures. I thought he was talking about the F2000 tire but then he mentioned a 185 H20...

Aaron, I shoot for 28 hot, but like Lamkin this is on a much heavier car. I suspect Ron's advise is going to be the best for you.
 
Aaron, not sure what issue you have been having with the bias ply tires. You will find that the radial slicks have much more grip using less slip angle. In the rear of the limited prep Spitfire that may not be a good combination. Since the rear transverse spring serves as upper control arms, you will likely find alot of rear alignment change depending on how the suspension is loaded. This rear suspension works well with bias ply and the progressive slip you can generate to limit some of the suspension loading. Base on my experience, the radial slicks work far better on cars with sturdy, well designed suspensions and chassis that do not flex. Unfortunately not all of our old race cars fit that for both front and rear suspensions.
 
I'm getting really aggressive wear on the inner edges of the rear. My setup seems to never net less than -3deg in the rear. I've been talking with Hoosier and the radial seems like it will be a good fit.

I can make the bias ply's last, but I end up swapping and moving a lot. The radials like the camber. I know John Stanford has run them (once at nelson) and I didn't get a chance to talk with him about the radials. He turned some good times at Nelson.

aaron
 
Just an FYI for those of us with cars in the 2000-2500 lb range. Hoosier says to shoot for 30-32 psi hot. If you're not sure where to start cold, aim high rather than low. These tires don't react too badly to overinflation (like the bias ply slicks) but they will fail if you run them underflated.

I gain around 6 psi during a session, so I start mine at about 24 or 25.

YMMV, but this info comes from different personal experiences (including my sad story) and sources within Hoosier Tire.
 
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