FIA Tire Size

[1795]

Originally Posted by peterpjb

in the main european historic races e.g. lemans classic and tour auto the tires are limited to front 215/70R15 and rear 245/60R15 (avon cr6zz)

Thans for the reply. 215's are not an option for me. Based upon some contact from Allan Garrow, who is racing in South Africa, the section width of the 25.5/8.5/15's and the 245's will be too wide for the front. So, I will be running 225/60/15 in the front and am now trying to deice between 245/60/15 and 275/60/15 for the rear. The 245's would provide a more even stance (225=25.8", 245=26.4") with the 275's having more of a rake towards the front (225=25.8", 275=27.6").

[*13*]

Originally Posted by 1795

Thanks for that information. I am trying to figure out which tires to run on my 289 FIA SPF/Riverside Racer. The racing organization that I will run with is specific about tires and sizes. I am going to go with Hoosier Street TD's and the sizes that I am allowed are: 225/60/15, 245/60/15, 275/60/15, 25.5/8.5/15 or 26.5/9.5/15

I am a little concerned about having adequate clearance, and also wanting to make sure that I have adequate rubber on the track. 245 seems way to small for the back, especially given that the 289 will have approximately 450HP at the flywheel.

Any thoughts? I am starting to lean towards 25.5/8.5/15 in the front and 26.5/95/15 in the rear, as they are a little less tall and slightly wider. that will help lower my center of gravity a little and increase grip. The car has transverse leaf springs, so lowering height means placing lowering blocks over the leaf springs.

I ran the 25.5 8.5 15's on the front of my car. They were a little "big" visually but, maybe good for track. I ran the 25.5 10 15's on the rear. They were really small visually(Short in height). Width wise, ok. Hope this helps. My gallery should have some photos

[Buddy Rawls]

FIA cars used 6.5 and 8.5 wheels, with 6.70x15 and 8.20x15 speedway special tires. when I research those sizes for old racing tires, they come out narrower than 235-60 and 295-50 typical go-to sizing. They came out closer to a 215-70 and 255-60. I know the 6.00x15 and 7.00x15 GY Vintage Sports Car tires shows much wider, but there is no way those could fit properly on a 6.5/8.5 set-up. they do fit well on the 7.5/9.5 set-up. what's the real story? does anyone have a early 60's race tire catalog?

Is 6.70 designation the tread width? meaning sidewall is around 8.5-9 in wide bias designs. perfect for 6.5 wheel.
Likewise the 8.20 tread would have a sidewall around 10-11 in wide, again perfect for a 8.5 wheel.

Just throwing it out there for continued discussion.

[mrmustang]

Originally Posted by Buddy Rawls

FIA cars used 6.5 and 8.5 wheels, with 6.70x15 and 8.20x15 speedway special tires. when I research those sizes for old racing tires, they come out narrower than 235-60 and 295-50 typical go-to sizing. They came out closer to a 215-70 and 255-60. I know the 6.00x15 and 7.00x15 GY Vintage Sports Car tires shows much wider, but there is no way those could fit properly on a 6.5/8.5 set-up. they do fit well on the 7.5/9.5 set-up. what's the real story? does anyone have a early 60's race tire catalog?

Is 6.70 designation the tread width? meaning sidewall is around 8.5-9 in wide bias designs. perfect for 6.5 wheel.
Likewise the 8.20 tread would have a sidewall around 10-11 in wide, again perfect for a 8.5 wheel.

Just throwing it out there for continued discussion.

Buddy,

As a new user here on Club Cobra, perhaps you missed the last posting date on this now, resurrected from the archives thread: 12-29-2016

Unlike other forums, sometimes it's best to start a new thread as the people you are responding to may no longer be on the forum, or even worse, deceased.

Enjoy your FIA, I know I do with mine

Bill S.

[peterpjb]

Bill, what is the meaning of the rotating star in your profile?

[1985 CCX]

Means we financially $ support this website.