13" DOT Competition tire availablity?

[510rcr]

Looking for DOT competition tires for my ex IT race car for track days. I still have steel fenders w/ 3 sets of 13 x 6" rims. Depending on which rims, I can either use 185/60-13 or 205/60-13. The Hoosier RS303's do not work with the cantaliever'd sidewalls in my wheel wells. What is the best bang for the buck and where can they be bought?

Thx,

[Dave Patten]

Matt,
Have you looked into a Hoosier bias ply? The 185 & 205/60-13 Street TD’s are still listed as DOT tires. They should have less sidewall cantilever because they are bias ply.

You can expect more slip angle from a bias ply tire. Your set-up (and driving style) will likely need some adjusting if you’ve been using radials. From my experience using DOT bias ply tires on my ITC 510, you will likely want more oversteer dialed into the suspension set-up. Understeer cannot be “driven around” as easily as you can when racing on radials.

The smaller DOT competition tires are getting harder and harder to find. Most all the 13” are now wider than 205 with 45-50 profiles (or like Hoosiers, just plain physically wider than the nominal sizing would indicate).

Maybe Dunlop or Avon has a tire that would work.

[defdes]

You could also try the Toyo RA1 Proxes they come in a 205/60/13 and are run by most of the 2002 and 510 racer in my group as they have lot's of heat cycles per dollar.

[Dave Patten]

Toyo Proxes RA1 & R888 are availabe in both 185 & 205/60-13 sizes.

http://toyotires.com/tire/pattern/proxes-r888

http://toyotires.com/tire/pattern/proxes-ra1

Looks like the RA1 get the nod from most competitors as being a better performer. I checked with VRG (a NE based vintage group) and Hoosier radial DOT tires are not allowed. It appears that most of the DOT competiton tires that are hot with SCCA road racing are not allowed by the group (or SVRA, who they base their tire rules on). The best definition I could understand is if the tread is molded at 4/32 and has what amounts to a couple grooves around the tire they don't allow them. If they have a full looking tread pattern (even if only 4/32") or they are bias ply they don't have any issues.

Here are the 2010 tire rules for SVRA's Group 3 Cars:

4. Approved tires:
Avon: 5.0/22-13 & 6.5/23-13, ACB9 only (ACB10 not permitted)
BFG: G-Force Sport; 205/60R15, 225/60R-15
Dunlop: any L-series; up to 5.50M-13, 14, 15; 135/545-13 & 165/580-13 Formula Ford (9092)
Goodyear: Vintage Blue streak up to 5.50-13, 14, 15
Hoosier: A70-13, B60-13, P205/60D-13, 14 Street TD, up to 5.50-15 Vintage TD, 185/65-15 & 205/60-15 Speedster
Kumho: V700; 205/60VR13, 185/60, 195/60, 195/55, 205/55-VR14
Yokohama: A008R or A032; 175/60-13, 185/60-13, 205/60-13, 175/60-14, 185/60-14, 195/60-14 & 185/70-15
Toyo Proxes RA1, R888: 185/60-13, 205/60-13, 195/55-14, 205/55-14

Certain unlisted DOT street tires MAY be allowed on a case by case basis. All exceptions must be pre-approved, noted in log book, and will only be considered in special cases. Minimum marked aspect ratio of 60 except as listed above, tread pattern must be symmetrical and have at least 2/32" remaining at all times. For details see appropriate Supplemental Regulations or contact SVRA Technical Director.

5. Specifically prohibited: Slicks or any of the following tires: Goodyear GS/CS, Hoosier DOT Radial, Kumho V710 or any other "cheater" or slick type DOT tire.

[510rcr]

Thanks for the feedback guys, I kind of fell off the planet for a while. I am going to flare my car so I can fit tires. I have been spoiled for a long time as until Spec racer ford changed their tires a few years ago from the Yokohama's, I was getting free front takeoffs (which amounted historically to about 10 - 12 sets of tires for me). So Dave, the Hoosier Bias Plys, I did not see them on your list, so are they Vintage legal?

Thanks, Matt

[dimeracer]

If you roll the fender lips and run 1/2" spacers on the front (you will need longer wheel studs) the 205/60/13 size Hoosier R6 (latest version of what was the RS303) will fit... in case you don't want to do full flares. I've been running them for years in my stock-fendered 510.

[Dave Patten]

Matt,
I believe the Hoosier "SPORTS CAR D.O.T. - BIAS" (Street TD) is what they allow. Like most sanctioning bodies they tend not to update rules to match manufacturer changes until a huge discrepancy exists.

Here is a link to the Hoosier DOT bias ply road race tires.

http://www.hoosiertire.com/specrr.htm#S ... DOT%20BIAS

[510rcr]

Thanks for the link Dave, I may try a set sometime as Ive been wanting to run with Steve's new B Sedan group http://www.transam-bsedan.com/. I was planning to go but ended up getting a divorse instead. I have ran the Toyos a couple times but never the 205's just the 185's. Racing the 185's would get pretty greasy about 2/3rds into a race (and I had them shaved to 4/32nds) but I always tried to keep my best tires on my lighter rims which are wider offset; the 185 Toyos (and 1st gen Hoosiers) would always have light rub marks on the outside of the rears & I figured the 205's would not work. I tried to find my paperwork to see what the offset of my Panasport ultra lites is, too long ago - but they are set out wider than the other 2 sets of rims I have (believe to be enkies?) - all are 6" IT legal. The other rims are only about 2 lbs heavier but I'm a "light" nut - heck, I have an old baby scale and I weighed about every part I put on my car and used the lightest of what I had. You can take 4 of everything and one will always be lighter.

My rear fenders have been rolled for years and I have even "massaged" them wider with various, incresaing sizes of pipe rolling them & the car forward & aft. Last couple years, post SCCA budgeting, I have the car cranked lower than IT specs as I have been working towards vintage prep. Being lower, it gets me into the double wall inside the rear fender and up about 1.5+" if I have the rear camber where I have felt it best to be at. Does anyone do anything to that upper inner lip - like cut it out? Today, I have to run more negative camber in the rear than I like to keep from rubbing the outside top of the rears on that upper inner lip. 1.25 degree neg always had the most even tire temps (within 10 degrees) inside, middle to outside. Today I am at close to 3 deg neg in the rear which I feel is too much but I figure it best to be lower to minimize the undercarriage wind turbulence drag. Obviously if I flared my car that upper inner lip would be removed. I'm just at a perplexed Y in the road type mental state as I want to flare & lighten my car up (with a GT3 type LB 20, fiberglass everything and Lexan windows - as at these driving schools I instruct at they all have these ultra high HP Beemers & Audis. I can keep up, and pass, as I corner so much faster but when they waive me by they almost have to ride their brakes :>). I'd like to blow by them on the straights as I could in the corners if they would allow it. So far, I just can't bring myself to cut my pretty car........ I have a couple spare bodies but they are rough & not sure what, if anything would be left after media blasting - then the adverture in spending rears it's ugly head again.

Some day I'll give you a call Dave and see if you have room in your prices for a "package" fiberglass body upgrade. But there in lies the problem as my wife recently did an unexpected "dash with the cash" with a bunch of money we borrowed for me to do a loads of home remodeling (New roof, siding and decks). It really sucks to have to borrow the same money twice; but on the bright side no one is around anymore to quell my passions in motorsports. My dreams are bigger than my budget these days but in time, that will turn around. Anyone out there have a late FIA head and intake for sale? If so, call me as I need one to put on a LB20 core I have which I can build. Matt - 785-213-1325.

Love the Realm - Knowledge in Kansas is rare, thanks to all who contribute.