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Discussion Starter #1 (Edited)
I participated in a HPDE at Infineon Raceway today. I run 18x11 rear CCW road race wheels with 305/35/18 Toyo RA1's in the rear and when I took them off today I noticed that I had some pretty good size gouges on the inside of the tires right above the rim on both wheels. Goes the entire circle of the tires.

Now my car is lowered in the rear with only a -1.0 camber alignment. The rear leaf spring sits really close to the inside of the rear wheels and during hard cornering it starts to shread my rear tires. I have rubber on the ends of my leaf springs.

Has anyone had this issue? What would happen if I shaved a little off the end of my rear leaf spring? How much will it affect my spring rate? I am looking for some options. Thanks.

I also want to add that it takes really aggressive driving (on a track) to get the tires to rub. I run 315/30/18 BFG's full time and never had them rub and my Toyo's havn't rubbed until today. My car leans during turns and I am wondering if sway bars will help.
 

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Sounds like its time for some T-1 bars. :thumb: :z:
 

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georges03zo6 said:
I participated in a HPDE at Infineon Raceway today. I run 18x11 rear CCW road race wheels with 305/35/18 Toyo RA1's in the rear and when I took them off today I noticed that I had some pretty good size gouges on the inside of the tires right above the rim on both wheels. Goes the entire circle of the tires.

Now my car is lowered in the rear with only a -1.0 camber alignment. The rear leaf spring sits really close to the inside of the rear wheels and during hard cornering it starts to shread my rear tires. I have rubber on the ends of my leaf springs.

Has anyone had this issue? What would happen if I shaved a little off the end of my rear leaf spring? How much will it affect my spring rate? I am looking for some options. Thanks.

I also want to add that it takes really aggressive driving (on a track) to get the tires to rub. I run 315/30/18 BFG's full time and never had them rub and my Toyo's havn't rubbed until today. My car leans during turns and I am wondering if sway bars will help.

After I lowered my car, I had it aligned for aggressive handling and after 13k miles I noticed a similar problem with tire wear.

After 13k miles the inner edge of the rear tires (only) showed much more aggressive wear than the rest of the tire. I asked Subdriver for some suggestions and he gave me some alignment specs to correct it. So far the car ride has significantly improved but I haven't had the new tires on (Toyo RA1s) long enough to ascertain a wear pattern.
 

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This is a common problem with wide(r) rims that do not have the correct offset built in. Note the SCCA allows a +0.25" offset. I recommend this as it corrects the scrub radius back to zero on lowered cars, gives you a slightly wider track for better handling and allows the proper clearance.

Clearance problems with the rear spring perch bracket are common with higher aspect ratio tires and wider rims. On hard acceleration, compression or cornering they may contact the spring perch. The higher aspect tires have taller side walls and flex more. You will either see tire shavings and pieces of rubber or metal shavings on the track. Check the spring perch bracket and the rim, for wear and metal contact.

The first and easiest solution is to use a 1/8" to 1/4" hub centric spacer plate.

The more expensive solution is get the proper rims with the proper positive offset.

I also recommend proper racing tires such as Hoosier or Kuhmo DOT A's & R's and/or true R tires. These have shorter and stiffer side walls and proper racing contours in the side walls. I do not recommend HP street tires such as the Toyo or Nitto's for track use.
 

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I disagree about Toyo RA1's

Toyos are as proper R-compound tire as there is. Definitely comparable to Kuhmo's. Obviously Hoosiers are faster, but at the expense of longevity. Also Hoosiers "A" are not really road course tire.

As far as rubbing, I'm running the same exact rear sizes on my car but using stock rims. I have not noticed any rubbing, but I haven't checked all that carefully yet. My car is not lowered or altered in any way from stock other than tires & brake pads.

I'll check about rubbing if I notice any I'll post back here. For now I assume it doesn't rub.
 

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Toyo RA-1's are NOT a proper Race tire. They come from the factory with 8/32 tread which is too large. The factory recommends shaving them to 4/32 IF to be used on the track. Tehy have too much tread "squirm". They are barely adequate on the track. They can be used as an intermediate rain tire for a damp track. They do not have the performance of a true R tire and in fact are heavier and can not handle the heat as a race tire does.

They are a HP street tire with a near R compound. Granted they are used in SCCA WC but they are a limiting spec (IE "...you can use this but nothing better").

They ARE and excellent street tire...and should be used accordingly.
 

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Discussion Starter #8
Thanks for the replys. I use my Toyo's up front and BFG drag radials in the rear for everyday street driving (5,000 miles per year) and only use my rear Toyo's for HPDE's which I do maybe 5-6 times per year.

Thanks for the tip on Mallets shorter spring. I have heard about this and couldn't find who made it. I'll look into it. I'll probably cut some off the ends of my stock spring.
 

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DJWorm said:
Toyo RA-1's are NOT a proper Race tire. They come from the factory with 8/32 tread which is too large. The factory recommends shaving them to 4/32 IF to be used on the track. Tehy have too much tread "squirm". They are barely adequate on the track. They can be used as an intermediate rain tire for a damp track. They do not have the performance of a true R tire and in fact are heavier and can not handle the heat as a race tire does.

They are a HP street tire with a near R compound. Granted they are used in SCCA WC but they are a limiting spec (IE "...you can use this but nothing better").

They ARE and excellent street tire...and should be used accordingly.
So, you think that Victoracer is faster then RA1's? I beg to differ. They are very similar in performance, durability, and weight. To give you an idea of Toyo's performance I ran 1:33.00 at Gingerman on brand new full tread Toyos with a passenger. Ron Fellows ran 1:33.9 on F1's without passanger and likely on a warmer day (it was 40's when I ran). Toyo's have the performance of a true R-comp tire, I have tried them I'm on my 4th set. What makes you think otherwise? Surely it's not their molded tread depth.
 

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DJWorm said:
Toyo RA-1's are NOT a proper Race tire. They come from the factory with 8/32 tread which is too large. The factory recommends shaving them to 4/32 IF to be used on the track. Tehy have too much tread "squirm". They are barely adequate on the track. They can be used as an intermediate rain tire for a damp track. They do not have the performance of a true R tire and in fact are heavier and can not handle the heat as a race tire does.

They are a HP street tire with a near R compound. Granted they are used in SCCA WC but they are a limiting spec (IE "...you can use this but nothing better").

They ARE and excellent street tire...and should be used accordingly.
In all fairness, if the Toyos are good enough for the Speed WC cars at 600 HP and heavily modified brakes and suspension, shouldn't they be okay for a DE?
 

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Mafia said:
I have not noticed any rubbing...
My car is not lowered or altered in any way from stock other than tires & brake pads.
That's one big reason you're not getting rubbing and the other guys are (including the offset issue). I had spring rub too when my car was lowered. Set it back to the stock ride height and you won't have this problem and the car will handle better!
 

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I'm really not a fan of the Victorracers either. They were slower than V700's and Hoosier R3S03.

For the track I prefer, use and recommend Hoosier A or R3S05's, or Kuhmo 710's for DOT tires and Goodyear G-19 Sportscar Special for R tires.

For rain I like Gooodyear VRS "S" Compound F1 Rain, Hoosier Dirt Stockers or Goodyear, or Goodyear Sports car Special rains

Thats all I will use on a track.
 

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wtknght1 said:
That's one big reason you're not getting rubbing and the other guys are (including the offset issue). I had spring rub too when my car was lowered. Set it back to the stock ride height and you won't have this problem and the car will handle better!
I totally agree, when the suspension is at stock ride height the suspension geometry is correct. The only really correct way to lower it is with dropped spindles which is how all of the World Challenge Corvettes do it. I realize this is a very expensive option so if that is not an option raise the car back up and get the camber, toe and shock setup right.
 

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Discussion Starter #15
I have been told by more than 1 speed shop that it would be o.k. to shave the ends of my rear leaf spring. I wanted to shave off the metal clamp that is located on the end of the spring but not cut the actual spring itself. Basically grind the metal down just to the spring and then stop.

I am really happy with the way my car is now except for the tire rubbing issue. If I could get away doing this I would be very happy. I don't see how it could be dangerous but would like some feedback before I do something like this.
 
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