Hi all, I have been around for a while but now I am building a car( 1969 GS 400 Stage 1) that I would like to race in the Pure Stock class. My question is what kind of tire can I use for it? Can I use 14 or 15 inch wheels, radial or bias tires? I would love to run redlines. Thanks David
The easiest way to answer that is, you can run what was on the car. If 14's were available, you run 14's. If 15's were available, you can run 15's. Radial or bias ply, but it has to be the same size as stock. This past year, I had been running a 'Pure Stock Tire Buy' trough Kelsey tires. FYI, big suprise, tire prices are going up next year!ou:
Thanks Rusty, are you saying that if the car came with 14's I MUST run 14's? Only 14's came on the car. David
You must run a 14" tire if that is what came on your car. You must run the stock size or 1 size larger. ex...stock F70x14 you can move to a G70x14. Jim:TU:
Even if your car came with 14 inch, I would think if 15 inch was available on a car like yours that year (69), it would be OK. Right? So a 68 Hurst must have 14's and a 69 Hurst can have 15's? 15 inch wheels were optional on 68's and many other cars. Bet they were on a 69 Buick, too. I think there's a big difference in what could come on a particular car and what actually did. o No: o No:
I don't think that you could get 15's on the 69 Skylark, but I am not sure. Here is how the rule reads: "Wheels must be Factory correct*, including correct* diameter, width and offset. All 4 wheels and tires must be same size. Original equipment reproduction bias-ply tires and radials allowed, no soft compound tires of any kind are allowed. Retread tires are not allowed. If the correct* tire for your car was originally a 60 series, you may run a maximum tire size of G-60 or the equivalent size radial, all other cars may run a maximum tire size of G-70 or the equivalent size radial. I guess the question is if the car came with a 70 series tire can i run a bigger 70series? Coker lists the car came with 775-14, 825-14 or G78-14 and the radial = 205-75-14 What I want to run is a 225-70-14 redline radial. Thanks, David
Don't get too caught up in getting big rim and tire sizes. Remember as an example that Copo Pete ran 11.70's on F-70 14. I swapped from the 8.00-14's to G-70 15's and saw .05 better ET.ou: That falls within run to run variation.:3gears: :laugh: Ran those tires for economic reasons but they added 40lbs.
Good point, Brian. I just compared the G70x14 on my W31 to the F70x15 on my 66. The G70 has to be 1 to 1 1/2 inches wider, same diameter. F70x15's cost me $180 for the set (ebay take offs from a restored Corvette) , new G70x14 are about $600. They stay.
David Buick only offered 14" rims and tires in 1969,not until 1970 did Buick offer optional 15" rims and G60 15 RWL polyglas Run some G70 14 Redlines they will look and perform great.
Thanks guys ! that's what i will do:TU: I will press my luck and ask which hook up better the bias ply or the radial ? David R
Do a hard burnout with a radial, then do a hard burnout with either brand of available bias ply's, then study the marks they leave. The radial will leave several streaks due to the large water channels in the tread pattern, where the marks from a bias tire will be almost solid. There is alot more rubber meeting the pavement with a bias ply vs. a similiar sized radial. Most of the quickest cars are running bias ply's, but I know of a few who hook pretty good with certain brands of radials. If your intent on running radials, shop around and compare tread pattern, and try to find a tire with small water channels or staggered tread to create as much contact patch as possible.
I don't know where you guys are getting the one upgrade in tire size rule from. This quoted rule here is from the F.A.S.T. F/S rules which is NOT PSMCDR rules. You guys are mixing different sanctioning bodies' rulebooks. That ^^^^^^^^ is from the F.A.S.T. rule book Here is the Tire ruling from the PSMCDR web site: Tires & Wheels: Reproduction tires or radial tires only. No soft compound tires of any kind allowed. Retread tires are not allowed. Use of traction compounds or rubber-softening chemicals on tires are strictly prohibited. Tire size must approximate what was originally installed on the car. All four tires must be the same size. No 60-series tires will be allowed unless they were originally available for the car's year and model. 60-series tires must be run on 15-inch rims as they were originally. Cars built before the introduction of 70-series Polyglas or Wide-Ovals are allowed to upgrade to 70-series tires of appropriate size for the car. Please call for clarification. Suspicious tires will be durometered. Factory wheels only. Wheels must be correct in size, offset, and style for the car's make, model, and year. All four wheels must be the same size and offset. The only upgrade allowed under PSMCDR rules is to move up to a 70 series tire which opens the door for the Studebakers, Brian's Mercuries, and Paul Richard's Corvette, and any other OE skinny tire car. There is nothing that allows for an across the board "one tire size" upgrade in the PSMCDR rules. In the F.A.S.T. rules, yes, but again, NOT in the PSMCDR rules. To get the radial equivalent, or for any other rule clarification, it is always best to contact Dan Jensen or Bob Boden for the "last word".
I must be loosing my mind? I thought that it was in the rules. I know that some of the organizers cars are running a 1 size larger tires. I know I didn't get it from the FAST guys because I have not considered that racing. Jimou:
Clarification......Jim considers F.A.S.T. as legitimate racing.....he has not considered participating though. :laugh: :laugh:
I may be mistaken, but I thought that therewas a disc brake option offered starting in '68 that also required an upgrade to 15" wheels. Might just be the meanderings of an old mind -
Bultaco Sweatshirts are illegal too, even in the original size. You must wear only factory approved sweatshirts in the car's original colors. British Motorcycle Shirts are, of course, approved in larger sizes. Japanese shirts are not allowed.:moonu:
