Metco Motorsports, the new owners of Todd Miller's silver car, are planning some upgrades to the car that will necessitate a bit more rear tire. They intend the replace the 15x8" Weld Aluma Star with a 15x10", and need info on the biggest rear tire that will fit within the stock wheel wells without modification. Does anyone have details on a proven combination that provides maximum footprint without interference? What backspace works best - 5''? Thanks very much for any help, Rick :beer
Might want to PM Phil (70GSCONVERT) on the board here. He's the most knowledgable one on here with lots of experience with wheel & tire combo's. For what it's worth, I can fit an 11.5 x 27" Hoosier QT Pro on a 15 x 8 rim, 4.5" backspacing on my 71 with no problems. Jim
I run 295/50/15's on a set of steel wheels 95 inch backspacing)with dog dish hubcaps. I have about a finger width between the side wall and 1/4. I also have plenty on the inside. You have to pay attention to the rim and lower shock eye. I have enough room,but can't remove the shock without removing the wheels. Phil runs 315's I believe,but there is some sacrifices. I think he trimmed a little in the lip area an has to run airbags too.
Hello. I currently run 325/50R15's on the back of my car on 15x10 wheels with 5-5/8" backspacing. For my car that backspacing is what centered them in the wheel wells. I have seen it not work on other cars. These cars were not built to exacting specs back then and vary as much as 1/4". That said, I did have to trim back the upper part of the wheel well lip. You cannot see it when you're looking at the car because it's just the top of the lip. I really didn't have to come down the sides at all. I cut back right up to the pinch welds that tack together the inner and outer rear fender. I did this to avoid any chance of rubbing. You could also roll the fender well lip back. I've seen that tool at Eastwood that does it. Then there is always the "GitErDone" baseball bat method. It is tight back there and this is the absolute biggest tire that will fit without starting to hack into stuff. I have about the width of my index finger between the tire and the frame on the inside. Also, I do run air bags to keep the back from bouncing much on the street. Seven or eight pounds is all it takes. This is because the inner fender is curved and the tire will rub up in there on a big "whoopteedoo" on the road or going over a speed bump and the like. The largest you will fit with no mods/trimming at all is the 295/50R15 and that should be on a 5" backspace to center it in the wheel well.....in theory that is. The best thing to do is put the biggest tire you can in there that you have and take some mesurements and see how much room you have to the wheel well lip and the frame rail on the inside. Then just start adding until you get to within 1/2" or so and that should do it. Here are the specs on my tire: Tire Compound: R2 Tire Overall Diameter: 27.9'' Average Roll Out/ Circumference: 88'' Tire Tread Width: 11.0'' Tire Section Width: 13.0'' Wheel Diameter: 15'' Spec Wheel Width: 10'' Tire Weight: 36.0 lbs Size Equivalent: 28'' x 13.50'' - 15'' Section width is the big number along with the diameter.
if you fold or grind the wheel well lip and massage front and rear of inner wheel well you will squeeze 305 60 15 american racer tires, soft compound and wrinklers on a 15 by 10 w 5.5 backspace. you will need stiff rear springs so it doesn't lean in corners and scatch inner tire. I did it and will be on second set of tires next year as I wore them out. 1.60 sixty footers drivng to and fro9m the track. only differece is I did it on 70 chevelle.
The tire listed above is just over 1.5" taller than mine. I'd imagine you'd really have to firm up the back and keep it from bouncing to avoid rubbing the inner fenderwell.
I have had 305-50-15's and N-50-15's on 10" wheels with 5.5 backspace. The N-50's were the tightest but still fit. I have 17x11's with 6" backspace and a 315-35-17 tire on another car which fit the 305's and N-50's exactly the same so I know they will fit the 70 Buick as well.
Here's the pic of my car with the tires on it. These are the BFG's 325/50R15 before I got the M/T's which are actually just a tad wider:
I missed this vital piece of info in the first post... They intend the replace the 15x8" Weld Aluma Star with a 15x10", and need info on the biggest rear tire that will fit within the stock wheel wells without modification. So,the only options they seem to have with the Alumastar wheels are 3,4,5,6 inch back spacing. This will determine alot with the tire sizes.
I INSTALLED 295/60-15 HOOSIERS. 29.0 TALL x 10.0 THREAD, 12.6 SECTION WIDTH. ON 15X10 DRAGLITES, WITH SLIGHT TRIMMING OF WHEEL WELL. p
Thanks for the Replies! There is some great information in this thread...and some great pics. Thanks very much! Assuming the fender lip will not be trimmed, can a 28x12.5" ET Street be squeezed under the fender without issues? Is a 29" tire just too tall? Is 5" of backspace the best choice for the 10" wheel? Thanks again, Rick
HAD 295/50-15 HOOSIERS ON, 27.0 INCHES TALL, LOOKED FUNNY ON CAR. 29.0 TALL TIRES WORK FOR ME. HAVE 3.73 IN REAR. :grin:
I was on BFGoodrich's website and couldn't find the 325/50/15. Is this something an authorized dealer can get? Is it a special order? Oh, and what wheels are you using? Your car setup is awesome.
Re: Thanks for the Replies! A 28x12.5 ET Street will be hit or miss on the outer lip. I ran that exact combo(10inch Weld w/5inch backspace) on my 70 Stage car for years. Had about 9/16 inch clearance to the lip. BUT, I had already removed about 3/8 of an inch of the lip to clear the M&H 325-50-15 stickies that I used to run. They were a bit fatter in the sidewall because of a 1 inch wider tread width than the 12.5 ET street. If you are looking for footprint and want treadwidth a Hoosier Quicktime Pro has a narrower sidewall width for a given size than an ET Street. We used Hoosiers on my little brothers 3rd gen Camaro in 29x11.5x15 and it took a bit different suspension and air pressure settings than the ET's but once we figured them out they hooked very well. I think the Hoosiers are a bit underrated or overlooked because of the bad rep from their lessser sportsman line. If you worry about fitment and just can't pull the trigger check out Hoosiers specs. They should have one that'll give you the room you need. BTW: Gotta be very careful in any kind of wet weather with the Hoosiers. Even less "tread" grooves than an ET Street. Hope this info has helped. BTW:
