My new new 15x10's are here!!! And now they fit!!! OK, I got another new 15x10's with 5-5/8" (now I can shim up to a 1/4" if I need to) backspacing from Specialty Wheel. While they wouldn't take the others back, they were VERY quick to make me another pair and get them out to me. But I did get the other set sold at a little bit of a loss. Oh well, live and learn. Anyway, I just thought I'd ask, does anyone want me to make measurements of one of the rims on the car before I put the tire on it so anyone can put a rim on their car to measure so as to determine what will exactly fit on their car? I'd just mount one tire and make all the measurements and then put the rim on and do the same. Let me know. I'll probably get the tires put on Monday and do all the measuring by Friday. Phil
Phil, I'd like to know for sure the exact backspacing required and IF a 10" wheel will clear on a stock '70 GS. I'm looking at Hoosier 27" x 11.5" (10" tread width) for race only and would prefer the 10" wide version. They recommend from 8-10" wheel but I have to think the 10" would work best if it will fit correctly. Isn't 4.75" the stock backspacing? Wouldn't that remain the same regardless of the wheel width? Forgive my ignorance.
holy backspacing WOW...I wanted to get a 6" backspacing for my AUTODRAGS but at the time they only offered 4 7/8. I did exact measureing with my 10X15 rim with 26.5 X 11 Quicktime pros on my ford/gm mount housing, and I believe I could have gone all the way with a 7" backspacing, fitting an even wider tire size in there. The key to my GS and being able to say I can have such a huge backspacing was the small tire diameter of 26.5 tire height. You couldnt even think about it with 29.5". And as some of the guys say, after the first 100 feet of track, those extra tall tires just become dead reciprocating weight anyway. I had to molest by inner wheel lip housing chrome trim, but you can't tell unless your look up at from inside the wheel well, which is impossible when the car is on the ground becuase the tire fills up the who damn thing. I used a sawzall to cut an inch or so off of the trim that was inside the wheel well, and then used a grinder to get it real smoth. The problem was before I did that, the chrome trim was digging into the sidewall of my tire when suspension flexed. Maybe I should get some pictures.
I already have the 325/50R15 DragRadials mounted on the 15x10's with 5" backspacing and they do fit under there with no modifications. It's just that I have 1-1/8" space on the inside and only 1/8" clearance on the outside by the fender well lip. That's why I'm going with the 5-5/8" backspacing. I should be able to get them dead-nuts centered. My tires have a 10.4" tread and a 12.9 section width and are 28" tall. I don't think you could get any taller of a tire in there with that kind of tire width. Like I said, I'll get them on this week and let everyone know and take some pics. Phil
Phil, I'm definately watching your progress, while I'll likely be going with 16 or 17" wheels, the backspacing, wheel width, section width and height of the tires will all be the same. Based on the measurements I've taken on my car 5 5/8" does seem to be the perfect center of the well, now its a matter of determining just how wide and how tall I can go. I'll be installing air bags to accomadate for load changes so I can push the envelope a bit. Good Luck
Phil-your perseverance is paying off.Thank you for keeping us so well informed of your progress.I want to go with the same rear tire size as you with the 10 inch wheel as well.Likely I could have used the 5 inch backspacing as I cut my rear wheel lip moldings to the "screw line"back a couple of years ago.With 275/60x15 I have approx. 1.6 to 1.7 inches clearance between the wheel lip and the tire(on factory 15 inch rims).I also use air bags as 28 inch tires will just rub the top of the wheel well on rather severe bumps.I was wondering what you have done re front wheels and tires.I think I will stick with 235/60x15 but on an 8 inch rim with 4 inch backspacing.Did you get your rims from Specialty Wheels or Stockton Wheels?I found Stockton on the web.Do you have any contact info for Specialty if that was your source? Our Buicks definitely need all the wheel and tire (rear) that will fit in there for the obvious traction reasons.Looks too are important with the rear end "bustle" these cars have.275s' look downright puny on the 70-72's where they look rather substantial on other vehicles.Again thanks for your efforts.Rod
My original post is in error. Wheels came from Specialty Wheel. Stockton didn't want to make them and Wheel vintiques said it could take weeks to months before they could make any as they had no good cores and WILL NOT use a customer's wheels as cores. Specialty wheel had the cores in stock and made mine and shipped them in about 3 days.......both timesou: I can't say enough good things about Specialty Wheel. My tires up front are factory 15x7 rims with 245/60R15 BF Goodrich radial t/a's. Front was lowered about 1" so top of tire is right at fender well lip. I had 275/60R15 Dragradials on, but got greedy for a bigger tire. I have a 1-1/4" sway bar on the front and the passenger side does just touch it and rub when fully turned to the left. Oh well, no real fast left handers. I never had a problem with the rear tires hitting the fender wells at all. The 275's were on 15x8 rims with 4-1/2" backspacing. Maybe I just didn't hit a big enough bump. I have brand new springs at all four corners and polygraphite bushings everywhere. One inch sway bar out back. I also am using Edlebrock IAS shocks all around, so that is probably helping in the bouncing department as they really keep the car flat in the curves. I've chased a few Mustangs and Camaros onto on-ramps and never did they pull away from me. I am also thinking about "trimming" my fender wells for added insurance. Maybe a 1/4" or so as I don't want to get too close to the screws holding the trim or the welds that hold the inner/outer fender together. They are tack welded, right? Anyway, I'll get to it probably Wednesday. Everyone keep their fingers crossed. Phil
Phil-Re the rear wheel wells:I had the body shop,in anticipation of my later grinding on the wheel lips, weld the inner and outer pieces close to the outside of the lips.To be honest I only once had the tires rub the top of the wheel wells and that was on a miserable secondary road which was a shortcut to a car show.I later installed air bags for traction reasons but find of course with 4 or 5 pounds of air in them they raise the rear to cover any road problems.I too find the Buick to handle flat through the turns with all poly bushings,good bars front and back,good shocks and in my case an AGR fast ratio steering box with their reduced assist pump.Do you have any contact info for Specialty Wheel?Thanks Rod
Here you go: Specialty Wheels Ltd.: http://yp.yahoo.com/py/ypResults.py...s&msa=6440&slt=45.523830&sln=-122.675346&cs=4 Don't have a specific person to talk to, they're all nice. Phil
wheels OK everybody, let me get in on this. I just got back Today from John Csordas shop upstate N.Y. I've been trying to get up there for 2 mos. but weather stopped me. After trying to fit 29" tires [Hoosier Quick Time Pro's] on Brand new centerline Auto Drag wheels with 4 7/8's backspacing it was a no-go we even trimmed the wheelwells and they still would not work without some serious rubbing! WRONG backspacing,I bought some new Warrior centerlines with 5" backspacing and new 28' tall Hoosier Quick Time Pro's. Both set's of wheels were 10" wide. Now they fit perfect there might even be room for a little more backspacing,maybe 1/4" before the inner side of the wheel gets close to the first obstruction[lower shock mount] all in all it is a perfect fit. I went from a 8" wide centerline auto drag with M&H's 275x60 to a 10" wide centerline Warrior [both liteweight aluminum] with Hoosier 28x11.5-15LT. I've always relied on M&H's.This is my first time trying a different tire.Keep in mind I run these on the street, I'm always trying to HOOK better. Time will tell, I can tell you the Hoosiers side by side with the M&H's although basicaly the same size are a 3/8" taller and laying on the side,are 1" wider,same tread width[10"]. I figure if nothing else,the 10" rim will give a bigger foot print and some more traction,which was the whole reason for this in the first place,I hope this helps some of you guys out. I know the frustration of buying the wrong parts I was lucky that Summit took it all back with no question asked,wheels that were mounted Hoosier tires that were removed of thier big white paint and lugnuts that were opened and used! I quess I lucked out on that one,but it did cost me $85 to send it all back,you gotta love that.:laugh:
Kenny, Let me see if I can get this straight..o No: I should be able to run a 10" wheel (Convo-Pro for instance) as long as the backspacing is 5"? I'll probably be using Hoosier QT Pro 27 x 11.5-15LT (27" OD and 10" tread) or MT ET Streets in 28 x 11.5-15 w/27.3" OD and 8.6" tread. I will not cut the wheelwell so want to get it right. Thanks.
My first set of 15x10's had 5" backspacing and it was NOT enough. I had to reorder a set with 5-5/8" backspacing to make it all work. I'll find out for sure this week. My tires have a 10.4" tread and 12.9" section width. Tires/wheels did fit under wheel well, but with only 1/8" clearance on the fender well lip. Who knows, maybe each car is a little differemt. Phil
Fitting wheels I think one thing that might make a difference is what type rear end is on the car. I've got a 10 bolt on my GS im told these might be different in length size,compared to a 12bolt. With Hoosiers Quick Time Pro's,28x11.5-15 on a 10" Centerline Warrior wheel,with 5" backspacing,when mounted section widrh is 12.5". When mounted on the car the closest interference is on the innerside of car by the bottom shock mount I'd say about 3/8 of an inch.Plenty of room on the outside fender lip HAS been cut and rolled due to earlier attempts to make a bigger tire fit. The cut and rolled lip is invisable to the eye unless you lay on your back on the ground and look up under the fender well. I'll be out today breking in these tires,I don't expect any problems I just hope thier stickie enough!!:Brow:
15x10's W/Pictures Ok, I got the new wheels and tires on today and took pictures. I'm still new at this so they might be a little blurry.Some pic's you can see the labels still on the tires;the first one shows the difference in a 275x15 radial compared to the new 28x11.5-15 Hoosier on a 10" rim
