275-60 vs 255-60 rear tires

[Kar]

Ok, I am stressing, I know which wheel style i'm going with ( AR Ansen Slots) for my 73 Mach, thanks to the way Totalled's car looks, I am planning on 15x7 245-60 front, and 15x8 275-60 rear. I am worried about the fit of the 275's, i do not want ANY rubbing, and I would like the rear to set down even with the top of the tires. My other choice is to run 255's in the rear, but really want the 275's. Can any of you guys post some ohots and experience with the 275's? Also should I go with the 7" or 8" in the front.

Thanks for all the help, I have been enjoying all the info you guys have to share.

 

[auron73mach1]

Here you go 45 mm of offset with the 05 mustang rims

 

[cazsper]

I actually just put new wheels and tires on my '73. It originally had 15x10's in the rear with 295's. They would have fit just right if the backspace was right. Unfortunately, they stuck out about 2 1/2 inches from the fender. My new wheels are 17x8 in the front with a 4.5" BS and 245/45-17. The rears are 17x9 with 5" BS and 275/40-17. They fit perfectly.


Sorry. I meant that to be two different pics..

 

[JimNiki]

no probs at all with the 275/60 rubbing. But you gotta be extra careful with backspacing. I've got discs on the rear so I had to get the offset adjusted on the 15x8 cragars on the rear. Made it by a few mm.

 

[nosdelacruz]

My 255 60's rubbed. I may have had saggy leafs though. I put adjustable shackles on and they now work and look fine.

 

[Kar]

This is what makes it so hard to be sure, and I like the comment i read that we get to try on shoes, why not tires. As much as we hate to say it, we could take 10 of these cars and set them side by side and start take messurments and we would end up with 10 different sets of measurments. One person will say a 15x8 wheel with 4.5" BS and a 245 does not rub on the front, and the next person will say that a 15x7 wheel with 4.25" BS and a 235 tire does rub. It will depend on ride height, soft or stiff springs, stock, repop, or aftermarket frontend components. I want the largest tires possible that will not rub with me and my three boys in the car, while we are doing 70 mph down the interstate and hit a dip, or turning hard into a driveway, and I want the car to set about even with the top of the tire. At this point i am leaning towards the American Racing Ansen Slots (mine is a 73, so these would look correct),15x7 - 4"BS and 245-60's front and 15x8 - 4.5"BS and 255-60's rear. I just really wanted those 275's (look at Totalled car).

 

[Totalled]

Well, now you had me thinking about it. As I said, my suspension is mashed out and original. The LR sits lower then the RR. It looks like the only place they rubbed, it on the driver's front. A small spacer might fix that, or running the 15x7 wheels.

I'm not sure I'd run the 255s on a 15x8, they might work better on a 15x7.

 

[Mister 4x4]

OK Totalled... what rims & tires are you running?

I'm planning 245/60-R15s on 15x7s up front, and 295/50-R15s on 15x10 or 275/60-R15s on 15x8s out back (depending on what fits better). I'm wanting the staggered look as well, and hoping to go fat in the rear. Either American Racing Torque Thrust IIs or Rocket Racing 'Fuel' rims, on BFGs (I may just say 'screw it' and get some Cragar S/Ss like Nance's car has). What can I say - I like the 'old school' look.

BTW - I got those tire sizes from the Mach 1 in my sig pic - I zoomed in the images of his wheels and found 255/50-R15s up front, and 295/50-R15s out back. Never did figure out the back spacing though.

 

[Totalled]

OK Totalled... what rims & tires are you running?

These: http://www.summitracing.com/parts/are-a695865

With: http://www.summitracing.com/parts/mtt-6027/overview/

and: http://www.summitracing.com/parts/mtt-6030/overview/

 

[mach71351c]

I ran 245/60/15s all the way around on 15/8s. The left front on a full turn would rub on one of the bolts that holds the steering box. I never felt it but the bolt head was shinny.

 

[Mister 4x4]

Very Nice! I've got more thinking to do - I don't know that 295s will be all THAT much better than 275s to justify any hassle that comes along. I also always liked Mickey T's, too...

Thanks for sharing! ::thumb::

 

[Kar]

Totalled, thanks for the photos, they help a lot. I think the 15x7 would fix the front end due to 4" back spacing vs 4.5" of the 15x8, even with the same 245. The rear has me more worried, it looks like the rear fender lips will rub if the back sets down a little more, and hit a dip road, or had kids in the back. I wish they made that wheel with 4.75" Back spacing, that would be perfect.

 

[Kar]

From everyones input, this is what I have come up with to install the biggest tire on the front and rear with out any modifications to the car (fender lips or rubbing). and not have the car set way up in the air, please correct anything that I state. All of this is based on using old school 15" wheels and tires, I have done 17" on my 68, but really want to keep the 73 period correct (not restored).

The best wheel size for the front:

Is a 15x7 with 4" back spacing (not 4.25" like most wheels come), the 4" back spacing should allow the use of 245/60's and not rub the steering box bolts during a hard turn or any contact with the upper A-arm.

The best wheel size for the rear:

Is a 15x8 with 4.75" back spacing (not 4.5" like most wheels come), the 4.75" back spacing should allow the use of 275/60's and not rub the outer fender lip with the rear setting down even, or a little over the tire.

Now for the hard part, finding old school 15" wheels that look right and meet these specifications. The only wheel i have come up with so far is the American Racing Salt Flat, which I do like, which is a bonus. Any opinions or thoughts?

http://www.summitracing.com/parts/are-470586547/overview/

I also think this wheel may look better with the black wall out vs raised white letters.

My other choice would be the American Racing Ansen Sprints, which come in a 15x7 w/4" BS, but the 15x8 has the 4.5"BS. These look great on Totalled's car, but the rears look close to the fender lip, and I want the rear to set a little lower, but the 275's and raised white letters look great on his car.

http://www.summitracing.com/parts/are-a695865/overview/

Always interested in others opinions and experiences.

 

[Jim and Jutta]

You've certianly done your research and I'm sure your end product will look awesome, looking forward to seeing it. If you're like me, even after you settle on tires and wheels there will come a time you see another car and say "damn" I wished I had done that.

Being the conservative I am, I went with the Magnum 500 wheels with TA's, 15X7's on front with 235/60's and 15X8's with 255/60's on rear, they look really good and of course no chance of rubbing, but when Totalled (Pat) parked his car next to mine, I had that V8 moment.

Jim

 

[Kar]

That is the exact set-up I had planned on until everyone had the 15x8 magnum's on back order, and while I have had some quality issues with the magnum's in the past, I thought this would be a good chance to try something different, and then I saw Pat's Mach and that sort of sealed the deal. The I thought why not try the 275's, and the snow ball took off from there. So now I don't know what I will end up with.

Your car looks great.

 

[Totalled]

Dooo it. Roll the fender lips.

Done.