Help with tire/wheel combo!

[dailycutlass]

Like many members I’m also getting myself some new wheels and tires for my 1978 Cutlass Calais.
It runs now on original 14” Rally wheels, and I want to keep that late 70’s look,
so its going to be chrome and 15” raised white letter rubbers.

Because there aren’t many Wheelshops around over here (Holland), I will order the parts online
so I just want to make sure ordering the right parts.

It’s for a 1978 Cutlass Calais 305

The look I’m looking for is the widest tire/wheel combo, without rubbing or tires sticking out.
But just the more “meaty” look without looking it like a skateboard.

For example, a wheel like this: http://www.uswheel.com/wheel.cfm?category=65

Which 15” wheels do I need, (all the backspace and offset stuff)
and the tires to go along with it?

Thanks 😀

 

[khan0165]

it depends on what you think "looks meaty".
I think almost any tire wider than 235/60 can look meaty on the right wheel.

an 15x8 is ideal for tires up to 275/60

small backspacing is key for avoiding rubbing issues... I would stick to 4" backspacing to stay safe. You can try upto 4.5 backspacing, but no guarantees.

many say a 275/60 tire is as large as you can go... But seeing as you are overseas and need a guaranteed fit, I would recommend going to a 255/60 tire instead. Visually, it would be a minor difference

you can safely go anything from a 215/65 to 235/60 tire in front... 245/60 could also work, but might be tight

... these are all conservative numbers in my opinion

on my 83 Grand Prix, I am using 15x7 wheels on front, 15x8 wheels on back
235/60 tire in front, 275/60 tire in back

but because my rear frame has been replaced, the dimensions are not 100% correct, and the 275/60 tire rubs

 

[dailycutlass]

You said 275/60/15 rear tires are rubbing a bit, how about a size smaller, 255/60/15 in the back?

So: 235/60/15 in the front?
and 255/60/15 in de back.
Is this combination better, so without hitting the tires against the fenders?


So with this combo I'm safe 7x15 front. 8x15 back?
That backspace thing ,4" is the same for the front AND rear wheels?

As you can see there is some room left in the back.

thx

 

[khan0165]

on these cars, the fenders are less to worry about... it's usually the frame rail on the inside of the rear wheel wells that the tires/wheels start to rub on.

a 275/60 could work, but it also could rub... I could not guarantee a good fit.

so yeah, in my opinion, it would be safer to run a 255/60 on the back... and it would not look much different from a 275/60
here is a Cutlass with 255/60s on the back, and 235/60s on the front

if you're looking for a staggered look (big tire on back, little tire on front), you can also go as small as 215/65 on the front

And if you're looking to save a little cash... a 255/60 could be used on a 15x7 rim... so you can order 15x7s for all four wheels, and use a tire anywhere from 215/65 to 255/60
And yes, 4" backspacing for Front AND Back




also for reference... here is a 275/60 that I use on my GP
as you can see, it is very close to the fender lip, and it sometimes hits when I go over a big bump

and on the inside, it is very close to the frame rail, and I have to use a small spacer

this tightness might be because my rear frame rails have been replaced and could be slightly out of geometry... And it *COULD* be a better fit for you car... but with big tires, you never know unless you try.

 

[dailycutlass]

Thanks Kahn for all your advice and tips!
I keep you guys posted with the final result!
😀