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275's all around on a B-body ?

Posted By: AlexP

275's all around on a B-body ? - 06/27/08 04:43 AM

I need some outside the box type thinking right now.

I want to put the same size tires all around on my Roadrunner. I've seen Todd (blackwidow69) manage to squeeze 275's in on the front of his 69 Roadrunner.



With 255's on 15x7 steelies (4 inch backspacing, right ?) I have rubbing at the rear of the front frame rail. In it's defense, that wheel is not the right size for even a 255 and the sidewall bulge is significant. With the right backspacing and right width wheel, I don't think I will have the same issue even with a 275 on a 9.5" wheel.

What backspacing would you use to get a 9.5" wheel onto the front of a 68 B-body ?
Posted By: polaraholic

Re: 275's all around on a B-body ? - 06/27/08 07:31 AM

Sorry I can't anawer that but is that sway bar in the pic hooked up right? Looks like it is upside down.
Posted By: autoxcuda

Re: 275's all around on a B-body ? - 06/27/08 07:50 AM

Quote:

I need some outside the box type thinking right now.

I want to put the same size tires all around on my Roadrunner. I've seen Todd (blackwidow69) manage to squeeze 275's in on the front of his 69 Roadrunner.



With 255's on 15x7 steelies (4 inch backspacing, right ?) I have rubbing at the rear of the front frame rail. In it's defense, that wheel is not the right size for even a 255 and the sidewall bulge is significant. With the right backspacing and right width wheel, I don't think I will have the same issue even with a 275 on a 9.5" wheel.

What backspacing would you use to get a 9.5" wheel onto the front of a 68 B-body ?



What diameter rims are you looking at?

What is Todd's combo? Just copy it.

If 17" I'd go 5.25 on a 9.5 width rim with a 275/40/17 tire. That will probably rub the inner fender at max turning, but won't rub the outside. You might be able to run a little less backspacing on a B-body. But you could always add a good .25" spacer.
Posted By: jcc

Re: 275's all around on a B-body ? - 06/27/08 09:49 AM

Quote:

Sorry I can't anawer that but is that sway bar in the pic hooked up right? Looks like it is upside down.



, but performance wise, it would not matter
Posted By: AlexP

Re: 275's all around on a B-body ? - 06/27/08 06:04 PM

The tech I spoke with took down my current numbers and suggested that I buy a 17x9.5" in a 5.5" backspacing, mount it up without tires and if it doesn't fit I can return it and try a different size.
Posted By: AlexP

Re: 275's all around on a B-body ? - 06/27/08 06:24 PM

Also, just for giggles...What backspacing would it take to get a 315 on the rear ? I won't modify, so if it physically fit I will just do 275 rears and call it a day.
Posted By: autoxcuda

Re: 275's all around on a B-body ? - 06/27/08 06:36 PM

Quote:

The tech I spoke with took down my current numbers and suggested that I buy a 17x9.5" in a 5.5" backspacing, mount it up without tires and if it doesn't fit I can return it and try a different size.



Do you have flat type upper ball joints or the domed type?
Posted By: 67Mopar

Re: 275's all around on a B-body ? - 06/27/08 06:59 PM

275-15 is the limit, may have to stiffen up the rear suspension if you are getting rubbing next stop tubs. I think there is room on the front, but have only tried with my old 67 plymouth I like the 4 all the same look as well and plan on doing that with my new toy Scamp
Posted By: AlexP

Re: 275's all around on a B-body ? - 06/27/08 07:12 PM

I have the flat topped Moog K772 joints in my tubular UCA's.
Posted By: Mr.Yuck

Re: 275's all around on a B-body ? - 06/27/08 07:40 PM

That would look silly. the car would look like a 4WD vehicle. And that sway bar is on upside down
Posted By: AlexP

Re: 275's all around on a B-body ? - 06/27/08 07:45 PM

Quote:

That would look silly. the car would look like a 4WD vehicle.



No, not really.
Posted By: Clair_Davis

Re: 275's all around on a B-body ? - 06/28/08 12:25 AM



With the right stance, it would look vintage nascar all day long. I'd rather see something like a 275/50-17 on all four, though, but I'm apparently funny that way...

Clair
Posted By: topside

Re: 275's all around on a B-body ? - 06/28/08 02:56 AM

Vintage NASCAR would be 10x15 wheels with about a 70-series profile tire with 10" of tread width.
As for the 17" setup, I can't help there, but I've seen a 305/50R15 tire in a stock-height '69 Roadrunner and it cleared fine. The rims appeared to be 9" or 10" wide; they looked wider than the 8x15s (& 295/50R15s) on my '68.

Attached picture 4516388-bluecar.jpg
Posted By: hulmule

Re: 275's all around on a B-body ? - 06/28/08 03:11 AM

I ran 275 60 15 on cop rims all the way around. looked like a old nascar or moon shine runner. I did notice that a little paint was rubbed of on the front frame rails. never heard it but it must have happen. If you want a picture send me a email address cause this site i cant seem to post any oictures . to big of a file. phil
Posted By: Anonymous

Re: 275's all around on a B-body ? - 06/28/08 03:34 AM

w/ some spacers and airshocks lol you can run these fatties in the rear. no wheel well modification. Special order Pirelli P-zero street tires.

I'm going to ditch these and go w/ magnum 500's though.

Attached picture 4516472-5077_12.jpg
Posted By: basketcase

Re: 275's all around on a B-body ? - 06/28/08 03:35 AM

Quote:

That would look silly. the car would look like a 4WD vehicle. And that sway bar is on upside down







Posted By: Anonymous

Re: 275's all around on a B-body ? - 06/28/08 06:42 AM

17"/9"/4.5 backspace 275/55/17in back and 245/45/17 up front with rear sway bar no rubbing at all but no room for bigger tire terry

Attached picture 4516654-rrpic021.jpg
Posted By: patrick

Re: 275's all around on a B-body ? - 06/28/08 01:25 PM

a board member had '01-04 mustang 17x8 rims on his '69 RR using 3/4" thick bolt on spacers (makes for 5" effective backspace) all the way around and 255/50R17 BF goodrich KDWS's and they fit fine. I have the same setup on my 5th ave
Posted By: Mr.Yuck

Re: 275's all around on a B-body ? - 06/28/08 02:40 PM

Posted By: Simonic

Re: 275's all around on a B-body ? - 06/29/08 07:57 AM

Quote:

Quote:

That would look silly. the car would look like a 4WD vehicle. And that sway bar is on upside down









Posted By: pro451bee

Re: 275's all around on a B-body ? - 06/29/08 05:26 PM

A 5 inch backside wheel should clear allaround with a 17x9.5 wheel 275 40 17 in front will work but will probablly track in road groves real bad . I think in 17 inch size , 17x8 in front with 245 45 17 and 285 40 17 in back on a 9.5 or 10 wide rim 4.5 back side all around . Also , on a large B boby a 26 inch tire is a bit short and a 285 40 18 inch size in back looks nicer at 27 inches tall . 5 inch back side is usually the most back side you can use without rubbing .

Attached picture 4518999-reartires.JPG
Posted By: autoxcuda

Re: 275's all around on a B-body ? - 07/01/08 04:14 AM

Quote:

A 5 inch backside wheel should clear allaround with a 17x9.5 wheel 275 40 17 in front will work but will probablly track in road groves real bad .



Why would it track bad? This A-body with 275/40/17's doesn't seem to track bad.





Quote:

I think in 17 inch size , 17x8 in front with 245 45 17 and 285 40 17 in back on a 9.5 or 10 wide rim 4.5 back side all around . Also , on a large B boby a 26 inch tire is a bit short and a 285 40 18 inch size in back looks nicer at 27 inches tall . 5 inch back side is usually the most back side you can use without rubbing .



When you lower the car down the smaller diameter tire doesn't show as much. But a 245/45/17 is about the same diameter as a 275/40/17. But one has more footprint and grip.
Posted By: pro451bee

Re: 275's all around on a B-body ? - 07/01/08 04:31 AM

Im sure the wide ones work great at the track , but hiway grooves are very anoying in my neck of the woods . Heck even new Vipers can drive you crazy around here .crazy:
Posted By: Clair_Davis

Re: 275's all around on a B-body ? - 07/01/08 01:41 PM

I think if you've got several degrees of +caster, bump steer is "fixed" (as good as it can get), and the scrub radius isn't zero OR some huge number, then tramlining or waller-fallerin' or whatever you want to call following the ruts in the road should be minimized. There's just going to be some that you can't get around when comparing the forces the road puts on a 205/70-14 vs. a 275/40-17.

Clair
Posted By: RV2

Re: 275's all around on a B-body ? - 07/03/08 10:54 PM

I cant get the pic any larger but maybee it gives you an idea, 275 60 15 on 15x8 all around.

Attached picture 4529148-70roadrunner.jpg
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