• Welcome to the CaliforniaSpecial.com forums! - You are currently viewing the forums as a GUEST. To take advantage of all our site features, please take a moment to join our community! It's fast, simple and absolutely free.

    If you have problems registering or can't log into your account, please contact Admin.

    Please Note: If you are an existing member and your password no longer works, click here to reset it.

. Help, backspacing question

TexAg

Well-known member
Joined
Aug 26, 2012
Messages
112
Location
Austin, TX
First, i’ve done my research, but I still don’t have enough experience to answer my question. Second this isn’t another what size/type wheel tire question.

The issue: My ‘67 has the Shelby A-arm modification and 620 lb 1” drop springs. I’m currently running a 225/50r16 on a 16x8 wheel. I love the way it looks, but I have trouble with the passenger front rubbing the fender under load. This isn’t a rub when the wheels at full turn, or going over a bump. This occurs when hitting a dip at speed causing the suspension to fully load, resulting in repeated fender damage. :eek:

Question: My wheels have a 4” bs. I’ve read that my 225/50r16 would work fine on a Crager or similar wheel with 4.25” bs, so I assume the issue is the .25” in bs. I don’t want to alter the stance (if possible) or drop the coin on a new set of wheels, if I reduce the tire width by .5” and maybe the diameter by .5” to a 215/50r16 would that be enough to make up for the missing .25” bs? I also am not really interested in a big rake, or looking like a funny car..

If this works, it seems like the simplest and cheapest way to fix the rub. Thoughts? Tire/wheel experts?

In the jeep world, I would increase the bumpstop size to reduce the suspension travel, but not sure how to do that on the mustangs
 

robert campbell

Well-known member
Joined
Apr 10, 2007
Messages
4,321
Looking at the 215 vice the 225 50 R 16 shows that it reduces the section width from 9.20 to 8.50. Basically almost 3/4 inch. this would bring the tire in nearly 3/8 of an inch on inside and the outside.

Looks like a good try to reduce your tire rub. I HATE tire rub!

Rob

https://www.summitracing.com/parts/bfg-03450/overview/

https://www.summitracing.com/parts/dlp-265029804/overview/

Or go to a 215 55R 16. huge selection and similar height just a bit taller.

https://www.summitracing.com/parts/bfg-35466/overview/
 
OP
OP
TexAg

TexAg

Well-known member
Joined
Aug 26, 2012
Messages
112
Location
Austin, TX
Update. I started to run into a problem with the narrower tires not being recommended on an 8" wheel, which might mean that I would have to go ahead and get new wheels anyway to achieve the needed clearance. I know some places won't pay attention to the manufacturer recommendations, but I do think that an 8" wide tire on an 8" wide wheel would start to look a little flat. Also, I'm not entirely convinced that even with reducing the width of the tire that the backspacing and offset won't still cause me a problem. I'm guessing that I would need to move the outer edge of the tire in about 1" to be completely safe.

Then, I found that Global West makes spring spacers for the mustang coil spring. Theoretically, I can raise the front end 1"-1 1/2". Maybe that will be enough without changing the stance too much.

I think I'm going to try this first. If it doesn't work, or if I don't like the look, I've only spent $40 instead of $300 for new tires, and maybe another $600 for two new front wheels.

It's always something....:punch:
 

robert campbell

Well-known member
Joined
Apr 10, 2007
Messages
4,321
Narrower tires on a rim is not a big thing next to a wide tire on to narrow rim. Especially on front tires. Do not worry, they will be just fine. Spring spacers or "knuckles" to raise a front end are such a band aid. Do not got that direction.

rob
 
Top