[Chevynut]

Guys, there has been a lot of talk about tire fitment, and one of the things that my spreadsheet doesn't address is tire clearance to the frame in front. The front of the car is the most troublesome, due to all the variables involved.

Could a few of you take a measurement across the INSIDE of your front tires, and then turn the wheels to full lock and measure the clearance of your tire to your frame? I would like to know what steering box you have as well as tire and wheel size.

I'm trying to come up with a good guideline for the minimum width of the front tires to prevent frame contact since that seems to be a common question. I'd do it on my car, but it has a C4 conversion and C4 rack and I have no issues with 245 tires . My stock 57 isn't readily accessible either.

Thanks!

 

[Ratpackin]

Hey Chevynut- thanks for collecting and providing all this great info for the members. :tu

 

[Had a few Tri 5's]

You might want to ask...

What brake kit they are running as well. Measuring the clearances without knowing if they have an increased width due to disc brake conversions will throw things outta whack. My 56 car vs my Nomad (both disc) vary an inch and a quarter from each other, and I don't remember what the stock width was. Also, the wheel offset is in play. One set I have is a 4" offset, the other is 4.5" offset.

Thanks for helping out on this. I have issues with trying to get a brake kit to work with a 7 inch wheel when lowering. I was thinking about narrowed A-Arms. Talk about throwing things out of whack. Anyone use narrowed arms around here and driven it for any distance. I am wondering if there are any different characteristics, good or bad.

MJ

 

[Rick_L]

Front mounting width 60.25" (+3/8" per side)
225/50/17 on 17"x7"x4.5"bs wheel
CPP500 box with stock pitman and centerlink.

The tires just touch the frame (behind the wheels) at full travel of the 500 box. The steering stops don't quite touch. Steering travel is slightly less than a stock box but I haven't measured it at the wheels.

 

[Chevynut]

What brake kit they are running as well. Measuring the clearances without knowing if they have an increased width due to disc brake conversions will throw things outta whack. My 56 car vs my Nomad (both disc) vary an inch and a quarter from each other, and I don't remember what the stock width was. Also, the wheel offset is in play. One set I have is a 4" offset, the other is 4.5" offset.

MJ

I was wondering if that really mattered, if I knew the inside width of the tires. I can calculate that if I have wheel offset, tire size, and mounting width. So I'm not sure any of that matters if I have the width across the inside of the front tires.

 

[Had a few Tri 5's]

Maybe I am missing what you are doing. I know I have the larger tires size on my Nomad vs my 56 H/T. I cannot however swap them because of the difference in the brake kits. My Nomad has wheels with 1/2 inch more B/S, and and less width to the disc brakes so a larger tire fits there. If I try to put the same tires/wheels on the car, they hit the fender without even turning.

If you ask someone what the width is between their tires, it will not hold true across the board because of the other differences. If you took my Nomad measurements for instance, and someone went to place the same combo on their car, but had a different brake setup, he would gain inner frame clearance, but lose outer fender clearance.

I am waiting for a nice kit like Wilwood etc to come up with a zero offset setup. So far all I have found is a GM type setup offered.

Anyone know different?

 

[Chevynut]

Maybe I am missing what you are doing. I know I have the larger tires size on my Nomad vs my 56 H/T. I cannot however swap them because of the difference in the brake kits. My Nomad has wheels with 1/2 inch more B/S, and and less width to the disc brakes so a larger tire fits there. If I try to put the same tires/wheels on the car, they hit the fender without even turning.

If you ask someone what the width is between their tires, it will not hold true across the board because of the other differences. If you took my Nomad measurements for instance, and someone went to place the same combo on their car, but had a different brake setup, he would gain inner frame clearance, but lose outer fender clearance.

What I'm trying to do is determine how narrow the tires can be on the inside and not hit the frame. I have somewhat empirically determined that about 67.5" is the maximum desired width of the outside of the tires to keep fron hitting the fenders with a car that's dropped a lot, like 3" from stock. That depends on year of car, actual drop, etc.

So I'd like a few of you guys to take measurements on your cars, or give me front end mounting width, and wheel size and backspacing, and tire size as well as clearance from tire to frame at full lock.

I don't believe brakes or anything else matters if I get a measurement across the inside of the tires, because the steering axis is still in the same place regardless.

Thanks!

 

[joeelutz]

The thing I've found on stock frames with wide wheels and aftermarket sway bars is the tires usually hit the sway bar and not the frame.

 

[Rick_L]

It happened for me, but I have a weird combo. I modified the sway bar by bending it a bit more. Probably a no-no, but we'll see. My tires hit the frame and the sway bar at pretty much the same time now.

The combo is +3/8" from stock each side on the wheel mounting surface, 225/50/17 tires on 17" x 7" rims w/ 4.50" backspace. Plus the comments I made in my original post.

I put a degree wheel on the box way back when, it's a little less than the stock manual box but not much. Not nearly what the goofed up shimmed 605 box I bought from McGaughy was.

 

[gregpharr]

I measured my 57 today.
inside tires (from widest point of section width to widest point) 49 3/16"
rear frame tire clearance 2 11/16" (@full lock)
front of frame 2 1/2" (@ full Lock)
mounting surface to mounting surface 58 11/16"
cpp 500 steering box
Hellwig front stabilizer just clears on both sides
tires 225/60/15
wheels 15"X 7" w/ 4 1/2" backspacing

Hope this helps...

 

[Chevynut]

I measured my 57 today.
inside tires (from widest point of section width to widest point) 49 3/16"
rear frame tire clearance 2 11/16"
front of frame 2 1/2"
mounting surface to mounting surface 58 11/16"
cpp 500 steering box
Hellwig front stabilizer just clears on both sides
tires 225/60/15
wheels 15" w/ 4 1/2" backspacing

Hope this helps...

Thanks Greg. I assume your tire to frame measurements are at full lock? Is this with the new spindles that move your tires inboard? What's your wheel width, 7"?

 

[gregpharr]

Thanks Greg. I assume your tire to frame measurements are at full lock? Is this with the new spindles that move your tires inboard? What's your wheel width, 7"?

Right... 7" wheels, front and rear to frame measurements are at full lock.

Williams/TCI spindles, Heidt's Tubular A-arms (lower arms with bolt in ball joints)