Wheel sizing thread

[69_Mustang 26]

I was looking for some wheel sizing ideas, but can't seem to find much, other than this http://www.dodgestang.com/Tire%20Fit...de%2069-70.pdf

 

That's good and all, but what about the guys that want to run a LOT bigger up front? What's feasible? What needs work?

 

Rear isn't as hard, I'm reading, stock wise for a 69/70 Mustang, you can fit up to a 315 back there. Anything beyond that needs work.

 

What i'd like to know, is how big we can run up front. If I'm able to fit 315s in the back, I'm going to want to be able to fit at LEAST 275s up front... :D

 

Input?

[miketyler 15]

I fit 275/40-17 on my 70 and was close at full left and right. Am pretty sure I would have rubbing while driving. Car is factory disc car and wheel I believe was 17x8 w 4.5 bs.

[buening 63]

The biggest issue with wider wheels is the tire rubbing the front valance at full lock. Take your current tires on the car and turn the wheel full lock. Check the clearance and then compare dimensions of current tire to a section width you'd like to use. Also check clearance of inside of tire to the frame rail at full lock.

[69_Mustang 26]

I put spacers on the front wheels, so they are wide like if they were wide tires. Driver sises rubs a bit, that's even after I trimmed the valance on both sides. So really, another 1/8" off and im good with a 25.2" tire. Might trim even more just to make sure I do fit.

 

I think I want to run 275/35/18 front and 315/40/18 rear. The front would be a 25.6" tire and the rear a 27.9". Maybe a 285/35/18 up front, but that would push the tire size to 25.9 I believe.

Edited December 5, 2012 by 69_Mustang

[69gmachine 15]

If you want to run really wide wheels and tires, you need to replace the stock spindles. I'm using the Wilwood Prospindle which has a removable steering arm. It is .4 inches shorter than the stock spindle, has a 3/4" drop, and a 10 degree inclination angle vs. 8 for stock. This will allow a P275 on a 17x9" or a P295 on an 18x10" wheel to bolt on without spacers and tuck up under the fenderwell enough so that it doesn't interfere with the front valance.

 

Getting a tire this wide tucked under the fender will require that the outer shock tower be cut down for clearance, but that isn't terribly difficult to accomplish. With the shorter spindle height, relocating the upper arm is a must, but most people have already done the "Shelby drop" anyway. The alternative is to use a drop down upper arm, which I also have.

 

I designed the rear steer arm required to make this work as the arm it comes with is front steer only. My steering arm is also significantly shorter than stock, greatly decreasing the turn radius which is necessary when converting to a J-car based rack & pinion, but still beneficial with any steering set up.

 

For regular street driving, a P245 is plenty big enough, but I started autocrossing last year, and my observation was that tires are the most important ingredient to being competitive, much more so than horsepower. Almost everyone in the class I plan to run in next year was running P315 Hoosier A6s all around.

 

I can't afford to buy all new wheels and R compound race tires any time soon, so I plan to run 275 Toyo RA1s on 17x9s up front since I already have them and get new Hoosier 295s for my Enkei 17x9.5s out back. Eventually I plan to get 295 A6s for 18x10s up front and 315 A6s for some 18x11s out back. Just waiting to win the lottery.

 

If a collector car is a mony pit, a collector race car is a money canyon.

 

You can PM me for more information about suspension, steering and brake options if interested.

[69_Mustang 26]

Wow, that's a lot of good information! That's exactly the stuff I'm looking for.

 

Where would I get all the front end stuff that you're running? That Wilwood spindle and that rear steer arm? Also, do you have any pics of what you mean by cutting the outside shock tower?

 

What I have planned is that I'm just going to buy the Street or Track front end kit (new U/LCA, springs, sway, etc) and then also doing the shelby drop while I'm in there.

[69gmachine 15]

See page 5 of my Cardomain site in my sig below for pictures of the spindle and the outer shock tower I'm using. I had new ones fabricated, but you can modify yours for much less.

[69_Mustang 26]

What does that outer shock tower do? Could you just remove that?

[Endeavour32 10]

69 Mustang, do you have any other profile pictures of your car. I'm trying to decide on what to do for wheels on my car but I really don't know if if want to go with large wheels. I like the look of the cragars on your car, if you have some other pictures that you wouldn't mind posting I would appreciate it.

Edited December 5, 2012 by Endeavour32

[69_Mustang 26]

These are the newest pics with the front and rear spacers installed:

 

Then with the rear spacers installed, not the front:

 

And here without any spacers:

[mattwash08 10]

sorry to get off topic.. but 69_Mustang, what exhaust are you running? ive been toying with the idea of running side exit exhaust.

[69gmachine 15]

What does that outer shock tower do? Could you just remove that?

 

They brace the shock tower from flexing by forming a complete cone (of sorts) as well as providing a bump stop for compression. If you plan to leave the stock design with the shock on top of the upper arm, I would not recommend leaving them off.

 

However, if you go with a coil over suspension with the shock mounting on the lower arm, you could probably get by with just fabricating a simple cross brace where the bottom of the OEM outer shock tower would be.

[Endeavour32 10]

Thanks for the pictures. As to with or without the spacers, I think it looks best without. With them the wheels just look to far out.

[69_Mustang 26]

That's the idea ;) an aggressive stance. My width from outside tire to outside tire is 72" and my track in the front is 65". Up from the oem 54" track width.

Edited December 8, 2012 by 69_Mustang

[69_Mustang 26]

I'm definitely thinking of picking up the Wilwood 2" drop forged spindle. It says on the sites (might be an upgraded version from a few years ago), that "The included bolt-on steering arm is strong and can be reversed to accommodate rear steer configurations". So, that's a plus, as it sounds like it can be a bolt on piece now.

 

I believe that combined with the street or track 1968-70 Mustang front suspension kit - Stage 3, with performance springs and 1 1/8" sway bar, should make the front end do quite well for a "basic" setup.