Inner Fender Placement

[Twentyover]

On my 70 F body, the steel inner fenders are mounted outside the outer fender, that is ,the bolt attaching them runs through the inner fender through (I assume) a J-nut bracketing the outer fender.

I guess i'm asking is this correct? I would think (and this is dangerous) that the original design would want to hide the inner fender joint behind the outer fender, so the bolt would go through the outer fender through the J-nut bracketing the inner frnder.

My situation is the the bolt head 'clips' the corner of the tire as it passes by going through steering lock. While blowing the front suspension apart this winter, I'm planning on replacing the hex head with something like a button head, but flipping the inner fender to the inside would give even greater clearance.

Also possibly related is the tire (245/45-17, nominally 25.8" tall) is rubbing the rear of the inner fender in turns.

Thanks for your help

[shep]

The inner fender goes on the out side or at least that is how GM put them together

[justasquid]

the tire size shouldnt be a problem. I ran 235-60-15's back in the day on my 74 trans am without any issues. those tires were 26.1 compared to your 25.8, so im not sure why they would be rubbing. The tires your running really arent that much wider than what I was running, only about 1/2 inch.

What size is your rim and what is your backspacing?

Is it stock suspension up front?

is it lowered?

I might suspect the wheels are offset to far outward. but without knowing all the particulars, its hard to say.

[Twentyover]

17 x 8, think I remember 4.5" backspace. current stock ride height

Minor rub at the upper lip, big rub at the back of the wheelhouse while turning.

[PARKERRS]

The inner fender mounts on the outside. What you are describing as far as rub and the areas is common with this wheel tire combo ( which is the best overall b/s tire size for stock sub-frame cars). If you have an aggressive alignment, say +4.5 caster it is very common whether lowered or stock. The only cure is to slightly massage the rear of the inner fender for clearance and the button head bolts. The upper usually only contacts under full compression and then only enough to scuff the paint.

This is all based on a 17x8 wheel with 4.5 b/s and a 275/45 tire. This is the combo I run on a '73 Camaro, and I auto-x and track the car. You will also notice a slight rub on the front sway bar at full lock.

On the new build I am converting the inner fenders to sit inside of the outer for a cleaner look and max clearance, but this is a large fab job for something that looks really simple.

[BonzoHansen]

On my 77, ~5.5* caster, 245/60/15s, taller than yours, rubs in the same place.


Tommy P, I'm surprised it would be that much fab work (not that I'm questioning you). I'll have to look next time I'm under there. Are you making more room at this same spot where the OPs is rubbing? Seems like it could be done w/o too much trouble.

[Twentyover]

Tommy-

While I have no difficulty wielding a large hammer, and I'm blowing the front end off for a rebuild this winter, the idea of flipping the mounting side is appealing. I'm thinking pie cutting the tin, or finding someone with an English Wheel to expand the edge of the fender. Also confirming the sway bar rub at full lock.

Any chace you could post some piccys so we can take a peek at the direction you're headed? A written description would also be helpful.

While the front is apart, thinking about adding a sliver of metal to the inner fender to create a bubble at the rear of th ineer for clearance.

[PARKERRS]

Well when you move the inner to the inside you both raise it up and move it back. You then have issues with it not being long enough to go over the front, while at the same time it also has the front section which runs all the way to the radiator support which will also come up short. Or if you go the other direction the rear comes up short. So you will also have to consider the clearance for brake lines at the master cylinder and also the rear mounting brackets for the fenderwell itself.

I'm using a DSE sub-frame and wanted to extend the inner fender to line up with the new frame rail. At the same time I thought it would be cleaner to have it on the inside of the fender lip and the slight raise would cure the upper clearance problem. I also noticed on the DSE test car and on Brian Finch's car that the tires made contact with the small trough stamped into the factory inners for the wiring next to it's attachment to the outer near the hood. This was happening under full compression.

On mine the front section that goes to the radiator support was removed and set aside, then the trough was cut out and replaced with a flat filler of the same dimension. The rear was pie cut and moved to the desired location and a filler formed and welded. The outer fender lip has been trimmed for a uniform appearance and the inner trimmed and fitted, they will fasten together with button head stainless fasteners. After this the front section which was set aside was trimmed and fitted and will attach to the radiator support in the factory fashion and to a lip which was fabbed on the inner fender with small button head screws and nuts. I haven't worked out the rear mont as of yet. Once all of this was done I carried the car to the chassis shop for the remainder of the cage work to be done and then the sheetnetal work will be finished when it gets back.

For a factory sub your easiest and cheapest solution is to come just inside the outer fender lip at the back and hammer and dolly or pie cut and stretch/fill to push the area of contact back. There is nothing you can do about the sway bar contact unless you care to experiment with a cutom bar similar to what is on the DSE frame. The parts are available from several circle track suppliers. I haven't gotten this deep into the gray car as it was built as a nice street car until I got hooked on track days and auto-X. When the new car is done it will return to being a weekend cruiser.

[Twentyover]

Thanks Tommy.

I'll take a look at what it will take to change the location of the inner fender (I'm runnng a stock sub) while I have it apart. I may cut the rear of the inner and add some metal there to pooch it for clearance.

Not planning any change in the swaybar or wire trough for clearance. I use the trough on the RH side to contain an A/C hose.