Tire clearance issue

[Nima]

My 67 truck got a hand me down wheels and tires from my 2005 truck! the wheels are 16X8 and the tires are 285/75/16 on all corners on the stock height. I like the shape and the stance but the front tires on both side hit the corner (the red arrow in the pic) when turning. I was wodnering if this is an alignment issue (which my truck needs one) or the combination is just too big for the stock height. Is triming the corners somethig which people do in this case?
Thanks

[Stocker]

Probably just a combination of tire size and wheel offset. I had the same issue when I first put wider wheels & tires on my K20 many years ago. These trucks being what they now are, I would not advise doing what I did. Grabbed my trusty hacksaw and notched the corners off that area of the fenders. Just an old work truck after all....

[kwmech]

I have 285s on my 68 GMC and they clear without any issues. Looks like we have the same rims. I'm still running the drums, are you?

[Nima]

I have swapped to disc brake many years ago.
I am assuming I have too much caster?!

[SCOTI]

Originally Posted by Nima

I have swapped to disc brake many years ago.
I am assuming I have too much caster?!

You might have additional Caster vs what the truck originally came with but technically that's better from a driving/handling perspective.

The tire being almost 33" tall is pushing it @ stock heights.

[LockDoc]

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I don't know if you have, and there is no guarantee, but new front springs might cure it. 55 year old springs tend to sag a little....

I trimmed the fenders on my '70 Longhorn 4x4. It had new springs but it had 20" wheels & tires on it. I welded small pieces of metal over the opening that the cut created and you couldn't even see it....

LockDoc

[LNP]

I agree good point Doc. I dont feel its too much caster as you point to the front of the wheel opening where the tire rubs. Positive caster leans the spindle rearward. I think the wheel offset is the issue. You and kwmech seem to have the same wheels so maybe you could compare wheel offset to see.

[SCOTI]

Originally Posted by LNP

I agree good point Doc. I dont feel its too much caster as you point to the front of the wheel opening where the tire rubs. Positive caster leans the spindle rearward. I think the wheel offset is the issue. You and kwmech seem to have the same wheels so maybe you could compare wheel offset to see.

Standard shim alignments will tilt the top of the spindle slightly reward to get/reach OE spec Caster targets. Shifting the lower BJ forward helps yield 'current/updated' Caster that's more aggressive & works in tandem w/the tire technology of today.

[kwmech]

I've got a 454 sitting in mine after I cracked a head on the 396. No AC, but everything else. 4 core rad, PS, PB. Stock springs.

[LNP]

Originally Posted by SCOTI

Standard shim alignments will tilt the top of the spindle slightly reward to get/reach OE spec Caster targets. Shifting the lower BJ forward helps yield 'current/updated' Caster that's more aggressive & works in tandem w/the tire technology of today.

I know why they change caster settings and how it can change the weight on the tire which makes steering lighter or heavier. My point was for caster to be an issue would have to be negative caster. Most people that say too much caster they usually mean positive caster. Anyway thats what I was gettin at. I still feel her issue is more wheel offset.

[Nima]

The springs wer changed few years ago when I did the disc swap with standard height stock version.
I have to search/measure the BS of the wheels since they are about 15 years old. ahving said that, there is no budget for new wheels therefore I may have to just notch that lower section a little. I just wanted to kow if that is a big "no no".
The other issue is I can't really drive it to alignment shot this way. I have played with shims to somedegreebut so far, it is the same.

[72c20customcamper]

Most likely the combo of the offset tire size and that you have disc brakes which pushes the tire wheel out further than drums is the cause. You can nip the offending piece of fender but it may still hit at times turning and hitting bumps . I have 265/75-16 on my 68 with drums . When I add disc I’m sure it’s going to hit . Real close now as it is

[72SB]

if cutting the fender is not something you (I would not) want to do...install a coil spring spacer. A 1/2" spacer nets 1" IIRC (2 x the thickness of spacer)

That should raise the fender higher than the crown of the tire way it sits now

[SCOTI]

Originally Posted by LNP

I know why they change caster settings and how it can change the weight on the tire which makes steering lighter or heavier. My point was for caster to be an issue would have to be negative caster. Most people that say too much caster they usually mean positive caster. Anyway thats what I was gettin at. I still feel her issue is more wheel offset.

You might know. I might know. Others may not.

I only wanted to mention there are different ways alignment specs can be changed thus impacting issues like this.

[michael bustamante]

Originally Posted by Nima

I have swapped to disc brake many years ago.
I am assuming I have too much caster?!

switching to disc kicked out your wheels 3/4 of inch each side in not a little more