Tire rubbing pitman arms, ideas?

[ehuppert]

So, finally, at last, driving the 1008. Prety harsh on GAS (converted) but bought this for a plow truck and heavy hauler...

Anyways, had bought Pro Comp 295/75/16's which i put on the stock rims. On full lock right turns the left tire hits the pitman arm.

Thinking a little less back space (4" instead of 4.5") might solve the problem. Need wider rims eventually as the tire mfr calls for 7-9" rim and they are indeed bulging in the center tread section.

Have to check runout on the rims, they all balanced out, but one was heavier than the others. Getting a vibration at highway speeds. Then again, the driveshaft has a good sized ding in it, that could also be the vibration...

Thoughts?

Eric

 

[AJMBLAZER]

Doesn't anyone do searches?

I've mentioned this several times.


You need a longer 3/8" fine thread bolt for your d-side steering stop. I think the one I'm using is 2.5" long.


How much air pressure are you running? Some tires do crown due to their construction. A lot of people mistake this for over inflation while other tires are damn near flat all the way across the tread no matter what.

 

[tsmall07]

The vibration could be caused by the dent in the driveshaft (assuming you mean the rear drive shaft).

 

[ehuppert]

AJM,

Yes, i did a search.... Comes up with 129 hits, most of which aren't relevant! Was looking for a specific BTDT, which you did supply!

Running 35 lbs in the tires. Will air them up once i start putting some weight in it. Been through this numerous times with trucks. Run them at tire and auto manufacturer specs, centers wear out, no warrenty. Had some BFG's on my old 3/4 ton which wore out in 15k. Went back for warrenty and was told overinflation. Asked the rep how much lower i should go under 30 lbs, gee, he had no reply.

Stock rims are 6.5, probably a little narrow for the 295's. Guess i'll know for sure once i get some 8's!

Cheers, Eric

 

[AJMBLAZER]

35 should be close to what you need, maybe a bit less. I run 35ish in my 110..R16's and think I need a bit less.

 

[rosco]

Wheel width is not everything. There is also the wheel "offset". The amount that the wheel extends on the inside of the bolt flange surface. Of course a wider wheel will allow the side walls to stand straighter, but you don't want the wider part on the "inside". The offset is easiest to measure when the bare wheel is laying flat on the floor, without the tire. Just measure through the center hole to the floor. Allow for that little flange on the wheel. Or you can use a short straight edge on the back side, again measuring throug the center hole to it.

I once had a Pilot Car working for me that had a flat on his "oriental hoopti". He stopped me while he changed to the spare that he had found somewhere. It had so much "Offset" on the inside (it was a rear wheel), that it was pressing against the inside fender well & he chinched her down anyway. Then he was squawking on the CB that he couldm't move & his clutch was smoking. It was so funny, that I still chuckle when I think about it.

Lee in Alaska

 

[AJMBLAZER]

Good point. However there aren't many modern 16x7's or 16x8's (or the few 16x9's) that come with more backspacing than the OEM wheels had from the factory. Somewhere near 5" if my memory serves me.

The issue when running larger tires on these trucks when stock is that you can fit a taller tire if you use stock GM wheels but the drag link is in the way. If you found wheels that might keep the tire off of the drag link they'd have so little backspacing the tires would be into the fenders no matter what.

 

[ehuppert]

Guys,

Factory backspcing on "our" rims is 4.5". Wheels with 4" backspacing are readily available. Need to get under the truck and determine if a 1/2" less backspacing is going to make any sort of difference. Not real keen on decreasing the turning radius (via longer stop bolt) as this will be used as a plow/work vehicle and doesn't have the best turning abilities as it is!

Have to look closer, a 1" block under the spring pack may also move the body/tire enough to help a little.

 

[AJMBLAZER]

It won't make much difference but a wider wheel with slightly less backspacing might make more difference. The sidewall bulge would be smaller and the sidewall would be 1/2" further away. Then however you'd likely be putting a tire into the fender.

Honestly the turning radius wasn't much of an issue for me except in my driveway which is a tight circle. The length of the truck no matter what always made it hard to make it around the driveway when my DD was sitting next to the house.

DO NOT PUT CONVENTIONAL BLOCKS UNDER YOUR FRONT SPRINGS! There's a reason NO ONE recommends this and it's specifically mentioned as a no-no in many states' codes. The only sort of "blocks" you would want to do are some 1" ORD zero rates as mentioned in my other threads.
www.OffRoadDesign.com
Since they bolt to the pack and therefore can not come loose and shoot out under stress they are perfectly safe to use under the front.

However how they would solve your drag link issue I can't say. The drag link will just be 1" higher in relation to your sidewall.

 

[CCATLETT1984]

FYI you could also put 1" dually wheel spacers on the front axle, then you wouldnt make the poor turning radius even worse.