I am considering putting some 285 BFG KO's on my new 04 GMC. I have searched throught the archives and could not come up with a clear answer to the question abouth whether or not the 285s will rub using the factory aluminum wheels. My question is: Will they rub with the bars cranked up? I have no problem cranking the torsion bars but I do not want to trim the painted factory air dam. I also do not mind having to modify the parking brake cable and/or the inner fender liner.

Please post additional comments and/or pictures.

Thanks guys.

When I ran stock wheels the airdam was OK w/ 285 AT but when I went to the wider H2 wheels w/ 285 AT I had to trim my 03 Chevy airdam on the inside corners.
Then I got an 03 GMC had to trim quite a bit on airdam.
Next came 04 Chevy and it was like 03 Chevy.
THen came 04.5 GMC and it just needed the inside corner trimmed.

So point is the GMC seem to be tighter than Chevy on airdam clearance and the GMC have some assembly plant variations, w/ 285 on stock wheels none of the airdams would have needed trimmed.

I am considering putting some 285 BFG KO's on my new 04 GMC. I have searched throught the archives and could not come up with a clear answer to the question abouth whether or not the 285s will rub using the factory aluminum wheels. My question is: Will they rub with the bars cranked up? I have no problem cranking the torsion bars but I do not want to trim the painted factory air dam. I also do not mind having to modify the parking brake cable and/or the inner fender liner.

Please post additional comments and/or pictures.

Thanks guys.
You will have to trim the air dam/bumper on the GMC. I can be done on the inside and is barely noticable.

The tire will not wear very evenly on that narrow of a wheel. Trust me I know......................

I've heard of many guys trimming the airdam but I didn't have to do a thing and had plenty of clearance. I cranked the torsion bars afterward anyway.

Original diesel, did u have to trim w/ stock rims or just the 16X8 that are in your sig line?

I've had plenty of room on all my trucks w/ stock rim/285 only had to trim w/ wider wheels and 285 tires.

Original diesel, did u have to trim w/ stock rims or just the 16X8 that are in your sig line?

I've had plenty of room on all my trucks w/ stock rim/285 only had to trim w/ wider wheels and 285 tires.
In my experience the BFG 285/75/16 on the factory wheels will require trimming on the 04 GMC air dam. It was very minimal and will probably vary from case to case, tire to tire. Even with 5 turns on the factory keys I still had to cut a small section out of the air dam on the inner side to keep from rubbing while turning.

The 16x8 required a much more "aggresive" trimming. GMC continues to shrink the wheel well size on the front with each front end change. I had to trim quite a bit out of the painted air dam and when 9 turns on the factory keys to get the 16x8s to fit. The negative offset of the Weld wheels did not help.

Original D, my 03 GMC was actually closer than my 04 is now w/ same wheels, so there is some assembly plant tolerances.

If u look at where the airdam hits below the center of tire, raising the bars make it get closer to the tire.

you could always dump the beer can bumper. it wont save anything should you hit something head on. I installed a road armor and have plenty of clearance for 315s on weld renegades. I know this is extreme, both cost wise and maybe appearance. consider that front end in a collision, both safety and cost

marc

Here is a picture of the trimming I am talking about on the inside. This shows where I had to trim to clear my 285s on 16x8s. I had to make a similar cut, just a lot less in the same place in order to keep my 285s on factory wheels from rubbing. http://img10.exs.cx/img10/91/IMAGE_001.jpg

I just got my 285s on today. I didn't really need to trim the front airdam, but I did just like the previous post. I also had rubbing on my factory style mud flap (from dealer). Trimmed both front mud flaps, even though only driver's side was the only one rubbing. I will reform the splash guard tonight on the front of the driver's side. It rubs a little while backing. I will have to wait until tax returns to get some 16x8 wheels. After all the adjustments now, I shouldn't have any problems when I get those put on. The truck looks a lot better now. It actually looks like a truck!