05 CC w/20's w/ WARP rear brake drums @ 3000mi's??

gotitbad · August 14, 2005

I have a 2005 GMC Sierra Crew Cab 1500 2wd, with just now over 3000 miles. I put a set of 20's on it a little over a week ago, and from the very SECOND i pulled out of the tire place, i had a vibration when braking (see http://www.gm-trucks.com/forums/index.php?showtopic=44429). Can anyone explain to me HOW putting or installing or whatever these wheels/tires could have warped my rear brake drums (crew cabs have drums not rotors)??? Let me make sure yall understand..they are WARPED..not out of round like need to be turned....they are, lay them on a true surface and will WOBBLE warped! And to make matters worse, they were 255.00 each....luckily i work for a dealership, and dont have a problem with that part, but i dont see how mounting a set of wheels to a drum that mates to a FLAT surface could have warped them? Any ideas people? You guys have really had some good suggestions on this before i figured out what was wrong...let me have some ideas!

THANKS

TONY

Stocklook · August 14, 2005

I've seen this before but not on a CC and not 20's, this was on an older OBS the installer when putting the wheels on they hit the rotor and and moved it out but did not notice it, and when they tighten the lugs tooo tight it put pressure on one side and between that and heat of braking it warped.

the tire shop ended up buying him a new rotors, this was only on one side, but he demanded the buy two because of brake allignment issues

Hope this helps,

crowebar · August 14, 2005

No idea. I've got a 1500 05 crew cab with 20" Boss rims and Eagle GTII tires and haven't had any trouble but my truck is the 4x4. I do have drum brakes though. I drove the truck about 100 miles with the stock wheels and tires before the switch and never noticed any difference (I drove the dealer trade from a lot about 100 miles away to the one that I bought the truck from). I've got about 2000 miles on the truck now. Sounds like you may have a warrentee issue. My dealer told me that the 20" rims would not affect my warrentee. They even took it in and had it done for me.

Good luck!

Markeaux · August 14, 2005

FWIW I had a 98 Z28 that exhibited the infamous warped rotor syndrome - brakes pulsed badly - but almost unbelievably when I had the wheels rotated the brake pulsation went entirely away. That seemed to indicate the warpage was due to previous improper lugnut torqueing or whatever.

lrymal · August 14, 2005

For those drums to be warped so badly.... I don't think the surface they were mounting to was flat. I'll bet two things happened:

Impact wrench without torque setting monitoring, and no "star" strategy on which lugnuts to tighten---the order, that is.

Speed clip on the lug bolt needed to be removed for the 20s. Wasn't removed. Wheel tightened down. Speed clip encounters the new wheel. Impact wrench tightened everything up. WARP

I'll bet it was one or both of these.

mcreyaufmiller · August 14, 2005

If the wheel lugs were not tightened to the proper torque, that will warp the drums and rotors as well. I have had this happen several times until now when I go into the shop and tighten the lugs myself (the shop managers are glad to have me do this to take the responsability off them for my praisedynobrake rotors).

SierraCrewGuy · August 16, 2005

You ever get the vibration out yet?

allenmehrer · August 16, 2005

I'd go with Larry's idea about the speed clip. Spome kid could have left them on.

gotitbad · August 16, 2005

If in the speed clip you are talking about the drum retainers on the lugs (2 on each side), they were NOT removed. I didnt put them back on when i replaced the drums. The drums DID fix it 100%. Stops like a new one now (lol..3000miles).....im just glad it is over....by the time i got through, i had blamed EVERYONE for it since i was SO PO'd....anyways, just got of the paypal site and ordered my new pcm from wait4me.....hope its as good as everyone says...guy talked real knowledgeable....also ordered one for my buddys new 05 xcab...so, we will see. Its the "tow/haul ass" mode that got me..lol. By the way guys..i am a parts manager at a local GM/Chrysler dealership here, and if i can help anyone on here in any way, just drop me a [email protected]

TONY

SierraCrewGuy · August 16, 2005

Glad you got your problem fixed. Sorry my information didn't help. When I got my vibration I had yet to learn about this forum so you talk about FREAKING OUT. Anyway, sweet looking truck!!!

GM Dude · August 17, 2005

When I installed my BOSS 20's, those retainer clips were my problem too. As soon as I got home I removed the 20's and reinstalled the original 17's until I could determine the problem. Lo and behold I noticed those retainers still on the drums and the BOSS wheels did not have a recess to accept them like the OEM 17' did. I removed those things, installed the 20's and not a single problem since.