OEM wheel size fitting question - The 1947 - Present Chevrolet & GMC Truck Message Board Network

kevinr1970 · 11-02-2007, 03:47 PM

Not sure if anyone can answer this or not, but...

On my 2006 GMC swb reg cab I have a 2"/4" lowering kit installed.
I am currently running a set of the 17" Denali rims with the tires that came stock on my truck - 245 70 17. These are ~30.5" tires by my calculations.

I have been looking for a set of OEM rims in a larger size, 20" I suppose?
The set I am currently looking at have 275 55 20 tires on them. These are ~31.9" tires by my calculations.

My question(s) is with the set-up on my truck now will I have any clearance issues if I run the tires for a while? I am more concerned with width than hieght.
How much of a difference will this make on my speedo? If the tire size is ~4% different will this equate to a 4% difference on my speedo; when it says 60mph I will actually be going ~62?

droppedgmc · 11-02-2007, 11:00 PM

the width will be just fine, the height, you might have a problem with. i've lowered alot of truck on a 2/4 and most used 275/45/20. that tire size sits it just right without rubbing.

kevinr1970 · 11-03-2007, 01:47 AM

DANG IT!
I wish there was a market for the tires that are on the rims. He won't split them.
I guess I'll just have to wait him out until he comes down enough to make it worth my while to just get rid of the tires?

DavesRide · 11-07-2007, 08:27 PM

A friend of mine has a 2000 SWB. It it lowered but not crazy low. Definately lowered. For a while he ran the 20"s and factory tires from a 2003 or so SS extended cab without problems. It's a Lingenfelter and the drag slicks looked way cooler in my opinion.

11-02-2007, 03:47 PM	#1
kevinr1970 Senior Member Join Date: Aug 2004 Location: Everett, WA Posts: 2,316	OEM wheel size fitting question Not sure if anyone can answer this or not, but... On my 2006 GMC swb reg cab I have a 2"/4" lowering kit installed. I am currently running a set of the 17" Denali rims with the tires that came stock on my truck - 245 70 17. These are ~30.5" tires by my calculations. I have been looking for a set of OEM rims in a larger size, 20" I suppose? The set I am currently looking at have 275 55 20 tires on them. These are ~31.9" tires by my calculations. My question(s) is with the set-up on my truck now will I have any clearance issues if I run the tires for a while? I am more concerned with width than hieght. How much of a difference will this make on my speedo? If the tire size is ~4% different will this equate to a 4% difference on my speedo; when it says 60mph I will actually be going ~62? __________________ 2009 Honda Fit CfC (bsf 44.9 mpg) 2000 Tahoe Limited 1991 GMC CrewCab Dually 2wd, will end up swb, not dually and replace CCswb below 1991 GMC CrewCab Dually 4x4, just going to fix things up for now 1982/1989 K5/GMC Jimmy 2wd 1987 GMC 1/2 ton swb 2wd Crew (sold)

11-02-2007, 11:00 PM	#2
droppedgmc Truck Enthusiast Join Date: Dec 2006 Location: Arlington, WA Posts: 1,346	Re: OEM wheel size fitting question the width will be just fine, the height, you might have a problem with. i've lowered alot of truck on a 2/4 and most used 275/45/20. that tire size sits it just right without rubbing. __________________ '85 swb

11-03-2007, 01:47 AM	#3
kevinr1970 Senior Member Join Date: Aug 2004 Location: Everett, WA Posts: 2,316	Re: OEM wheel size fitting question DANG IT! I wish there was a market for the tires that are on the rims. He won't split them. I guess I'll just have to wait him out until he comes down enough to make it worth my while to just get rid of the tires? __________________ 2009 Honda Fit CfC (bsf 44.9 mpg) 2000 Tahoe Limited 1991 GMC CrewCab Dually 2wd, will end up swb, not dually and replace CCswb below 1991 GMC CrewCab Dually 4x4, just going to fix things up for now 1982/1989 K5/GMC Jimmy 2wd 1987 GMC 1/2 ton swb 2wd Crew (sold)

11-07-2007, 08:27 PM	#4
DavesRide Registered User Join Date: Oct 2007 Location: Garageless, Missouri Posts: 408	Re: OEM wheel size fitting question A friend of mine has a 2000 SWB. It it lowered but not crazy low. Definately lowered. For a while he ran the 20"s and factory tires from a 2003 or so SS extended cab without problems. It's a Lingenfelter and the drag slicks looked way cooler in my opinion. __________________ R.I.P ESLL Even as the body dies the spirit lives on in the people you touched



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