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73-87 Chevy _ GMC Trucks => 4 Wheel Drives => Topic started by: 784x4ron on October 06, 2005, 09:50:00 pm

Title: what size tires can i put on...
Post by: 784x4ron on October 06, 2005, 09:50:00 pm
i have a 1978 chevy k10 3/4 ton 4x4 i,m putting a 3" body lift on it.can any one tell me what are the biggest 15"tires i can put on it with out cutting the finders down. i would like too put 35x12.5x15..it,s still stock and i have 33x11.5x15" on it now.  thank you...

Title: Re: what size tires can i put on...
Post by: roundedline on October 07, 2005, 10:53:00 am
You need 4" of lift to clear 35x12.5's without rubbing.  Technically you shouldn't be able to clear 33's on a stock truck.  Have the fenders been clearanced?

Chris Lucas
www.73-87chevytrucks.com
www.captkaoscustoms.com
Project Su
Jimmy 2WD Project

Title: Re: what size tires can i put on...
Post by: 79GMC4x4 on November 02, 2005, 12:13:00 pm
I currently have a 79 3/4 Ton 4x4.  It is stock and it also clears 33's.  

Title: Re: what size tires can i put on...
Post by: Lt.Del on November 02, 2005, 05:44:00 pm
Ensure your rear axle ratio can handle that size tire.  If it is a high gear rear, you may want to lower your ratio.  Large tires make a big difference in rear end ratios.
SgtDel

Title: Re: what size tires can i put on...
Post by: 1976Scottsdale on November 02, 2005, 09:10:00 pm
Yes, that is true.  I have 3.08 posi's in my 78k10 and that poor thing will barely go up a hill and hold speed with the 33's on it.  3.42 will do fine, 3.73's are better, but 4.10's are... dare I say it, God-like.  Hope gas milage is of no consequence.

Title: Re: what size tires can i put on...
Post by: Lt.Del on November 03, 2005, 11:22:00 am
I have a 91 sub w/ 33's on her.  The rear is a 3:73, which, with those larger tires,  translates to close to a normal set up 3:08 rear, when you look at the rpm's.

SgtDel  

Title: Re: what size tires can i put on...
Post by: DieselTech on November 14, 2005, 06:34:00 pm
My 78 has 38.5"s on it with 4.88 gears. A little too low sometimes, but with 3.73's it was a total dog. It now gets up to speed like it should, but runs around 3200 Rpm's at about 65 mph. Gas mileage is terrible! Big trucks drink the gas!