what was the tire size for a 68 3/4 ton? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

mikep · 01-13-2003, 01:23 AM

what is the stock tire size for a 7500 lb GVW 68 3/4 ton ? Or what would it be in modern tire sizing ?

**GMCPaul** · 01-13-2003, 06:30 AM

In looking at our GM data 2 different GM books show 2 different stock sizes on 1968 stock base 3/4 ton they were
7.50 X 16.5 6ply
8.75 X 16.5 6ply
I seem to have lost my tire size convertor out of my favorites so can't help on the modern day size this compares to, I'm sure someone will jump in here with one though!!
GMCPaul

mikep · 01-13-2003, 08:07 AM

My owners manual shows 9.5 X 16.5 for the 7500 GVW model with the springs I have. I have no idea what that translates to in modern sizing.

cabin94 · 01-13-2003, 02:03 PM

I have a 68 3/4 ton I put new wheels and tires on last year. I got 16 x 8 chrome American Racing Wheels with 265/75-16 tires. My tire guy says that this is pretty close to the original tire circumference. They are much wider, however. Fill up the wheelwells pretty nice. This made a huge difference in how it drives. The tires I replaced were 25 year old bias ply on 16.5 split rims.

da-burb · 01-13-2003, 04:07 PM

I have 7.50X16 tires on my motorhome. When I change the old bias plys over to a 10ply radial I will use a 235/85x16. It is within .10 inches of the original tire.

cheyenne10 · 01-13-2003, 04:32 PM

I have always seen and been told that the popular size LT235/85R/16 was the appropriate fit. I guess one would have to look at dia. of old 16.5 spec vs these. I think they are close as speedos seem to be close on couple I've had. I have seen the LT225/75R/16 used for a little lower sleeker look (often take offs from newer rigs). I like the looks of the LT265's just not sure on stock height truck with old springs if it might be a little too big. My opinions!! Sounds like your going to use that nice 68 to build something a little different. I appologize for never calling, wife wasn't big on idea of switching trucks again and it looks like your going to keep her. I still haven't headed up to WA. yet, got sick and am on the mend.

mikep · 01-13-2003, 08:38 PM

No prob. I'll just keep this one and sit on the others for a few years. As my brother is fond of telling me...I need a project. Its kind of a creative outlet. I am sure you all understand.

About the tire size. I am just trying to figure the difference for speedometer calibration. I hardly ever take it out on the highway and even then I never wear a watch so figuring out the speedo calibration is difficult. No one knows what the circumpherence of a 9.5 X 16.5
tire is? I'm running 265/75 X 16 tires now.

01-13-2003, 01:23 AM	#1
mikep Used to have a truck Join Date: May 2002 Location: port orchard WA Posts: 1,552	what was the tire size for a 68 3/4 ton? what is the stock tire size for a 7500 lb GVW 68 3/4 ton ? Or what would it be in modern tire sizing ? __________________ No truck :-( Last edited by mikep; 01-13-2003 at 01:32 AM.

01-13-2003, 06:30 AM	#2
GMCPaul Senior Member Join Date: Mar 2000 Location: Rockville,In. USA Posts: 3,718	In looking at our GM data 2 different GM books show 2 different stock sizes on 1968 stock base 3/4 ton they were 7.50 X 16.5 6ply 8.75 X 16.5 6ply I seem to have lost my tire size convertor out of my favorites so can't help on the modern day size this compares to, I'm sure someone will jump in here with one though!! GMCPaul __________________ Secure Online Catalog for-GMCPauls Truck Parts Email- GMCPAULS@GMAIL.COM

01-13-2003, 08:07 AM	#3
mikep Used to have a truck Join Date: May 2002 Location: port orchard WA Posts: 1,552	My owners manual shows 9.5 X 16.5 for the 7500 GVW model with the springs I have. I have no idea what that translates to in modern sizing. __________________ No truck :-(

01-13-2003, 02:03 PM	#4
cabin94 Registered User Join Date: Mar 2002 Location: Auburn, NE USA Posts: 19	I have a 68 3/4 ton I put new wheels and tires on last year. I got 16 x 8 chrome American Racing Wheels with 265/75-16 tires. My tire guy says that this is pretty close to the original tire circumference. They are much wider, however. Fill up the wheelwells pretty nice. This made a huge difference in how it drives. The tires I replaced were 25 year old bias ply on 16.5 split rims. __________________ 1968 Chevy C20 327 4spd Custom 66k

01-13-2003, 04:07 PM	#5
da-burb "Ochre Ogre" Join Date: Apr 2000 Location: Springfield, MN Posts: 3,558	I have 7.50X16 tires on my motorhome. When I change the old bias plys over to a 10ply radial I will use a 235/85x16. It is within .10 inches of the original tire. __________________ Bowtie Truck Stop Inc. Mid-West GM Truck Restoration Parts Supplier Your Key Parts, Auto Metal Direct, Dynacorn, and Goodmark dealer. like us @ www.facebook.com/BowtieTruckStop 1971 C-10 Suburban (Ochre) 1971 K-10 Suburban (Ochre) 1972 C-10 Suburban (Ochre) 1972 K-20 Suburban (Yellow- that just aint right!) Springfield, Minnesota 56087

01-13-2003, 04:32 PM	#6
cheyenne10 Senior Member Join Date: Apr 2000 Location: Oregon Posts: 2,512	modern size I have always seen and been told that the popular size LT235/85R/16 was the appropriate fit. I guess one would have to look at dia. of old 16.5 spec vs these. I think they are close as speedos seem to be close on couple I've had. I have seen the LT225/75R/16 used for a little lower sleeker look (often take offs from newer rigs). I like the looks of the LT265's just not sure on stock height truck with old springs if it might be a little too big. My opinions!! Sounds like your going to use that nice 68 to build something a little different. I appologize for never calling, wife wasn't big on idea of switching trucks again and it looks like your going to keep her. I still haven't headed up to WA. yet, got sick and am on the mend. __________________ Bob

01-13-2003, 08:38 PM	#7
mikep Used to have a truck Join Date: May 2002 Location: port orchard WA Posts: 1,552	No prob. I'll just keep this one and sit on the others for a few years. As my brother is fond of telling me...I need a project. Its kind of a creative outlet. I am sure you all understand. About the tire size. I am just trying to figure the difference for speedometer calibration. I hardly ever take it out on the highway and even then I never wear a watch so figuring out the speedo calibration is difficult. No one knows what the circumpherence of a 9.5 X 16.5 tire is? I'm running 265/75 X 16 tires now. __________________ No truck :-(



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