Proper Tire Size - The 1947 - Present Chevrolet & GMC Truck Message Board Network

70ChevyCST · 04-19-2009, 04:19 AM

1970 Chevy CST-10 came from previous owner with 235-70-15" tires on original Chevy 15X8 rally wheels. Love the rally wheel look so I want to keep them. The tires look a bit small though...could be just me?..I've looked over the body/glove box tags but cannot find anywhere what size tires the truck came from the factory with. Anyone know?

Thanks, Bob

Tx Firefighter · 04-19-2009, 06:53 AM

The closest radial to original size is a 235/75/15. Your tires look short due to the 70 series instead of the correct 75 series.

That little difference between a 70 and a 75 series profile affects the overall tire height by right at an inch.

In my opinion, I prefer to run 275/60/15 tires. They are the same overall height as stock tires were, but a good bit wider and they look very good on rally wheels. This tire was the stock size on Chevy's 454ss truck in the 90s.

lax54650 · 04-19-2009, 07:05 AM

from reading here they came with letter designation. and i am too young to remember anything about them. as i recall though the stock letter tire converted to metric equalled between 225 75 15 and 235 75 15. longhorn man will know. i too am wrangling what size to use. i think i will run 225 70 in front and 245 70 in rear here is a linkhttp://www.ajdesigner.com/fl_tire/tire.php to a calculator. it will tell you the difference in measurements height width circumfrence etc. of each size. kind of fun to play with.

**70cst** · 04-19-2009, 07:36 AM

Quote:

Originally Posted by 70ChevyCST

1970 Chevy CST-10 came from previous owner with 235-70-15" tires on original Chevy 15X8 rally wheels. Love the rally wheel look so I want to keep them. The tires look a bit small though...could be just me?..I've looked over the body/glove box tags but cannot find anywhere what size tires the truck came from the factory with. Anyone know?

Thanks, Bob

I assume you realize this but our trucks never came with Rally Wheels. Theses are original to Chevy and I agree they look sharp on our trucks. I also agree 60 series tires look better than 70 series. Thats what I have on mine...but once I put on my TT wheels...these will be gone.

lax54650 · 04-19-2009, 08:10 AM

from reading here they came with letter designation. and i am too young to remember anything about them. as i recall though the stock letter tire converted to metric equalled between 225 75 15 and 235 75 15. longhorn man will know. i too am wrangling what size to use. i think i will run 225 70 in front and 245 70 in rear here is a linkhttp://www.ajdesigner.com/fl_tire/tire.php to a calculator. it will tell you the difference in measurements height width circumfrence etc. of each size. kind of fun to play with.

lax54650 · 04-19-2009, 08:22 AM

from reading here they came with letter designation. and i am too young to remember anything about them. as i recall though the stock letter tire converted to metric equalled between 225 75 15 and 235 75 15. longhorn man will know. i too am wrangling what size to use. i think i will run 225 70 in front and 245 70 in rear here is a linkhttp://www.ajdesigner.com/fl_tire/tire.php to a calculator. it will tell you the difference in measurements height width circumfrence etc. of each size. kind of fun to play with.

lax54650 · 04-19-2009, 08:23 AM

**Boog** · 04-19-2009, 08:29 AM

The original letter designation sized tire would probably have been a G78/15 and the modern metric sized equivalent is about a 235/78/15. If the 235 looks a bit narrow for the rally wheels you can step up to a 255/70/15, same diameter and a touch wider. I run them.

Longhorn Man · 04-19-2009, 11:33 AM

Quote:

longhorn man would know

Nope. I have no clue. I am too young, and never understood those old tire sizies.... nor the old style heavy truck tire size either.

70ChevyCST · 04-20-2009, 04:08 PM

Thanks everyone for your input. Well....The previous owner that put these tires on wasn't too far off then....sounds like only 1 size too small...My local tire shop guy said that 255/70r/15's would be about right, so I guess he wasn't too far off either.

To 70CST:...You know...I did not know that our trucks didn't come with rallys...so thanks for the info. When did Chevy start putting them on their trucks? The cars were getting them in 70....right?

Thanks again guys...You've been a big help to me.

Bob

Longhorn Man · 04-20-2009, 04:21 PM

they showed up in 73

71c10bbsuper · 04-20-2009, 05:59 PM

my glove box show's h78-15 not sure what that converts over to but i think i will be going to 275/60r15 for the width

04-19-2009, 04:19 AM	#1
70ChevyCST Registered User Join Date: May 2007 Location: usa Posts: 71	Proper Tire Size 1970 Chevy CST-10 came from previous owner with 235-70-15" tires on original Chevy 15X8 rally wheels. Love the rally wheel look so I want to keep them. The tires look a bit small though...could be just me?..I've looked over the body/glove box tags but cannot find anywhere what size tires the truck came from the factory with. Anyone know? Thanks, Bob __________________ I'm a grateful Christian not perfect in any way, but always striving to become better with Christ's help. I'm grateful for what He did for me on that cross at Calvary. I hope there is a desire in your heart for the same: If you confess with your mouth that Jesus is Lord and believe in your heart that God raised him from the dead, you will be saved. Romans 10:9

04-19-2009, 06:53 AM	#2
Tx Firefighter Watch out for your cornhole ! Join Date: Jun 2003 Location: Azle, Texas Posts: 14,162	Re: Proper Tire Size The closest radial to original size is a 235/75/15. Your tires look short due to the 70 series instead of the correct 75 series. That little difference between a 70 and a 75 series profile affects the overall tire height by right at an inch. In my opinion, I prefer to run 275/60/15 tires. They are the same overall height as stock tires were, but a good bit wider and they look very good on rally wheels. This tire was the stock size on Chevy's 454ss truck in the 90s. __________________ I'm on the Instagram- @Gearhead_Kevin

04-19-2009, 07:05 AM	#3
lax54650 Registered User Join Date: Aug 2008 Location: lacrosse wi. Posts: 426	Re: Proper Tire Size from reading here they came with letter designation. and i am too young to remember anything about them. as i recall though the stock letter tire converted to metric equalled between 225 75 15 and 235 75 15. longhorn man will know. i too am wrangling what size to use. i think i will run 225 70 in front and 245 70 in rear here is a linkhttp://www.ajdesigner.com/fl_tire/tire.php to a calculator. it will tell you the difference in measurements height width circumfrence etc. of each size. kind of fun to play with.

04-19-2009, 08:10 AM	#5
lax54650 Registered User Join Date: Aug 2008 Location: lacrosse wi. Posts: 426	Re: Proper Tire Size from reading here they came with letter designation. and i am too young to remember anything about them. as i recall though the stock letter tire converted to metric equalled between 225 75 15 and 235 75 15. longhorn man will know. i too am wrangling what size to use. i think i will run 225 70 in front and 245 70 in rear here is a linkhttp://www.ajdesigner.com/fl_tire/tire.php to a calculator. it will tell you the difference in measurements height width circumfrence etc. of each size. kind of fun to play with.

04-19-2009, 08:22 AM	#6
lax54650 Registered User Join Date: Aug 2008 Location: lacrosse wi. Posts: 426	Re: Proper Tire Size from reading here they came with letter designation. and i am too young to remember anything about them. as i recall though the stock letter tire converted to metric equalled between 225 75 15 and 235 75 15. longhorn man will know. i too am wrangling what size to use. i think i will run 225 70 in front and 245 70 in rear here is a linkhttp://www.ajdesigner.com/fl_tire/tire.php to a calculator. it will tell you the difference in measurements height width circumfrence etc. of each size. kind of fun to play with.

04-19-2009, 08:23 AM	#7
lax54650 Registered User Join Date: Aug 2008 Location: lacrosse wi. Posts: 426	Re: Proper Tire Size <object width="300" height="605"><param name="movie" value="http://media.ajdesigner.com/fl/tire.swf"></param><embed src="http://media.ajdesigner.com/fl/tire.swf" type="application/x-shockwave-flash" width="300" height="605"></embed></object><br><a href="http://www.ajdesigner.com/index.htm">By AJ Design Software</a>

04-19-2009, 08:29 AM	#8
Boog laying low Join Date: Mar 2001 Location: Searcy, Ark. USA Posts: 13,683	Re: Proper Tire Size The original letter designation sized tire would probably have been a G78/15 and the modern metric sized equivalent is about a 235/78/15. If the 235 looks a bit narrow for the rally wheels you can step up to a 255/70/15, same diameter and a touch wider. I run them. __________________ Boog 69 Chevy stepside, 358/T350, 4.11 posi, 4.5/4 drop, rallys, poboy driver primer is finer 91 Chevy sportside, Tahoe, Yukon & GMC Crewcab All GM..'nuff said. I stand for the flag and kneel at the cross

04-20-2009, 04:08 PM	#10
70ChevyCST Registered User Join Date: May 2007 Location: usa Posts: 71	Re: Proper Tire Size Thanks everyone for your input. Well....The previous owner that put these tires on wasn't too far off then....sounds like only 1 size too small...My local tire shop guy said that 255/70r/15's would be about right, so I guess he wasn't too far off either. To 70CST:...You know...I did not know that our trucks didn't come with rallys...so thanks for the info. When did Chevy start putting them on their trucks? The cars were getting them in 70....right? Thanks again guys...You've been a big help to me. Bob __________________ I'm a grateful Christian not perfect in any way, but always striving to become better with Christ's help. I'm grateful for what He did for me on that cross at Calvary. I hope there is a desire in your heart for the same: If you confess with your mouth that Jesus is Lord and believe in your heart that God raised him from the dead, you will be saved. Romans 10:9

04-20-2009, 04:21 PM	#11
Longhorn Man its all about the +6 inches Join Date: Jan 2001 Location: Hilliard Ohio Posts: 2,690	Re: Proper Tire Size they showed up in 73

04-20-2009, 05:59 PM	#12
71c10bbsuper Registered User Join Date: Jan 2007 Location: wyo Posts: 61	Re: Proper Tire Size my glove box show's h78-15 not sure what that converts over to but i think i will be going to 275/60r15 for the width



Register or Log In To remove these advertisements.

Register or Log In To remove these advertisements.