tires and rear end ratio - The 1947 - Present Chevrolet & GMC Truck Message Board Network

cam · 05-15-2002, 07:47 AM

Just curious what size radial tires are closest to stock on a 70 c10. I have the original 78 LT 15 as the spare but the original owner put 215 SR15 radials on the pickup and they look small.
Also was wondering if there was a set rear-end ratio for pickups with the 350/auto/heavy duty rear springs options. I took the pickup out on the highway last night and it seems to be reving to high at speeds above 50mph.
Thanks again

texnician01 · 05-15-2002, 10:34 AM

take your truck, jack up one wheel (rear) and put the tranny in neutral. (make sure to block the front tires) and turn the wheel 2 full turns. count how many revolutions the driveshaft makes. this will be the rear end ratio. if it turns 3 times and just a little more it is a 3.07 if it turns 3 times and most of a fourth then it is a 3.73, if it turns 4 times and a little more it is a 4.11. this should get you close anyway. I have some gearsets and carriers if you are looking to change them. as for tire size I have 235-75R15's on mine and they look pretty good.

Nathan

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1969 C-10 292 I-6 4 spd in the middle of a restoration. going to get a 327 and 3.07 gears but keeping all of the original parts so I can put it back to original later on down the road.
55 chevy 4 door 150
47 Willys CJ-2A

stelth2002 · 05-15-2002, 11:06 AM

Hey texnician01, do you have any carriers for a 3.07 ring and pinion. Series 3 I think? Email me @ nt_expert@hotmail.com

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67 Chevrolet LWB with rebuilt 292. 415 ft. lbs of torque, 4 speed, 3.73 Posi, straight and almost painted.

cam · 05-16-2002, 09:51 AM

I bought 235 75 15's yesterday, much nicer, and it seems as though the rpm's are a bit lower at highway speeds. I'll try the rear-end ratio suggestion tomorrow. Thanks!

Longhorn Man · 05-16-2002, 10:37 PM

I have 3.07 gears on mine. With the 275/60 15 inch tires, the speedo is 100% correct. That means it is the right diameter. (28 inces tall I think)
RPM's are not too bad either

------------------
'69 G.M.C. 350/350. Trying to clean up the left over damage from the Dope-Smokin-Old-Man
I've been dubbed the Longhorn Freak/Fanatic/Expert, I just hope I can live up to it.
FINALLY got the HORNIAC...a '70 one ton Longhorn with a Pontiac 350/350 and lots of 'personality'. Check out The Longhorn Webite.
E-mail longhornmail@yahoo.com
My name is Andy...not Randy...I'm in Ohio...Not Illinois...close enough?
Columbus Ohio

*Zkast* · 05-16-2002, 10:44 PM

If the Speedo is correct... better hope that gas gauge is NOT lol

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Pictures and more...
Email me
'71 LWB
350/350T, PS/PB
Special options? Yes, RUST... Need some?

Garrett
Olathe, Kansas

Longhorn Man · 05-16-2002, 10:46 PM

LOL, it is right too, it will sputter and p!ss me off at the 'M'. I still had a few miles to go ...not worried yet.

------------------
'69 G.M.C. 350/350. Trying to clean up the left over damage from the Dope-Smokin-Old-Man
I've been dubbed the Longhorn Freak/Fanatic/Expert, I just hope I can live up to it.
FINALLY got the HORNIAC...a '70 one ton Longhorn with a Pontiac 350/350 and lots of 'personality'. Check out The Longhorn Webite.
E-mail longhornmail@yahoo.com
My name is Andy...not Randy...I'm in Ohio...Not Illinois...close enough?
Columbus Ohio

05-15-2002, 07:47 AM	#1
cam Registered User Join Date: May 2002 Location: Helena, MT, USA Posts: 64	tires and rear end ratio Just curious what size radial tires are closest to stock on a 70 c10. I have the original 78 LT 15 as the spare but the original owner put 215 SR15 radials on the pickup and they look small. Also was wondering if there was a set rear-end ratio for pickups with the 350/auto/heavy duty rear springs options. I took the pickup out on the highway last night and it seems to be reving to high at speeds above 50mph. Thanks again __________________ 1970 GMC 1/2 ton 307 4spd 1970 dorF dump runner

05-15-2002, 10:34 AM	#2
texnician01 Senior Member Join Date: Mar 2002 Location: 12 Miles South of Des Moines, Iowa Posts: 359	take your truck, jack up one wheel (rear) and put the tranny in neutral. (make sure to block the front tires) and turn the wheel 2 full turns. count how many revolutions the driveshaft makes. this will be the rear end ratio. if it turns 3 times and just a little more it is a 3.07 if it turns 3 times and most of a fourth then it is a 3.73, if it turns 4 times and a little more it is a 4.11. this should get you close anyway. I have some gearsets and carriers if you are looking to change them. as for tire size I have 235-75R15's on mine and they look pretty good. Nathan ------------------ 1969 C-10 292 I-6 4 spd in the middle of a restoration. going to get a 327 and 3.07 gears but keeping all of the original parts so I can put it back to original later on down the road. 55 chevy 4 door 150 47 Willys CJ-2A __________________ 69 C-10, 340HP 327 55 chevy 4 door 150 47 Willys CJ-2A 05 Harley Night Train 06 1200 Sportster (Wife's bike) 70 Honda CL350 OIF2 & OIF7 Veteran Nathan & Tiffany

05-15-2002, 11:06 AM	#3
stelth2002 Young Gun wth Fast Inline Join Date: Jan 2002 Location: Idaho Posts: 1,475	Hey texnician01, do you have any carriers for a 3.07 ring and pinion. Series 3 I think? Email me @ nt_expert@hotmail.com ------------------ 67 Chevrolet LWB with rebuilt 292. 415 ft. lbs of torque, 4 speed, 3.73 Posi, straight and almost painted. __________________ 1967 Chevrolet LWB with built 292! 415 ft. lbs of torque, 4 speed :O with 27% overdrive too, 3.73 Posi. Frame and body done... getting painted!!!

05-16-2002, 09:51 AM	#4
cam Registered User Join Date: May 2002 Location: Helena, MT, USA Posts: 64	I bought 235 75 15's yesterday, much nicer, and it seems as though the rpm's are a bit lower at highway speeds. I'll try the rear-end ratio suggestion tomorrow. Thanks! __________________ 1970 GMC 1/2 ton 307 4spd 1970 dorF dump runner

05-16-2002, 10:37 PM	#5
Longhorn Man its all about the +6 inches Join Date: Jan 2001 Location: Hilliard Ohio Posts: 2,690	I have 3.07 gears on mine. With the 275/60 15 inch tires, the speedo is 100% correct. That means it is the right diameter. (28 inces tall I think) RPM's are not too bad either ------------------ '69 G.M.C. 350/350. Trying to clean up the left over damage from the Dope-Smokin-Old-Man I've been dubbed the Longhorn Freak/Fanatic/Expert, I just hope I can live up to it. FINALLY got the HORNIAC...a '70 one ton Longhorn with a Pontiac 350/350 and lots of 'personality'. Check out The Longhorn Webite. E-mail longhornmail@yahoo.com My name is Andy...not Randy...I'm in Ohio...Not Illinois...close enough? Columbus Ohio

05-16-2002, 10:44 PM	#6
Zkast Account Suspended Join Date: May 2002 Location: Olathe, Kansas Posts: 929	If the Speedo is correct... better hope that gas gauge is NOT lol ------------------ Pictures and more... Email me '71 LWB 350/350T, PS/PB Special options? Yes, RUST... Need some? Garrett Olathe, Kansas

05-16-2002, 10:46 PM	#7
Longhorn Man its all about the +6 inches Join Date: Jan 2001 Location: Hilliard Ohio Posts: 2,690	LOL, it is right too, it will sputter and p!ss me off at the 'M'. I still had a few miles to go ...not worried yet. ------------------ '69 G.M.C. 350/350. Trying to clean up the left over damage from the Dope-Smokin-Old-Man I've been dubbed the Longhorn Freak/Fanatic/Expert, I just hope I can live up to it. FINALLY got the HORNIAC...a '70 one ton Longhorn with a Pontiac 350/350 and lots of 'personality'. Check out The Longhorn Webite. E-mail longhornmail@yahoo.com My name is Andy...not Randy...I'm in Ohio...Not Illinois...close enough? Columbus Ohio



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