What gear ratio works best for 33's? - Page 2 - The 1947 - Present Chevrolet & GMC Truck Message Board Network

Apache · 04-27-2005, 03:55 PM

If he wants to drive it alot, sometimes its best to fear the gear. I have 4.88's under the nova now....would be a bit much daily driving.

nu2-72 · 05-01-2005, 07:52 PM

I am sure many of you recieve the Off Road Adventures magazine like I do. It has a reader question on gears and tires. It states that simply, rule of thumb is 31" = 3.73. 33" = 4.10. 35" = 4.56. 37"-38" = 4.88. 39-40 " = 5.13 and 44" = 6.0:1
I would guess this depends upon 4 spd vs. automatic and does not take into account for any overdrives.
The formulas used here were;
equivalent ratio= new tire dia./old tire dia. X original gear ratio. This is to match your new setup to your old ratio.
effective ratio= old tire dia./ new tire dia. X original ratio. This tells you the new tire and gear combo.
Several months ago when I asked this question the answers were heavily 4.10. Seems like a lot of 3.73 answers now. Interesting.

Jason915 · 05-03-2005, 12:49 PM

I went from 33's and 3.08's to 33's w/ 3.73's very noticeable difference and decent on the HWY. then went to 4.10's with the same 33's and will never go back. The 4.10's and 33's work great for towing and climbing but I live in CO. at 6200' of altitude and go to 11K+ altitude with mountain pass towing and stuff where the speed limmits are only a max of 60MPH. If I lived at a lower altitude with no mountain passes and I wanted to be able to go 75mph+ for miles on end then yes I would want a higher gear ratio. It really depends on what your using your truck for.

uncle_handsome · 05-06-2005, 10:46 PM

Quote:

Originally Posted by Jason915

I went from 33's and 3.08's to 33's w/ 3.73's very noticeable difference and decent on the HWY. then went to 4.10's with the same 33's and will never go back. The 4.10's and 33's work great for towing and climbing but I live in CO. at 6200' of altitude and go to 11K+ altitude with mountain pass towing and stuff where the speed limmits are only a max of 60MPH. If I lived at a lower altitude with no mountain passes and I wanted to be able to go 75mph+ for miles on end then yes I would want a higher gear ratio. It really depends on what your using your truck for.

Does your truck have an automatic or manual transmission?

Jason915 · 05-09-2005, 12:42 PM

4 speed M465

04-27-2005, 03:55 PM	#26
Apache Registered User Join Date: Jun 2004 Location: South Carolina Posts: 419	If he wants to drive it alot, sometimes its best to fear the gear. I have 4.88's under the nova now....would be a bit much daily driving. __________________ 54 Chevy Bel Air 4dr powerglide 54 Chevy SWB 58 Chevy Big Window SWB Fleetside project 58 Chevy LWB 235/4spd 76 Chevy Nova 350/TH350 4.88's *10kmiles on "new" engine 79 Chevy 4x4 SWB 350/4spd 3/4 ton 81 Mazda RX7 84 F@!d Mustang 96 F@!d Ranger 2.3L/5spd

05-01-2005, 07:52 PM	#27
nu2-72 Senior Member Join Date: Apr 2001 Location: Amazonia, Mo. USA Posts: 2,821	I am sure many of you recieve the Off Road Adventures magazine like I do. It has a reader question on gears and tires. It states that simply, rule of thumb is 31" = 3.73. 33" = 4.10. 35" = 4.56. 37"-38" = 4.88. 39-40 " = 5.13 and 44" = 6.0:1 I would guess this depends upon 4 spd vs. automatic and does not take into account for any overdrives. The formulas used here were; equivalent ratio= new tire dia./old tire dia. X original gear ratio. This is to match your new setup to your old ratio. effective ratio= old tire dia./ new tire dia. X original ratio. This tells you the new tire and gear combo. Several months ago when I asked this question the answers were heavily 4.10. Seems like a lot of 3.73 answers now. Interesting. __________________ 72 3/4 4x4 350 4spd 72 3/4 4x4 350 auto 2004 Duramax Silverado 4x4 2006 Duramax Crew cab 4x4 2010 Harley Ultra Limited 2011 Harley Street Glide

05-03-2005, 12:49 PM	#28
Jason915 Registered User Join Date: Jan 2005 Location: Colorado Springs Posts: 693	I went from 33's and 3.08's to 33's w/ 3.73's very noticeable difference and decent on the HWY. then went to 4.10's with the same 33's and will never go back. The 4.10's and 33's work great for towing and climbing but I live in CO. at 6200' of altitude and go to 11K+ altitude with mountain pass towing and stuff where the speed limmits are only a max of 60MPH. If I lived at a lower altitude with no mountain passes and I wanted to be able to go 75mph+ for miles on end then yes I would want a higher gear ratio. It really depends on what your using your truck for. __________________ 1971 GMC K1500 SWB Fleetside, 4" skyjacker softride and, 14 Bolt FF, HD Dana 44 4.10's 1970 K5 TBI conversion lifted etc SOLD 1968 C20 camper truck SOLD “To ban guns because criminals use them is to tell the innocent and law-abiding that their rights and liberties depend not on their own conduct, but on the conduct of the guilty and the lawless.” Jeff Snyder

05-09-2005, 12:42 PM	#30
Jason915 Registered User Join Date: Jan 2005 Location: Colorado Springs Posts: 693	4 speed M465 __________________ 1971 GMC K1500 SWB Fleetside, 4" skyjacker softride and, 14 Bolt FF, HD Dana 44 4.10's 1970 K5 TBI conversion lifted etc SOLD 1968 C20 camper truck SOLD “To ban guns because criminals use them is to tell the innocent and law-abiding that their rights and liberties depend not on their own conduct, but on the conduct of the guilty and the lawless.” Jeff Snyder



Register or Log In To remove these advertisements.

Register or Log In To remove these advertisements.