gearing and axle questions - The 1947 - Present Chevrolet & GMC Truck Message Board Network

snacob14 · 08-02-2010, 11:04 PM

I'm running a 285 rear on a 20" wheel. I've got an 87 w/700r tranny. My rearend is currently either 2.73 or 3.08, I haven't gotten under it a checked yet. My question is what are you guys running for gears on this size tire. Overdrive is kinda useless unless I'm doing 80. I'm thinking 4.10's would be good, but I don't want it to be screaming down the highway. I was thinking it would cost quite a bit to do the gears, even if I did it myself I'd be 300 deep in parts. I may just look for a rear already geared or even a 9inch if the wms width was the same. What are you thoughts.

f.monroe · 08-02-2010, 11:11 PM

Exactly what size tire ? 285/??/20.
Frank

snacob14 · 08-03-2010, 08:28 PM

285/50/20

85burb · 08-03-2010, 08:55 PM

If that is about 33 inch tire 4;10 will be good. I have a 85 4X4 burb with 285/75/16 (33 or so). Got a 700R4 and 4:10s they a little low for in town but i love the set up. Hits overdrive with converter lock up at about 45-55 if i baby it. My week old 350 does not have trouble keeping up. It will also do over 100 MPH on high way. What axle do you have. If you do have 3.08 you will have to change your carrier i beleve.

STOCKISH · 08-03-2010, 09:00 PM

I WOULDNT GO ANY LOWER THAN 3.73 GEARS. SEEMS TO BE THE BEST ALL AROUND GEAR. SORRY, MY CAPS LOCK APPEARS TO BE STUCK ON

DubDubU · 08-03-2010, 10:01 PM

My rear tires are 28.5 in. tall. With the 700r4 and 3.73 gears I'm running 65 mph just under 2000 rpm. The tire calculator I use says your tires are 31.2 inches tall. At 2000 rpm you could be cruisin at 70.

snacob14 · 08-03-2010, 11:11 PM

Quote:

Originally Posted by DubDubU

My rear tires are 28.5 in. tall. With the 700r4 and 3.73 gears I'm running 65 mph just under 2000 rpm. The tire calculator I use says your tires are 31.2 inches tall. At 2000 rpm you could be cruisin at 70.

Dude! Where are you at in STL. I live just south in Festus. I saw at one time there was a truck show in Arnold Park a while ago.

DubDubU · 08-03-2010, 11:25 PM

I've been at that show for the last 3 or 4 years. This year its on August 21st, at 11 am till 3 pm. Same place. Bring your truck up and have a good time. I live in Brentwood, near 170 and 40.

08-02-2010, 11:04 PM	#1
snacob14 Registered User Join Date: Oct 2006 Location: Desoto, MO Posts: 225	gearing and axle questions I'm running a 285 rear on a 20" wheel. I've got an 87 w/700r tranny. My rearend is currently either 2.73 or 3.08, I haven't gotten under it a checked yet. My question is what are you guys running for gears on this size tire. Overdrive is kinda useless unless I'm doing 80. I'm thinking 4.10's would be good, but I don't want it to be screaming down the highway. I was thinking it would cost quite a bit to do the gears, even if I did it myself I'd be 300 deep in parts. I may just look for a rear already geared or even a 9inch if the wms width was the same. What are you thoughts.

08-02-2010, 11:11 PM	#2
f.monroe Senior Member Join Date: May 2004 Location: Caldwell,Tx. Posts: 3,648	Re: gearing and axle questions Exactly what size tire ? 285/??/20. Frank __________________ Born and proudly residing in a Red State !

08-03-2010, 08:28 PM	#3
snacob14 Registered User Join Date: Oct 2006 Location: Desoto, MO Posts: 225	Re: gearing and axle questions 285/50/20

08-03-2010, 08:55 PM	#4
85burb Registered User Join Date: Dec 2009 Location: lindale,tx Posts: 2,373	Re: gearing and axle questions If that is about 33 inch tire 4;10 will be good. I have a 85 4X4 burb with 285/75/16 (33 or so). Got a 700R4 and 4:10s they a little low for in town but i love the set up. Hits overdrive with converter lock up at about 45-55 if i baby it. My week old 350 does not have trouble keeping up. It will also do over 100 MPH on high way. What axle do you have. If you do have 3.08 you will have to change your carrier i beleve. __________________ 82 c10 5.3/4l60 84 c20 5.3/sm465 85 chevy k10 suburban LQ4/4l60 91 chevy c10 suburban Lsa 5.3/4l60 2017 Silverado whipple 5.3 1964 Vw beetle 1974 vw beetle

08-03-2010, 09:00 PM	#5
STOCKISH Formerly- 1972SuperCheyenne Join Date: Oct 2008 Location: Wake Forest NC Posts: 5,782	Re: gearing and axle questions I WOULDNT GO ANY LOWER THAN 3.73 GEARS. SEEMS TO BE THE BEST ALL AROUND GEAR. SORRY, MY CAPS LOCK APPEARS TO BE STUCK ON __________________ --Josh My Build Thread:http://67-72chevytrucks.com/vboard/s...d.php?t=799218 A good crossthread is better than Loctite any day. Life is not about what you have, but who you have to share it with.

08-03-2010, 10:01 PM	#6
DubDubU Registered User Join Date: Mar 2007 Location: st louis,mo Posts: 313	Re: gearing and axle questions My rear tires are 28.5 in. tall. With the 700r4 and 3.73 gears I'm running 65 mph just under 2000 rpm. The tire calculator I use says your tires are 31.2 inches tall. At 2000 rpm you could be cruisin at 70. __________________ '79' shortbed

08-03-2010, 11:25 PM	#8
DubDubU Registered User Join Date: Mar 2007 Location: st louis,mo Posts: 313	Re: gearing and axle questions I've been at that show for the last 3 or 4 years. This year its on August 21st, at 11 am till 3 pm. Same place. Bring your truck up and have a good time. I live in Brentwood, near 170 and 40. __________________ '79' shortbed

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