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5.13's in a 10 bolt front

jonathon

jonathon

1/2 ton status
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Washougal, WA
Too much gear? I'm running 35's and the front will be open, and it won't be wheeled.

I was thinking 4.56's but with the hills we got around here I'm leaning towards lower..
 
Oy, that'd be WAY low. Sticking with the 35's? MAYBE 4.88's.

What gears did it have with the stock 31's?
 
I'd go 4.88's....actually I did. I normaly run a 36" tire. I can pull hill just fine. I regularly pull a 4 place snowmobile trailer throgh some decent hills (nothing like what's out west though). Most times I can leave it in 4th (Sm465) and let the motor grunt it's way up. Rarely do I have to downshift to third. Ofcourse I have a torquey 355.
 
3.73's and it did great unloaded but not so much towing. I've got OD so cruising isn't an issue..

With 5.13's at 60mph I'll be turning 2200rpms with the tc locked up.. at 70 it'll be 2600. Most of the highways here are 60mph.

With 4.56's at 60 it'll be about 1990rpms and at 70mph 2300 rpms.

I'm getting 11mpg now with 35's and 3.73's and not using OD. If it stayed the same or got better I'd be happy, but the off the line grunt sucks around town. I don't think the MPG will be radically different than it is now with better gears, if anything it'll improve with either set.
 
It's been along time sense mine's been on the road but what I remember it turn about 1900 to 2000 @ 70 mph.

It has 5.13, 700r4, 205, Tires are 39" MT baja belted on 16.5 x 14 wheels, so they only measure about 37" tall.

They would work but 4.88 might be better for that tire.
 
jonathon said:
I've got OD so cruising isn't an issue..

With 5.13's at 60mph I'll be turning 2200rpms with the tc locked up.. at 70 it'll be 2600. Most of the highways here are 60mph.

With 4.56's at 60 it'll be about 1990rpms and at 70mph 2300 rpms.
Click to expand...

5.13 is too much gear for 35's. Don't try it unless you will be switching to at least 38's or 39.5's.

For 35's, go 4.56. 4.88 would work if you really like low gears.
 
jonathon said:
3.73's and it did great unloaded but not so much towing. I've got OD so cruising isn't an issue..

With 5.13's at 60mph I'll be turning 2200rpms with the tc locked up.. at 70 it'll be 2600. Most of the highways here are 60mph.

With 4.56's at 60 it'll be about 1990rpms and at 70mph 2300 rpms.

I'm getting 11mpg now with 35's and 3.73's and not using OD. If it stayed the same or got better I'd be happy, but the off the line grunt sucks around town. I don't think the MPG will be radically different than it is now with better gears, if anything it'll improve with either set.
Click to expand...

What tranny/tcase are you running?
 
I'm running 35's with a 700R4 and 4.56's and wish i had went deeper. II probably would have been happy with 4.88's but now that i already have 4.56's and the cost to do a gear swap it isn't worth it to me to only step up to 4.88's so when i do finally go deeper it will be to 5.13's. Now keep in mind i have 1 ton axles and if you don't have a D60 up front that pinion is going to get really small with a 10 bolt and 4.88's or 5.13's so i would stick with nothing more than 4.56's.

I'm assuming since it's a 91 V2500 burb it has the 4L80E judging by the RPM's you've calculated.
 
350/700r4/4.56s/35"s i kinda wish i had gone deeper but i pull the mountains round here in OD with my 4.56s and i can get 16mpg if i drive rite... plus i do hit 70 for some short spells
 
Heavy ass burb plus mountains is a little rough around here, even when it was stock. If it stays 10mpg or better I'm okay with it. I'd rather it work less to do what it does now.
 
you will notice a serious difference i had 3.08s on my 35"s then went 4.56s... hell for the first year on 3.08s i didnt know i had a 700r4 cause i only used 3 gears.... after the 4.56s i found out i had an extra one in there
 
Its amazing what gear changes can do, Ive owned a 4:10 shortbox on 39s, a 4:56 1 ton truck I built( orange one) on 38 tsls.. and now my compleatly factory longbox, has 3:42s....

sm465 is the only way to go, but an automatic will definatly respond better to the gears,

I would go 4:56 for mileage, 4:88 for pure towing factor
 
go 5.13 if it is too low go up to a 37 when its time for tire's and you could probably get by with the same lift.
 
Running 5.13's with the 700r4 in OD (5.13 x 0.70 = 3.60) will be almost exactly the same rpm range on the highway as you are doing now with 3.73 and not using OD. So if you are happy with how it cruises at speed now in drive (D), then 5.13's will be perfect since you will have much better low end take off but almost identical highway cruising.

Keep in mind, saying that 5.13 is way too much gear for 35's when you have a 700r4 is identical to telling someone that 3.60 gears are way to much gear with 35's if you had a SM465, TH400, or other non-OD equipped transmission.
 
350/700r4/241 37's and 5.13's, don't have a tach but it seems to cruise just fine, doesn't sound to high at least.:wink1:
 
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