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Old 07-20-2003, 08:00 PM
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1049251

The big day of my SOA is coming up which means I will be buying new wheels/tires shortly... I have a 91 YJ with a 4.0 in it, the ratio for the axle is only 3.07... I have read somewhere that it would be better to get lower gears for bigger tires. I was just wondering if this is absolutly necesary, has anyone out there ran larger tires with a ratio like this? [addsig]
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Old 07-20-2003, 08:00 PM
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1049264

I am using that gear ratio with 35's but I have a chevy 350 motor. Both of my yokes for the rear end drive shaft have broke already, so beware.[addsig]
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Old 07-20-2003, 08:00 PM
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1049266

I think its possible, but the Jeep will be a pig. I am runnin 32's on the stock gears in my 2.5 w/ 4.10 gears. Here is a formula to compute what the ratio will be-



tire size now X gear ratio

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wanted tire size





Figuring your Jeep has 30" tires now, that will give you a equivilent of about 2.63 gears in the axles- This will make your Jeep a slug [img]modules/phpBB_14/images/smiles/icon_cry.gif[/img] [img]modules/phpBB_14/images/smiles/icon_cry.gif[/img] ,



Try Gears Site and find some gears that will work for you- They shouldn't be too much, expect around $350-400 total for gears... otherwise you will be putting a lot of stress on your tranny and clutch trying to turn those meats with stock gears....



Hope that helps- its my $.02 worth[addsig]
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Old 07-20-2003, 08:00 PM
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1049277

This is kinda fuzzy logic but it works for me, as a rule of thumb, or a wild arsed guess.

The standard overdrive is about 15% (10-15) over. Every two inches of tire works out close enough to be the same. Starting at a 27" tire stock, you would be adding about four more overdrive gears. Or a drop of between 200 and 300 RPM for every two inches of tire to go the same speed. The peak torque (power) of your motor is 2200-2400 RPM at 60 MPH, you could be running at near idle speeds, in fifth gear, to be doing the same 60 MPH.



Like the man said it would be a slug.[addsig]
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Old 07-20-2003, 08:00 PM
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4.88s they run 129$$$ a set lol j/k try what u have tttttttttttttttttthhhen gat 4.88s



gears rule i'm just now getting 5.38s talk about kic az [img]modules/phpBB_14/images/smiles/icon_cool.gif[/img] [addsig]
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Old 07-20-2003, 08:00 PM
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It all depends on how much road driving this truck sees. If you still do a fair amounmt then you should consider 4.27's. If you are in between then 4.56's and if you primarily run offroad then 4.88's or better. The 3.07's with 35's will make it a chalange to even get your truck into 4th gear. Forget 5th unless you get up to about 90. Your 0-60 should take approx. 3 days. I don't suggest running those tires until you get some gears. Yes you can get gears for about $129 but always remember to get the master install kit with those. You should change out your seals and your bearing while your in there and these should come with a good masterr install kit. These kits run between $100 and $150 per axle. The other thing is to consider that you will need a new carrier to put in these gears, they are about $100 each also. So the budget of $400 - $500 per axle is about right. Good luck, Let me know if you have any questions



ECOR



darrin@eastcoastoffroad.com[addsig]
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Old 07-20-2003, 08:00 PM
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1049946

Right Now I'm running 35's the stock 3.07 gears, and the performance sucks, my main usage for my rig is everyday driving and occasional off-roading. My question is, why use 4.27's instead of 4.88's. Also, I am thinking about changing my tire size to 32's and I'm wondering if I should keep my 10" wide wheels[addsig]
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Old 07-20-2003, 08:00 PM
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1049972

i ran 35's with 3.73's for a week, i already had the gears and

lockers just not installed, and it was a pig. It accelerated terribly

and fifth wasnt ever used, even at 65-70 on the expressway.

when you switch gears get the steepest you can, even on the

road you wont regret it. Im using 5.13's for 37's cause the 4.56's

were good but not great on pushing the jeep around, but i also

have the overdrive in the nv4500 tranny i have.[addsig]
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Old 07-20-2003, 08:00 PM
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Bad idea running 35" with 3:07's Like Ecor said, It'll take ya 3 days to get up to hwy speed! [addsig]
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Old 07-20-2003, 08:00 PM
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1050397

yeah dude... that's way too big of tires...[addsig]
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Old 07-20-2003, 08:00 PM
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1050411

Get on the phone w/ Rusty at Rustys Offroad.He has had a deal that you can get some 4.56 w/ master install kits for $379.Good deal.He also said he would sell me a carrier at $60.Good deal.Also dont forget unless you are highly skilled take it to a shop to get your gears done.But watch out, a place around here wanted $800 and i went to another place and they only wanted $450.So shop around and do some research.[addsig]
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