Re-gearing help

[Shooter04]

Not sure if this is the right sub-forum.

My truck is currently running the stock 3.73's (pretty sure) but i want to re-gear before the summer. I want gears that are ideal for 40" tires because that's my ultimate goal with the truck. What would be the optimum ratio?

Thanks

[bruce51d]

here is a good formula (40/31) X 3.73 = 4.81 so a 4.88 or a 4.56 would be your best bet

[Raul@Stealth Automotive]

i had 4.30 with 40" tires and wished i had gone 4.56....

[Shooter04]

So 4.56 or 4.88's? They seem pretty similar in ratio, so should I just go for the 4.88's to be safe?

Is this a DIY job at home or would it be safer to have a professional do it?

Where do i buy new gears at?

[GregsSD]

Originally Posted by Shooter04

So 4.56 or 4.88's? They seem pretty similar in ratio, so should I just go for the 4.88's to be safe?

Is this a DIY job at home or would it be safer to have a professional do it?

Where do i buy new gears at?

I would go 4.88's definitely!
If you have never set up gears then you better have a shop do it! To set them up correctly requires some special tools to get the tolerances just right so they will last.

[Raul@Stealth Automotive]

i would go with 4.56... and def not a DIY thing... let the prof do it.. i can get you the gears and install kits but an install shop is going to charge you at least 250.00 per axle to change the out....

[JStranberg]

I had the same question. I have 37's and the stock 3.73's. I used a ratio calculator and found that 4.30's would bring me back to about the same ratio as the 33's with 3.73. Is there a brand you should look for?

[Shooter04]

Originally Posted by GregsSD

I would go 4.88's definitely!
If you have never set up gears then you better have a shop do it! To set them up correctly requires some special tools to get the tolerances just right so they will last.

Why 4.88's over 4.56's?

Originally Posted by Raul@Stealth Automotive

i would go with 4.56... and def not a DIY thing... let the prof do it.. i can get you the gears and install kits but an install shop is going to charge you at least 250.00 per axle to change the out....

And why do you say 4.56's over 4.88's?

Yes i may take you up on the ordering from you. I can't seem to find them online. How much do you sell them for? And i have Innovative diesel here in Houston that i already talked to about doing it and they can.

[Raul@Stealth Automotive]

well i ran 40's on 4.30 and wished they were a tad bit lower... and i have been in trucks with the same size tires and 4.56 and they are just too low... you want something that will still let you be around 2krpm at 70mph.. the 4.56 will be to low for that... if you did those it would be great for stop and go but at highway speeds your going to be at around 2200 at 70mph

-Raul

[crdenoyer]

i agree. i did the calculations for my 37's and it came out to be 4.45. so should i go with 4.30's or 4.56's