I know the guy that is going to install the gears in my truck and he said that Yukon 4.88s will still put strain on my truck with 37s-40s so he said to me too get 5.13s for both axles. Now i know yukons dont make 5.13 in the front for reverse cut but told me that they can make they for a little bit extra. So now asking all of your opinions what do you guys think in getting 5.13s front and rear in my truck and only running 37s and then going up to 38s or 39s ? Or should i just tell him to go with 4.88s anyways and well leave it as that. Im getting this all done tongith so when i wake up my time ( Iraq ) i can call him to let him know my final answer bc the truck is going in tonight to get final specs on the axles and what stuff to order.

 

I think 4.88's will do just fine.

 

How well do you know this guy. My first thought is that he can make more money off a ring and pinion set that he builds/sells than the Yukon that you want to bring him.

#2) I don't think a 5.13 will fit in our stock axle housings.

I could barely slide the pin that goes between the axles back in when I did my 4:88s. I actually had to shave a little off one tooth to get it back in.

+ my truck now is still over all geared lower than stock still with 4:88s and 38's on.

5:13's wouldn't be bad if you got it to work but 4:88s work great and thats what almost everyone is running.

 

Ok BC he said it would cost about $80-200 more to have someone at Randy & Pinions to make 5.13s for the front axle which is 8.8 ...... Bc the rear axle which is 9.75 they already make 5.13s for them. So he was saying in all it would cost roughly $1800 to have those gears made for up front and have everything installed to roll back out... He also told me this will be the 2nd f150 he has done for the 5.13s front and rear.. So what do you all think now that this can be done if i plan on running 39s or 40s later on ? Do you think 5.13 will be a better gear to run with running that big of a tire and also would my rpms be good with 5.13s and running 37s for now ? I looked it up in the gear ratio thing and says my rpms will be able 2881 ?

 

If he's done it before I'd say go with it. As long as you think the new gears will be up to par quality wise with the Yukons.

I didn't do the math but, I ran 4:88s with 35's for quite a while and it was fine so I'd think that 5:13's and 37's wouldn't be bad.

My motor's definately not screaming now going down the highway. And if you may go up to 40's, the lower the better.

 

Oh did you mean 2881 rpm's at what speed 70?

if so that's be fine.

 

Yeah heres the link but it says at 65MPH but mybad it say 3000RPM with 5.13s and up i move up then it goes back to about 2900


http://sierrabronco.com/TireGearRatio.htm

 

yea well it also says that I'll run at 2805 with my 38's and 4:88 gears. That's BS

I run about 2400 at 70 I've got a pic somewhere...............

 

so guess they will be lower than that so which it will be alot better. Truck is on its way to get the axles specs for sure and then they will be putting them on within the week and ill be home on mid tour very shortly

 

35's and 4:88 gears

 

Not bad at all man looks like ill be around there too so it should not be bad at all. Also whats your MPG's like ? Mine were 11 when i used to run my 37s so im not sure how its gonna be when i re gear with 5.13 may go down to 10 MPG haha so well see i guess.

 

I get an average of 11

It was about the same with 35's and 4:88s.

I've gotten as good as 12.3 but as low as 9.9 depending how I'm driving but 11 the average.

 

yeah that sounds like how mine was and im sure its the same now since i got my 37s back on..

 

the RPM calculators dont take into affect overdrive.

you will be around 2400 with 5.13's and 37's at 65 MPH

 

yukon actually makes a 5 13 for our trucks heres a part number i found [YG F9.75-513] on a site called alljeep.com