PDA

View Full Version : GEARS for 37's?



Bult4mud
December 6th, 2005, 01:54 PM
thinking about going up a size in tires
running 35's right now, with a 4.0/3speed tranny/410 gears
what should i change for 37's

Roadhouse
December 6th, 2005, 02:18 PM
BDR is running 4.88's with his 37's but I believe the Rubi's auto's have OD. So not sure if you want those kinda rpms with 4.88 and no OD. What kinda rpm's are you turning with 4.10's and 35's?

Bult4mud
December 6th, 2005, 02:33 PM
2600 ish at 70 right now

no od would be bad with 37's i think

Jarhead
December 6th, 2005, 02:42 PM
<div class='quotetop'>QUOTE(Bult4mud &#064; Dec 6 2005, 12&#58;54 PM) 6951</div>

thinking about going up a size in tires
running 35&#39;s right now, with a 4.0/3speed tranny/410 gears
what should i change for 37&#39;s
[/b]

I have a Gear Ratio Guide for Larger Tires in Word Format (*.doc) and Excel Format (*.xls). It starts at 22" tires and goes up to 44" tires. The axle Ratios start at 2.35 and goes up to 7.17. I will try to append the word document to this post. If it doesn&#39;t work I could try to send it to you another way, if you like.


[attachmentid=46]

Bult4mud
December 6th, 2005, 02:44 PM
HOORAH Jarhead thanks man

ive been using this one too im leaning twards 456

http://www.4lo.com/calc/geartable.htm

Roadhouse
December 6th, 2005, 03:23 PM
Jim just some added info. I have 4.56&#39;s w/32&#39;s on my ZJ. At 70mph I turn 2700rpms, off course I have OD.

I want to put 37&#39;s under my ZJ, I already have the 1/2ton axles geared to 5.13 w/detroits.
From what I have figured out 5.13 w/37s is about the same as 4.56 w/32s

Here is another useful site

http://www.ring-pinion.com/content/calculators/default.asp

Bult4mud
December 7th, 2005, 12:57 AM
it shows me at 2829 with my current set up and if i kept same gears id get 2676 isnt that better on the highway??

but then not as good off road or around town right?
if i keep 410&#39;s and 37&#39;s

Jarhead
December 7th, 2005, 07:01 AM
<div class='quotetop'>QUOTE(Bult4mud &#064; Dec 6 2005, 11&#58;57 PM) 6973</div>

it shows me at 2829 with my current set up and if i kept same gears id get 2676 isnt that better on the highway??

but then not as good off road or around town right?
if i keep 410&#39;s and 37&#39;s
[/b]

My Hummer H2 comes stock with a 410 Rear End and 35" Tires which nets 13 mpg. I replaced the 35&#39;s with 37&#39;s and I am still getting 13 mpg.

lgottler
December 7th, 2005, 09:13 AM
Mileage really depends on how hard your engine is working to push that metal brick down the road. (Jeep or Hummer&#33;)

I jumped from 12-13mpg to 15-16mpg actual mileage. I went from 3.73&#39;s and 33&#39;s up to 5.13&#39;s and 36&#39;s. My engine did higher RPM&#39;s but it took a lot less power to turn it all. I had a best of 17mpg going through the UP last summer. Before I couldn&#39;t make it up the Zilwaukee without going to 4th, now I can stay in 5th without a problem.

My speedo is way off, so I use a GPS to mark mileage and then just fill it up about 3 times one way up north and take the average.

I&#39;d be going to 5.3+ if I didn&#39;t have to drive everywhere. 5.13&#39;s are a bit low for a DD on highways alot. I&#39;d guess 4.56 would be good for a lot of road miles.

Good luck

Lucas

Bult4mud
December 7th, 2005, 10:07 AM
Im thinking of doing a Teralow too so that would take care of the off road problems of not running low enough gears