Novak Conversions Jeep Wrangler TJ engine mounts

Going down in tire size (33s and 4.88 gearing)

With the 6-speed and 33’s I had 456 gearing and had plenty of gear. With 488 I’d think 1st is going to be really really short. Have you plugged the numbers into Grimm Jeeper? As long as you’ve done that and are ok with it then 👍🏼

I did plug it all in grimmjeeper. I looked a few different scenarios. I think it will be good. I don’t drive fast or get on any freeways.
 
I did plug it all in grimmjeeper. I looked a few different scenarios. I think it will be good. I don’t drive fast or get on any freeways.

I just plugged them in too. Even at 70mph your rpm’s in 6th will be 2920 (with a true 33”). You’ll likely have a 32.5” tire, and higher rpm’s, but 3000’ish should be totally fine.

I’m at 3500 at 70mph in 3rd (42rle).
 
  • Like
Reactions: Peppergat
I just plugged them in too. Even at 70mph your rpm’s in 6th will be 2920 (with a true 33”). You’ll likely have a 32.5” tire, and higher rpm’s, but 3000’ish should be totally fine.

I’m at 3500 at 70mph in 3rd (42rle

IMG_4077.png
IMG_4076.png
 
  • Like
Reactions: JMT
I was just looking at these tires since I have the 35” version just as a comparison. Any other recommendations in a 33x10.50?
 
  • Like
Reactions: JMT
I just plugged them in too. Even at 70mph your rpm’s in 6th will be 2920 (with a true 33”). You’ll likely have a 32.5” tire, and higher rpm’s, ...

33s are going to be closer to 31.5" effective rolling diameter. This is what have found multiple times when measuring hub heights, and also doing the rpm and gps speed calculations.

35s are typically about 33.875" effective rolling diameter.
 
I don't typically run mine up that high, I usually shift somewhere around 3K, depending on what I'm doing, but you're right, a lot of people seem to be racing through the gears, shifting way too low in RPM, or even running in 5th/OD at 35 mph. I've seen people who thought they had to shift by 2,500 for some reason no matter what, and at that range most engines are lugging bad into the next gear.

Lugging is a factor of rpm AND load. I run 40 in 5th all the time. Cruising at 1500 under very light throttle is just fine.
 
  • Like
Reactions: hear
Lugging is a factor of rpm AND load. I run 40 in 5th all the time. Cruising at 1500 under very light throttle is just fine.

Right, and the OD gear is multiplying that load. If you want the engine to tell you that you are lugging, just apply some extra throttle or a slight incline, and listen to what she says (clang-clang-clang-rattle). At that exact same speed in a lower gear/higher RPM (reduced load), it won't talk back to you like it does at 40 in 5th.
 
  • Like
Reactions: LONGJP2
I have 33s and 4.88s. But I have the 42RLE automatic. It's terrible honestly. I went with a trusted gear shop where I live and the sales guy convinced me to go with 4.88 gears over 5.13. Really wish I would have went with 5.13. ANYWAYS. If you have the manual it should be very nice
 
  • Like
Reactions: BC Moto and srimes
My 2005 TJ Rubicon came with budget 35" in combo with 5.13 gearing, which wasn't a good combo IMO with 42RLE. Replaced those with a fresh set BFG M/T KM3 in 33x12.5R15 prox 3 wks ago and it's the "sweet spot". That, plus a new PCM from WranglerFix has RPMs and shifting in the "happy zone"...
 
Last edited:
I have an 05 tj 6spd manual on 33s with 4.88 gearing. 3.5 lift.

Super happy with where it is at, takes me wherever I wanna go.

On Road, 1st gear will get you thru an intersection, but plan on shifting I to 2nd soon after.

On freeway, its drives fine... 70mph is my new top speed, 65mph in 6th is cruising. It can hit 80 in 6th.. but youll know your pushing it.
 
Just an FYI, it would appear the OP sold the Jeep back in May to another forum member (and hasn't been on since), the topic may be moot* at this point. :)

*FIFM :D
 
Last edited:
  • Haha
Reactions: Sancho and JMT
I’ve got 33” tires & 4.56 gears with the 6 speed transmission & I think it’s perfect for me. If I had 4.88 gears my 1st gear would essentially become a “granny gear” which would be kind of useless. Of course, it would be awesome off road.

This ^^^^

I am completely happy with the 33 / 4.56 combo with the 5 spd. Never once thought I should have gone with 4.88
 
  • Like
Reactions: Mudflat
Yeah, I can no longer hear the topic either, Chili...

😉

The topic is certainly not mute, but it is probably moot. ;)

In my defense, it was 2:44 am... :geek:

It would appear now that my statement may be the moot bit, given renewed thread activity, so I should probably mute m'self. 😁
 
Last edited:
Novak Conversions Jeep Wrangler TJ engine mounts