35s & 4.56 gears experience

[Binfordtools]

Good to read a "real-world" account of this. On paper, a 315/70/17 (about 34.5 size tire) and a factory 255/75/17 (about a 32 size tire) is around a 7 to 8% increase in diameter. It's strange just how much this impacts driveability. Then again, the width is quite a bit wider (like a 24% increase) so you do lose some power there. And of course, there are weight differences too. So added up, I guess this all makes sense. Cool write-up, thanks for posting.

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[MrKnowitall]

great to hear that your 6pd-4.56-35" combination is working well.
BTW- hand calc for those interested:
=(Tire revs/mi)...from vendor/mfg spec sheet
X(rear axle ratio)
X(trans top ratio)
X(highway speed)
/(60min/hour)
with numbers it looks like:
(600)X(4.56)X(0.72)X(75)/(60)=2462.

 

[Rejectbassmaster]

Thanks for posting this!

 

[Binford]

Thanks for this post OP. I got my regeared Gladiator back yesterday and chose 4.56 based on this post, as I considered both 4.88 and 4.56. I only got to drive it briefly as I then dropped it off again today for a full Ceramic Pro treatment but my brief drives def like it was back to stock feel and similar to your posted experience with my 35" Ridge Grapplers on it.

 

[colindo]

Thanks for this post OP. I got my regeared Gladiator back yesterday and chose 4.56 based on this post, as I considered both 4.88 and 4.56. I only got to drive it briefly as I then dropped it off again today for a full Ceramic Pro treatment but my brief drives def like it was back to stock feel and similar to your posted experience with my 35" Ridge Grapplers on it.

Do you have a manual or auto? I think it will help no matter which tranny you have but I'd like to get more feedback on the auto. Currently saving up for this one.

 

[Binford]

Do you have a manual or auto? I think it will help no matter which tranny you have but I'd like to get more feedback on the auto. Currently saving up for this one.

I have the 8 speed auto

 

[Uparms]

Max Tow, 35s, 8spd. Auto. Runs amazing. 1

17 MPG avg, Better on the big roads. A little more time in 7th.

Yes I will do 4.56s but not till I can find non-air lockers for front and rear. Preferring E-Lockers.

 

[Jonny A]

Perhaps if I were to go 37's I may think to get gear to the 4.56. I have 35's and 4.10s now, and I have absolutely no want for more gear. All is well and I average 18-19 mpg on mixed terrain and roads. Auto tyranny.

 

[syreeves]

Perhaps if I were to go 37's I may think to get gear to the 4.56. I have 35's and 4.10s now, and I have absolutely no want for more gear. All is well and I average 18-19 mpg on mixed terrain and roads. Auto tyranny.

sounds like you are repressing yourself!

 

[Gren71]

Perhaps if I were to go 37's I may think to get gear to the 4.56. I have 35's and 4.10s now, and I have absolutely no want for more gear. All is well and I average 18-19 mpg on mixed terrain and roads. Auto tyranny.

I wish I was still getting 18-19. Pretty sure my dealer did PCM update or some such a while ago and now my mpg just sucks...average 16-17 with mostly highway driving and nothing else has changed. I also don't see 8th on uphills like I used to. 4.56's are still on the list for me, intentionally this summer. Im just afraid of over gearing since I have 34's and its a daily driver.

 

[Jonny A]

I wish I was still getting 18-19. Pretty sure my dealer did PCM update or some such a while ago and now my mpg just sucks...average 16-17 with mostly highway driving and nothing else has changed. I also don't see 8th on uphills like I used to. 4.56's are still on the list for me, intentionally this summer. Im just afraid of over gearing since I have 34's and its a daily driver.

I usually only see 8th on level ground. Most inclines it will kick down to 7 th. That makes me happy though. Wife Camero would stay in top gear until almost lugging the engine. Don't care for that. I personally like the sub 2000 rpm's at 70 mph.
This 3.6 engine to me seems as good or better than any of the anemic engines in cars and trucks I owned from the late 70's through now. Just don't be afraid to put my foot in the gas when needed.
Unless I start doing stuff with my JTR that would really benefit re gearing, I am quite happy with what I got.
Really... reading these threads sometime makes one feel something should be changed just because " everybody else is doing it".

 

[Tufelhundin]

I wish I was still getting 18-19. Pretty sure my dealer did PCM update or some such a while ago and now my mpg just sucks...average 16-17 with mostly highway driving and nothing else has changed. I also don't see 8th on uphills like I used to. 4.56's are still on the list for me, intentionally this summer. Im just afraid of over gearing since I have 34's and its a daily driver.

Hey Gren, I’m running 315/70-17’s with 4.56

I see 8th at 45mph, LOL

Here’s a pick at 65mph, just for reference ... speedo is on

 

[brog]

@Chaosmtb

looks like about 2100 at 70. The closest I could get tire size/mph using 2 speed apps and Waze was about 1 mph less than indicated. So I was roughly going 69mph via GPS.

I know one thing, with the 4.56 it should be call a Max Sport, lol.

Edit: I just looked at Grimmjeeper and at 70mph it shows 2091 rpm.

Dumb question: Does the digital speedo get it's information the same way the analog speedo does? This looks like the analog shows about 72mph. I just ask bc since my lift and 35" tires my analog seems to be 2-3 mph higher than the digital display.

 

[Tufelhundin]

@brog I’m not sure how the info is sent...the angle from the phone makes it look off “analog” but it reads the same .

 

[Gren71]

Hey Gren, I’m running 315/70-17’s with 4.56

I see 8th at 45mph, LOL

Here’s a pick at 65mph, just for reference ... speedo is on

nice! What kinda of MPG are you seeing with regular driving? and what kit did you use?

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