4.56 with 32" tires, any problems ?

[green rust]

Sorry for another gear question and/or hijack...

How would 3.55 (stock for an auto) be with 32's?
How bout 3.73 (ford 8.8) for 32's?

To be honest, i'm pretty heavy on the gas.
Thanks and sorry again. :farmer:

It sucks that's what i have. I'll be going with 4.56 soon. I waiting for the 8.8 conversion first. unless i can find a descent locker for the 8.25.

 

[JeepinAudiophile]

Thanx for the equations Woody, i was a bit busy(and lazy) to figure them out on my own.
[edit]
Thanks to your equations i did the math and just called my local jeep guy to have him put together a price for d44 rear, 4.56s and all the trimmings.
(Santos Jeep Service in Worcester Massachusetts 508-755-8005)
He's one of the nicest guys you'll meet, if your in the area give him a shout, you can stop by and see his absolutely ridiculous Golden Eagle CJ.

 

[JeepinAudiophile]

just for added information, Bridgestone Dueler A/T Revo's- 255/70-16 are given as 30.1"diameter, at 693 revs per mile. Mathematicaly these tires have a rolling diameter of 29.102" In case anyone comes across this site interested in the same tires. This is my second set, and with mostly on-road driving through evil winters and all I have fallen in love with these tires, they are also pretty damn good in loose, offroad conditions. So heres what i'm looking at with 4.56s, Automatic:
(all # are estimated)

3rd Gear: *(rpm=mph)
2000=38 , 2500=47.5 , 3000=57 , 3500=66.5 , 4000=76 , 4500=85.5

Overdrive:
1500=40.68 , 2000=54.24 , 2500=67.81 , 3000=81.37 , 3500=94.93

 

[Jump This]

Didn't get the R&P work done this weekend :bawl:
Shipping co. didn't deliver as promised......
I was hoping to deliver to you all the definitive answer to the question of drivability of the set up.....oh well....next saturday I guess.
(Although I am happy to read all the possitive responces here!)
Rick

 

[mission-inc]

Great, thanks for the info guys! :worship:

 

[Starboard M]

I was just about to ask this very same question. It seems that 4:56's are the way to go. One question though...I plan on going to 35's after my 32s wear out. Would it be wise to go to 4:88's now or later? Sorry about the hijack.

 

[marcusguy]

just for added information, Bridgestone Dueler A/T Revo's- 255/70-16 are given as 30.1"diameter, at 693 revs per mile. Mathematicaly these tires have a rolling diameter of 29.102" In case anyone comes across this site interested in the same tires. This is my second set, and with mostly on-road driving through evil winters and all I have fallen in love with these tires, they are also pretty damn good in loose, offroad conditions. So heres what i'm looking at with 4.56s, Automatic:
(all # are estimated)

3rd Gear: *(rpm=mph)
2000=38 , 2500=47.5 , 3000=57 , 3500=66.5 , 4000=76 , 4500=85.5

Overdrive:
1500=40.68 , 2000=54.24 , 2500=67.81 , 3000=81.37 , 3500=94.93

This is interesting because with my 4.56's in my 99auto (.75 OD right?) and 32" BFGs my jeep is at 2700rpm at 70mph, according to my gps. I know that bfg's run small, but I'm turning more rpms than Jeepinaudio with 30" tires. What's up with that? Maybe torque converter is slipping? Interesting.

Marcus

 

[JeepinAudiophile]

first off, remember that i mentioned that these were all estimated as I do not have my axles re-geared yet. also, the rolling diameter is different from the unmounted diameter. I went off off of the equation that Woody gave, my tires diameter is 30.1, but rolling diameter is 29.1, im trying to save up to get regeared, and we'll see for sure then...

 

[Beezil]

I run 32's on my DD w/4.56's and an AW4. I tach 3,000 rpm at around 70 mph. .

can't be......unless your aw-4 is not locking in overdrive, or your speedo gear is inaccurate.

the mechanical truth of your posted working combo is:

4.56 gears, 31.7 MEASURED tires, 70MPH......

.71OD aw-4 rpm= 2537
.75OD aw-4 rpm=2402.

the fact that you say you are turning 3000 rpm in this relationship points to a problem, and the testimony is misleading for the folks trying to choose the right combos.

hope this helps.

 

[REDXJ4FUN]

for those who are to lazy to do it on paper heres a easy way to figure out what your doing. http://www.ring-pinion.com/calculators/calculatorsind.html

 

[Kejtar]

A simple formula for figuring out speed @ a given RPM

tire diameter x RPM / Axle ratio x gear ratio x 336

ex: 30" x 3000 / 4.56 x 1 x 336 = (90000 / 1532) = 58 MPH @ 3000 RPM in 3rd (auto)
or in (?.7?) Overdrive: 90000 / 1073 = 84 MPH

This is just a guide and doesn't account for drag/parasitic losses found in the real world. (actual speed over ground will likely be less than the #s shown) Also use the tire's loaded radius (hub center to the ground) x 2 for the 'true' diameter.

Extended trips at +- 3000 RPM is IMHO not excessive for a solid 4.0l engine.

Cool, I jsut calculated using this for 31's and 4.88's and it's not looking to bad: I should be doing ~70mph on my way to the Con

 

[Jump This]

Just finished the R&P work yesterday....okay so Ryan just finished the R&P work yesterday. Gotta' say....so far I love it!
He installed Detroits front and rear and changed the ring and pinions.
The only thing I noticed is that it now has a push in corners...nothing too bad though....
I need to adjust my pinion angle a bit (spings going bad) to get rid of some vibes but I think I am going to love this.....32"s with 4:56!!
Rick

 

[Kejtar]

Just finished the R&P work yesterday....okay so Ryan just finished the R&P work yesterday. Gotta' say....so far I love it!
He installed Detroits front and rear and changed the ring and pinions.
The only thing I noticed is that it now has a push in corners...nothing too bad though....
I need to adjust my pinion angle a bit (spings going bad) to get rid of some vibes but I think I am going to love this.....32"s with 4:56!!
Rick

kind of curious: since you already have 32's why didn't you go with 4.88's

 

[Jump This]

Don't make 4:88's for the 8.25.
What can I say?
Although I didn't put a tape to Ryans 33's they don't appear to be any taller than my 32"s (just rolled them up to his)
I think when I go to 33"s I'll be fine....
(unless you upgrade to a Dana 60 next year and want to part with your 44!)
Rick

 

[Kejtar]

Don't make 4:88's for the 8.25.
What can I say?
Although I didn't put a tape to Ryans 33's they don't appear to be any taller than my 32"s (just rolled them up to his)
I think when I go to 33"s I'll be fine....
(unless you upgrade to a Dana 60 next year and want to part with your 44!)
Rick

Oh ok OH yeah.... after I drop in so much $$ there is no way that's I'd part with it for less then $1k which means that it'll stay under my XJ.
The scary part is that since I didn't buy the 33's yet (and won't till the end of summer) I started to wonder what would it take to put 35's underneath

 

[Jump This]

Remi......you are starting to suffer from 'inchitus'!! The only cure is a set of 37's or is that 40's....wait.....44's.....no I mean 49's!
Rick :cheers:

 

[Kejtar]

Remi......you are starting to suffer from 'inchitus'!! The only cure is a set of 37's or is that 40's....wait.....44's.....no I mean 49's!
Rick :cheers:

Oh I started to suffer from inchitus with my 86 when I stashed 235 and I started to rub in rear under load..... The only thing though his that inchitus is incurable and it gets progressively worse.

 

[Jump This]

I wonder if I can barrow a set of 35s....just to see!

 

[Kejtar]

I wonder if I can barrow a set of 35s....just to see!

I fear to even venture that way cause I might like it too much which might cause me to overspend the budget even more!

 

[Tom R.]

can't be......unless your aw-4 is not locking in overdrive, or your speedo gear is inaccurate.

the mechanical truth of your posted working combo is:

4.56 gears, 31.7 MEASURED tires, 70MPH......

.71OD aw-4 rpm= 2537
.75OD aw-4 rpm=2402.

the fact that you say you are turning 3000 rpm in this relationship points to a problem, and the testimony is misleading for the folks trying to choose the right combos.

hope this helps.

Right on. I thought the same thing when I read that post. I have the same set up and don't hit 3000 RPM(no "s") until I'm well past 75 MPH......probably around 83 to 85 MPH.