What gears with with 35" tires?

[ArmAir1]

I split the difference and went with 4.27's.

[Suddendeath]

I split the difference and went with 4.27's.

An FYI to FSJ'ers who are thinking of 4.27's/4.30's...

Virtually all 90-97 Isuzu Rodeo's and Honda Passport's came from the factory with Dana 44's in the rear axle, with 4.30 thick gears. Gotta use the old body style, the boxy ones are the ones you want, the curvy ones won't work. Pull two sets, and you've got your gears.

The 4.30 thick gear lets you use your stock 2.73/3.31 gear carriers, saving you the cost of new carriers.

Just some useful tech.

[SNO*MAN]

I have 35's with a 700r/ 241c conversion. I have the upgraded hi and low range kit in the 700r conversion. I also have the 4.27 spicer gears. I also have (just installed) the dakota digital dash. I can cruise at 70mph in OD at a bit over 2600 rpms. I have only had it back for a day so I will re-check the calibration in another couple days on the dashboard for accuracy.

[derf]

I have 35's with a 700r/ 241c conversion. I have the upgraded hi and low range kit in the 700r conversion. I also have the 4.27 spicer gears. I also have (just installed) the dakota digital dash. I can cruise at 70mph in OD at a bit over 2600 rpms. I have only had it back for a day so I will re-check the calibration in another couple days on the dashboard for accuracy.

I would check to make sure you're getting into OD with RPMs like that. The way I calculate it, you'd get around 2600 in 3rd gear (1:1) on the highway. If you hit overdrive, you should drop down closer to 1800-1900ish

[ArmAir1]

[quote=Suddendeath]An FYI to FSJ'ers who are thinking of 4.27's/4.30's...

Virtually all 90-97 Isuzu Rodeo's and Honda Passport's came from the factory with Dana 44's in the rear axle, with 4.30 thick gears. Pull two sets, and you've got your gears.
The 4.30 thick gear lets you use your stock 2.73/3.31 gear carriers, saving you the cost of new carriers.

Note on this swap....the Isuzu pinion bearing is bigger than the waggy dana 44. No problem if you are using the bearings that came with your doner. If you are looking to replace the bearings while you have it apart, call up Randy's R&P and tell them you have Isuzu gears and they will put a bearing kit together for you (if you order a standard dana 44 kit, the pinion bearing will be the wrong size)

If anyone is interested in this swap, I have two sets of the Isuzu 4.30 gear sets (with bearings) for sale... I want 100.00 plus shipping for the both of them. Thought the Detroit locker I had was 3.73 and down, but it was a 3.92 and up, so the Isuzu thick cut 4.30's wouldn't work with it.... I had to buy new gears.

[jeepfan93]

hmm, I'ma take a day or 2 and think about this.

[MonsterZ]

I'm only going to 33's, so I am gonna load up 3.92's. But, if I was going to go any bigger, I would probably go with the 4.10's. The 75 is family rig however, and most of mine is still under 5'3".

[serehill]

well

I'm running 3:31's with 33's & wouldn't have it anyother way. I've got low range for off road so I guess I don't get it. Looks like a waste om money to me. I'm running 3 K at 35 MPH I couldn't stand any lower/ 4:56 with 35 would be doing 3K at about what 55?

[imiceman44]

I ran 35" tires in my 75 waggy with stock D44's loaded with 3.54 gears.
It wasn't a drag racer off the line, but I could cruise at 70 mph and keep up with traffic while being able to talk to my passengers.
Off road the QT did pretty good by providing me plenty of torque.
I did anything from dune running to snow wheling to mud and rock crawling on the Rubicon, it worked fine.
I could have been better with the 4.10 but it was cheaper to stay with the stock axles.

[SNO*MAN]

I ended up with 4:27 in my wagon with 35"s and an 700r overdrive.
I think that 4:10's would have been fine with its current power curve the way it is. I am not sure what the stock power curve is for an AMC 360 (2100-2500rpm?)
She seems to cruise at 60mph 2000rpm right now, that is if the dakota is calibrated correctly.

[Sberry]

Im running 5.38's with 35's. Sure my spedo is off by a lot. Yeah i get really bad gas milage. But when you are on the trails that power makes all the difference

[Carnuck]

I have 4.10s with O/D, but my tires are 40"

[sma97tj]

so according to the calculator I would need 42 inch tires and 410 to be back to stock I have 272 gears now with 29 inch tires 360 with an auto trans?

[Carnuck]

It'll act like you have 2.8 ratio

[CutterN55]

My waggy has 4.10 thick gears. with 33x12.50's on it was a little much at freeway speeds. I was around 3K at 65-70 with the 727. I did swap to a manual Np435/205 and that lowered my RPMs a bit. about a 180-200 RPM difference at freeway speeds.
When I stepped up to 36's, I lowered those RPMs a couple hundred more. The tires (HMMWV Bias Ply Goodyears) were sustantially heavier but once up to freeway speeds, the cruising was much better.

For me, the most significant change to gearing (for the money) was the tranny swap.
The super deep low end gears in 1st (granny) and 2nd was a much bigger difference than the initial differential gear change, and I still had a good ratio on the top end for cruising. With 33's on the truck, I should have kept the 3.31's and been fine with the tranny swap. My truck hasn't been wheeling in 4-Lo since I installed the Granny 4-speed. Just doesn't need it. All in all, the axles gearing cost me about $900 and was a good improvement on the low-end but didn't help at all for highway driving. The trans/T-case swap cost me about $600 and was a way bigger bang for my buck. Low end gears are way deep, and I still had tall gears for street driving in 3rd and 4th gears. The drive train strength improvement is also a major plus and maintenance on a manual is less of a factor. Just took a lot of research and sweat.

A change to axle gearing is necessary for a big tire size jump, but for those considering a trans swap, do that first and see where you are at before you throw money into axle gearing. you may find you are overgeared or spent money that may have suited you better in other places.