How civilized are 35s?
- Thread starter CybrSlydr
- Start date
Starrs
TJ Guru
Drive your rock crawler to IN and I’ll gladly let you drive mine. Mostly pavement around here tho. I’ll even detail yours for you hahaha can’t remove dents and scratches tho
The only trans where 4.56/35 would be workable is the 32.
For 35's; 4.88/5.13 with 6 spd; 5.13 with either 5 spd; 5.13/5.38 with 4 spd auto depending on Rubicon or not; 4.56 with 3 spd auto.
The worst trans Jeep uses is the 42. The steep drop off to OD is ridiculous. In order to use such a tall OD, it should have been designed as a 5 spd auto, at minimum.
If you look at all the combos, the best was with the 3 spd and 3.73. Even stock the Rubicon with 4.10's is under-geared with the 42 and only decent with the manual.
Unless you are/were a car guy, many do not know trucks/Jeeps, etc of years past came with 3.73 and 4.10 as commonplace. Nobody was claiming rpm's are too high. The reason for tall gearing is to keep rpm's down for emissions, not mpg. Look at every combo Jeep has produced, they are all within 1-2 mpg no matter the trans or gearing, 4 or 6 cyl. With new vehicles people are just used to low cruising rpm's and freak out over anything above 2k'ish.
Some people are perfectly happy going up 5-7 tire sizes on the same gearing. Most aren't.
42rle/30.5/3.55 = 2024rpm @ 75mph
42rle/30.5/4.10 = 2337rpm @ 75mph
42rle/34.5/4.10 = 2066rpm @ 75mph
42rle/34.5/5.38 = 2712rpm @ 75mph
35" tires, 4 speed auto with 4.10 gearing is equivalent to 31" tires with 3.55 gears. Should people regear their stock auto Rubicons to have higher gears?
Keep in mind that in the early days of the TJ, Jeep commonly rolled this combination off the assembly line.
32rh / 29.5" / 3.73 = 3033rpm @ 75mph
Find anyone who ever complained about this.
This "debate" is far more of a simple math problem than it is personal opinion or preference.
42rle/30.5/4.10 = 2337rpm @ 75mph
42rle/34.5/4.10 = 2066rpm @ 75mph
42rle/34.5/5.38 = 2712rpm @ 75mph
35" tires, 4 speed auto with 4.10 gearing is equivalent to 31" tires with 3.55 gears. Should people regear their stock auto Rubicons to have higher gears?
Keep in mind that in the early days of the TJ, Jeep commonly rolled this combination off the assembly line.
32rh / 29.5" / 3.73 = 3033rpm @ 75mph
Find anyone who ever complained about this.
This "debate" is far more of a simple math problem than it is personal opinion or preference.
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Kinda like when I explained on that other site that putting 35's on his 3.73's were basically turning them into 2.73's.
Fun fact of the day: When AMC was building the CJ they actually used 2.73's on a lot of them. We used to re-gear them all the time along with replacing the two piece Model 20 axles with one piece, primary Summers Bros.
Fun fact of the day: When AMC was building the CJ they actually used 2.73's on a lot of them. We used to re-gear them all the time along with replacing the two piece Model 20 axles with one piece, primary Summers Bros.
Starrs
TJ Guru
Just so I’m understanding this. Those TJs our there that have 3.21 gears and 31s have a crappy undergeared ride too then right? Or is it just 35s and 4.10s? I’m no engineer...my degree is in healthcare so math I did ok at for this “simple math problem”, but I’m still not following how a math problem can be the judge on how a vehicle drives? I would think this is going to come down to personal preference and how you want the gears to be.
Having sufficient experience with what rpms work well with various tire/engine/transmission combinations is the key to understanding what we're talking about. Since you don't yet have that experience, it's understandable you aren't getting what we have been trying to explain to you. Sometimes you just have accept what those with a lot more experience have to say rather than just arguing a subject you're inexperienced in. We know what rpms work well, you clearly don't. It's clear you'd just rather argue from a position of inexperience with this particular subject.
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TJ never came with 3.21, that is a JK gearing. 3.07's did, however. I would guess that 3.21 and 35's would indeed be under-geared, even on the more powerful JK engine.
If you are good with what you are running, party on. I think the point trying to be relayed is that there are better options.
If you are good with what you are running, party on. I think the point trying to be relayed is that there are better options.
Correct, if the TJ came with those gears.
If it is your preference that a vehicle operate outside it's power band then you aren't paying attention to the needs of the vehicle and are not allowing it to be healthy.
I'm an art handler in the museum industry, btw.
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A built AMC 20 was an underrated axle. The one I had in my CJ-7 had the axle tubes gusseted and stitch welded to the center section, Summers Brothers one-piece axle shafts, 4.56 gears and a Detroit locker. I ran it behind a Ford T-19 transmission with 35" tires and abused it regularly but try as I might I couldn't break it. Mine came stock with 3.54 gears but I remember the pile of 2.73 ring and pinion gears in the scrap heap at my local jeep shop and that the jeeps they came from were real dogs before being re-geared.
To bring this back around to @Starrs's stock gear ratio with 35" tires: It may drive "okay" now but you may feel differently about how well your jeep actually drives if you have the opportunity to drive another jeep with the gear ratio better matched to those large tires. In fact, I would suggest that you do just that rather than blindly follow advice on the Internet from someone you don't know or who postures themselves as the "Hey Google" of the jeeping world. As @mrblaine, the real TJ guru, often says, "You don't know what you don't know." Try it for yourself and make your own decision.
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Starrs
TJ Guru
Hey I like this statement haha. I can live with this.Correct, if the TJ came with those gears.
If it is your preference that a vehicle operate outside it's power band then you aren't paying attention to the needs of the vehicle and allowing it to be healthy.
I'm an art handler in the museum industry, btw.
ohiopatriot
TJ Enthusiast
Yeah, they sucked with the 32s it came with, constant hunting especially when towing the camper. Regeared to 4.56 real quick.
The 20 is as strong as a 44 when all dolled up. Its downside was thin walled tubes. Lots of guys stitched the tubes like you did and added a truss. We did. bunches of those.
I think this is how the original poem ended...
"I shall be telling this with a sigh
Somewhere ages and ages hence:
Two roads diverged in a wood, and I,
I took the one less traveled by,
After regearing and going to 35s,
And that has made all the difference."
Robert Frost
"I shall be telling this with a sigh
Somewhere ages and ages hence:
Two roads diverged in a wood, and I,
I took the one less traveled by,
After regearing and going to 35s,
And that has made all the difference."
Robert Frost
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