4.88 Gearing, Will I Be Glad/Regret?

[Nay]

I also dont understand the concern with the RPMs at highway speeds on this engine.

I agree with this, which is why I went 5.29's (I am still about 13% low with big 37's). With a SC, you must have gobs of easy cruising power at those higher RPMs.

The sweet spot in NVH (noise, vibration, harshness) for the 1ZFE is in that 2,000 - 2,500 RPM range, but the sweet spot for cruising power is 2,700 - 3,200ish (I rarely cruise over 3K RPM as that is 75 mph for me).

This disconnect is one of interesting features of the 1ZFE, and it keeps many people recommending staying close to stock gearing to tire ratios when pulling OD RPM up about 300 RPM makes cruising so much easier as well as adding hugely beneficial crawl gearing offroad.

You will almost never find anybody complaining about having gone too low in diff gearing, but you will see plenty of people do it twice.

 

[locrwln1]

I don't get the concern over a few hundred rpm's either, my mileage stayed the same from stock gears/265's as it is with 4.88's/35's. I regularly run at 80mph (75 zone) on I80 through NV. My wife, when she is driving pretty much runs 80-85 mph. Do it quite often. In fact, 80 seems to be the "cruising" speed for my LC, everytime you look down at the speedo, the damn thing is doing 80.
I pretty much have to set the CC to drive slower on the freeway.

Jack

 

[tenmile]

Murf,
Thanks, I'm somewhere between excited and hesitant with the splurge on the additions. How is your road-handeling while towing and driving with 55's? How would the 4.56 be with 35's compared to stock? I am considering a jump to 295's or 305's after my 285's are spent.
Jeff

 

[tenmile]

Linus,
This is the way I am leaning, mostly because the labor on the re-gear even with the axle service is still pretty steep. Aside from the tire size I am also concerned about the extra 500-600lb I'l be adding to the 97 with the SC/Winch/ARB and future rear tire carrier.
Thanks Jeff

 

[tenmile]

Nay,
You are a CO guy also, so with 285's for the forseeable future, what would you gear too?

 

[Romer]

I wouldnt go 4.56's. Think you would regret it

 

[headhunter]

agreed your gonna be disapointed with 4.56 just to much money with not much return. I would not even consider regearing unless you need at least 4.88 just not much diff between 4.1 and 4.56. Truthfully I was dissapointed when I went from 4.1 to 5.29 just did not make as much diff as I expected probably would not do it again just not worth being able to run od on a 3rd truck to me.

 

[Nay]

Nay,
You are a CO guy also, so with 285's for the forseeable future, what would you gear too?

I wouldn't for 33's. Just do the Yellowbox speedo correction as that will make a nice difference because your shift points will be correct.

At the point you get tires again if you really want to step up I'd do the 35's and 4.88's. There is just no point in building around 285's.

 

[tenmile]

Thanks Nay, I am not going to regear, you guys have helped a bunch, I may bump up to 295's when my 285s are done, can you point me to the yellow-box thing? Where is it purchased, how difficult to install?

 

[LINUS]

I wouldnt go 4.56's. Think you would regret it

I agree completely, in fact I almost think 4.88 isn't going far enough. At least w/o a supercharger on 315's it's not like I am rev happy in the least.

IDK what 5.29's are like with only 315's - but along the lines of the above posts about how we really don't rev these things enough/too much, it sure sounds like a viable option to me, especially for 3fe guys where there isn't a band-aid like having a blower, or even us 1FZ guys if you don't like the blower concept for whatever reason.

 

[Nay]

Thanks Nay, I am not going to regear, you guys have helped a bunch, I may bump up to 295's when my 285s are done, can you point me to the yellow-box thing? Where is it purchased, how difficult to install?

Do a search here - it's a motorcycle aftermarket thing that works for us due to the type of speedo signaling or something to that effect.

Install is wiring cut and splice in a tight space - good to be up on your Yoga practice. For another $100 you can have a simpler install with the Marks correction that Slee sells.

 

[Nay]

I agree completely, in fact I almost think 4.88 isn't going far enough. At least w/o a supercharger on 315's it's not like I am rev happy in the least.

IDK what 5.29's are like with only 315's - but along the lines of the above posts about how we really don't rev these things enough/too much, it sure sounds like a viable option to me, especially for 3fe guys where there isn't a band-aid like having a blower, or even us 1FZ guys if you don't like the blower concept for whatever reason.

5.29's are pretty low - I did them with 35's and there isn't much difference on 37's. If you only drive 70 mph, they are incredible. Want to keep up with Romer and you aren't going to like them.

Most people will prefer 4.88's with the 1ZFE. If you rock crawl and you don't want to drive a lifted rig 75+ mph, 5.29's can be a perfect option. I wouldn't do anything else, but I also fit the usage above.

Plus once you have 5.29s 37" tires are a no brainer, and the 80 loves 37's

 

[Romer]

Last night driving on the highway at 80 MPH I was at 2950 RPMs. 70 MPH was closer to 2600 rpms.

My speedo is corrected.

So the concern with getting 4.88's and 35's and driving on the highway isnt what some portrayed it to be.

 

[Nay]

Last night driving on the highway at 80 MPH I was at 2950 RPMs. 70 MPH was closer to 2600 rpms.

My speedo is corrected.

So the concern with getting 4.88's and 35's and driving on the highway isnt what some portrayed it to be.

I run around 2,750 @ 70 mph with 5.29's and 37's, just in case anybody is interested in the comparison. 75 mph is around that 2,950 mark. Over 75 is "you realize you are running 37" Interco tires, right?"

 

[Grench]

Last night driving on the highway at 80 MPH I was at 2950 RPMs. 70 MPH was closer to 2600 rpms.

My speedo is corrected.

So the concern with getting 4.88's and 35's and driving on the highway isnt what some portrayed it to be.

2x. Almost identical set up. I round it though and simply call it 3000 RPM = 80MPH in overdrive.

4.88 + 315/75R16 Duratrac + TRD SC + OME 2.5Heavy =

 

[landtank]

- the suspension work for 33's vs. 35's is "that little bit" that is such where you could end up with mystery vibrations in your drivetrain after a 3"+ lift .

I've done a lot of setups in this range for 35" tires and never have had a mystery vib problem. And that would be all the players of spring manufacturers.

Now people might not be able to find it but to imply that they are not identifiable or repairable I think is wrong.

If you have vibrations there is a reason for it.

 

[LINUS]

I've done a lot of setups in this range for 35" tires and never have had a mystery vib problem. And that would be all the players of spring manufacturers.

Now people might not be able to find it but to imply that they are not identifiable or repairable I think is wrong.

If you have vibrations there is a reason for it.

I should have been a little clearer, the whole regear to spin 35"+ tires, plus the various meathods of CC people choose (or omit) leave some people chasing their butts trying to figure out new vibrations, myself included. I've even spoke w/ Christo about my situation & he himself told me he'd seen people who never solve the issue & that me throwing money at the situation didn't mean it would positively go away.

It wasn't there when I was on a simple OME lift, and maybe I just selectively read, but I've never read anyone saying that a OME kit induced vibrations.

 

[Grench]

I should have been a little clearer, the whole regear to spin 35"+ tires, plus the various meathods of CC people choose (or omit) leave some people chasing their butts trying to figure out new vibrations, myself included. I've even spoke w/ Christo about my situation & he himself told me he'd seen people who never solve the issue & that me throwing money at the situation didn't mean it would positively go away.

It wasn't there when I was on a simple OME lift, and maybe I just selectively read, but I've never read anyone saying that a OME kit induced vibrations.

If changing nothing else but tires caused you to go from no vibrations to vibrations, then at least one of the following might be the issue:

1. Tires improperly balanced. The FZJ80 rims actually require use of a truck-spec cone on the balance rig that not every automotive shop has. Doing it wrong feels like it should be obvious - putting 2lbs of weight on one end of a tire... But I have seen it done - to my truck - by some clueless clowns at a tire store.

2. Tire shop bent or cracked a rim.

3. Lugs are improperly tightened. They like to use impact wrenches and rarely clean the hub before mounting. Take the wheels off, clean the mounting surfaces, put them back on and hand torque them. If you need exact directions on how to change/(re)mount a wheel, ask here and I'm sure 20+ people would be more than willing to supply the answers with pictures and four part harmony.

4. Bad tire(s). Manufacturing defects -do- happen. Do you have a same-size spare that you can work through the positions to see if swapping out one of the tires fixes the issue?

5. Something is -in- the tire. A buddy of mine that worked at a truck tire store told me a tale of finding dead small furry animals or their nests inside truck tires. In theory it shouldn't happen...

6. Tire is mounted improperly or on an improperly sized rim. Are your rims stock? Exactly what tires do you have? Are they all matched including the load rating?

7. Flat spots. Use a depth gauge at 12 or so points around the tire. Is it the same all over?

Those are the basics. There are other reasons, but if it were me I'd start at the top and work down on that list.

 

[LINUS]

Grench - thanks for all the thoughts there, but it was when I swapped from a 2.5" OME Heavy to a Slee 4" - it was the suspension geometry, not the tires themselves as the vibes were there even with the 33" still on with the 80 as I drove to the tire shop to go 35" tires, and no vibes before the 4" lift riding around on the 33's.

I've got some ideas & Rick & I will be massaging the finer points of my lift - I have a decent idea of why my 4" lift is acting up, but I need to prove it out before I say more.

I should have shut up about the 35's as the only reason I even mentioned them was as the reason to move from my OME/33's to a Slee4"/35's - the tires aren't a variable in my vibration equation - I'm giving the "evil eye" completely at my caster correction / pinion angles until they prove themselves not to be the issue.

 

[badmuthatrucka]

I plan on re-gearing to a minimum of 4.88. From all I've heard, and from all the gearing calculators I have seen, 4.88 would be the minimum to get what you actually want from the switch.

Just my $0.02.