15" to 16" Wheel Change - Regear

[phattyduck]

It seems to illustrate pretty easily roughly where you should be in terms of gear ratio per tire size. This site also helps covering tire sizes...https://tiresize.com/calculator/

I was thinking of upgrading my diff to an Eaton 913A610. Does anyone have any feedback on this unit?

https://www.summitracing.com/parts/dtl-913a610

Just don't pay much for a 4:10... they should be all over for nearly free!

As for the LSD - Torsen-type LSDs are great for street driving. Always working, completely smooth and seamless operation. If you are ever going to be in a position that lifts a rear tire off the ground, it won't do anything - so not great for off-roading.

My personal plan for my 4Runner involves front and rear Truetracs, along with some other stuff...

-Charlie

 

[JDM_4Runner]

Thanks Phattyduck!

I'm going to start hunting for a set of 4.10 gears.

So perhaps a locker would be better for me since I'm 2WD and I do occasionally like going on trails. However, I also like to visit my friend in Reno Nevada and have driven through snow, I wonder what the temperament of the locker will be. I guess the traction control will keep things in check.

Here's the Eaton locker...
https://www.drivetrainshop.com/Detroit_Locker_p/eat-187sl61b.htm

Any thoughts guys?

 

[A2toHgt]

If the car doesn't feel *too* slow, I wouldn't bother with the regear. The difference in your speedo is probably not that great. If you want to calculate the difference, it's super easy:

1) Divide the new tire & wheel diameter by the old. This is calculated with the following formula:

(Wheel diameter) + (Tire width x Aspect Ratio x 2) = Tire % wheel diameter

Note that you need to convert the wheel diameter from inches to mm.

2) Multiply the fraction you calculated in step 1 by what the speed is reading. This will give you the correct vehicle speed.

 

[JDM_4Runner]

A2toHgt, thanks for the info. It definitely doesn't feel too slow but I need to regain a little more power back since I'll be towing my track car on a trailer.

 

[octanejunkie]

A2toHgt, thanks for the info. It definitely doesn't feel too slow but I need to regain a little more power back since I'll be towing my track car on a trailer.

Total towed weight (trailer plus track car) shouldn't exceed 3000-3500# to be safe with a 5000# vehicle, and I would want trailer brakes more than an eLocker for that task.

EDIT, I just noticed a post of yours saying you drive to Reno, my gf lives there. How Ironic. I've done both 395 and I-80 with snow in my 2WD, it did fine with ECT mode and no chains. I have a 4.1 rear and 16" wheels.

 

[JDM_4Runner]

Total towed weight (trailer plus track car) shouldn't exceed 3000-3500# to be safe with a 5000# vehicle, and I would want trailer brakes more than an eLocker for that task.

EDIT, I just noticed a post of yours saying you drive to Reno, my gf lives there. How Ironic. I've done both 395 and I-80 with snow in my 2WD, it did fine with ECT mode and no chains. I have a 4.1 rear and 16" wheels.

Yeah I'm hoping to score a lightweight aluminum trailer at just over 1,000 lbs. and my track car weighs 2,250 lbs., so I definitely expect to be in a good range.

I drove my 4Runner back down the 395 a day after heavy snowfall and had to drive on ice packed road. I was really impressed how well the traction control/stability assist kept my truck in check and safe with no chains.

I would like to add a little more overall capability to my 4Runner, just not sure if a locker or LSD satisfies 1. Towing 2. Occasional Snow 3. Occasional Off Road

 

[octanejunkie]

I won't difinitively take a position here but I'm a fan of LSD for all around use, wheeling specifically an eLocker seems to be the hot ticket (read 99 Limited) but I can't comment on towing from experience.
I can say that if you have 16" wheels and are gonna tow 3K to Reno and back you might want the bigger Tundra Brakes. I'm sticking with stock brakes, personally.

What color is your rig? We may have passed each other on 395 - I always notice other 3rd Gens.

Sent from my Nexus 5X using Tapatalk

 

[JDM_4Runner]

I won't difinitively take a position here but I'm a fan of LSD for all around use, wheeling specifically an eLocker seems to be the hot ticket (read 99 Limited) but I can't comment on towing from experience.
I can say that if you have 16" wheels and are gonna tow 3K to Reno and back you might want the bigger Tundra Brakes. I'm sticking with stock brakes, personally.

What color is your rig? We may have passed each other on 395 - I always notice other 3rd Gens.

Sent from my Nexus 5X using Tapatalk

Thanks, kind of what I was thinking. And yup, I did the Tundra brake upgrade about 2 months ago and I'm loving it! I'll need to post up everything about my 4Runner soon, once I find a good way to share images since photobucket screwed us haha.

I've only made it up to Reno once, earlier this year to visit my buddy and his fam. I'm hoping to go back up in November to visit again. I wouldn't be towing the car up there, mainly Buttonwillow and Willow Springs.

 

[JDM_4Runner]

Hey Guys! Haha long time no update! I suck sorry, just don't have as much time as I used to. So here's where I'm at. I bought a whole rear end for $100 bucks from member 1904runner out of San Diego who said he upgraded his rear end to an E-Locker. "I have a 4.10 rear axle that was recently taken out of my 3rd gen. Worked perfectly fine before I replaced with a a locker axle. Located in SD"

I finally got around to swapping out my original 3rd member a week ago for the one that's supposed to be a 4.10. Guess what...when I hit highway speed I get the same damn exact result as I did with my original 3rd member! Yup, that's 70 at the cluster around 2,400 RPM, while GPS is saying I'm doing 75. WTF???

I tested the same GPS on my bone stock 02' Civic, 70 at the cluster and 70 on the GPS.

So, did I get gypped by 1904runner? Or is there some other explanation?

 

[Skulking]

Hey Guys! Haha long time no update! I suck sorry, just don't have as much time as I used to. So here's where I'm at. I bought a whole rear end for $100 bucks from member 1904runner out of San Diego who said he upgraded his rear end to an E-Locker. "I have a 4.10 rear axle that was recently taken out of my 3rd gen. Worked perfectly fine before I replaced with a a locker axle. Located in SD"

I finally got around to swapping out my original 3rd member a week ago for the one that's supposed to be a 4.10. Guess what...when I hit highway speed I get the same damn exact result as I did with my original 3rd member! Yup, that's 70 at the cluster around 2,400 RPM, while GPS is saying I'm doing 75. WTF???

I tested the same GPS on my bone stock 02' Civic, 70 at the cluster and 70 on the GPS.

So, did I get gypped by 1904runner? Or is there some other explanation?

It seems you may have missed the post below from 2017 letting you know why re-gearing wouldn't fix your speedometer.

All 4Runner door stickers list 15" tires... so that's no clue.

V6 auto 15" wheel trucks will have 3.73 gears. That's what my '99 had.

Changing gear ratios will not change the speedo on any 4Runner with ABS (which all 2001/2002's had). The speedo is driven by the ABS system from wheel speed sensors. You will need to put a speedo calibrator on the signal from the ABS box in the passenger footwell that goes up to the gauge cluster. Imgur is having an issue, otherwise I'd show you a pic of one in my truck...

You will be happy with 4:10 gears, which will get you very close back to how your truck was stock. You should be able to get the stock diff from many 4WD 4Runners that have been upgraded.

-Charlie

 

[JZiggy]

Time to count revolutions to confirm your gear ratio. You should be able to confirm if this way.

Also, [MENTION=66706]JDM_4Runner[/MENTION] please don't throw other forum members under the bus until you know what's actually going on. Maybe not even after, in fact. We have a great community here that is technical, helpful, and generous. Let's keep the BS for Facebook. I'll get off my soapbox now

 

[phattyduck]

It seems you may have missed the post below from 2017 letting you know why re-gearing wouldn't fix your speedometer.

What's confusing me is why the RPMs are so high. That's more like a 4.3 gear with stock size tires at 75mph. It should be ~2300 with the 4.1 gears and ~2200 if tire size is bumped up from stock to "metric 32's" (265/75-16 or 265/70-17).

But to reconfirm - the speedo reading is only related to tire size. Gearing has no effect on the speedo for almost all 3rd gen 4Runners.

-Charlie

 

[JDM_4Runner]

Well I understand the Speedo/ABS relation, however, ignoring the speedo for a minute and referring to the GPS speed I'm getting the same value as before swapping over the third member. That tells me the tires are spinning the 4Runner faster forward, with my original 3rd member and the one I swapped in giving the same result.

OK, so I'm going to just count the teeth of my original 3rd member to find out once and for all what it actually is, and going with the logic that the 3rd member I swapped in is identical. I'll report back once I've counted!

 

[JDM_4Runner]

JZiggy, I hear ya dude. Definitely appreciate everyones feedback and help. I'll follow up once I've counted the teeth on my 3rd member.

 

[Skulking]

Well I understand the Speedo/ABS relation, however, ignoring the speedo for a minute and referring to the GPS speed I'm getting the same value as before swapping over the third member. That tells me the tires are spinning the 4Runner faster forward, with my original 3rd member and the one I swapped in giving the same result.

OK, so I'm going to just count the teeth of my original 3rd member to find out once and for all what it actually is, and going with the logic that the 3rd member I swapped in is identical. I'll report back once I've counted!

You say you understand the Speedo/ ABS relation, but I don't think you do. If you did you would understand why regearing didn't change how far off your speedometer is.

 

[Bad Luck]

Well I understand the Speedo/ABS relation, however, ignoring the speedo for a minute and referring to the GPS speed I'm getting the same value as before swapping over the third member. That tells me the tires are spinning the 4Runner faster forward, with my original 3rd member and the one I swapped in giving the same result.

OK, so I'm going to just count the teeth of my original 3rd member to find out once and for all what it actually is, and going with the logic that the 3rd member I swapped in is identical. I'll report back once I've counted!

Changing the gear ratio does not affect your speedometer because the wheel speed sensors are after the differentials. The tachometer will change with gear ratio changes, but the speedometer doesn't care what gear ratio you are using. The speedometer to actual speed travelled will be affected by tire size changes. If your speedometer is reading slower than your actual speed then you have larger tires than what the ABS module is calibrated for.

EDIT: The above information applies to 3rd Gen's with ABS. Non-ABS equipped 4Runner's use a speed sensor in the transmission (2wd) or transfer case (4wd) for the speedometer.