Regear with 37s

You are 100% correct. ECG told me I have a 10.5" rear end in my 2023 non hybrid. That was false.

Thanks for the clarification.

Brad

 

Any updates on gear options? Been trying to get in contact with Nitro/Just Differentials to discuss re-gearing and they've been unresponsive for a few days now. All gear packages are labeled up to 2021.

 

I messaged Nitro Gears on their IG back in September and they said they're working on it. They have been unresponsive ever since.

 

Same thing I was getting. I even got to texting with someone from Nitro earlier today but after they apologized and asked what I was trying to figure out, I got the same message along with suggesting I wait for a response via email. It's been a few days now so I guess we'll just wait and see what comes later.

 

I wonder what gear ratio is most appropriate for 37" tires if the goal is back to stock power, feel, and full use of all 10 gears. 4.10, 4.56, or 4.88? I highly doubt that any of us using 35" tires or larger are using all 10 gears.

I wonder what gear ratio options Nitro will offer.

 

In the world of FJ Cruisers and 4Runners, 4.56 is what is considered appropriate to get as close to stock. I opted for 4.88 with 37s and I was glad I did. The change was underwhelming, so 4.56 would've definitely left me wanting more gearing. The Tundra has quite a bit more power and torque though, so the change in gear ratio needed to get back to stock may not be as big of a jump. My Tundra has 37's and KMC beadlocks that weigh just over 34lbs and the change in acceleration was noticeable. I'm between 4.88 and 5.29 but leaning more towards the latter for the type of off-roading I enjoy. Just need to hear from the gear experts first. I only want to re-gear once, and I feel those will suit the truck well, especially when I add more metal.

 

Unfortunately, we will be at the mercy of the aftermarket manufacturers when it comes to what gear ratios are available. You only have 4.88 and 5.29 to choose from for the previous generation Tundra. Hopefully, we get more than 2 gear options for the Gen 3 Tundra.

 

Going back to my previous question on the optimum gear ratio for specific tire sizes with the goal of going back to stock power. I've done some research and here's what I hope companies like Nitro Gears end up manufacturing for our Gen 3 Tundra.

Gears for 35" tires = 3.55
Gears for 37" tires = 3.73

 

I'm still waiting to hear back from anyone at Nitro. I wish parts for the 3rd gens waasn't so slow to make it to market. I'd be happy with 4.88 at minimum. Don't think I'd notice anything lower than that.

 

Gearing on 3rd Gen is different. I don’t think 4.88 will be offered. Stock gear is 3.31 and you’re going to jump to 4.88?

 

Definitely 3.31. Next week a Suprrlift 6 inch lift with 37's gets installed. I would love to gear down to compensate for the massively big change in tire size, but I cannot find a gear for the 3rd gen Tundra anywhere yet. The 5.29 offered everywhere for the 07-21 Tundra would be perfect, but it just doesn't exist yet.

 

No one makes re-gear kits yet for the new Tundra. Where did you get the idea that 5.29 ratio is the way to go? Would like to know the reasoning. For 37s, I see a more realistic 3.73 to 4.11 gear ratio range offering from the aftermarket.

 

There's no golden standard for re-gearing as everyone's truck and intended use will differ. Tire size, wheel size, gross weight, etc will all play a role in choosing what's best for you and your rig. Not to mention the varying schools of thought between those who ride stock, overland, rock crawl, and prerun. Gearing calculators are a great tool for those wanting to re-gear to help choose a good number, but it doesn't guarantee it's what you're going to need or like in the end. Those calculators are set up to get you back to stock range, but again, that's not everyones MO.

My FJ Cruiser stock gearing was 3.73 IIRC and most owners swapped to 4.56 based on gearing calculators and word of mouth from those wanting to get as close to stock as possible. I opted for 4.88 and was underwhelmed. Though it worked out well for me for the years that I owned it with 4.88s, I could've been happier with something taller. The FJ just didn't have the power and torque to move big heavy tires and the taller gears help, especially when getting off the line. RPM at highway speed, even at 80 MPH was still in a relatively low range that wasn't annoying or burning excessive fuel on long road trips. The Tundra on the other hand has plenty of power and torque and from what I can tell, isn't really struggling to move with 37s and maybe a few hundred lbs over stock curb weight. So, as of now, doesn't really need a re-gear. That will change as the added weight continues to raise.

 

I think the Tundra would benefit from a re-gear to enable the full use of its 10-speed transmission to gain some of the fuel economy and power back. Although I agree that even with 37 inch tires the Tundra doesn’t feel underpowered.

 

I've had the 6 inch lift and 37's on now since Tuesday, so five days. The truck definitely doesn't feel underpowered at all, but I am yet to pull my 12 foot, enclosed tool trailer that I use for my work. I build decks, so there is quite a bit of weight to the trailer because of all the tools. Probably because this truck has loads of hp and torque, there is no sluggishness at all when it's just the truck with no trailer. The 10 speed transmission helps also, I'm sure. When I pull my trailer home on Tuesday, I'll let everyone know what it felt like pulling some weight.

I have a Pedal Commander, so it's easy to get the feel of extra power when I bump up the Pedal Commander, but I am aware this adds no actual power - only the illusion of more power simply by throttle response. Perhaps the Pedal Commander can at least compensate a bit if there is sluggishness. At any rate, I'll update.

 

You dont want 4.88's on a 3rd gen because the transmission ratios are a lot shorter. Toyota's historically needed super short axle ratios because their tranmission ratios were extremely tall. 1st gear in the AB60 6 speed trans from the 2nd gen Tundra is only 3.33:1 and the 1st gear in the A750 and A760 that is in the FJCruisers4Runners/lexus GX is 3.5:1.

Meanwhile, Ford and GM's 6 speed transmissions were running 4.17:1 and 4.03:1 respectively so their axle ratios could be taller. An F150 with 3.55's still has a shorter first gear than a 2G Tundra with 4.30's.

All the new 10 speed transmissions are in the high 4:1's. 4.7-4.9:1 usually. So they can run tall axle ratios like the 3.31 and still have a super deep first gear in comparison to a 2G tundra.

I'd be surprised if there was anything much higher than 4.30 or 4.56 available and even that would be pretty short. Like I said previously, the F150 Raptor comes with Factory 37's and runs a 4.10 axle with very similar transmission gears to the 3G tundra.

 

But again, the transmission ratios in the A750 you had in the FJC are very tall. You needed a ton of axle gear to make up for:

A: the stupid tall transmission gears
B. The massive jumps between gears in the 5 speed transmission.

The new 10 speeds transmission has a nearly 40% shorter first gear and has 8 gears in the same ratio span as the 5 gears the A750 transmission has. so you FJC would shift 4 times to the 10 speeds 7 times, meaning the 10 speed is much better at staying at the ideal rpm and powerband.

If you undergeared your FJC it sucked because then you were spinning 4000 rpm instead of 2500rpm on a hill due to how big of a jump it was to downshift one more gear. The 10 speed has so many gears that it's shifts are only 500 rpm or so.

The main issue with the 10 speed is that you want to keep 10th functional. I really think 4.10's is probably about right to both realign the gearing with 37's and also overcome the added rolling resistance and drag of the larger more aggressive tire so that it can stay in 10th gear on the freeway.

4.10's in first gear with the 10 speed would be like having 5.73's in your FJC.

 

It's nice to see someone is on the same page as me. LOL. What you said is exactly what I have been saying. Stock 3rd Gen Tundra comes with a 3.31:1 gear ratio and Tundra owners think they need 4.88 or 5.13 gears with no basis for their reasoning. What is reasonable in my opinion are gear ratios between 3.55:1 and 4.11:1 for 35-inch and 37-inch tires, specifically 3.55 and 3.73 for 35-inch tires and 3.73 and 4.11 for 37-inch tires.

 

Im kinda going through the same thing right now with the AE80 8 speed transmission in my LX570. It has similar ratios as the 10 speed. My options are to go to 3.91 or 4.10's just based on whats available for the land cruiser axle, and even the 3.91 would be a pretty aggressive jump for 35's compared to the stock 3.31's. 3.91's are actually pretty close to what would be a dead match for 37's.

Granted, of the 3000 miles ive driven the truck nearly 2500 of it has been towing a 5500 lb trailer where I am rarely using 7th and virtually never in 8th, so having those shorter gears will be helpful in my case.

 

That's a tough one, man. I would not know what to do in this case. Maybe get the 3.91 and stuff 37s under the wheel wells. LOL

 

All good points and the 10-speed is definitely a game changer, though nothing new. Still, I maintain a change to a 3.XX gear ratio likely isn't going to give me what I want and I may not even bother with a regear at that point. Like I said, I don't feel the Tundra is underpowered or undergeared now, so something like a 3.55 isn't really enough to compel me to make that change unless I add a ton of extra steel (think back-half/tube chassis) and need whatever additional gearing I can get to move. Either way, I'm still hoping for a 4+ which I understand seems like a leap to most. But I'm not as conservative and practical as most, which is why I only stated it's what I was open to. My truck won't be an overlanding rig, so having 10th gear, better MPG, and good highway mannerisms isn't on my list of priorities but of course, would be nice to have. The good news is axles can be re-geared after being re-geared if I don't like what I choose. Though, I for one, wouldn't mind zipping through the first couple of gears and being quick off the line. Ever see/hear the Hoonicorn launch off the line? LOL

I do agree, that if anything above 4 is offered, it won't be by much. Unlike the Raptor, there just isn't the demand for something higher than that for the Tundra. Unless we start seeing more tundra trophy trucks and pre runners rolling on 40s...I'll take a 4.10 and probably be happy with it.

 

4.56, 4.88, and 5.13 are out there for the Raptor. Though, I don't know how many are running 5.13, but if you know anyone or lurk on their forums, you'll see there are happy owners with OEM/aftermarket 37's with 4.56 and 4.88 on their daily. Just depends on what you want and your driving style. I suppose they're more like-minded with other prerunner folks. And yes, we do have similar trans gear ratios and I doubt you'd notice any significant difference between the two, all things being equal.

Going to a 4.56 or 4.88 on the 3rd gens seems like a large leap because of the stock 3.31 gearing and it would be if I kept the stock 265 (~32") tire or something similar. I have 37s and the stock gearing is a bit high for the size and weight, but doesn't seem like it all the time because the tundra has a good amount of torque. Fair to say, if Toyota also offered factory 37's, they would also gear the axle around a 4.10. So, having 37s AND changing to 4.56 and 4.88 isn't as big of a jump as you think. People's reactions around going to a 4.56 or 4.88 are as if they didn't change to a larger and heavier wheel/tire package and add additional gear weight.

I fully anticipate adding quite a bit more weight over time and there's never going smaller from a 37" tire. So, yes, a 4.56 or 4.88 sounds about right for me if they ever offer it.

 

I doubt you'd notice change with a 3.55 and maybe slightly notice the 3.73. 4.11 with 37s would probably be like driving a stock tundra with stock tires and that's great if that's your MO. But if you plan on adding significant weight via offroad/camping gear, you might benefit from something a little shorter. That's just my opinions based on my own knowledge and experience with re-gearing or "basis". Sticking with 4.11 or less is probably "safe" though.

 

I agree that 3.55's are a waste of time. I just dont think it would be worth the cost to open up the diff for the marginal gain in wheel torque. At that point just let the transmission with its 10 gears handle it.

 

Hi Guys,
I founded Nitro gear and Axle but sold the company a few years ago. Unfortunately, as things would go in the corporate world they have been very slow to develop new products among other things...
I personally am on my second third gen Tundra on 37s and would love to have gears for these. There's not much point in debating gear ratios as nobody offers them. If somebody told you 488 or 529 they are talking about prior generation vehicles. The third gen comes with 3.31 and the transmission gearing is not the same as the old ones. The 4.10 or 4.30 would be ideal. My TRD Pro with stock tires would not even get into 10th gear on the freeway no matter how hard I tried unless I was going 80 downhill. With the 37s, it never goes into 10th or 9th gear and hardly eighth. Since there are so many gears, and they do make good low-end torque, it kind of masks the problem and they are decent to drive. But let me tell you if we had for 4.30 Gears with 37s life would be grand. First gear would pull off the line like crazy and we would actually use our 10th gear and most likely improve fuel economy considerably. This is not a new Theory we had done this for every Toyota model among others. Wish I could help more.

 

Any updates on gears available? I'm currently running 285/75 and would go to 37x12.50 if a gear set was available.

I'm also interested in a speedometer calibrator if one is available.

 

Same as above. However, I did recently do some investigative tear down on the diffs and they are completely different than any prior models, so would for sure require developing and Manufacturing gears. Unfortunately the current state of the aftermarket I don't see anybody doing these anytime soon.

 

Isn't the GX, LX, and some Tacoma's and LC's using the same axles? I bet there is a market fairly soon.

 

I recently toasted my differential and thought, why not regear while I'm at it. I'm disappointed there isn't a solution yet. Considering the rear-end was taken from the land cruiser, I would have figured a solution was already out there.

 

Toasted ?