Not sure 5.29's were the right choice for me, thoughts?

Dang, Im getting ~12 mpg 50/50 driving with 33's and stock gears... I've not tested either but 4.10's are highly likely since truck has no tow package

 

88 mph will still active your flux capacitor so whats the problem?

 

It is a mph limit. Been awhile since I messed with it, so iirc, the PCM speed limiter is not based on the dash speedometer, does it’s own calculation independently. That’s why adjusting the PCM calibration corrects it, but not the speedometer. Pretty common to raise the mph limit when tuning, so that factors in also.

 

Yes, we're saying the same thing. The limiter is not based on the speedo which is why gears affect the limiter.

 

Interestingly, I was thinking exactly the same thing.

 

Are you calculating for the slightly larger tires?

 

Seems kind crappy needing gotta calculate for .7" vs 2.4" (compared from stock)... though honestly I care not for mpg. This thread had me thinking of truck feel, 4.88's are slowly gaining ground for a daily.

 

Ah, I think that could be the only difference, I have the 4.30 which I think is okay with 35s, not unbearable so I want a 4.88 yet.

 

Right, I was just saying that if it's not accounted for you are getting better MPG than what you posted. Minimally better, but better.

I agree with not caring about fuel economy. It's the only way to be happy in a Tundra.

 

what size are your tires?

 

I have tracked my MPG in an app since i got my truck in 2016 and have gone thru a few tire and gear configurations. truck has gotten progressively heavier as more mods have been added over the years. Adding 5.29 gears did not help my MPG, actually dropped it some, but made the truck move quicker and towing much easier. after my 37s wear out in a few years, i may step down to 35s. I have had a DAP tune since early on and the truck has always been able to hit 100mph for any of the below configurations.

stock 4.30 gears & 285/55/20 BFG KO2 tires

• averaged 15-15.5 mpg for daily
• up to 16.5mpg for long highway drives

stock 4.30 gears and 295/70/18 (34.3" x11.5") ridge grappler

• averaged 13-13.5 mpg for daily
• up to 14.5mpg for long highway drives
• 8-9 mpg towing a 26' travel trailer

5.29 gears and 295/70/18 (34.3" x11.5") ridge grappler, hypertech speedo calibrated, 46 gallon tank

• averaged 12.5-13 mpg for daily
• up to 13.5mpg for long highway drives
• 7.5-8 mpg towing a 26' travel trailer

5.29 gears and 37/12.5/18 - Toyo RT, hypertech speedo calibrated, 46 gallon tank

• average 11-12 mpg for daily
• 11-11.5 mpg for long highway drives (past 80mph it drops fast)
• 6-6.75 mpg towing a 26' travel trailer

 

What app do you use?

6mpg....If my wallet had nuts they just got kicked

 

36in , 325/60r20 , weigh 77lbs per tire.

 

BFG KO2's 35x12.5 R18 here
stock gears
lifted 3/1
average 13 to 13.5 mpg

Don't feel the need to change gears with 35's KO2s.

 

With the 4.30 and 295/70/18
This is pretty much exactly what I am seeing, except a little lower on long highway drives (no trailer) my mileage is around 11-12 mpg (between 75-80 mph).
The 8-9 mph you are getting with the 26' TT is about the same as I get with a 7x7x14 tandem axle enclosed aluminum trailer (approx 3000 lbs w/toys). The weight seems not to be the killer but the wind envelope (size trailer) that is created. and that 8-9.5 mpg is towing in S5 and around 60 mph making sure the torque converter doesn't unlock - major PITA and makes it for a very long drive when we go across WY/MT/UT/ND

 

Have you adjusted your dash readout for the bigger tires? And then for the gears? This sounds like you’re only going by what the dash says, and it’s not correct once you start changing things.

A 35 is 34.5” in diameter, which is 7.5% larger in circumference than stock. So with each revolution of the tire, you’re going 7.5% farther. So in order to get an accurate dash readout (which in my experience has always been really close to actual hand calculation), you just need to multiply by 1.075. If you got 12.8 on stock gears after going to 35s and adding a bunch of weight, then your corrected dash readout would be 13.76mpg. 2mpg loss for a ton of added weight and what might be the heaviest of the AT 35s (the ridge grapplers) isn’t too bad…

It takes more than this to account for gears, too, but I’d bet you haven’t lost as much as you think. Get a GPS tracker app. Start it with a full tank, and run it in your truck until you fill up again. Divide the total tank mileage by the gallons you refill your truck with. That will tell you literal miles per gallon.

Do not top off your tank, ever.

 

I got 35s and want 5.29s. Probably get the regear before I Supercharge. Already found an install/tune shop.

 

34s here. I get 10-11 mpg weighing in at 8000#s with factory gears. I am struggling with regearing as well. I tow a side by side some and it searches for gears at highway speeds. This post has me concerned about changing. I cant afford to lose even more mileage.

 

I got 5.29's on my 295/70/18 tires. Before re-gear I was getting 11-12.5 mpg [was getting 14's on stock tires]. Roughly around 13-13.5 now after break-in. I do city during the week and then highway down to the beach on the weekends. I've done 1 90% highway trip to lake George and got 14.1 there and 14.4 back (75-80 mph). The 5.29's have been nice as I used to downshift on slight up-hill parts/overpasses on the highways near me, after re-gear I don't down shift anymore.

I love the 5.29's but if my truck got totaled in an accident and I got another tundra, I do not think I would prioritize it as much as I did before -- I'd still get it done but it would probably be right before/if I got a supercharger. I carry maybe 200 lbs in my bed every day and I'm on fox 2.5 dsc on all corners; so not a super lifted nor heavy truck with built bumpers.

 

I am on 35’s with Icons top stage suspension with S2 secondaries in front, full steel armor completely under the rig, the large tank in the 2018’s and 5.29’s. I would do the same thing again in the future, no problem.

When I first regeared I was tuned for the stock gears and the performance and mileage was shit. Once the tune was adjusted to the new gears I simply LOVE a driving my truck. Leave it in the normal mode driving easy in the skinny and she shifts just fine around town. If I go into sport mode my tune keeps the gear you selected and it will not shift unless you shift “or” there is a need for the computer to shift (to prevent staling) and I a love that mode when I drive on the highway.

 

If my calculations are right, 5.29s when adjusted to the actual effective ratio with 35s is equivalent to running 4.84 gears on stock sized tires. That’s pretty steep! 4.88s with 35s is equivalent to 4.47 gears on stock sized tires which is just a tad lower than factory. The extra pep is probably nice. I would expect more fuel usage out of 5.29s than 4.88s but I have no personal experience nor skin in the game. A regear isn’t in my current plans. I would expect crap mileage with either ratio though once you have 70+ lb tires on each corner, which also are usually high rolling resistance tread patterns to boot.

 

It is a simple little app called Mileage. Just have to input the odometer, gallons and cost per gallon.

Yeah the 6mpg hurt pulling the trailer from San antonio down south to my buddies hunting lease and back.

 

I have a similar experience with 4.88. I have kenda klever rt 35x12.5 and b4 the regear my tank average was between 13.4 and 13.6. And it was common to get single trips that were 14 to 16 mpg. With a best of 19mpgs. After the regear my tank average is between 12.8 and 13.0(sometimes i can get it to 13.2). with single trips, i cant get anything higher than 14. My speculation is that it probably has to do with the fact that my stock gears were 4.10 so the shift points are probably way off. (I did notice the gears seem to linger longer than before) It probably doesnt effect the guys that had 4.30 gears as much.

 

Where does one get an ECU "Flash" or "Tune" to update the new gears? I haven't really found any info on this in any thread. Does anyone know?

 

https://overlandtailor.com/remote-tuning

 

5.29 is absolutely the right choice for 35s.

I noticed the OP is claiming that mileage is down after adding gears and tall, heavy tires. If you’re comparing little tires with 4.30s, then yes. You will have lower mileage now. People claiming to get the same mileage with 35s and 5.29 as they got with 32s and 4.30 are running a calculation wrong. Ain’t happening.


My experience:
100% stock truck. P275/55-20 OEM tires and gears ~17 mpg on highway. Never really lower than 16.5.

LRE (heavier) stock size LT275/55-20 tires with stock gears ~15.5 on highway.

LRE LT275/65-20 with stock gears ~13.5 mixed driving, and 14 on highway. I installed a RC speedometer calibrator at this time to correct for tire size.

(Current setup) LRE LT275/65-20 with 5.29 gears gives me the same mileage as stock gears and these same tires. I spin a little more rpm, but holds gears better and is so much nicer to drive. Acceleration is effortless and quick.

I will soon be moving to a LT285/75-18 and expect my mileage will stay really close to what it is now. They’ll be an inch taller, but tire/wheel combo is no heavier than my current setup.


A few things I’ve learned.

Changing gears in a Tundra does NOT affect your speedometer. It does in a lot of vehicles, because their speedometers are fed by transmission (or transfer case) output shaft speed. Tundra reads off wheel speed sensors. The speedometer has no clue what your gear ratios are.

Low gears do reduce your top speed. As mentioned earlier, this has to be because the computer recognizes a specific rpm in 6th gear and it says you’re going too fast. I’ve played with this, and when I hit the limiter, I rolled more throttle into it. It downshifted, but the speed would not increase. With my 5.29’s, this is about 93-95 mph. Fast enough for 99% of my driving, but I’ll adjust if I get a tuner.

 

Almost 100k miles supercharged and 50k miles with 5.29 gears. Currently running 305/70/17 tires, about 34". Previously ran 305/55/20, a 33" tire.

All stock - 15 mpg - top speed 107
Stock gears and 33" tires - 14 mpg - top speed 108
Supercharged, stock gears, 33" tires - 12-13 mpg - top speed 108
Supercharged, 5.29 gears, 33" tires - 12 mpg - top speed 102
Supercharged, 5.29 gears, 34" tires - 11 mpg - top speed 105

My truck could easily eclipse the top speed, but when you hit the limiter, the gas cuts and it feels like you are hitting a wall.

Recently drove my father-in-law's stock Tundra on 33s, and it felt much smoother, actually. Supercharger and gears makes the truck feel a lot more frantic and eager, but I prefer it. It's never short on power or feels like it's in the wrong gear, and passing is never an issue. Better gas mileage would be nice, especially when cruising, but it's a trade off for the power.

 

So I have 5.29’s on 37” tires and at first it shifted like shit. Was horrible but… was an easy cheap fix and something you should consider and I’ll help you out with the customization if you move forward. I purchased the

$170 Rough Country Speedometer Calibrator Inline for 2014-2021 Toyota Tundra - 90017

SpeedoCalibrator off Amazon and installed. Left the usb under the dash and plugged into a cheap PC laptop to drive, pull over and tune. Was able to match the speedometer perfectly to GPS from my Garmin, Waze and Rear View Mirror Dash Cam GPS. Got it dialed so perfectly it’s not even off a mile. This did 100% change the shifting pattern a bit and was easier to drive. Took 15 minutes and some math to adjust the settings. Second was I met with TK421Tuning and added a custom tune. This was a INSANE difference. Best upgrade I did and recommend. I then took the driveshaft to get balanced and done. Truck is smooth, shifts like a Cadillac, getting accurate miles, getting 12-13MPG HIGHWAY (my truck is build and heavy) and beyond pumped. Offroad also with those 5.29’s is a game changer.

Hope this helps.

 

^^^^ Agree with everything said here. I did tires and speedo calibrator first, then added gears. A year later, I was able to pick up an HP Tuner and have a reputable tuning shop work its magic. The difference is well worth it, fellas.

 

Just some ideas for people who are wondering if they should spend the money on a regear...

Try using S mode if it seems to be hunting for gears; for instance S5 if it hunts between 5th and 6th on the highway. 5th with 4.3 is nearly identical to 6th with 5.29s.
Also try putting it in Tow-Haul mode.

I wonder if part of reason mine seems fine with stock gears (and I average just under 18 mpg on the highway) is because I did not calibrate the speedo... maybe?