Performance 5.29 fuel mileage thread

[Berserker__taco]

Tire size: 33"
Gear ratio: 5.29
Tune: Valley Runner
Truck weight: ~6,000 lbs
Mpg @ 1800-2100 rpm: 13-14 mpg
Mpg @ 3000-4500 rpm: 10-12 mpg

Milage before gear swap:
Tire size: 33"
Gear ratio:  Stock
Tune: OVTune 2.0
Truck weight: ~6,000 lbs
Mpg @ 1800-2100 rpm: 14-16mpg
Mpg @ 3000-4500 rpm: 12-13mpg


Anyone with 5.29 gears, what kind of fuel mileage are you getting?

Id like to start a thread just simply stating tire size, gear ratio, tune if any, and average milage before and after the swap so anyone considering a gear swap can have a rough idea of what to expect.

During my research before installing them I couldn't find any info or statement from anyone with 5.29s regarding fuel mileage changes after the swap. The general consensus was that the swap is great, you'll fall in love with your truck all over again, you wont regret it bla bla bla.
I'm at the end of my break in and changing the fluid this weekend. After 500mi I have mixed feelings. While the truck certainly does not labor as it did with a noticeable improvement in torque.. the fuel mileage sucks. On the highway I can now run in 6th gear no problem at 2500rpm at 70mph but surprisingly the fuel mileage is worse than when the truck would jump between 4th and 5th constantly running long stretches at 3000rpm in 4th. I've been averaging around 13mpg since the change and before I was right near 15mpg. I have the truck tuned with Valley Runner for the 5.29s and 33s. I know, 1000lb over weight and running larger tires will suck fuel but I figured helping the truck move better would increase MPG at least a little bit rather than take it away.

 

[Tyler]

Tire size: 37”
Gear ratio: 5.29
Tune: OVTune 2.0
Truck weight: ~7,500 lbs
Mpg @ 1800-2100 rpm: 13-15 mpg*
Mpg @ 3000-4500 rpm: 8-12 mpg*

*mpg shown on dash. Numbers aren’t true because of the 37” tires. Never bothered to figure out the actual numbers but I think bigger tires = better mpg than shown on the dash? I know bigger tires = driving faster than shown on dash (when my truck says I’m going 65 mph, I’m actually going 81 mph, lol).

—

I did the 5.29s a few years ago so I don’t have a lot of direct comparisons. But I do remember feeling underwhelmed. I did have OVTune before the 5.29s, so that might be why I was underwhelmed. People talk up the tune all the time, and they’re right; OVTune will make a huge difference. People also talk up the benefits of a re-gear, and they’re right. At certain tire sizes, the 4.88s or 5.29s will be a perfect ratio and they shine a bit when driving up hills, “engine breaking” down hills, off-road, and maybe on heavier trucks. Like you said, you’ll feel the torque.

With that being said, should your re-gear increase mpg? Probably. If I had to guess, the reason it didn’t is because 1) the Valley Tune or 2) your tire size.

1) I tried the Valley Tune on a trip from NY to CA. I was satisfied with my OVTune but Valley Tune made me a 5.29s/37” tires tune (my OVTune is 5.29s/35” tires). For that whole trip, my dash was reading 6-11 mpg depending on driving conditions. When I switched back to OVTune, the numbers at the top of this post came back.

2) I can’t personally speak to the tire size. I can imagine people running 33s do a lot of research on 4.88 vs 5.29 for that tire size. If the general consensus is 5.29s for 33s, maybe it does have to do with your tune.

 

[mgmyota]

Tire size: 34”
Gear ratio: 5.29
Tune: None
Truck weight: A little more than stock
Highway mpg: 18-19
City mpg: ~15


I’m averaging 18-19 mpg through the week just driving highway miles for work. 70-80 mph 80 miles round trip a day. My Speedo is recalibrated for the 34’s. I have 5.29 gears as well but I’m not tuned. Now I’m sure the dash is still a little off for mpg but I wouldn’t be surprised if I’m still getting 17 or better mpg. I’m actually going to get gas today so if I remember I’ll do the math. I don’t have much extra weight though so that’s probably a huge reason I get that mpg. Just the roof rack and a probably 50-60lb box of tools and stuff in the bed and a full size spare. Not much else extra weight.


I would recommend gears if you’re on bigger tires for sure. If the moneys not there, I’ve heard great things about getting just a tune as well. There’s a lot of tunes out there these days so it could take some experimenting to find what works best.

Gear ratio to tire size definitely plays a factor though. 5.29 with a smaller tire really won’t run too well. With 33’s you’re right on the line between 4.88 and 5.29 like Tyler said. I’d say if you’re going to run 33’s and not much more weight in the future, 4.88’s would probably be okay. But if you plan on running extra weight or a lot of extra weight or plan on going with bigger than 33” tires in general, then 5.29 is the way to go.

If your fuel milage is dropping off you could also do a basic tune up of your truck as well. Clean or replace intake filter, clean the maf and throttle body etc. basic stuff but a clean engine is a happy engine.

@Berserker__taco in your case I would maybe try a different tune Could try getting rid of the tune all together as well. Or dump 500lbs if you can

 

[New Holland Overland]

Tire size: 33"
Gear ratio: 5.29
Tune: KDMAX PRO XT
Truck weight: ~6800 lbs
Mpg @ 1800-2100 rpm: 13-15 mpg*
Mpg @ 3000-4500 rpm: 8-12 mpg*

To be honest...I havent noticed any mileage change from stock to 5.29's when I changed. The way the truck accelerates is dramatically different, and the engine sounds way happier when towing. It made the truck feel like a stock accelerating truck again.

 

[mgmyota]

filled up today and calculated it. The mpg is about spot on from what I stated

 

[Trudog]

Tire size: 38"
Gear ratio: 5.29
Tune: OVTune 2.0
Truck weight: ~6800 Fully Loaded
Mpg @ 1800-2100 rpm: Averaged 16-18 during trip to Wyoming July 2022
Mpg @ 3000-4500 rpm: 9-13 mpg

I decided to calculate all mileage using a GPS device versus the Toyota sensors for accuracy during a 9 day 3200 mile trip to Wyoming, the best I did was at 24 mpg (low rpm on pavement) and the worst at 4low all day was 9! A solid average was 15.

5.29 gears are the first thing that took place when the modifications began with this rig / I never intended building the Black-n-Tan to save on MPG however the gears for me where to push bigger tires and the auto transmissions are horrid / hindsight should have grabbed a manual! Regardless of use I recommended switching gears if one has an automatic IMO

 

[Berserker__taco]

Tire size: 37”
Gear ratio: 5.29
Tune: OVTune 2.0
Truck weight: ~7,500 lbs
Mpg @ 1800-2100 rpm: 13-15 mpg*
Mpg @ 3000-4500 rpm: 8-12 mpg*

*mpg shown on dash. Numbers aren’t true because of the 37” tires. Never bothered to figure out the actual numbers but I think bigger tires = better mpg than shown on the dash? I know bigger tires = driving faster than shown on dash (when my truck says I’m going 65 mph, I’m actually going 81 mph, lol).

—

I did the 5.29s a few years ago so I don’t have a lot of direct comparisons. But I do remember feeling underwhelmed. I did have OVTune before the 5.29s, so that might be why I was underwhelmed. People talk up the tune all the time, and they’re right; OVTune will make a huge difference. People also talk up the benefits of a re-gear, and they’re right. At certain tire sizes, the 4.88s or 5.29s will be a perfect ratio and they shine a bit when driving up hills, “engine breaking” down hills, off-road, and maybe on heavier trucks. Like you said, you’ll feel the torque.

With that being said, should your re-gear increase mpg? Probably. If I had to guess, the reason it didn’t is because 1) the Valley Tune or 2) your tire size.

1) I tried the Valley Tune on a trip from NY to CA. I was satisfied with my OVTune but Valley Tune made me a 5.29s/37” tires tune (my OVTune is 5.29s/35” tires). For that whole trip, my dash was reading 6-11 mpg depending on driving conditions. When I switched back to OVTune, the numbers at the top of this post came back.

2) I can’t personally speak to the tire size. I can imagine people running 33s do a lot of research on 4.88 vs 5.29 for that tire size. If the general consensus is 5.29s for 33s, maybe it does have to do with your tune.

From the handful of us that dropped stats here I'm with you that it sounds like the tune may be the issue. I may reach out to @TermLimits and see if we can meet up and adjust some things.

 

[Berserker__taco]

Tire size: 34”
Gear ratio: 5.29
Tune: None
Truck weight: A little more than stock
Highway mpg: 18-19
City mpg: ~15


I’m averaging 18-19 mpg through the week just driving highway miles for work. 70-80 mph 80 miles round trip a day. My Speedo is recalibrated for the 34’s. I have 5.29 gears as well but I’m not tuned. Now I’m sure the dash is still a little off for mpg but I wouldn’t be surprised if I’m still getting 17 or better mpg. I’m actually going to get gas today so if I remember I’ll do the math. I don’t have much extra weight though so that’s probably a huge reason I get that mpg. Just the roof rack and a probably 50-60lb box of tools and stuff in the bed and a full size spare. Not much else extra weight.


I would recommend gears if you’re on bigger tires for sure. If the moneys not there, I’ve heard great things about getting just a tune as well. There’s a lot of tunes out there these days so it could take some experimenting to find what works best.

Gear ratio to tire size definitely plays a factor though. 5.29 with a smaller tire really won’t run too well. With 33’s you’re right on the line between 4.88 and 5.29 like Tyler said. I’d say if you’re going to run 33’s and not much more weight in the future, 4.88’s would probably be okay. But if you plan on running extra weight or a lot of extra weight or plan on going with bigger than 33” tires in general, then 5.29 is the way to go.

If your fuel milage is dropping off you could also do a basic tune up of your truck as well. Clean or replace intake filter, clean the maf and throttle body etc. basic stuff but a clean engine is a happy engine.

@Berserker__taco in your case I would maybe try a different tune Could try getting rid of the tune all together as well. Or dump 500lbs if you can

Yeah the weight definitely pushed me to the 5.29 as well as potentially going to 35s. If o could drop 500 I would but it's all pretty permanent at this point lol. I'm thinking a different tune is needed. What RPM are you hitting when cruising at 70-80?

 

[mgmyota]

Yeah the weight definitely pushed me to the 5.29 as well as potentially going to 35s. If o could drop 500 I would but it's all pretty permanent at this point lol. I'm thinking a different tune is needed. What RPM are you hitting when cruising at 70-80?

I’ll have to remember to check next time I’m driving. I didn’t include it because I honestly couldn’t remember lol

 

[mgmyota]

Yeah the weight definitely pushed me to the 5.29 as well as potentially going to 35s. If o could drop 500 I would but it's all pretty permanent at this point lol. I'm thinking a different tune is needed. What RPM are you hitting when cruising at 70-80?

Hey I finally remembered to check lol. 70 I’m at 2100 and 75 I’m like 2300 so 80 is probably about 2500. I’ve also used the hypertech module to recalibrate my speedo. But I didn’t tell it that I have 5.29 gears. I input stock gearing. Was a noticeable difference from telling it I have 5.29 gears vs stock. Drove better when I input stock gearing. Maybe recalibrating your Speedo could help because you mentioned you are at 2500 rpm at 70. Worth a shot maybe