Jeep Gladiator - Do 35"s kill gas mileage and performance? 

Awesome, it's always nice to hear the content was helpful to someone. Thanks for watching!

Happy to share! I know what you mean, so much of what's posted on the forums is fairly subjective opinions... one person thinks it's no big deal, vs someone else who thinks it is terrible. I'd rather see some data and decide for myself. I love the way the lift and 35"s look, but they definitely had an impact on gas mileage. Congrats on the new Jeep btw!!

Hi. Just curious if you used a Pro Cal or similar to readjust shift points etc?

I learned nothing from this. Did a final MPG get told?

Glad the video was helpful. Yea, the size/weight of the tires really has an impact. Though in all fairness, the fact that you can run 35"s without gearing and still get reasonable gas mileage is impressive. I think back to my XJ on just 31"s and was probably getting similar gas mileage. It would have been a dog with 35"s haha.

Glad it was helpful! Thanks for watching!

I agree, it would be interesting to know how much impact the tires had on braking distance. While I can't say that in normal daily driving that I've noticed any real difference in braking, the reality is that heavier/taller tires will certainly increase braking distance. I have also towed an 8.5x16 enclosed trailer with my race car in it without any issue, though the trailer has trailer brakes, and I installed a Redarc trailer brake controlled.

Congrats on the new tires. I think you’re really going to enjoy them!

It's not exactly sports car handling on the highway, but it's good enough. On the 2020 models like mine, they have a TSB for an updated steering gear box, which I have since gotten. My understanding is that all 2021 model were built with the new gear box. Since your Rubicon will have 4.10's and stock 33"s, you shouldn't have any gearing issues at all! And congrats on the new ride! Thanks for watching.

Just got my 2021 gladiator Rubicon the PSI on both the rear and front was set at 37, it bounce all over the place. I messed with it a little, I air down to 33 and made a huge difference. Rides like a Cadillac now…..well not really, but it’s a lot smoother ride.

Glad I could help. Thanks for watching.

Thanks for watching and subscribing!

Glad it was helpful. Thanks for watching!

Happy to share. And congrats on the new Overland!

Just ordered a '22 Overland and had the same thought. For our use, 33" seems the way for us to go. Thank you.

I'm thinking of 32s on mine.

I totally agree.....this changed my mind about going with the 35's

255 70 18, if that is factory, is already a 32.

Thanks for watching!

I don't regret going to 35"s. I think they look awesome. But the extra height and weight definitely has an impact on fuel economy. but since you have the 4.10 gears, that should help some.

If you start off with the 4:10 35 is fine. I think it’s more of a function of his 3:78 gearing

If you go/went with 37’s you will never see 20+ mpg ever again

@@rocketman3776 I did. You are right. Never better than 16 and never 8 speeds. Thanks for your videos.

Congrats, you'll love your new Jeep. I don't honestly still really love my 35"s but that increase in tire size doesn't come without some sacrifices. I saw another Gladiator on the highway this weekend, it looked like he had a leveling kit an 33"s, and it also looked really good. Can't go wrong!

When ego goes up, might goes down. Perfectly balanced, like all things are

Nice, 17mph with 37"s isn't bad at all. I wonder if the improvement came from the motor breaking in some, and maybe the new fender flares are more aerodynamic?

I agree. While the 4.10's still aren't ideal either, they are incrementally better than the 3.73's. At the moment though, especially since I'm not commuting to work because of Covid, it really hasn't bothered me that much. Even pulling my 8.5x16 enclosed trailer, it's not the end of the world. It runs in a lower gear and turns higher rpm, but again, it's not something that I'm doing very often at the moment. But I do eventually see going to either 4.56 or 4.88 gears. Or trade it in for a diesel, haha.

No we used to put under drive and weight reduction pullys on camaros, firebird's, mustangs. There is a drag race formula I'm old now so can't remember exactly but basically ever pound you take off of an object like the wheels, pullys drive shaft it's equal to 8 pounds of weight on the car. If you add 20 pounds per wheel that's 80 x 8 pounds...so that's like throwing 640 pounds of shit in your bed and hauling it around

@@yamahansolo but that’s all for accelerating. Once at speed and not accelerating your only energy use is drag. Air drag and rolling resistance. That noise big wide mud tires make is all energy transfer from the tire lugs to the road and it’s a huge negative energy flow

Glad you liked it! Thanks for watching.

Yea, I think the 8spd auto can mask it a little better, but the taller heavier tires definitely have an impact. A close friend just bought a JT with the 6spd and he's trying to decide what size tire he wants to go with. He's leaning towards more like a 34" tire since he's not in a position to regear in the near future.

That’s way too much for regear 😂

Awesome, glad the video was helpful. Thanks for watching.

A 285/75/18 is a 34.8". So pretty much the same rolling diameter as most 35"s. Though obviously not was wide, which would save some weight. But bottom line, a taller/heavier tire will definitely have an impact on gas mileage. I love the way it looks, but it's not without a few drawbacks. Good luck on your decision!

I'm thinking of going with a 285/70/18 that's a 33.7 inch so I think it would be a good middle ground between size and mpg

interesting. I was going to buy the sport s with max tow, lift it 2 inches and put 285/75R17's on it, but get 2 more mods directly from mopar: The stainless steel cat back dual exhaust and the cold air intake with the washable filter. together I figured these 3 might work. however...2 weeks ago, ended up settling for a 2022 rubicon, just nothing else available where I live. 12 days in, throttle position sensor goes all crazy, command start fails, red warning light, uh oh, goto dealer, they scan it, cleaned some oil & water out of the air filter compartment. the senior electronics technician tells me its coming back through the pcv valve, jeep has no fix for this yet, its too new. but stay posted they might come up with a recall or a solution. its got 4:10 gears and 285/70R17's from factory. trip meter says 14.5 liters per 100 km up to 15 sometimes. window sticker says 12.3...havnt seen it yet...and this is sticking to 105km/hr. mostly hiway for now. so, the question is? would the exhaust and intake help either of us? the jeep technician told me flatly, he didn't think it would help at all. but I watch these vids and read the comments, cuz mabey someone tried it. dont know if this helpful to you any, have you made any changes since?

Did you adjust your speedometer before doing the test? Otherwise, the mpg on your infotainment is calculated wrong

That's awesome. The torque of the diesel makes a huge difference. If I could change one thing about my Gladiator, it would be to have the ecodiesel.

Glad it was helpful! Thanks for watching.

@@ScrufsGarage :) greetings from Honduras

that is almost 50% :)

Thanks. And hopefully it helped eliminate any impact of elevation changes too. Thanks for watching!

Glad the video was helpful. Thanks for watching!

Yea, the gas mileage is definitely something to consider. I've done a few longer trips. Went for NC up to DC to pick up my race car, and took an overlanding trip to the NC mountains last year. But both of those trips I was towing a trailer so not the best comparison on gas mileage. I have just over 6k miles on the Jeep now. No real change in the gas mileage. Average 13-15mpg mixed driving.

I had debated on going with 35"s vs 37"s. I'm glad I went with 35"s. The 3.73 definitely aren't ideal. They get it done, but regearing would be nice. 4.88's may be in my future. With Covid and work from home, I'm not driving it that much, so it's not a pressing issue at the moment. I really wish Jeep would offer the max tow (ie 4.10s) with the Overland model. I wanted some of the creature comforts that come in the Overland model, but it comes at the sacrifice of getting the max tow and 4.10s.

I’m using a Tazer mini for calibrating the speedo for the tire size change. has some useful features (disable auto stop for example) but doesn’t add any horsepower of course.

I've got a Tazer mini and have been happy with it. Aside from recalibrating for tire size, it also lets you turn off the autostop engine shutoff, and various other things (double tap mute to turn on the rear camera, can activate the rear camera when you use your turn signals, etc). Might be worth considering also.

Did you make the switch to the 35’s? If so, how do you like them?

I’m using a Tazer mini to recalibrate the speedometer. So the tire height difference is accounted for between the tests. 👍

Excellent point. I didn't do any A-B testing to compare, but taller/heavier tires are definitely harder to stop (can't change physics). But daily driving it's not something that I've noticed. Even towing my 8.5x16 enclosed trailer (with trailer brakes), I don't have any issues with stopping power. I'm sure if I had done 60-0 stopping distances tests, I would have seen an increase in stopping distance. Or repeated 60-0 tests would probably produce brake fade earlier. But in normal driving conditions it's not something I notice at all. Hope that helps!

Not really any changes. For normal mixed driving I get a13-14mpg. And on long hwy trips I might get up to 17mpg.

How well does it pull your camper?

What was your mileage with the camper?

@@glenwoolsey4698 11MPG ---will be doing 2200 MILES starting second week of August on 35x12.5s so that should be quite costly

@@DeanJohnson67 True but life3 is fun and what you make of it. I have a Gladiator max tow 31.5's and it is my main tow vehicle for my RV 3000lb empty. Like 33's or 25's but taking my time to think about it.

Yes, using a Tazer mini to recalibrate the tire size.

The 4.88's may help some, but I don't think it would be significantly better. There's still the realities of poor aerodynamics and heavier rolling mass of the tires. 3.73 gears in 7th gear (0.84), would be very similar to 4.56 gears in 8th gear (0.67). So you're still turning similar rpm's on the hwy. So instead of running primarily in 6th and 7th gear on the hwy, you would run in 7th and 8th gear. But the rpm's the engine is running at would be similar. What you gain is more power in the lower gears though, so that's a benefit.

@@ScrufsGarage ok gives me a better idea if I really have to regear. Thank you👊🏽

Two things that might help: 1. For 35s and the V6 4.56 would be more appropriate, my 2Dr gets 21mpg with 37s and 4.88 2. Spend the money on lighter wheels. Not much you can do about the tire, but keeping unsprung weight down will help immensely

TrailRecon did a video and real world test with re gearing, worth watching, good discussion during the test about all those factors too.

That's really good. A few weeks ago I drove from NJ to NC, and was going slower than normal since I had a motorcycle carrier on the bike, so I averaged under 65mph down I95. I got 17.5-18mpg on that trip, which is the best I've recorded. Going a little slower definitely made a difference.

Yes these machines are not made or intended for spirited driving unless there’s a 392 lol. Also they recommend a fuel of 89 or higher to help with the better mpg. I use 93 it apparently Can also keep your engine from the notorious Jeep ticking that they’re known for. I commute 2 hours a day round trip to help put perspective to it

You don’t need a lift for 35’s on a Mojave let alone a 2” spacer for the stock wildpeaks. I just got 35” Maxxis (11” width) and they’re perfect.

Interesting, I'll have to look that up. Thanks for the suggestion!

Speedometer was recalibrated using a Tazer Mini.

Yes, the 4.10's should be slightly better than the 3.73's.

Yea, the motor just has to work so much harder on the highway, and you really see it in the gas mileage. I haven't decided yet if/when I'll regear. It partly depends on if I think I'll eventually go to 37"s, or if I'll stay with 35"s. I would lean towards 4.88 gears, though they would be a bit aggressive with 35"s. So basically I'm undecided at the moment, haha.

4:88’s for sure, I have JLUR on 35’swhich came with 4:10

I went to 4:88’s on 35’s on my JLUR. It didn’t help much with gas mileage, you do get 7th&8th gears back!

I have about 15k miles on the setup now. Honestly no change in the shifting. Like anything, you get used to it after a while. I towed my enclosed trailer and race car to the track a few times, and it does what I need it to do. Overall I'm happy with it.

Yes, that's correct. For the taller tire size, I used my Tazer mini to recalibrate the speedometer. It also does the timed 0-60 runs, etc.

Yes I did. I’m using a Tazer mini.

Braking performance isn't something I was able to measure, but realistically a taller heavier tire will have some impact on braking performance, especially under repeated hard braking. In a day to day setting, I can't say I've noticed a change. I didn't do any towing when my Jeep was stock, but since the lift and tires I towed my 8.5x16 enclosed trailer with the race car in it several times and didn't have any issues with braking. (the trailer had its own brakes).

Nice, that's quick, especially for a Jeep. How do you like the 4xe in general?

Yes, using a Tazer mini to recalibrate for the tire size change.

Correct, I’m using a Tazer Mini to recalibrate for the tire size change.

In my opinion, the 8 speed largely negates the need to regear, at least from a gas mileage perspective. The Trail Recon channel did a mpg comparison after regearing his Gladiator and saw very little improvement.

I have about 4,500 miles on the tires now. And I'm using a Tazer mini to recalibrate for the tire size. I have not noticed any changes in the shifting. It still downshifts frequently on the hwy and often holds a lower gear much longer than seems necessary and so the gas mileage is still around 15mpg. The 3.6L motor makes peak torque at 4,400 rpms so I guess it's not surprising that the transmission needs to downshift and run the motor at a higher rpm. The motor makes plenty of power, it just comes at a higher rpm.

@@ScrufsGarage hmmm, now I’m considering 33’s over 35’s. I think gas prices are going to go sky high, in the near future.

Yea, it's definitely something to consider. The bigger tires add a lot of rolling mass. Another popular option is a leveling kit and running 285/75/17 tires. Roughly a 34" tire. And they weigh about 10 lbs less. (assuming a Ridge Grappler).

I went with a Rusty's off-road 2" lift. I talk about the lift in more detail in this video if you are interested. ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-yCeFm7L_ncA.html

I've got right at 6k miles on the Gladiator now. When I filled up yesterday (mixed driving) I think my average was around 14mpg. It typically varies from 12-15 mpg depending on the type of driving. So I have not really seen any real change in the mpg since putting the tires on. (I have since added a HD front bumper and a winch, so a bit of added weight). While I don't love how much it downshifts on the hwy, it's not really the end of the world. It's still very driveable. Regearing would be a "nice to have" but at the moment I don't think it's "required" if that makes sense.

@@ScrufsGarage Have you or have you considered programing you jeep for the 35's? To help shift points

@@jasonmatheney9425 Yes, I am running the Tazer Mini to recalibrate for the 35"s. (testing in the vide was done with the Tazer installed).

Have you considered re gearing to bring it back to a stock feel?

Nice. I had a ‘96 XJ for many years. Loved that Jeep.

Speedometer was recalibrated for 35”s with a Tazer mini.

@@ScrufsGarage I did hear that toward the end of the video but something’s not right. Your mileage should not be THAT bad. I would expect a 3-5 mpg drop given increased weight and wind resistance… that’s what I saw in my old lifted Wrangler, and it got much worse once so regeared. Lol

FYI I’m running a Tazer mini to recalibrate for the tire size change. It also has live functions like the 0-60 timer. 👍

Good info, thanks for replying 👍

Correct. The computer was recalibrated for the tire size change using a Tazer Mini.