MPG with Rubicon Suspension Swap + 33” Falken Wildpeak ?

[Davecritz]

Just put the rubicon suspension swap (shocks & springs) on my 2019 JLU Sport S, and added 33” Falken Wildpeak A/T off a 2020 Gladiator Launch Edition. Looks fantastic couldn't believe it was the same jeep. Anyway i noticed the MPG went down from roughly 20-21 now to roughly 17 in two days. Hopefully it doesn't keep going down. Is this normal? What can i do to get it back up? Thanks

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[digitalbliss]

On my '18 JLUR I was getting roughly 18-19 MPG when it was stock. My commute is mostly city, but not heavy stop and go. Now with 35's (no lift) its roughly 15-16 MPG. Tire size/weight has a lot to do with it.

 

[Davecritz]

On my '18 JLUR I was getting roughly 18-19 MPG when it was stock. My commute is mostly city, but not heavy stop and go. Now with 35's (no lift) its roughly 15-16 MPG. Tire size/weight has a lot to do with it.

I might do a spare tire delete maybe that will help shed a few pounds . They look pretty good too

 

[Strommen95]

It shouldn’t go down any further then that with similar driving conditions. Since you ask how to get it back up I have to ask.. Is the lower mileage surprising to you? Seems it is unless I’m misinterpreting your post. No disrespect meant but it’s pretty obvious adding weight and adding some lift would bring worse fuel economy.

I don’t have the Rubicon suspension but when I went to 33s my highway mileage went from 21-22ish to 18-19ish. I’m curious how you feel the Rubi suspension drives and feels compared to the regular Sport one?

 

[Davecritz]

It shouldn’t go down any further then that with similar driving conditions. Since you ask how to get it back up I have to ask.. Is the lower mileage surprising to you? Seems it is unless I’m misinterpreting your post. No disrespect meant but it’s pretty obvious adding weight and adding some lift would bring worse fuel economy.

I don’t have the Rubicon suspension but when I went to 33s my highway mileage went from 21-22ish to 18-19ish. I’m curious how you feel the Rubi suspension drives and feels compared to the regular Sport one?

The first day it went from 21 to 19, I was like alright that makes sense, than later in the day 18, woke up this morning 17 and it went down to 16.7 then back up to 17. I was just worried it would keep going down. My brother has a V8 ford raptor that gets like 15 with 35’s on it. Got me worried. But I think the rubi suspension is alot more solid. I got mine from rubitrux and they advertise as the firmest springs off a 2020 jlu with 100 miles hardtop/tow/steel bumper. I was actually shocked when i saw it because originally i wanted a mopar 2” but didnt want to deal with all that extra shit that comes with - but i didnt expect such a difference in height with the rubi swap. I did also add .75 rc spacers in the front and the 33’s off a gladiator launch edition. It drives more solid not as floaty as other people have said. I would not go back to the stock suspension even with the lower mpg.

 

[El Zilcho]

Is this normal? What can i do to get it back up? Thanks

If you did not program your new tire size, than yes, its normal. When you program it, you will get a bit better mileage, but it does go down.

 

[powelld353]

Put the same WildPeaks on mine (no Rubi suspension, still stock) and mileage went down to 17.9ish. I put in a Tazer and programmed the tire size correctly and it now hovers around 18.5mpg depending on my driving habits. On the interstate it gets around 20.5mpg. All in all about a 2-2.5mpg drop from the stock Michelin's.

 

[EDH_JL]

Mine dropped about the same (Rubi + Falken MT), but I noticed anything over 68-70mph really starts dropping the MPG's fast. Watch your speed and see how it changes.

 

[digitalbliss]

That's a good point. You want to flash your Jeep for the correct tires size. That will help with the computers mpg calculation and it will ensure your speedo is showing the correct speed.

As for the spare tire delete, it's not really just the pure weight that causes the mpg decrease but the weight of each tire that the axle is having to turn along with the added rolling resistance of each tire.

For example, put a 200 lbs human in the Jeep and you probably won't have any changes in MPG but split that 200 lbs four ways to add 50 lbs to each tire and the results are drastically different.

 

[Burntoutaccountant]

Noob question. In theory wouldn't MPG increase when you regear for the proper size tires? More tire means less revolutions of the tire. Regearing should correct this thus fixing the mpg?

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