Loss of mpgs with lighter tire/wheel combo?

silverflash · Apr 16, 2015

went from the 46 lbs oem 17" wheels with gy wrangler sras to a 16" drap 9 wheel and yoko geo ats tire of size 215/70R16. My new combo weighs about 2 lbs less overall with the new wheel being far lighter than the stock wheels but the new tire being slightly heavier than the stock tires though I am not 100% sure as yokos site says the tire weighs 28 lbs and tire rack says it weighs 30 lbs. The new wheel is 16.55 lbs.

why would i lose mpgs? I lost 1 it seems but on'y been a few days. it also drives like it's a tad heavier. is this all due to the aggressive tread? bigger sidewall?

Terasec · Apr 16, 2015

silverflash said:
went from the 46 lbs oem 17" wheels with gy wrangler sras to a 16" drap 9 wheel and yoko geo ats tire of size 215/70R16. My new combo weighs about 2 lbs less overall with the new wheel being far lighter than the stock wheels but the new tire being slightly heavier than the stock tires though I am not 100% sure as yokos site says the tire weighs 28 lbs and tire rack says it weighs 30 lbs. The new wheel is 16.55 lbs.

why would i lose mpgs? I lost 1 it seems but on'y been a few days. it also drives like it's a tad heavier. is this all due to the aggressive tread? bigger sidewall?

I would say its the tire/tred
better traction comes at a price MPG's

stock tires are usually a compromise of performance and MPG's
getting those published MPG's is important factor in stock tire choices

silverflash · Apr 16, 2015

so how would it affect my power/low end torque in an off road situation where i am crawling up a bumpy road/hill in 1st gear (it's a manual trans)? speed will be 5-6 mph due to roughness of road but i might can go faster now with the better tires...

the new combo is 1.5 lbs lighter than the stock combo. i expected more power at the low end buy a hair. due to higher traction is that negated?

thoughts?

SREJECT · Apr 17, 2015

I would say since the rotating mass is now located further outward on the tire rather than the inner part of the wheel. The rotational g forces are causing the wheel/tire with more weight on the outer edge of the rotating part to have more drag.

At least that is what I would assume, if that makes sense at all to anyone.

bwpakk · Apr 17, 2015

How are you driving it? All city, some city some rural., half crawling? How many tanfkfulls of gas, how long have you been running new combination?

silverflash · Apr 17, 2015

Just got the wheels and tires this Monday. Have only driven 100 miles or so on them so far. I have a scan guage that monitors mpgs. I got 25 mpgs last night on way from work which was abt 5 minutes stuck in traffic not moving at all then 15-20 minutes of 70mph for half of that and 45-50 for the last part. I would expect to get abt 27 or so as i have had in the past. Its got to be tied to the tread design.

rcguymike · Apr 17, 2015

What's your tire pressure at? In my new mud tires I put it up to 42psi and that seems to help MPG.

silverflash · Apr 17, 2015

rcguymike said:
What's your tire pressure at? In my new mud tires I put it up to 42psi and that seems to help MPG.

35 per the card in the car door area. think i should up it?

i don't want excessive wear

rcguymike · Apr 17, 2015

silverflash said:
35 per the card in the car door area. think i should up it?

i don't want excessive wear

When Discount Tire put my tires on they recommended 40PSI. Due to the stiffer sidewall different tread compound that might be a better pressure. My tires are also rated up to 50PSI unlike the stock ones. It really depends on the tire, check with the manufacturer for a recommended pressure. Or up it and check the tire wear periodically, it'll wear the center more if the pressure is too high.

The_Jeep_Life · Apr 17, 2015

Tire balance? Alignment? Weather? Driving Habits? Fuel?

1ish mpg I don't think is too big of deal is it?

silverflash · Apr 17, 2015

i just upped it 2 more psi. as far as mpgs go, i watch that alot on my scan gauge. For example, the trip from my local walmart to my house, i can get 32 mpgs per scan gauge. it's only 3 miles. But I have gotten 28-32 since I have had the jeep these past couple years on that trip. My trip down to the coast over about 170 miles? I got (on the stock sra tires and wheels) 27/29 mpgs and that's going 55 the whole way give or take a few lower speed areas and one area where I go 65 for about 15 minutes... That will be the true test i think next time I do that.

today's trip to walmart, I got 26 mpgs. Lowest i have seen in past is 27 or so.

I will see what 37psi does for me and report back after the weekend....

i am thinking that just upping the psi a few pounds will help me and NOT wear the tires beyond how they would wear at 35 psi.

remember, i have the same exact diameter wheel/tire combo as stock 17" with sras. The width is same exact. Only difference is sidewall height- i added 1/2 inch all around- and tread. Supposedly the tires i have now are exactly the same weight as the stock good years in 215/65r17 size. Oh and the wheels i chose weight 16.5 lbs each versus the stock 17" wheels 18 lbs or so.... So I am lighter......hmmmmm, i should be getting better mileage!

it seems like i have lost more than 1 mpg, perhaps 2 or even 3. Which seems way excessive to me. But this weekend with another 2psi will hopefully fix that.

My other vehicle, 2007 xterra 4x4 was listed as 17/21 mpgs stock. I upped the tire size on that by one (went to the off road model's size) and went with a heavier tire. It's tires alone weigh 51 lbs versus 47 lbs stock, each. On that truck i lost 1/2 mpg highway and 1/2 mpg around town. It has an aggressive tread and is a c load versus p load tire. I get about 16.5 around town and 20.5 on the hghway going 65/70 mph.

thanks guys!

silverflash · Apr 18, 2015

Good news. Seems that extra 2 psi made all the difference. More responsive and doesn't feel sluggish any longer. Trip to coast tonight, 170 miles, average was 28 mpg!

So am at 37 psi. It feels not quite as soft as at 35 but better than OEM setup by far!! Amazing it just needed another 2 psi!

rcguymike · Apr 18, 2015

There are so many factors that effect MPG. Temperature, humidity, altitude, wind, weight, bad gas, engine temperature, atmospheric pressure, tire pressure, etc etc. Everything right you'll probably hit 30+mpg. Get everything wrong you're down to 18mpg. Don't sweat short term changes measure long term changes and compare it year to year.

dixiedawg · Apr 18, 2015

How does the overall diameter of the tire compare to stock? Could be your speedo is off a little bit now?

silverflash · Apr 18, 2015

dixiedawg said:
How does the overall diameter of the tire compare to stock? Could be your speedo is off a little bit now?

Identical. Stock is 28". The Yoko geo ats 215 70 r16 is 28". Exactly same.

Jeep felt sluggish at 35 psi and new tires. I ran stock tires at 35 and it felt great since I owned it. It was only sluggish with new tires this past week at 35 psi. Upped to 37 yesterday before my trip and its no longer sluggish and mpgs are back up!!! Def the pressure helped.

silverflash · Apr 20, 2015

Averaged 29mpg this weekend on a 400 mile trip. Not too shabby! That was sticking to two lane roads and going 55/60.

Jeeperitis · Apr 20, 2015

Fuel consumption

I have 235/70/16 General Grabber A/T2 tires and alloy 16X8 Pro Comp Wheels,and the RRO lift.The wheel and tire set up is 9lbs. a corner heavier than stock,not to mention the tire is quite a bit wider than the stock 215/65/17's. On the highway I get from 8.4L/100Kms.(32MPG) to 9.5L/100Kms.(30MPG)...once I got below 8L/100KMS. actually into the mid to high 7's....but conditions were good,wind at my back etc.......and this is @ from 80-Kmh to 60-Kmh....mostly around 90-Kmh. Today I hadn't reset my fuel consumption gauge,from my last outing which was all highway.Today I was city driving all day....when I did scroll onto the fuel consumption stats...just to see where I was at...I was sitting at 10.7L 100/Kms. 28-mpg..so that is averaged between highway and city driving.

I'm quite happy about those fuel consumption stats,particularly with those wheels and tires. So with lighter and narrow wheels you should be getting pretty good fuel consumption figures on the highway...although it does depend on how hilly the roads you drive on are,and wind condition and direction on any given day,and if you pass a lot and are heavy on the accelerator....and in the city if you flog it hard then the fuel consumption suffers substantially.

Cheers,
Bill.

rcguymike · Apr 20, 2015

Is that in imperial gallons? According to Google 10.7L/100kms is 22mpg which seems much more accurate to me.

Jeeperitis · Apr 20, 2015

Fuel effeciency

Yes it is imperial gallons,that is what we go by here in Canada...even so there are a lot of days on my way to and from work that I am getting from 28 to 30+ (US) mpg. on those bigger and heavier tires and wheels.....and if my trips to work were longer the gas mileage would be even better,as it is dropping the whole way to work.

When fishing season starts, and I start making the longer,less stop and go trips on the highway,I'll keep posted, how the fuel consumption is...if it is anything like last year,even though I have the heavier wheels and tires now, I should be into the low 8L/100Kms. to mid to high 7L/100Kms.....or definitely into the 29 to 30+ (US)mpg. And I'll be able to compare the fuel economy to the stock 50lbs. a corner, and what I get now with the 59lbs. a corner set up ...I find the difference is there in city stop and go driving......there is a difference between the two wheel and tire set ups( getting the bigger heavier tires rolling),but on highway driving,that difference isn't that pronounced.....once everything is rolling,and on cruise control,the Patriot seems quite efficient..pretty close to stock wheel and tire fuel efficiency.....if you let it.

Cheers,
Bill.

silverflash · Apr 20, 2015

Well I am quite happy with my mpgs and 30 mpg on a long trip I stellar for a 4x4 vehicle like the patriot and with the all terrains on it to boot!

I did take it easy though just kept it no faster than 60 on average and drove it mainly easy the whole trip. Probably would have gotten 26/27 mpgs if I drove it more spirited and probably 25/26 if I took the 70 mph for 120 miles route.

The route I took is less miles and takes same amount of time as the "faster" route. In that case I'd rather take it easy and save money with no time lost!

Loss of mpgs with lighter tire/wheel combo?

silverflash

Terasec

silverflash

SREJECT

bwpakk

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rcguymike

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rcguymike

The_Jeep_Life

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silverflash

rcguymike

dixiedawg

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Jeeperitis

rcguymike

Jeeperitis

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