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[blueaudi18]

anyone jump from 18 to 19 and notice a difference in mpg. I'm getting about 15.5 mpg with the 19's while i had about 18mpg when i had my 18's.

[magmd]

19's = 20.9 mpg
20's= 19.1 mpg

[blueaudi18]

Originally Posted by magmd

19's = 20.9 mpg
20's= 19.1 mpg

what psi you running? i have no highway driving either.

[montreal red]

bigger wheels with more weight would make the mpg suffer

[wj4]

I didn't noticed much of a difference when I went from 18s to 19s. Maybe 1 MPG different at max, but a number of factor can be associated to that.

[david @ eas]

There isn't much MPG difference at all... If you really look into it, it might be 1 mpg at the highest. I really doubt it would be higher than that. Haven't done the research myself so I can't be 100% but it cannot be too high...

[Michael Schott]

Originally Posted by montreal jet black

bigger wheels with more weight would make the mpg suffer

The change would be barely noticeable. It's like putting a set of golf clubs in the trunk. Certainly not 20%.

OP, did the diameter of your wheel tire combination change? If so maybe that's throwing off the car's calculation.

Thanks, Mike.

[S4to335]

Originally Posted by blueaudi18

anyone jump from 18 to 19 and notice a difference in mpg. I'm getting about 15.5 mpg with the 19's while i had about 18mpg when i had my 18's.

If they are accompanied by wider tires...more rolling resistance...or if the wheels are heavier...you will have slightly less mileage on a bigger wheel/tire package

[GregL]

Some wheels are pretty damn heavy, Tire Rack has 19" wheels starting from 20.5lb to the low 30s. To the OP, I'm assuming your 18s are oem while the 19s are aftermarket? Either way, what exactly are they? Also Michael has a very good point, did you buy tires with the proper rolling diameter?

[blueaudi18]

Originally Posted by GregL

Some wheels are pretty damn heavy, Tire Rack has 19" wheels starting from 20.5lb to the low 30s. To the OP, I'm assuming your 18s are oem while the 19s are aftermarket? Either way, what exactly are they? Also Michael has a very good point, did you buy tires with the proper rolling diameter?

18 m6 reps. 18x8 all around.

now i'm runing 19 lm reps. 8.5 in front, 9.5 in rear.

what psi is everyone running.. i'm only running 38.

[GregL]

Originally Posted by blueaudi18

18 m6 reps. 18x8 all around.

now i'm runing 19 lm reps. 8.5 in front, 9.5 in rear.

what psi is everyone running.. i'm only running 38.

I'm guessing you have 235/35/19 tires on the front and 265/30/19 at the back?

You might want to open your driver's door and check what the sticker on the lower B-pillar says, there should be a chart breaking down tire combinations and the appropriate pressure, my E90 330xi for example recommends 32 front, 35 rear if I'm not mistaken.

[blueaudi18]

Originally Posted by GregL

I'm guessing you have 235/35/19 tires on the front and 265/30/19 at the back?

You might want to open your driver's door and check what the sticker on the lower B-pillar says, there should be a chart breaking down tire combinations and the appropriate pressure, my E90 330xi for example recommends 32 front, 35 rear if I'm not mistaken.

32?35?... i was running 38psi and it looked like it needed some air.

I jsut did 40psi all around. Going to see if there's any difference.

[GregL]

Originally Posted by blueaudi18

32?35?... i was running 38psi and it looked like it needed some air.

I jsut did 40psi all around. Going to see if there's any difference.

You really should check either the manual or your pillar sticker to see what is recommended. 40 is awfully high as a cold pressure, would go up to around 43 when warmed up. Also some tires naturally look partially deflated, it's the softer sidewalls.

[MrSteak]

Originally Posted by blueaudi18

32?35?... i was running 38psi and it looked like it needed some air.

I jsut did 40psi all around. Going to see if there's any difference.

I'm not sure how tire pressure would affect mpg, but I'd go higher for everything else.

This past September took a stunt driving course, and learned a LOT about tires. Those stickers on the doors with "recommended psi” are bullshit. (They’re more of a compromise between, performance, safety, and COMFORT.)

We were taught to inflate our tires 5psi above the maximum psi on the sidewall of the tire. (Where it says…”do not inflate past ## psi”, so that +5.) It sounds crazy, I know but it’s actually the best thing for you and your tires. (And not just for “stunt driving”, it’s actually better for daily driving, and bad weather.) The only thing is that you have to inflate your tires to this +5psi when they’re newer, b/c doing it to old/damaged/worn out tires will just put stress on whatever damage they already have.

Basically… higher PSI = 1. Stronger Sidewall, 2. Better contact patch on wet roads, and 3. longer tread life. (The only downside is that the ride comfort will suffer a little.) I could go on but I’ve said enough.

[E90330iS]

ya I do my tire pressure above recommended level also. 38/40

and back to the topic, my mpg did suffer. i went from a 320mi full tank to a 300mi full tank.

acceleration is worsen also as higher rpm is needed to reach the same speed in the same time frame. but i personally think the looks is worth the performance/efficiency downgrade.

[b8b]

Are there any other threads which compare the MPG for wheel sizes/types? I upgraded from OEM 156's (16") to OEM 162's (18") and my MPG is suffering greatly, as is my free-wheel roll (going downhill in neutral). Thanks!