How much will my MPG change?
 

I have a stock 2017 lx, but I want to upgrade the wheels. I got a set for free from a friend that will fit my car, but I'm worried about the impact on my fuel economy. The wheels are 15" konig heliums with 205/55/15 DZ102s.

https://www.wheel-size.com/calc/?whe...cl=50mm&sr=0mm

Everything checks out, they are .6% taller than stock, so no real change to the effective final drive. They are also about 5 lbs lighter than the stock wheel and tire combo, but the tires are obviously wider and sticker.

Right now I average about 37 mpg on my commute. Realistically, how much can I expect this to change if I put the new wheels on?

Thanks

I dont have real "input" but.... huge favor .... can you do some fuelly receipts with your current set up ... like 3-5 tanks worth of data

and then .... once you slap on those free wheels .... can you do the same .... 3-5 tanks worth of data... and report back with your mpg findings?

TY in advance, I'm curious to see your outcome!

what are fuelly receipts? I don't actively track my gas mileage, 37.7 is just what the car shows as my average for the last few hundred miles.

for example, this is my prev car:

ct200h (Lexus CT200h) | Fuelly

if you could keep track of a few fuel up's (using your receipt at the gas pump) ... that would provide us with some useful data


https://cimg7.ibsrv.net/gimg/www.fit...c260f87722.png

https://cimg4.ibsrv.net/gimg/www.fit...76543db68f.png
the point of this exercise ... is to see if there are any changes/trends. like this:

Ok I signed up, but I can't start tracking anything until I get gas again. Is the mpg reading on the car not accurate enough?

I dont want to spoil the fun and magic for you, by answering that question =)

report back in 2-4 weeks. I cant wait to hear your findings!

updates?


/msg length

really tho .... updates?

Ill probably get gas again today or tomorrow, but right now I only have 2 fuel-ups measured. I started working from home, so I only commute once a week, about 12 miles with very little highway driving. My 2 recorded fuel-ups so far are for 36.2 mpg (with the obc reporting 37.7) and one for 38.8 (with the obc reporting 39.3). The higher one was a lot of interstate and highway driving.

I'll do at least one more, maybe 2 more measured fuel-ups before I swap wheels, I need hubcentric rings anyway.

So my experience from doing 205/50/16 from the stock tires size of 185/55/16 showed there was no real difference in mileage just from going with a wider tire on stock rims.

I'd be surprised if the lighter wheels made that much difference on a regular commute.

Are you accounting for the taller tire and the change of miles actually driven, or are you just depending on the obc to report mpg. obc has been pretty optimistic for me. Typically it's been 1-2 mpg optimistic versus calculating by hand.

off topic..... you ever wanna sell those konig heliums ..... pm me

Hey sorry I haven't replied in so long.
Stock Steelies - 35.6mpg
Konigs/Dunlops 34.6mpg

I put 2200 miles on the stock setup and 3000 miles on the aftermarket wheels. So the mileage did go slightly down with the aftermarket wheels but honestly not enough that I would ever notice if I wasn't tracking it this closely. Really it would be a rounding error for most people.
The aftermarket wheels made the car feel heavier and slower to respond at lower speeds (in the city) but made it much more stable at higher speeds (freeway on-ramps). I don't autocross or anything like that with this car so the insight I can offer is limited.

strange, I'm reporting the total opposite. my avg went from 36 ---> 38+


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