Installed 15" MB Wheels "Viper" in an effort to maintain MPG

I know, I know. Make up my mind already right?

Driving around on the Lexus CT200h wheels I grew to like the upgraded look over the OE plasticky wheel covers but the fuel economy hit was pretty substantial vs. the 15" Energy Saver A/S (6-8mpg loss). The ride was worse as well although still pretty damn smooth for 17s thanks to the Primacy MXM4 tires and lower air pressure.

I knew I would have a hard time selling the Primacys for what I paid for them despite being brand new so I used Michelin's 30-day satisfaction guarantee to return them for a new set of 15" Energy Saver A/S tires. Because America's Tire Company here in Woodland has been so good to me I wanted to make it worth their time so I bought a set of 15x7" MB Wheels "Viper" wheels to go with the Energy Savers. Because the 17" tires were so much more expensive than the 15" tires I used the extra credit towards the new wheels. So when I sell the Lexus wheels I will somewhat wash out if you don't count the extra set of brand new tires I will save.

The idea behind all of this was to explore the effects of 17" wheels on the GenIII. I performed a similar test on the GenII and came to some solid conclusions. I decided to keep a set of 17s because they look so nice compared to the OE 15" wheels but after seeing a 47mpg (calculated) tank I decided the looks were not worth the FE loss and slight reduction in ride comfort. The problem was I didn't want to go back to the ugly, to me, OE wheels. I don't like the plastic covers and I don't like the wheels (black or silver). So I decided to try a set of aftermarket 15" wheels that were cheap and decreased the offset enough to bring the wheel a little more flush with the wheel well. This is not great for FE but it does make the little wheels look a little nicer. The OE wheels tuck into the wheel well pretty far. The offset on the new wheels is +38mm. I would have liked to go +40 but I'll see how this works. The wheels weigh 16.3lbs according to Discount Tire.

So here it is with the aftermarket 15s and Energy Saver A/S tires before lowering. I'll update the pics after we lower the car later in the month. Please keep in mind that this experiment is a compromise between good looks and great FE. Obviously a set of larger wheels would look better but you do suffer an FE hit and 15s are the only reasonable size that the Energy Saver A/S will work on a Prius.

 

Thanks!

I didn't get a chance to weight them but they are fairly heavy. I am going to check with the manufacturer next week. However, I don't think weight plays a huge factor in mpg, especially on long commutes. I feel the difference isn't great enough to warrant a higher priced wheel or one that I don't like the appearance of.

 

It is totally possible to get near 60mpg with 17s but it takes a good commute or careful driving. My average indicated speed is at least 43mph so 17s hurt. On the last tank I gave up and just drove it. When I used to do that with 15s I would still get around 57mpg. With the 17s it resulted in 50mpg indicated. So to answer your question, yes. If you are getting 57mpg I dictated with 17s then you could easily get over 60mpg with most LRR 15s and it is guaranteed with the Energy Saver A/S.

 

Here are a couple of side shots to show wheel offset. It's not bad but really borderline. I would have been more happy if it was a +40mm offset and/or a narrower wheel. The rear is fine but the front juts out to the body line ever so slightly. This is mainly the bulge of the tire and not the wheel.

 

Now I am reading somewhere that the 15x7 is 16lbs. I'm going to have to call or bring my scale by Americas Tire next week.

 

The guy at America's Tire ran my credit card then gave me a receipt to sign with a fortune cookie on it.

MB is made by Liquid Metal. So who knows.

 

Hater.

 

Why should you be? You're driving around in a badass ride of which I could only afford the wheels.

 

I emailed Discount Tire today and was told the 15x7 wheels weight 16.3lbs. The 17x7.5 weigh 20.2lbs. The 17s look a lot nicer but...

Here is what the other version of the wheel looks like.

 

Aye, the theme is similar to a lot of OE wheels coming out on cars like the FR-S and a new Porsche or was it Aston Martin?

 

I'm also noticing that the car seems to corner much better than it did with the same tires. Could this be due to the fact the wheels are 1" wider (thus increasing tire section width) and the reduced offset created a wider wheelbase? I know it sounds weird but handling now feels like something between my OE 15" setup and my 17" setup. Shear grip is relatively the same but sidewall stiffness seems much tighter and I'm running less pressure now too. Weird.