NOOB Question.. Lower Wheel Weight = Worse Fuel Economy ???

I seriously doubt that Toyota would say something that incorrect.

A lighter tire+wheel combination will improve gas mileage, but by such a small amount that you won't be able to measure it.

Different tires will most likely change your fuel economy enough that if you are keeping close track you will be able to see a difference. The rolling resistance of you tires greatly evershadows and difference in wheel+tire weight.

 

Less weight will result in better mileage. However this may be drowned out if you use wider wheels/tires which will have poorer aerodynamics than thinner wheels/tires.

There are more complicated issues having to do with weigh at the rim versus weigh at the hub, but a lack of LRR tires and bigger tires blocking more air will be your main issues.

Now F8L will come by and explain it all better than I can.

 

You know how far you can go on $2,200 in gas?

 

Nice wheels... My votes go to SSR... Since you are in love with these wheels I would say go for it... just get some LRR tyres to go with them and I think you should be doing fine...

 

Unfortunately that is not the case. I have tried lightweight 17s as a replacement for my OE 15s and in every test I could conceive I observed a net loss of 4-9mpg depending on the tire choice and driving techniques. LRR tires will not mitigate this loss.

As already stated by xs650 and Jimbo:

1. Lighter wheels/tires are good for acceleration and braking but do not contribute much to mpg. The investment on super lightweight wheels will not be returned in fuel savings within the lifetime of the car.

2. The lightest tires are not neccessarily the best for gas mileage and may not fit your needs based on specific driving conditions. You are better off determining what your needs are then finding a LRR tire that meets those needs. Unfortunately there are not as many choices above 16".

3. Upsizing your wheels will result in a mpg loss. It is inevitable. No one has found a way to get around the loss. You can, however, reduce the loss by limiting yourself to a Plus 1 upsize (16"), keep the stock offset if possible and use the best LRR tire available which is the Energy Saver A/S or Ecopia EP100. The 16" wheels looks nicer, especially if the spokes extend to the edge of the wheel making the wheel look larger. Handling will also improve. A Plus 2 upsize will drop mpg considerably 4+mpg in my experience with the GenII and what others have also experienced. I was losing around 7mpg with my 17s and the Primacy MXM4 which is a LRR tire.

4. Don't go for the hellaflush look. Choose a wheel offset that will reduce the chance of rubbing and keep the wheel/tire tucked in the wheel well and out of the air stream. You will also want to maintain a narrow tire width to reduce friction and aerodynamic penalties for increased frontal area. Lastly face wheel design can affect areodynamics so try to choose one with a smooth face and trasitions. I realize this affects appearance and aerodynamic wheels may not be aesthetically pleasing.


If you purchased the car for mpg then you really should reconsider this upgrade unless you drive less than 12,000 miles a year. In which case the mpg loss won't add up to much in annual fuel expenditures.

 

Now where did that inertia come from, I wonder ?

 

Well said... Especially point 3... But if I am TS I would still go for it cos life is just too short for letting such a nice set of wheels go... I am having 15" and IMHO they are just a bit too small for the look department...

 

There is no such bulletin from Toyota regarding wheels. Do as others have suggested: find the best LRR tire, the narrower the better, then get the wheel to match it. You'll spend a lot more time seeing the MPG gauge than the wheels.

 

You are welcome. I totally understand the desire to pimp the ride...

 

I understand 'pimping' the interior; after all, the owner sits in it for hours and hours. The money people will spend on wheels has always amazed me.

 

We expect pictures and a full report after installation.

 

You own a Prius, you have already beat the general public in mpg. Go for it and get the Bling your heart desires. Make your car a statement of just how cool you are. Stand out and be proud of what you drive. Your the one that has to find it where you parked it last. How cool is it when you experence that "Hey there is my Car" moment. Enjoy

 

so what wheels did you get?

 

Wow 4lbs lighter? Good choice tho, I like the look.

 

I'll forward this idea, lighter wheels will see the most MPG benefit when the Prius c is driven mostly in an urban/suburban setting. More acceleration/decelerations with less rotational inertia. Benefit will be lower on the highway. Both driving conditions would benefit from lower unsprung weight. As a relatively light car, a decrease in unsprung weight will always be to your advantage. Try to make every change improve performance.