Prius 15's are better than aftermarket 17's! (Wrong wheels/tires can wreck your MPG)

[RedDevil]

It has to be said, the way you use your car may influence what tire size is best.



Guess this size gives best FE in severe traffic jams, and lets you be the only one home in time for dinner...

[sidecar]

this phenomena is well known among Prius owners, switch to 17" equipment and fuel economy goes out the window,usually to the tune of US 4 MPG. Although this is something I wanted to do, Im still looking at wheels but have been researching more exotic 15" dia wheels in an effort to drop more weight and make the best of it. If light is good, lighter with LRR tyres is even better, right?

We think stock 17" optional factory alloy wheels are 11kg and 15" alloy wheels are 7.4kg. Stock tyres in Au are 195/60 Green X, conservative pressures at 42 psi, unless you are fond of bone jarring in this aluminium chassis.

Handling isnt great in stock configuration, so in an effort to hold cornering speeds I figured being closer to the same speed would actually save me fuel, so I decided I actually needed a wider footprint and a lower car, in doing so I considered lowering the car and just using spacers on the wheels. People say handling is greatly improved lowering the car and fitting heavier sway bars. This is what it would look like [photoshop simulation]. But Im unsure about bearing loads on a FWD etc... by spacing the rims out 20mm rear and 12mm front.



and how it actually looks stock


Just maybe theres something wrong with me but I love this freakin car! Ive done 4.2 litres per 100kms for 1002 Kms on 44 litres using glide technique, ordinarily Prius is rated at 4.9 litres 100 Kms.

[RedDevil]

Maybe a silly idea, but how about painting the rim at the holes between the spokes to make the wheels look optically larger?
It might look like this: (MS Paint & stubby fingers)

[wyatt]

Originally Posted by sidecar

Handling isnt great in stock configuration, so in an effort to hold cornering speeds I figured being closer to the same speed would actually save me fuel, so I decided I actually needed a wider footprint and a lower car, in doing so I considered lowering the car and just using spacers on the wheels. People say handling is greatly improved lowering the car and fitting heavier sway bars.

If you are talking about wanting better tracking, the 17's did a wonderful job at that. I wanted better FE, so I didn't want them. My wife didn't like the fact that the car "wouldn't steer back on it's own", so she didn't want them either. I currently have them sitting in our garage waiting to be sold on Craigslist. I figured when I list them, I will say that they greatly improve tracking.

[sidecar]

Originally Posted by wyatt

If you are talking about wanting better tracking, the 17's did a wonderful job at that. I wanted better FE, so I didn't want them. My wife didn't like the fact that the car "wouldn't steer back on it's own", so she didn't want them either. I currently have them sitting in our garage waiting to be sold on Craigslist. I figured when I list them, I will say that they greatly improve tracking.

I always thought it more likely toe in/toe out settings are responsible for that, mine is the same. I am told that lowering them makes them a lot more stable, something of a transformation.

[sidecar]

Originally Posted by RedDevil

Maybe a silly idea, but how about painting the rim at the holes between the spokes to make the wheels look optically larger?
It might look like this: (MS Paint & stubby fingers)

I couldnt see what you had done at first
......but while the difference is subtle, its there!

[wyatt]

Originally Posted by sidecar

I always thought it more likely toe in/toe out settings are responsible for that, mine is the same. I am told that lowering them makes them a lot more stable, something of a transformation.

I can only answer by saying that my car was much more "responsive" with the 17's. It tracked better, and turning was more "instantaneous". I didn't want them because of the relatively poor FE. This was confirmed when the wife complained about these trates when they were on her car. Her "problems" went away when we swapped back to the 15s.

[sidecar]

Originally Posted by wyatt

I can only answer by saying that my car was much more "responsive" with the 17's. It tracked better, and turning was more "instantaneous". I didn't want them because of the relatively poor FE. This was confirmed when the wife complained about these trates when they were on her car. Her "problems" went away when we swapped back to the 15s.

maybe 16's are the best compromise
I dont hear any FE complaints about them, and it 'seems' like there would be a handling improvement. Otherwise why the Touring version,... just a thought ..

[RedDevil]

My 16" rims on the Insight bring a sharpness to the steering that I have not experienced before.
My narrow winter tires on 15" steel rims were much less defined, though raising the pressure improved it somewhat. The FE on the 16" wasn't bad either, given that the Insight was still breaking in when I had them on, and I was fairly new to the game at the time. See my fuel log.

The 16" may give you 80% of the handling improvement that the 17" would yield compared to the 15"es at only 20% of their FE loss.
You just need to find the right tires for that rim.

[rmay635703]

No offense but all the data says that the "more" rubber you have the lower the RR. To keep the same outer diameter what do you suppose happens to the rubber going from 15" to 17"?

I would say the old SR standard for tires was much better than having a rubber band around your rim and I really don't understand the fixation of driving on rims anyway.

Give me a smaller tire with lots of rubber