Tire question...opinions needed

It is very likely that your poor MPG is due to the 17" tires on the car. The wheels have a minor effect but the tires are the real culprit. Even a LRR 17" will cause a drop in MPG when compared to a LRR 15" tire. The weight of the wheel is important but not as important as the tire composition and design. The OEM 17" Prius wheels are very heavy yet the MPG loss is not large when LRR tires are used. Fortunately the GenIII doesn't seem to suffer as great of a MPG loss as the GenII does when larger wheels are used.

If you want to get the best MPG possible then find a set of used 15" Prius wheels for cheap or purchase a lightweight set of new wheels that you like. Put a LRR tire like the ones you listed or that are on my LRR Tire List.

If you are happy with the 17s then you can try a LRR 17" tire like the Michelin Primacy MXM4 or the Continental ContiProContact.

I have been switching between 15s and 17s since I've owned the car and I always see a 6+mpg gain when I go back to the 15s. It's ultimately your call. Do you want better handling or better gas mileage?

 

If you do not like to take corners fast then the 15" tire is fine. The MPG difference between my 15s and 17s has been fairly drastic. With my current 17" wheels/tires (w/ LRR tires) I was observing a 45mpg average. I could likely have bumped this a bit more with careful driving but I doubt it would have been more than 47mpg. I then swapped to my 15s with LRR tires and I am able to get 55mpg with careful driving.

A few months ago I was running on my 17s but with older tires and I was observing 42-44mpg. Prior to that I was getting 50-52mpg even in the winter with my 15s.

My point is in my experience over the last 5yrs, every time I put the 17s on my car the MPG drops by 4-6mpg or more. Here is an old thread detailing my experience. This is with 2 different sets of tires than I currently run but the MPG loss is the same. http://priuschat.com/forums/gen-ii-...59-swapped-17-s-back-instant-drop-in-mpg.html

 

The OEM 17" wheel is approx. 24lbs. The 15" wheel is about 15lbs.

For what it's worth, my 17" wheels are 15lbs and I still see the MPG drop.

Yes, the lighter the wheel the better but don't expect too much of a gain from just a lightweight wheel. Keep in mind that a 17" tire will weigh approx. 21-22lbs whereas the 15" tire weighs approx. 17-18lbs.

 

Keep an eye on the Private Sales forum here and also flea-bay. I have noticed a few sets in that general price range, usually with good tires.

There is a set on flea-bay without tires now for $440 buy-it-now price
2011 TOYOTA PRIUS 15" WHEELS RIMS STOCK OEM FIT COROLLA | eBay

 

I don't think the oem wheels are all that aerodynamic so I think you will be fine with another lightweight wheel. Since I have not tested this personally please take my advice as merely a guess.

 

Side aero drag can hurt mpg if you do a lot of highways, but it's not nearly as big factor as rolling resistance. Weight is not as big of a factor as you think either. If you upgrade to larger wheel diameter and wider tires, the increased rolling resistance from those is a much bigger factor than weight and side aero drag.

What were the specs of your 17" wheels/tires? Even the relatively heavy but aerodynamically-designed factory 17" with 215/45-17 tires get only a ~1.7 mpg hit compared to stock 15". Go larger or wider than that and your mpg will drop further regardless of weight or side aero drag.

 

Last fall I was looking into snow tires for our Touring Model (comes stock with the 17" rims). Our dealership parts department quoted (roughly) $350 for the 15" and $390 for the 17", per rim.

To complete the 15" package you still need the $70 (each) covers. (Unless you want to forgo them. And then you might want to spring for the centre caps, which are maybe $70 for 4, ridiculous outlay for a few pieces of chromed plastic...). You might also need different nuts, say another $50, tops.

Ok, assuming you go with covered 15", so far that's up to $1730. That's still a long way from the $2400 you were quoted, and this is all Canadian funds, hmmm...: maybe Tire Pressure Monitors?

Also, mount/balance and valve stem will set you back $15~30 per.

BTW, for our snow tires I ended up going with steel Corolla rims: $70 per, and didn't bother with TPM's.

 

Howdy there,

Good to see you did increase tyre pressure, however, I run mine at 49/48PSI. As long as you do not inflate the tyres above max wall pressure (this is indicated in the wall of the tyre, my MWP is 53).

But 15 inch would be much more suitable, it's all dependant on $$$

Once the ICE has worn in you will notice an improvement also

 

read this: When Round and Black Becomes Lean and Green

Not sure if the mediocre numbers on Fuel Max tests were related to "new tire" effect. I did not take chances. With 15" Michelin Energy Savers A/S at 42/38 last tank is 62MPG, 60MPG since last oil change (3,500mi). YMMV

 

I have Michelin Energy Tires, 195x65x15, for over 44,000 miles now.

All four are inflated to Max sidewall pressure of 44 PSI, Costco Nitrogen.

I expierenced a 2-3 mpg gain over the factory Yoko Avid tires. The tires are wearing quite well with over 60,000 miles estimated life at this point with 44,000 miles.

Last fillup was over 54 mpg, calculated, with these tires in real world driving on vacation with 3 people and vehicle gross weight of 3,800 lbs.

alfon

 

If you go with Savers a couple pointers:
- going over 42psi (44 max) does not do much for MPG but decremental to grip
- they are soft and make car more sensitive to cross winds. Reducing rear pressure to 38psi helps with stability
- they are not grippy in dry but they retain grip in wet much better then others
- do not have 1st hand experience but people say they are very mediocre in snow