15" Tires on a model five.

Unless they also tested the 15"-wheel Prius, you can't make that claim as the difference could be from testing methods used (stationary or with wheels spinning).

 

I thought that Toyota reports a drag coefficient of 0.25 for the gen 3 Prius, but a drag coefficient of 0.29 for the Pirus V.

 

I might be unusual but I am one of those members that gets above 50 MPG always in my V/Five. My lifetime average calculated is 52.61 MPG in 21,5xx miles and one year, two months. I have gotten right at 50 MPG but I have never went below 50 MPG yet. My tires are not LRR (Bridgestone Turanza EL400 02), but they are inflated to 42 PSI front and 40 PSI rear. My Constant indication on the MID is usually around 54-57 MPG. Granted I live in the tropics I usually commute around 60 miles each day from sea level to around 1,000 feet with a mix of rural and freeway driving at speeds from 35-70+.

I know I would and could get higher MPG running OE trim Two-Four stock 15 inch wheels. I would be willing to try and do a swap with 15" wheels if someone on Oahu has some they are not using.

Justin I know your numbers are on a Gen. II, I would be interested to see what kinda numbers you get when you do swap once you get your Gen. III?

Did you get it yet?

 

It's something to do with that tropical air.

I know there are folks who get 50+mpg even with 17s but we are never able to test what they would get with 15s. I picked up my new baby today and once the 15s are broken in and the weather stabilizes I will start testing with my 17s. To make things interesting, The Critic and I are going to swap tires for a few weeks to see if my 15" mpg drops when using his Primacy MXV4 tires and if his mpg goes up using my OEM Yokohama Avids. There will be so much swapping going on that we may have to give our review post a XXX rating.

 

I just finished reading your new car adventure thread.

Congratulations on getting your new Gen. 3!!!

I went by my local dealer on the way home to test drive a "c" for kicks and drool on the MY 12 third gens. they are sweet I like the new front facia and the tail lights.


Posted from my iPhone via the Tapatalk app.

 

I have a 2011 Prius II which came with the factory 15x6 wheels with Yokohama Avid S33D 195/65/15 tires. My wife has been averaging around 56 mpg overall driving about 50 miles per day with about 75% freeway and 25% city. She gets better mileage when she is stuck on the Bay Bridge traffic in the mornings.

She amazed me with a 60.3 mpg reading after driving around 125 miles. The car has around 5,500 miles. I just picked up a used set of factory 17x7 Prius wheels with 215/45/17 Toyo Proxes A20 tires with about 80% treadlife. These wheels look so much nicer than the stock 15" wheels.

So here are the answers that everyone is looking for. These are the pros and cons.

Pros:
Better looks.
Better handling.
Car feels more stable at highway speeds.
Better for charging your battery when braking.

Cons:
Slower acceleration.
Slight increase in braking distance.
About a drop of 5 mpg.
More road noise.
Slightly bumpier ride.

These are some of the things that I can think off the top of my head. I think if you changed the tires to a 205/50/17 LLR, the road noise, bumpier ride will improve. Don't think the mpg will change much though.

But these factory 17" wheels do look nice!

 

I was really hoping I was wrong and the post above scares me.

How many tanks have you logged with the new 17s? I assume you have tried to account fr weather and commute variables?

 

I'm not surprised, it is consistent with my experience (drove a mule PHV with 15" for 4 days while my 3G is 17") and chatting with other Prius owners here.

 

Too bad the mpg takes a hit with the 17" wheels
I have the factory 17" wheels I'm averaging 51-52mpg in mixed driving over my first 3 days commute to work. I'll take a small MPG drop cause IMO the 17"'s just make the car look sooooo much sportier.

 

Are you MPG numbers hand calculated or from the CONS. display on the MID?

 

Sorry, should have mentioned- 51-52mpg indicated via CONS.

 

Still not bad for 17s and your environment. That should calculate out to 48mpg or so.

 

I did not take into account the wet weather we are having in NorCal these past couple of days. The gas mileage dipped down to 54.6 on the cars computer. I would think that there will be a 3-6 mpg drop depending on driving conditions with these larger and heavier wheels.

I actually decided to weigh the 2 stock wheels. The 15x6 wheel with almost brand new Goodyear Assurance 195/65/15 tire weighed in at 35 lbs. The 17x7 wheel with the Toyo Proxy A20 215/45/17 with about 85% treadlife weighed in at 43.4 lbs.

That is a whopping difference of 8.4 lbs of unsprung weight per wheel. That's almost 34 lbs of extra weight and the worst kind at that. Unsprung weight really takes its toll on acceleration, braking and handling.

But damn those 17" wheels look nice.

 

Sidney, first thank you for actually weighing the wheel/tire combo. Those numbers are helpful. Please keep up posted on your mpg situation once this wet weather clears up. I had contemplated swapping to my17s to compare them to the OEM 15s but this storm hit and would have ruined any attempt at scientific observation.

My new AVID Ascent tires come in tomorrow so i'llhave to postpone the test until I get a couple thousand miles on them. My Primacy MXM4s have over 5,000 miles on them so I need to get the Ascends close to that before I can claim accuracy.