I am thinking about putting 17" on my HCH II. I have some sitting in the garage, but I need to get some new tires. The tire guys at the shop recommended 225/45/17. I looked it up on the tire calculator and that is the right size. I would like to upgrade them for something wider for handling.

What are some input on changing the wheels to 17"? Will it have a huge affect on mpg? The wheels that are going on there are OEM Honda wheels if that makes any difference. I am not sure about the weight though.

if you do decide to do this please keep us posted, I hate the stock wheels. I have read on other places on this site of horrible mileage due to tire and wheel changes.

2 1/4 in exhaust
Exhaust Pix
Intake and CC Breather

I've have a potential "worst case scenario" setup on my car, with some fairly heavy, not very aerodynamic 16"s (stock is 14" on '03) with tires that are 20mm wider (205 vs 185) and not specified as Low Rolling Resistance. Initially, mileage hit was absolutely huge, as in >20%, although I believe this was mostly due to some unrelated problems with the battery management system that I accidentally "fixed" by draining my 12v battery. The battery then recalibrated itself and performance immediately improved by a noticable margin, and the mileage "hit" was cut in half to 10%. Since then, the tires broke in some more, I adjusted for the fact that the old tires were actually slightly smaller diameter due to all the tread being worn off, and found that actual difference is 6-8%, depending on temperature (though this is still showing signs of improvement). That hit is definitely worth it to me though -- the ride is smoother, the car corners FAR better, and wet handling is leaps and bounds better. The look of the car is also greatly enhaced with the wheels. The stock low rolling resistance tires toward the latter part of their treadlife would begin to slide even on dry terrain, would spin when starting on wet roads, and were downright scary for wet cornering. Even new though, they were still quite poor.

As far as mileage hits go, you'd probably see about the same amount of extra fuel consumption in absolute terms on a gas-only vehicle, and a hybrid (all things equal). However because hybrids are so efficient in general, that will represent a 6-7% hit instead of a 3-4% hit. The same is true of running Air Conditioner -- the same amount of gas burned might be a 12% hit on a hybrid, and a 1% hit on a huge SUV, having that huge MPG display in front of you though makes the whole deal seem a lot worse.

I will definately keep you guys updated and have some pics taken. I am going to go shopping for some tires. On a side note...anybody know of a hookup for tires in Chicago? LOL.

There are a few threads on this elsewhere; I will give you my summary. I replaced my wheels with reasonably lightweight 17" rims, on which I put a non-LRR tire (215/40R17).

This change coincided with the change in seasons, so this exacerbated the MPG impact from the tires, so I won't really know the honest difference until the warmer weather returns. However here are some observations:

- Going 60-65 miles per hour I still get close to, or over, 50 MPG
- Going 70 and above, my MPG seems to suffer more than before (because of non-LRR tires?)
- On my short slow city commute, there seems to be little difference

I love the new rims and the improved handling on the car. At this point, if I were to do anything different, it would be to fork over the money for LRR tires. I don't *know* for a fact that they would make a difference, but I think it would be worth a try. However, the extra cost may be as much as 50 dollars per tire -- hence my original choice.

I'm also one of the folks who supports doing what you like to your car -- rims, tires, racks, etc. -- that makes it more functional and enjoyable for you. The real measure, in terms of MPG, will be relative to what you would have gotten in a similarly equipped (rims, racks, etc.) non-hybrid.

does anybody know the offset of the standard wheels?

Because of the different diameter of the tires doesn't that mean that your speedometer is off therefore also affecting the mpg calculation?

2 1/4 in exhaust
Exhaust Pix
Intake and CC Breather

Yes you're absolutely right, thats why it's so important to use a tire size calculator if moving between diameters. I have 17" rims on my car and the winter tires are 16" rims but I was able to match the tire sizes with a calculator so that my speedometer is 99.8% accurate as compared to the 17" wheels.

This one works well enough.

http://www.miata.net/garage/tirecalc.html

Jayson

got it, thanks!

2 1/4 in exhaust
Exhaust Pix
Intake and CC Breather

My posted values already account for the speedometer error. Actually, the tires I have were only slightly larger nominally, since I went with a lower profile tire, but the difference was slightly exaggerated by the fact that the old tires had most of their tread worn off, which will tend to make the actual smaller significantly smaller, making the mileage falsely read higher near the latter portion of a tire's lifetime.