I need some input on replacing the stock wheels on my '06 HCH. I do not want anything drastic. I am a guy who likes a nice set of stock wheels. And I cannot stand the wheels that are on there now. I am particularly interested in the stock EX 16" rims. I have found several take-off sets on ebay. I am very close to buying a set but I do not want to make an impulse buy without some feedback from you guys. I have several concerns. Would they fit? How would it effect the spedometer and also FE? Do I need to look at something lighter? Has anyone already done this?

I look forward to your comments...

My adventures in tire/wheel replacement is here:
http://greenhybrid.com/discuss/03-hc...14.html?page=1

Here's an upgrade to an 06:
http://greenhybrid.com/discuss/17x7-...82.html?page=1

I'd check with a Honda dealer if you're concerned about fit. As for FE and the spedometer, the diameter of the tire is what you want to watch. Going larger or smaller than stock will affect it. To what degree, I can't say. Maybe others can. There has been LOTS of discussion about weight and how much it matters, if it matters at all. I chose a ground rule that I'd reduce the unsprung weight - did so by 2.7 lbs per wheel. So far I feel good about saying it hasn't hurt FE in any way I can tell. Won't know till the summer (when weather is not a factor) to know if it's any better. In all, I'm thrilled with the new wheels, the better tires, better handling, and a tad quiter ride.

*** Retired after 65,000 outstanding miles ***

I would suspect that you are safe going with any of the rims made for the Civic EX. These should have the same diameter as the hybrid, and not effect the gauges. There will likely be a weight penalty though, as I haven't seen the weight of the stock EX rims listed. You may be better off getting some lightweight aftermarket rims. The weight of the stock Hybrid rims is well documented here, and Tire rack and other sites have many nice lightweight rims available.

The rims on the EX are 16inches and the ones on the HCH are 15". I personally like the rims on the HCHII and they also help in reducing the drag on the vehicle due to being mostly closed in.

Thanks for the input guys! I would prefer stock honda wheels but I will check out what tirerack.com has to offer. I just wish the stock EX wheels were lightweight because I think they look really sharp.

Doesn't anyone make carbon fiber wheels for cars? I know you can get them for motorcycles. Now that would be lightweight. Your wallet would also be lightweight after buying them

I observed a few things with after market wheels. First, if you're worried about weight, even 'lightweight' 17" wheels may be the same as stock 16". The reason I only went from 14" to 15" on my 03 was because 15" wheels can weigh 9-11 lbs. Those same wheels in a 17" were 15-16 lbs, which was actually more than stock (~14.25 lbs). Not to mention, 17" wheels are MUCH more expensive than 15". You pay a price for lightweight. It was actually very, very difficult for me to find the right cross-section of a) nice looking, b) right size, c) reasonable cost, and d) fit the car.

Tirerack has a good selection - I also bought a few racing magazines (amateur racing mags) which had an even wider selection. I was drawn to a few brands that had the look and price I was after - Motegi (Track-lite and Track-lite2), OZ (Superleggera), SRR, Kosei (the ones I bought).

If you start going down this path, I found it very difficult to find out the weight of a stock wheel. Honda either did not know or (more likely) would not tell me. I had to take it off the car and put it on a scale.

In the end, to be truthful, I don't know if it was worth all the fuss. I like what I got, but in retrospect I may have lightened up on the whole weight thing and gone with a 16" or 17" (lightweight, of course ) and a 205/50 tire.

*** Retired after 65,000 outstanding miles ***

Hadn't thought about it, but if you upgrade to a 16" or 17" rim, I would assume that the lower profile tire would weigh a bit less, and cancel out some of the added weight of the rim? Either way, I can't imagine a pound or two of extra unsprung weght would make much more than a percent or so effect on FE.

It's not just the unsprung weight. It's the mass moment of inertia of the wheel/tire. The farther you push the weight outwards, the greater the wheel/tire's mass moment of inertia. The equation of rotational motion is torque=inertia*angular acceleration. The mass moment of inertia for a cylindrical object is 0.5*mass*radius^2. So if you choose a 17" wheel over a 15", in the inertia equation you've changed the (15/2)^2 to a (17/2)^2. You'd have to choose a 17" wheel with a mass about 0.779 times mass of the original wheel to keep inertia the same.

Note that this doesn't include that you'd have to also calculate the change in inertia for the tire. You would use the inertia formula for a thin ring which is mass*inner radius^2. So using a 17" tire, you've increased the mass moment of of inertia of the wheel/tire combo again which means you'll need an even lighter wheel.

Clear as mud?

You clearly know your stuff. So how much extra power in your estimation would it take to move the extra mass added in this upgrade if you added 2 lbs in an increase from 15" to 17" rims?