Where is the update Tim!

 

I know this topic is somewhat old, but I will comment:

4 pounds is too much speaking of strictly inertia. The rotational intertia of a theoretical ring with all the mass located at the rim, a "worst case scenario" is the equivalent of double its own weight (rotational inertia + translational intertia). I'd guess the interia of that wheel/tire combo is equivalent to about 1.8lbs on the car. While he reduced the overall weight of the wheel, he may actually have the same overall inertia as more of the weight is located in the tires as opposed to the wheel.

A more significant difference will come from reducing unsprung mass, unrelated to rotation -- this should make the ride softer, as it will transmit less energy in the springs of the car. This should also mean the springs heat up slightly less going over bumps, wasting less energy.

 

Tim,
How about an Update?

I tried buying aftermarket wheels for my Hybrid, although I didn't pay attention to the weight. I believe the wheel weighed about 17 pounds, and the tire weighed 21.
The rims were 15" and the tire was 205/60R15.
Any speed over 40, there was a vibration throughout the whole car. I tried 2 different kinds of rims (but I used the same brand tire, BF Goodrich Radial T/A), and they both did the same thing.

I have to believe it was the weight that caused the vibration. Maybe the suspension couldn't handle it....I am not sure (and yes, the balance was checked, the wheels/tires were round and fine).

I am looking on TireRack right now, but am kind of worried about buying wheels.

The wheel I am looking at now weighs 13.5 pounds and the tire is 18 pounds (the tire is a 195).....

Maybe I shouldn't even bother...its just that those skinny hybrid wheels are so ugly!

What do you think?

 

I was going to wait one more month, but I'll go ahead and update now. I can do the subjective stuff now - I'll have to wait until Monday morning and I'll update this post with the data. I can get the hard FE numbers that way.

Noise: The Continentals are quieter than the Dunlops, but only by a bit. I still think the car is noisy, but it's more tollerable now.

Ride: Profound handling difference. Grip and cornering are, dare I say, fun. Granted I don't push it often, but I've taken some hard corners - haven't slid the car at all.

Inclement Weather: I have not driven them in snow yet, but lots of rain. Wet weather driving seems just fine. I've never had an issue or even a close call due to the tires.

MPG: [Updated] Since I got the new tires in November of last year, I comapred my avearge MPG over the Nov - August time frame for each year I've owned the car. Below, 2003 means Nov 2002 - Aug 2003, 2004 is Nov 2003 - Aug 2004, etc.

Year MPG MIN MAX
2003 44.08 39.00 46.70
2004 45.46 42.82 48.75
2005 45.95 41.36 50.09
2006* 44.45 42.48 47.03

* This is the year with the new setup. There's clearly a 1 - 1.5 MPG difference between this year and the last two. This is probably the best comparison, since my driving habits in 2003 were still "bad". My driving style since 2004 has been relatively consistent. So it would seem this setup does not perform as well as the original. Disappointing since I thought the reduction in weight would make a difference. I'd have a hard time attributing the drop to anything other than tire width and possibly the tires themselves. I run them at 40 psi, which is where I had the Dunlops.

But, I'm not unhappy at all. I like the way the car looks and handles, which more than offsets the 1 MPG hit. So a successful experiment if you ask me.

Here's a recent pic, with my newly tinted windows.

 

The vibration is odd. Your setup is about 6 lbs heavier per tire, but I think other people have done the same. Did the overall diameter change? That was something I was very careful about. My new setup is within about .5" in diameter of the old. A 205/60 may be taller than your old - something worth checking. That's about all I can suggest...

 

Hi,

Thought you might like to see these two-links.

http://www.cleanmpg.com/forums/showthread.php?t=1400

http://www.cleanmpg.com/forums/showthread.php?t=1385

These Links show my 2006 HCH II with Complete Body Changes and Wheel Changes.

Terry (tiger)

 

Very nice! I like your mods - good looking car!

 

Tim,

I was just looking at your HCH I with the New Tint job the other day and forgot to mention to you at that time your HCH I is looking just {Fine}. Very Nice indeed.

Have not been over here much lately I will have to try to come back here and read more Threads/Post so I can stay up on what's New here with you all.

Terry (tiger)

BTW, Thanks for the Compliment.