Which tires?
 

Okay, looking around at what's available for my 02 Corolla. Turns out I can get either the stock 175/65 R14 or 185/65 R14. But the real question is: what is a good rolling resistance value? Do I need to shoot for under 0.01? Any experience with the Sumitomo HTR T4s?

Can you fit potenza RE-92s on there?

Yes, the RE92s fit (RR of 0.0107). I noticed that the RE92s come in an XL load rating, which I think is the Prius OEM. The treadwear life on those, however, is reported to be awful. Other fits: Bridgestone B381s (RR of 0.0062), Goodyear Integrity (RR of 0.0097). TireRack's customer reviews on the Integrity are pretty bad, no review on the B381. More fits: Sumitomo HTR 200 (RR of 0.0092). Michelin Hydroedge Green X (RR of ????, but supposed to be LRR).

I believe it is only the 185/70/14 Bridgestone B381 that has been tested to have a rolling resistance coefficient of .0062, same deal with the Integrity. If the diameter changes, so will the rolling resistance coefficient. Though I'm sure they will still roll quite nicely if you get them in the OEM 185/65/14 size if the only change is the diameter and not the construction of the tire.

chuckm -

The Integrities are used by the Toyota Prius, so I am guessing they have a good "LRR Pedigree". The tread looks similar to mine, so you should get road wiggle on "grooved" highways :

http://ecomodder.com/forum/119089-post10.html

CarloSW2

The TireRack crowd has their priorities wrong (as far as ecomodders are concerned), and most of them don't have scangauges. So they judge tires by noise, ride, handling, and treadlife, and most LRR tires fall flat in terms of customer reviews.

Do you think there is much advantage between 175s and 185s, either way? The contact patch should be the same size for the same psi. However, the wider tire will have less distortion in the direction of rotation. That would seem to me that this would lower rolling resistance.

I'm happy with the HTR200s I have. I do notice the car following grooves in the pavement, though. It doesn't happen on all grooved surfaces, just a few specific patches of road near where I live.

The FE seems to be pretty good with them pumped up to sidewall max, as well.

-soD

I really like those B381's. I think those may be the way I'm going to go when I need to replace my tires :thumbup:

Okay, throw the Viva 2 into the mix as well. I've seen people here say it is LRR, but I can't find ANY specs worth a damn. Walmart here carries them in my size, but no info appears on their website. Even Goodyear has NOTHING on their website.