How much do tires contribute to MPG?

[gsfent]

I know the insight uses special low rolling resistance tires to help it achieve its phenominal mileage. How much does that contribute to its mpg? If you put those tires on say, a civic hybrid, how much more mpg would you get? Or alternatively, if you put "regular" tires on the Insight, how many mpg's would it lose?
Regards,
Jerry

[retepsnikrep]

Several comparisons have been done on this site, have you searched the forum. I typed in "tire comparisons" in the search box and got several useful results.

The concensus is they help a lot probably adding 5-20mpg to the figures. If you replace them with some cheapo ones you'll soon find out

I imagine any car they fit would benefit from them in mpg stakes, but they are hard and some don't like the grip in winter etc.

[gsfent]

Thanks. I did find one promising link in one of the threads, but it is no longer active.

I know Insight tires and wheels are light, so I was trying to isolate mpg impact. If I put Insight wheels and tires on a hybrid civic, how much mpg do I pick up? Has anyone actually done the measurement, or is it simply a bit of a SWAG? Or if I have an Insight, but find the tires handle so poorly as to require better tires, how many mpgs do I give up? Any insight?(pun intended! )
Regards,
Jerry

[Guillermo]

The Insight tires have a low load rating because Insight's weight is 1900 lbs.
Civic hybrids weigh considerably more then Insights, installing tires with lower load ratings then the stock tires is highly discouraged because it over stresses the small tires.

I noticed a fuel consumption difference of about 10% between OEM 165/65R14 tires and 195/55R14 summer tires.

[japanev1]

Yes, I just put a new set of stock OEM Bridgestone tires on my Insight from tirerack and the MPG has jumped from 58mpg to 66.5mpg with CVT. The Insight tires are much narrower than the wide Toyos that were on my car before so her drag coefficient is much better now. The wider Toyo tires were not flush with the face of the alloy wheel like the stock wheels are, and that sidewall protrusion from the non-OEM tires was a huge drag on her side airflows which significantly influences overall aerodynamics of the vehicle. She looks much better now with the OEM tires, even more futuristic especially from the rear 3/4 view. I love the OEM Bridgestones so much I may buy another set just in case they quit making them again!

[gsfent]

Good info, thanks for sharing!
Regards,
Jerry

[Dougie]

Conversely, I'm currently running Bridgestone Blizzaks 175/75R13 and don't see much of a difference...