wheel disk covers... MPG myth or not?

[collegekid01]

so ne one notice a difference in mpg with these?

[theholycow]

Yup:

Originally Posted by JanGeo

OOPS - been working like crazy for the lasta few months - only added gas twice $25 each time since May25 but it looks like I get a couple more MPG with the racing disks. I do notice that coasting north on RT24 in Portsmouth down the hill that I pretty much maintain 50-55mph for most of the way now when before I would slow down about 5mph. Still haven't had a trip on the highway alone in good weather yet with the Racing Disks so until I get out to the Cape I will not know the highway impact but I am pretty sure it will be better that it was. One thing for sure they clean up a lot easier than the factory mag wheel covers.

They cover the valve stem since I had short stems on the rims - the stems do not extend past the lip of the rim.

[GasSavers_BEEF]

metroMPG did a study on these and noticed only a few tenths (if I remember correctly) his site has a lot of good experiments that he has done and a lot of good advice too. from what I can tell, his experiments seem to be non-biased so I tend to put more trust in his results than others. he also tries to explain out why something did or didn't work.

it is a long read but you should check it out. metrompg.com

[palemelanesian]

Someone just tested this at ecomodder. 4.6% improvement at 65mph.

http://ecomodder.com/forum/showthrea...-6-a-4368.html

[JanGeo]

A really simple test would be to jack up the rear wheel and spin the tire with a motor and let it coast down with various hubcaps on it or none at all and see what the difference is in spin time. Of course the weight difference would be a factor.

[theholycow]

That test isn't similar to the normal aerodynamic usage of a car wheel, which is not only rotating but moving forward too.

[JanGeo]

OK Guys I finally made the trip to Cape Cod on Tuesday this week . . . 44.1mpg going there typical highway speeds 88 miles average 51mph - then coming back there were headwinds so I took the old (lots of stop signs in certain areas) Route 6 all the way to North Darthmouth and when I returned to Newport RI . . . 49.0mpg!!

Seems the racing disks work pretty good at lower speeds.

[collegekid01]

Hmm mayb I'll make my own... idk... the wai is up next on the list of mods for me I think

[Jay2TheRescue]

Pimp'in the Volvo with pizza pans...

[Z man]

I have 11 pound wheels but they are not smooth at all. I know they help with moving from a stop but are worse at high speed. I save 32lbs total from stock.

http://www.1010tires.com/images/whee...e_black_lg.jpg


I believe the smooth hubs work, look at the factory wheels for the Civic Hybrid.