How much power depends on how big a tire and weight of the wheel.  I
switched to a 1" taller tire and noticed it.  Since the RPM stays the same
relative to you speedo, you just wind up cruising a little faster on the
highway, but just 3-4 percent though at that size.

If you replace 14" steel wheels with 15" alloys that are lighter and the
tires are the same diameter, you won't loose power and you'll gain a little
better handling.  But that's about it, other than a nicer look.

>From: jeff livingston-carr <jlivingstoncarr@GMAIL.COM>
>Reply-To: jeff livingston-carr <jlivingstoncarr@GMAIL.COM>
>To: vanagon@GERRY.VANAGON.COM
>Subject: Power loss with 15" wheels?
>Date: Fri, 3 Mar 2006 14:38:48 -0500
>
>Hi All,
>Does anyone think switching from 14" to 15" wheels will cause a significant
>loss of power as perceived by the driver?  I've heard that the bigger tires
>and wheels may slow the vehicle.
>
>Thanks.
>
>Jeff
>1991 MV