Re: Speedo vs. MFA WRT Tire Size

["Chris Campbell" <Chris.Campbell@eastbridge.ns.ca>]

Hi Jeff,

Correct me if I haven't had enough coffee yet and am way off, but 
shouldn't your speedometer read *slower* if you put larger diameter 
tires on?  So your odometer should tick off the miles slower, and your 
fuel mileage (reported by MFA) should go down (actual shouldn't 
change, or possibly improve since your engine will rev slightly lower 
for a given actual (not reported) speed).

Just my 2 cents :)

Chris

> 
> Howdy all,
> 
> I am aware that our speedos are optomistic but the MFA is quite
> accurate.  Can someone explain to how this happens?  
> 
> My curiousity stems from the fact that I am contemplating going with
> a 215/45R15 tire that has a radius of 287.25mm.  Stock is 282.75mm.
> I know the speedo will be higher by an additional 1.4mph but what
> about the MFA or overall milage (not gas milage but total miles
> driven)?  
> 
> Cheers,   
> 
> ----
> Jeff Newton
> 
> 
> 


----------------
Chris.Campbell@Eastbridge.ns.ca
Campbell@hfx.andara.com