Hi Guys,

Just wondering why the stock tires come with different profiles from front to rears.

Is it important to maintain this when chosing your tires?

 

Aspect ratios are different, profile HEIGHTS are (practically) identical.

205*.55 = 112.75
225*.50 = 112.5

Both are 25" diameter. You want to keep pretty close to the same diameter f/r for the ABS.

 

[QUOTE=ZDan,May 20 2007, 05:32 PM] Aspect ratios are different, profile HEIGHTS are identical.

205*.55 = 112.5
225*.50 = 112.5

Both are 25" diameter.

 

It will have some impact, whether you noticed or not is another question. I'm sure the algorithms can handle quite a difference in diameter, but it will affect ABS performance. I would bet that with taller rears the ABS prevents them from contributing as much under max braking, as the system would think the rears are a smidge closer to lockup than they really would be. Again, not terribly likely you'd even notice.

 

Key word here is ratio - the numbers aren't absolute, they are the ratio - wider rears = a lower ratio even though "height" is unchanged.

 

yea, there may be a theoretical effect... but my 255/50 were RA-1's and id say i hit max braking many times on track... so, if i wasnt seeing it there, it would be hard to see it on the street...

 

To maintain proper rotaional diameter so the Speedo doesn't get thrown off