Tire aspect ratio

[RandyR]

I've seen several discussions of wider vs narrower tires on this forum. But I don't recall any discussion of changing the aspect ratio of the tires. tire width x aspect ratio = height of the tire.

 

The stock rear tire on the 2nd gens is: 150/90-15 where 90 is the aspect ratio that determines how high the tire sits, and hence its circumference. Its also part of the overall gear ratio of the machine. ie: a taller tire is going to require fewer rpm's of the engine than a shorter tire (using the same transmission gear).

 

This implies that a well worn tire will be 'geared' lower than a new tire...

 

How about that?

 

Lower aspect tires have less side wall flex than higher aspect tires, so may be considered stiffer. That might mean better in the twisties?

 

A thought occired to me that one way to achieve a lower gear ratio, much as one does by using a Vmax rear end, could be achieved by using a slightly smaller aspect rear tire?

 

Has anyone tried this? or even thought about it?

 

This is also a possible alternative to installing lowering links.

[GigaWhiskey]

 

This is also a possible alternative to installing lowering links.

 

You won't get much lower - yanno like 90 to 70 or whatever. Think about it, each inch shorter of total tire height will only gain you half an inch. You are not in that range here.

 

When I dropped momma's ride, I went from an 18" rim to a 16" rim only to gain one whole measly inch. To get the other two inches, I used two inch shorter shocks. That was an expensive and time consuming 3 inches, lol. I wont even go into what it took the get three inches in the front.

[KiteSquid]

I think most people state it incorrectly.

 

They are telling you to buy a narrower tire (130 vice 150), to decrease the radius of the tire across the tread.

 

This will make the "coning" of the tire more pronounced with the same lean angle, which should decrease the turning radius with the same lean angle.

 

This should make it easier to make tight turns in a parking lot.

 

 

 

 

That and practicing what is shown in the Ride Like A Pro DVD...

 

 

 

A lower aspect ratio would probably hurt you in the twisties as the coning of the tire would probably be decreased.