Tire profile

[AgentX]

This is a carryover from the cheap aluminum rims thread; didn't want to hijack it. Apologies to those who've already given input over there...


I use/plan to use Dunlop (k70/k81), Avon (am26), or Heidenau (k34) tires which don't have front- and rear-specific designs. Stock, my bike (Enfield) calls for 3.25f/3.5r tires on wm2 rims.

Now, the 3.25 and 3.5 sizes correspond, per manufacturer's spec and general information, to a WM3 rim size, with the WM2 considered within the acceptable range. But if I put WM3s front and rear, the smaller 3.25 will have a more squared-off profile than the rear. This seems undesirable in theory; I'd assume you want a rounder profile in front and a more square shape in back for the best handling and tire life.

So:

-Am I correct? And even if I am, is it of any real-world significance in the use described?

-What would you guys do? WM2 up front for the 3.25 and WM3 in rear for the 3.5? Or just put the WM3s on both ends?

 

[mydlyfkryzis]

Personally, I would put the WM2 in front, WM3 in rear. It is what I actually did. This keeps the round profile of the tires the same relative to the original intent.

Your handling would then be similar to the OEM intention, which is usually a good intention.

Square profile is not desirable front or rear. For raving, a V-shaped profile works because of the very high side loading as they progress through tight turns. For street use, at a somewhat lower pace, the rounder profile give more consistent, easy to control handling. You do not want the contact patch of the front or rear to change more than minimally as you lean over in a turn. this way your traction, feel and handling are consistent and manageable.

If you are racing on a track, different set of standards, and you need to get into a lot more details, such as rubber compounds, track surface, weather, etc......So a good track tire is not necessarily a good street tire.