Thu Oct 24 11:07:29 1996
- Message No. 112
From: Martin Franz <100265.3434@CompuServe.COM>
Subject: Re: more pressure in tires
Hi !
I had some discussions with other bikers about tires. Hope to solve some
"mysticles":
>but on my AT the front tyre gets worn quicker on THE SIDES
>and not in the middle. I made the experiences that the so being built
>"mountain" in the middle can be eliminated a bit, if you have more
>pressure, because you don't ride on the sides as long as you aren't in
>curves. Also while braking you use only this "mountain".
The "mountain" comes from the stearing powers in turns. When performing a turn
(at higher speeds than 20km/h) you pull the stearing to the opposite direction,
causing the moped to lean over the other side, hence turning. (there are some
physics out there, who still believe that the rotating forces cause the
turn...they drive constantly wheelies). Until the bike reaches the correct
"leaning position", the front tire rotates "square" to the road. This forces and
the "slipping" cause more rubber loss on the sides, leaving the "funny hill" in
the middle. The tire starts to get a somewhat "triangular" shape.
On the @ (as long as you not going desert riding) you use the "plate style"
tires. On an "used" front tire, you will see, that the plates wear out
asymetric, the front of the plates gets higher than the rear, making your tire
look like a saw.
When those two "asymetries" reach a certain amount, they will cause
instability/nervousness in driving. Depending on tire make and driving style,
the asymetry starts to get "feelable" at 6.000km +/- 2.000km. There will be
still enough rubber left. If you change a tire because of asymetrie or not, is
heavily depending on things like usage, driving style, expectations...
There is a simple rule: more pressure == less grip == longer lifetime. The "less
grip" thing is not so hard as it may sound. On normal, "gripy" asphalt roads,
you very seldom reach the "grip limit" of your tires. Also, on "normal" roads
the "performance loss" caused by "asymetrie" is not very critical.
Bad roads/offroads or constantly trying to go at Vmax on "slopy roads" is
another story, obvious, you need every posible grip, pressure reduction is a
must.
>>> too much pressure kills tire on highway driving
don't know why. Normaly, you fill in more pressure, when going on highways. It
increases stability in "high speed turns" and reduces grip (in the positiv way,
cause the tires do not overheat and less gasoline usage). If you use the 2.0
pressure and go 150km/h with socia on highway, the rear tire gets so hot that it
even starts to smell (like it does on burn outs).
>>> better handling with more pressure
IMHO: on most other bikes, I would agree, but for the @, humbly, humbly no. The
reason is, that "those other bikes" are normaly equipped with a superwide front
tire, making a "mega fast looking". On those bikes, you have to pull the
stearing like an ox, cause of too much grip and the rotating forces caused by
the weight . The "too much grip" problem can be reduced by higher pressure, the
weight problem by simply mounting a non oversized front tire (or by buying an @
:-))).
The @ is equipped with a very nice "spaggeti sized" front tire (some people say,
that looks weird...)., I personaly think, the @ already has optimal handling.
have a nice slide, Martin
P.S. anybody knows, what kind of stuff to put on the disc brakes during "winter
sleep", so they don't rust ? That stuff should also be easy removeable by
standard disc brake cleaner...
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