Strange wear pattern on front tire

Hi all,

Not a problem (I think), but I am curious.

When I looked at my VF400F while the sun was about
to set, I noticed a strange (but regular) series of shades
on my front tire.

The tire is a Dunlop Arrowmax K625A, mounted correct,
and the wheel is balanced. There is no vibration on the
handle bars too.
The tire is about halfway it's life, about a year old
(I don't take a note when I buy a tire), it is not dried
out, and never repaired.
I ride the bike on average 4 times a week, which
is approx 400 miles each week.

Note that the pattern on my tire differs from the
arrowmax K625A shown at the dunlop web site,
so I describe the pattern below.
The pattern on the rubber looks as fat arrows, split
over the full length from point thru shaft in a straight
line, so it looks as if there are a series of split arrows
on the tire. The arrow-points hit the tarmac first,
which is the way it should be.

Arrows are 3" long, the head is 2" wide, 1" long,
and the shaft is 2" long and 1" wide.

The strange wear pattern that I have is on
the last part of the shaft, about an inch (25mm) long,
and that shaft end is about 1/32'' (1 mm) lower than
the next arrow point (which comes about 1/16" (2mm)
after that lowered shaft end).
So the shaft ends all wear faster than the rest of the
arrows. This I can imagine because the shaft is
smaller than the arrow heads. But.......

a) The strange thing is that only the shaft ends
of the left 'splitted' arrows are lower. The right hand
is still at the same level as the rest of the arrow.

b) The 'worn out' shaft end dives neatly (not abrupt)
with a curve to that lower position. And all of
the arrows have the same wear of that left shaft
end.

Now, I am a front breaker (rear doesn't do much)
and the anchor plate of the brake holds on to
the left front fork. So I thought that that could
be the reason.

Wrong tire pressure would affect both shafts, not
only the left hand side (I suppose). Could be
a worn out shock on the left side (I had that for
a while), but I don't know.

But maybe somebody out of cycles.tech-land has
seen this before and can enlight me on the cause.

Rob.

 

Do your roads have a camber on them?

Cupping, I believe it is called. If your road has a camber, and you ride on
right, the left of centre does indeed wear in a different pattern to the
right.

My current bike is displaying similar right of centre, as have many tyres in
the past.

HTH

 

Ignore the reams of crap from Albrecht, saying you ride harder in
left-hand corners than right. The answer is, quite simply, road camber.

 

The Older Gentleman schreef:

I would believe Albrecht, because his explanation seems logical,
if it wasn't a fact that I lean over in right hand corners more than
in left hand corners. I really do. Maybe that is caused by the fact
that there are more right hand corners (in and out highways) in
The Netherlands than there are left hand corners. So I am
more confident because I've done right_hand much more times.
There used to be one left_out of the highway near The Hague,
but it was changed because it created a lot of accidents when
people on the slow lane (right) had to switch to the left lane
(high speed) in order to get off the highway.

So it could be road camber. But I ride for about 50 years (of
which 40 years daily) and never saw anything like it.
And my other VF400 (I have two 'brothers' that differ the
last digit in framenumber, engine-number and license plate)
with a Firestone Battlax that is almost at end_of_life also
seems to wear out evenly. But the profile of the Battlax is
totally different. That may help.

Thanks for your answers.
Rob.

 

Well, it is a little more than just camber. Just a little more. Mostly
camber.

Most of the time, the bike is ridden upright. The camber may only be a few
degrees, but it is there. This generates camber thrust. Imagine a
'scrubbing' at the tyres/road bit.

The tread blocks do not distort evenly. They squirm.

Anyways, there is some good stuff on this link.

http://www.t595.net/messageboard/thread.asp?thread=14322

 

Badger schreef:

Thanks, good stuff to read.

I'm convinced now. Street camber plus block pattern. This
probably is my first Arrowmax, and probably my first tire
that has a deep straight groove all around it.

When I exaggerate the arrow-shaped blocks into
a big head (size of a fist) and two very thin lines
of rubber as shaft trailing that head, it is pretty
easy to imagine what happens to the left hand shaft
when you ride a camfered road.

And I learned some new words: scalloping and squirm.

Thank you all,
Thread can be closed.

Rob.

 

You googled the correct picture that I could not find.

They no longer groove freeways in The Netherlands. I once crossed
Belgium from the west coast to the eastern border on such a road.
I would not call that 'wiggle furiously'. It is a plain murder attack.

Looks somewhat like an Avon I once had. Nice sticky tire that was,
but (of course) it did not last very long.

Oh, and we need rain tires here. it's a pretty wet country.

Rob.

 

According to this link..."road crown plays no part whatsoever in left side
tire wear"....

http://www.rattlebars.com/valkfaq/tirewear/

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