Very high tyre pressures

amirm wrote in message
...
Claude wrote:
Putting 100 PSI in my hybrid's tyres even though the tyre says 75 is
recommended. Means I don't have to pump the bloody things up so often.
Of course it makes the ride harder. Does anybody know if there's a
serious downside to this practice (I weigh 100 kgs)?

I use Continental Super Touring 2000 which are rated at 85 psi max. I
inflate them to anything between 85 and 100. They have done 4000 km
now, and I can see very tiny cracks on the side walls of the rear tyre.
Not sure they are because of the tyre pressure, or just signs of
natural wear and tear. However, I cannot feel the difference in terms
of the ride quality and drag between 85 and 95 psi. Before these, I had
Specialised tyres rated at 100 psi. First I kep them at 80 psi. Not
much comfort anyway, so I decided to pump them up to 100 psi. After
2000 km, I had to replace them under warranty because all thread and
sidwall surfaces were falling apart (got Conti's instead). The conti's
have much better ride quality and lower drag at 85 than the
Specialised's at 100 psi.

By the way, depending on the structure of the tyre, overinflation can
harm rims. I had to replace two spokes with my specialed tyres once I
started to inflate them to 100psi.

That's probably related to the increase in shock that is transfered to the
spokes. I imagine the cracks that are occuring are also cause by an
increased transferral of shock to the rim from the road.

Why did you over-inflated your tires to 95 psi if it makes no difference to
the ride?
---
DFM

Deep Flayed Mar wrote:
amirm wrote in message news:3f4962a2$1-
...
Claude wrote:
Putting 100 PSI in my hybrid's tyres even though the tyre says 75
is recommended. Means I don't have to pump the bloody things up so
often. Of course it makes the ride harder. Does anybody know if
there's a serious downside to this practice (I weigh 100 kgs)?

I use Continental Super Touring 2000 which are rated at 85 psi max. I
inflate them to anything between 85 and 100. They have done 4000 km
now, and I can see very tiny cracks on the side walls of the rear
tyre. Not sure they are because of the tyre pressure, or just signs of
natural wear and tear. However, I cannot feel the difference in terms
of the ride quality and drag between 85 and 95 psi. Before these, I
had Specialised tyres rated at 100 psi. First I kep them at 80 psi.
Not much comfort anyway, so I decided to pump them up to 100 psi.
After 2000 km, I had to replace them under warranty because all thread
and sidwall surfaces were falling apart (got Conti's instead). The
conti's have much better ride quality and lower drag at 85 than the
Specialised's at 100 psi.

By the way, depending on the structure of the tyre, overinflation can
harm rims. I had to replace two spokes with my specialed tyres once I
started to inflate them to 100psi.
That's probably related to the increase in shock that is transfered to
the spokes. I imagine the cracks that are occuring are also cause by an
increased transferral of shock to the rim from the road.
Why did you over-inflated your tires to 95 psi if it makes no difference
to the ride?
---
DFM

Good point!

Since tyres loose pressure, I try to save on checking/pumping frequency.
At the same time, I wouldn't like to go below 80psi. What I didn't
mention in the previous posting is that although I cannot feel a
tangible difference between 85 and 95 psi, I can feel a noticeable
difference in drag in lower pressures (such as 70 psi vs 85 psi).

So by keeping my tyres a little over-inflated, I remain in the green
zone in-between pumpings. Apparently, ~10 psi above nominated rating is
not having a huge adverse effect on the ride quality (comfort) and
tyre's life.





--
--------------------------
Posted via cyclingforums.com
http://www.cyclingforums.com

Deep Flayed Mar wrote:
amirm wrote in message news:3f4962a2$1-
...
Claude wrote:
Putting 100 PSI in my hybrid's tyres even though the tyre says 75
is recommended. Means I don't have to pump the bloody things up so
often. Of course it makes the ride harder. Does anybody know if
there's a serious downside to this practice (I weigh 100 kgs)?

I use Continental Super Touring 2000 which are rated at 85 psi max. I
inflate them to anything between 85 and 100. They have done 4000 km
now, and I can see very tiny cracks on the side walls of the rear
tyre. Not sure they are because of the tyre pressure, or just signs of
natural wear and tear. However, I cannot feel the difference in terms
of the ride quality and drag between 85 and 95 psi. Before these, I
had Specialised tyres rated at 100 psi. First I kep them at 80 psi.
Not much comfort anyway, so I decided to pump them up to 100 psi.
After 2000 km, I had to replace them under warranty because all thread
and sidwall surfaces were falling apart (got Conti's instead). The
conti's have much better ride quality and lower drag at 85 than the
Specialised's at 100 psi.

By the way, depending on the structure of the tyre, overinflation can
harm rims. I had to replace two spokes with my specialed tyres once I
started to inflate them to 100psi.
That's probably related to the increase in shock that is transfered to
the spokes. I imagine the cracks that are occuring are also cause by an
increased transferral of shock to the rim from the road.
Why did you over-inflated your tires to 95 psi if it makes no difference
to the ride?
---
DFM

Good point!

Since tyres loose pressure, I try to save on checking/pumping frequency.
At the same time, I wouldn't like to go below 80psi. What I didn't
mention in the previous posting is that although I cannot feel a
tangible difference between 85 and 95 psi, I can feel a noticeable
difference in drag in lower pressures (such as 70 psi vs 85 psi).

So by keeping my tyres a little over-inflated, I remain in the green
zone in-between pumpings. Apparently, ~10 psi above nominated rating is
not having a huge adverse effect on the ride quality (comfort) and
tyre's life.





--
--------------------------
Posted via cyclingforums.com
http://www.cyclingforums.com