Tight frame-tire fit

My geared 29er, BlueShift, has a Big Apple tire on it right now. I
started with the Nanoraptor which had quite a bit more clearance than
the Big Apple. I like the ride of the Big Apple better, especially at
high pressure.

Our group went on a ride Saturday and I pumped the tire up to 60psig
and brought it along. It made a grinding noise like a garbage disposal.
I could still barely see clearance from the top of the tire to the
bottom of the crown but the wheel was slightly out of true and it
rubbed occassionally. Not enough to make the horrible grinding noise I
was hearing. I thought it was one of the bearings going out.

Wobbly-John was in town and he surmised that the tire picked up bits of
grit and ground against the crown. I still thought that was not the
problem, it was too loud. When I got home I let air out of the tire
(down to 35psig) and the problem disappeared. In 5psig increments I
found that I could run the tire at 50psig and still have clearance.

The tire must have stretched over time because I remember (as well as I
can still remember) that I had run it at 60psig before. I left the tire
deflated while stored and put a large label on it reading "50 psig
MAX."


--
harper

-Greg Harper

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So what made the grinding noise?


--
forrestunifreak

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forrestunifreak wrote:
So what made the grinding noise?


Musta been the Starbucks he was passing at the time.


--
U-Turn

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-- Dave Stockton
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forrestunifreak wrote:
So what made the grinding noise?



Wobbly-John and U-Turn are correct. Grit from the road and coffee chaf
from Satrbucks were grinding on the crown.


--
harper

-Greg Harper

B L U E S H I F T

*jc is the only main man. there can be no other.*

This is still my nth post....*AWESOME!!!*
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pics of the clearance? sounds pretty close.


--
Evan Byrne

"Guns cause crime like flies cause garbage." -Harper
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harper wrote:
and put a large label on it reading "50 psig MAX."

You should add "also for unicyclists!" as you know unicyclists tend to
ignore max pressure labels on tyres.

That's interesting that the BA seems to have stretched. I have
carefully measured my BA size when it was new. Must remember (as well
as I can remember) to do it again. Although on average I have only 40 -
50 psi in there. This could be a way to increase your wheel size for
free, as much as air is for free.


--
Klaas Bil
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Clearance at 60 psig is zero. Clearance at 50 psig is 1mm. The increased
wheel diameter doesn't buy you much speed if it's dragging on the
crown.


--
harper

-Greg Harper

B L U E S H I F T

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'Here's a link to the clearance with the Nanoraptor tire.'
(http://tinyurl.com/d6wgw)


--
harper

-Greg Harper

B L U E S H I F T

*jc is the only main man. there can be no other.*

This is still my nth post....*AWESOME!!!*
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harper wrote:
'Here's a link to the clearance with the Nanoraptor tire.'
(http://tinyurl.com/d6wgw)






that looks like plent of clearance.


--
Evan Byrne

"Guns cause crime like flies cause garbage." -Harper
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Harper said the Nano had plenty of clearance, its the BA thats giving
him the clearance problems.

Don't worry Harper, once you've got a few hundred miles on the beast
you'll have worn an extra mm from the tyre and will be able to get it
to 60psi no problem . Just get riding!

Loose.


--
Loosemoose

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Officially a  & ~ expert.

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