Re: how long should a fork hold air pressure?

[Michael Dart]

Bill Sornson wrote:
> Reyd wrote:
>> My fork seems to hold it for about 6 hours, and its almost brand
>> new(had it for a couple days)
>> I did ride for 4 or 5 hours, but I've had to pump it back up to
>> pressure each time I want to ride.
>
> How do you know it's losing air -- with a gauge or can you actually
> "feel" the fork becoming too soft? It's pretty unusual for a nearly
> new fork to have /multiple/ air leaks -- shouldn't have ANY, of
> course -- so that's why I'm asking about how you're measuring the
> pressure.
>
> Shock pumps can be tricky to use, and often will read lower
> immediately after use because the hose loses a bit of pressure every
> time it's pulled off the valve.
>

Hackshirly it's the other way around Mr. Bill...
Ideally the schrader valve closes before the shock breaks it's seal
maintaining the set pressure in the chamber. The perceived pressure loss is
from reattaching the pump and the volume of air filling the hose and pump
chamber. Most shocks have a low volume, high pressure chamber where it
doesn't take much loss in volume to result in a considerable loss in
pressure.

Perhaps this is what you are experiencing Reyd?

Mike

 

[Bill Sornson]

Michael Dart wrote:
> Bill Sornson wrote:
>> Reyd wrote:
>>> My fork seems to hold it for about 6 hours, and its almost brand
>>> new(had it for a couple days)
>>> I did ride for 4 or 5 hours, but I've had to pump it back up to
>>> pressure each time I want to ride.
>>
>> How do you know it's losing air -- with a gauge or can you actually
>> "feel" the fork becoming too soft? It's pretty unusual for a nearly
>> new fork to have /multiple/ air leaks -- shouldn't have ANY, of
>> course -- so that's why I'm asking about how you're measuring the
>> pressure.
>>
>> Shock pumps can be tricky to use, and often will read lower
>> immediately after use because the hose loses a bit of pressure every
>> time it's pulled off the valve.
>>
>
> Hackshirly it's the other way around Mr. Bill...

Whaddya, MD, the Psssssst! Police?!?

(You're right, of course, but you didn't read it here.)

> Ideally the schrader valve closes before the shock breaks it's seal
> maintaining the set pressure in the chamber. The perceived pressure
> loss is from reattaching the pump and the volume of air filling the
> hose and pump chamber. Most shocks have a low volume, high pressure
> chamber where it doesn't take much loss in volume to result in a
> considerable loss in pressure.
>
> Perhaps this is what you are experiencing Reyd?

Listen to Shirley.

 

[Michael Dart]

Bill Sornson wrote:
> Michael Dart wrote:
>> Bill Sornson wrote:
>>> Reyd wrote:
>>>> My fork seems to hold it for about 6 hours, and its almost brand
>>>> new(had it for a couple days)
>>>> I did ride for 4 or 5 hours, but I've had to pump it back up to
>>>> pressure each time I want to ride.
>>>
>>> How do you know it's losing air -- with a gauge or can you actually
>>> "feel" the fork becoming too soft? It's pretty unusual for a nearly
>>> new fork to have /multiple/ air leaks -- shouldn't have ANY, of
>>> course -- so that's why I'm asking about how you're measuring the
>>> pressure.
>>>
>>> Shock pumps can be tricky to use, and often will read lower
>>> immediately after use because the hose loses a bit of pressure every
>>> time it's pulled off the valve.
>>>
>>
>> Hackshirly it's the other way around Mr. Bill...
>
> Whaddya, MD, the Psssssst! Police?!?
>
> (You're right, of course, but you didn't read it here.)

Don't worry I'll keep it on the down low. ;^)

>
>> Ideally the schrader valve closes before the shock breaks it's seal
>> maintaining the set pressure in the chamber. The perceived pressure
>> loss is from reattaching the pump and the volume of air filling the
>> hose and pump chamber. Most shocks have a low volume, high pressure
>> chamber where it doesn't take much loss in volume to result in a
>> considerable loss in pressure.
>>
>> Perhaps this is what you are experiencing Reyd?
>
> Listen to Shirley.

He's not jesting.