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Old 09-23-06, 11:26 PM   #1
serpico7
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How can I get my Silca track pump to perform better?

My Silca track pump worked fine for my mtb, but on my road bike, it takes many strokes to get up to 110psi. As I pump, the needle swings back and forth, rising slowly over time. Is this normal, or is there anything I can do to improve the performance of the pump (aside from working on my triceps)?
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Old 09-24-06, 03:17 AM   #2
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Are you sure the pump head is on all the way? I've noticed that when the head isn't fully engaged the air being pumped into the tire will first compress in the pump and then shoot into the tube. i believe this is caused by the valve on the tube not being completley open.
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Old 09-24-06, 09:20 AM   #3
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Quote:
Originally Posted by Ingleside
Are you sure the pump head is on all the way? I've noticed that when the head isn't fully engaged the air being pumped into the tire will first compress in the pump and then shoot into the tube. i believe this is caused by the valve on the tube not being completley open.
Do you mean all the way on the valve stem? If so, yes. And yes, I always completely open the presta valve before seating the pump head on the valve stem.
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Old 09-24-06, 06:38 PM   #4
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If this is a floor pump, when is the last time you greased and/or replaced the leather seal in the pump?
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Old 09-24-06, 08:40 PM   #5
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Ummm, there's a leather seal in the pump? So the answer is no, I have not greased or replaced the leather seal in the 5 years I've owned the pump.

Would this cause the type of issue I described?

I guess I just need to unscrew the head and apply a little grease (assuming it's not already too dried out)?
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Old 09-24-06, 10:58 PM   #6
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I have not seen the leather gasket/seal fail with the symptoms you describe. When mine have gone, the resistance to pumping dissapears because the seal is not being maintained. It is a very odd feeling because your body is expecting to exert some force against the pump handle to inflate the tire. Instead there is no resistance and you feel like you almost hyper extend your elbows and then you get the jolt as your pump handle abruptly bottoms out.

The MTB pumps are designed to more efficiently get larger volumes of air at lower pressure into tires as opposed to smaller volumes, higher pressure for road bikes. They did this on the Silca pump by enlarging the diameter of the barrel. I would expect it to be a little more difficult to pump up your road tires but I don't know how much. Any chance you could try another pump, even if not a Silca to see if there is a real difference in effort?
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Old 09-25-06, 09:11 AM   #7
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Quote:
Originally Posted by masiman
I have not seen the leather gasket/seal fail with the symptoms you describe. When mine have gone, the resistance to pumping dissapears because the seal is not being maintained. It is a very odd feeling because your body is expecting to exert some force against the pump handle to inflate the tire. Instead there is no resistance and you feel like you almost hyper extend your elbows and then you get the jolt as your pump handle abruptly bottoms out.
Definitely not what I am experiencing. I checked, the pump I have is the Super Pista (the one with a pressure gauge that exceeds 200psi).

I looked at the manual - the closest symptom they describe to what I am experiencing is the pump shaft lifting by itself (and corresponding drop in pressure gauge). This is caused by a dirty non-return valve or damaged non-return valve washer. The procedure for cleaning/replacement of the non-return valve is labeled as "extraordinary maintenance" and the manual states that it should only be performed by "qualified staff".

Has anyone done this? In your opinion, is this the type of procedure a guy who performs the majority, but not all, of the wrenching on his bike can perform himself?
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Old 09-28-06, 08:36 AM   #8
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In case anyone is having similar problems with their Silca track pump, I'll update this thread with what I've done.

Cleaned and applied some grease to the pump shaft (ok guys, let 'er rip), and found that the pump operates a little bit more efficiently. I still think the inner valve assembly may need cleaning/replacement. Ordered a new inner valve assembly ($4), and will open the pump up when I receive the extra assembly.
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Old 09-28-06, 08:56 AM   #9
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That would make sense. Some or all of what you pump in comes right back out. It's not a pump anymore but a see saw, lol.

I assume the valve is in the brass assembly where the gauge and hose attach. I have never taken that off of mine. I guess you would treat the fitting like a gas fitting. I am not sure if there is a compound that you should apply to the threads when you reassemble (maybe just plain teflon tape will do).

Where did you find the replacement valve? Let us know how the replacement goes.
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Old 09-28-06, 09:10 AM   #10
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Quote:
Originally Posted by masiman
That would make sense. Some or all of what you pump in comes right back out. It's not a pump anymore but a see saw, lol.

I assume the valve is in the brass assembly where the gauge and hose attach. I have never taken that off of mine. I guess you would treat the fitting like a gas fitting. I am not sure if there is a compound that you should apply to the threads when you reassemble (maybe just plain teflon tape will do).

Where did you find the replacement valve? Let us know how the replacement goes.
Yeah, the see-saw effect I was observing has been reduced since greasing the pump shaft.

Yes, it's similar to a gas fitting. Just picked up some PTFE tape for gas (the yellow tape) to wrap around the threads when reassembling.

The replacement valve assembly is Silca's part #24.7. Had the LBS special order it (their distributor's catalog had just about every part of Silca's pump available - that's the nice thing about expensive pumps - you can replace parts as they wear and use the pump for many years).

I'll update when I open the pump up to inspect the valve.
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Old 09-28-06, 10:44 AM   #11
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Quote:
Originally Posted by serpico7
Yeah, the see-saw effect I was observing has been reduced since greasing the pump shaft.
You probably already know this but for anyone else that might read this.

Don't overdue the oil or grease that you use on the pump. Too much and it will come spurting out your hose and into your tubes or onto you, first hand experience .
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Old 09-28-06, 12:16 PM   #12
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Quote:
Originally Posted by serpico7
My Silca track pump worked fine for my mtb, but on my road bike, it takes many strokes to get up to 110psi. As I pump, the needle swings back and forth, rising slowly over time. Is this normal, or is there anything I can do to improve the performance of the pump (aside from working on my triceps)?
If it works well on the MTB and not on the road, then likely the road valves are 'stickie'. Might try poppin em open to break the 'seal', before putting the head on. Swingin needles, seems normal as long as it stops when you stop. If I have a particularly stickie valve, the needle will swing up and slowly settle back down as the air squeezes past the valve
I'll take a look at my Silca Trackie 2nite and see what else might be worth a look-see.
Honestly, in 30 years of owning my 'Trackie' I haven't done squat in maintenance other than replace the head gasket a few times (which, BTW, are becoming impossible to find... I need a source if anyone has one, I'm due for some new rubber again). And it goes to 110 and beyond (from about 80) in about a dozen strokes.
Dam thing is way older than any of my, now adolt, kids...
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Old 09-28-06, 12:23 PM   #13
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In my case, it's not the road valves. MTB is easier b/c there's much less stress on the pump to pump to only 40psi, so even a poorly greased pump with worn out washers can get the job done. At higher pressures, the tolerances are much tighter, and any deficient parts are more quickly exposed.
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Old 10-23-06, 10:33 AM   #14
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Quote:
Originally Posted by masiman
Where did you find the replacement valve? Let us know how the replacement goes.
Update: The pump is operating much more efficiently now.
Step 1: Cleaned and greased the pump shaft
Step 2: Removed inner valve (aka non-return valve) assembly, turns out the non-return valve has some corrosion on it. I replaced the entire assembly with a new assembly (from Speedgoat, $4). Used PTFE tape for gas on the cap threads. Turns out replacing the inner valve assembly is actually quite simple.

Step 1 reduced the number of strokes needed to get my road tires up to pressure, but the pump shaft would still rise by itself. Step 2 eliminated this problem, while further reducing the number of strokes required.
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Old 10-23-06, 11:21 AM   #15
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Excellent, thanks for the update!
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