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Beware cheap manual pump pressure readings!


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I don't air up my tires often. My KS18L has slime in it and my newer V10F...well, it's new and I haven't slimed it yet.

They both hold air very well for weeks at a time, so my checks have slowed way down.

A few days ago , though my 18L started feeling low. I checked it and it came in at about 30PSI. Not too bad, I usually start feeling it low when it hits below that. But, I wanted to bump it up to 33-35psi. 

Well...unfortunately the tube I put on my KS last year has a really tight nozzle, not bent far. So I used a fairly well rated manual pump as my compressor kept stalling due to pressure issues. 

After about 40 pumps (very small bicycle manual pump), I just got the pressure guage on it to show ~33psi. I stopped , used my good car tire guage to verify, it was at 42psi! YIKES! That was 10 psi over!

Just a reminder on how a good guage is a must.

Ride safe.

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1 hour ago, Funky said:

Feeling tire with fingers/hand - best measurement.

It most definitely is not. The current trend of motorcycle tires are way too stiff to be felt adequately by your hand. Besides, a cold and a warm tire will feel drastically different at the same exact pressure.

 The last time I measured a tire that the user inflates only by hand feel, it was at 15 psi.

Get a meter. Then confirm that it works. Then use it.

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12 hours ago, mrelwood said:

Get a meter. Then confirm that it works. Then use it.

Have and can confirm it works.. That's why i said +-1 PSI..

As for temperature, i do it every time before ride.. So tire is at room temp. K66 tire middle gives in, maybe because of that center grove. 25 vs 30 PSI there's quit big difference in feeling. Whole tire center can be pushed in at 25 PSI. At ~30ish PSI only middle budges little bit. (Maybe i got "stronger arms". Go lift some weight Bruh.) :D 

Ofc i check my PSI once a while when i connect my pump. Over a month i have maybe lost ~2 PSI. If you don't want to connect pump every time - simply feeling the tire with hand is "good enough" measurement. Same thing as on regular bike. Only thing that has changed - the tire is "harder" on EUC. But anyone could tell the difference from 25 vs 30 PSI. (At least i can..) :efeebb3acc:

Go pump your own tire at 25 vs 30 vs 35 PSI. I guarantee you will feel difference using only hand to measure. (Ofc check pump gauge first and then feel it only.) Once you have felt it - you will have imprinted in mind that "feeling".

 

Again it's simply to let me know i'm good enough to ride.. When i pump my tires, i always pump it with pump gauge..

Edited by Funky
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