Mountain Biking - Rear Shock PSI loss

Hey buddies,

I would like to know from you guys what the "norm" or "average" PSI loss is in the rear shock in relation to use...I know if i pump it to 115 its not going to stay at 115 forever.

I pumped my shock up last Saturday, and I have probably put about 20 miles on it give or take a few, of variable condition riding - about half and half hard and easy...Here it is Thursday, I check my PSI and it looks like I might have lost 2 to 5 PSI (my shock pump blows off around 7 - 10 PSI when removing it from the shock...so I filled it up to about 127 PSI...and when I checked it today it was right at 115 PSI)...my sag is normally right at a 1/4 inch and today it was about 1 or 2mm more than that...im probably being anal about it, but for future reference I would just like to know what is the "normal" amount of PSI to be lost in a given amount of time/milage...Hope this post wasn't too confusing...

Thanks!

Hope this post wasn't too confusing...



I am confused as to why you're concerned with a possible 2-5 PSI loss when your measurements fall within an estimated 3 PSI range.

Now leave it alone and don't check it again until you actually feel a difference while riding.

Oh, and how long is your shock stroke? 1/4 inch doesn't sound like nearly enough sag.

its what my LBS recommended im not sure of my stroke...its a rockshox Ario 2.R set at 4 inches of travel if that helps

im probably being anal about it, but for future reference I would just like to know what is the "normal" amount of PSI to be lost in a given amount of time/milage...Hope this post wasn't too confusing...

Thanks!

Hey MaxBA. Yes, some shocks will lose air between rides, and it's pretty normal and nothing to worry about unless it's a large amount in a short time. Just check your air pressure before every ride, and refresh as needed. My Progressive used to lose air between rides, but was a great shock. The Fox stuff I now run rarely lose air though.

... Brad

its what my LBS recommended im not sure of my stroke...its a rockshox Ario 2.R set at 4 inches of travel if that helps

Use your micrometer (or whatever it is you're employing above to determine your sag to the millimeter) and measure the exposed shock shaft. Per Rock Shox website, it'll be either 1.5 or 2.0 inches. Take 15-30% of that number, and that's how much sag you should be running. Feel free to experiment and see what feels good to you. Remember that if your shock is not bottoming occasionally, you're wasting travel.