leeubok Posted August 9, 2015 Posted August 9, 2015 Howsit What would happen if one used a normal car tyre pump or even an air compressor to try and pump up a fox rear shock?
PeterF Posted August 9, 2015 Posted August 9, 2015 It will not end well.......A bicycle suspension (back and front) does not take a large volume of air, so you must use a proper shock pump to get the correct pressure or you will damage the shock or fork.
porqui Posted August 9, 2015 Posted August 9, 2015 It should not damage your shock but you have next to no chance of getting the right pressure or reading for that matter. Just get yourself a shock pump - very useful even for taking along on a ride so you can try different pressures.
Skylark Posted August 9, 2015 Posted August 9, 2015 I'd be very careful with an air compressor, especially if it's a big one and you aren't careful I'm pretty sure you could pop the seals. That being said I have used a petrol stations compressor to pump a pap shock before. A shock pump is the only way to get it right, I'd get as soon as the opportunity arises.
leeubok Posted August 10, 2015 Author Posted August 10, 2015 Thanks for the advice guys. My problem is I live on a farm far from any towns, so wanted pump the shock somehow until I get an opportunity to get to a cycle shop again
BMXER Posted August 10, 2015 Posted August 10, 2015 Don't do it. You will never get the correct pressure. In all probability you will damage the bike.
peds Posted August 10, 2015 Posted August 10, 2015 Order a pump online rather and get them to courier to you if you can't get to a cycle shop. Will cost you less than having to replace your shock afterwards.
HowardSteele Posted August 10, 2015 Posted August 10, 2015 A shock pump has a small bore so you can achieve a higher pressure up to 20 bar(pressure increase is just Volume compressed) it has an accurate gauge to register pressure and a dump valve to reduce pressure in small amounts.The Excellent seals and small size of the pump bore also matter when you attach it to the shock you are opening the valve ...so when you attach a large volume bicycle pump or car pump the air from the shock will blow out into the large bore of the pump.Trust me the smallest push on the valve air release pin on your rear shock and you can loose serious pressure .Offer a MTB experience on your farm and you'll have tons of visitors ridding out with shock pumps.
Sepia Posted August 10, 2015 Posted August 10, 2015 (Slight hijack} What is a recommended pump to get then? Mine is now bust. (hijack off)
JXV Posted August 10, 2015 Posted August 10, 2015 Typical rear shock needs a small volume of high pressure air. Depending on type and your weight you will need anywhere from 8 bar to15 bar (100 to 200 psi). A regulated workshop compressor (normally controlled to 100 psi) will give about 7 to 8 bar. A bicycle pump won't get close. An unregulated 12v car compressor could quickly overpressure the shock. Best to get a proper shock pump.
HowardSteele Posted August 10, 2015 Posted August 10, 2015 (Slight hijack}What is a recommended pump to get then? Mine is now bust.(hijack off)I looked at the streamlined options, that did away with the conventional round pressure gauge and flexible hose connector...(taking up less space in my backpack) but after reading reviews it seams the sliding pressure indicator is not as accurate and without the flexible hose it gets difficult to read the gauge...I have a version like the Ice tools and it has served me well for over 10 yearshttp://www.cwcycles.co.za/catalog/parts/pumps?page=1
Spez247 Posted August 10, 2015 Posted August 10, 2015 What I have done in an emergency out in the sticks, is use a bomb to inflate the rear shock. I use the cheap and cheerful one that allows you to turn the knob to regulate the airflow. But it takes very little air, so start real slow... It won't tell you the pressure, but it will get you home or back on the bike.
deanbean Posted August 10, 2015 Posted August 10, 2015 What I have done in an emergency out in the sticks, is use a bomb to inflate the rear shock. I use the cheap and cheerful one that allows you to turn the knob to regulate the airflow. But it takes very little air, so start real slow... It won't tell you the pressure, but it will get you home or back on the bike.I've done the same, just let a small amount of CO2 in at a time, and test.
leeubok Posted August 11, 2015 Author Posted August 11, 2015 before I posted this topic I tried a normal hand pump (a car tyre one, not bicycle). That obviously didn't work as all the air escape the moment you take it off the valve. I just hope I didn't damage the shock in any way!
igg Posted August 11, 2015 Posted August 11, 2015 before I posted this topic I tried a normal hand pump (a car tyre one, not bicycle). That obviously didn't work as all the air escape the moment you take it off the valve. I just hope I didn't damage the shock in any way!The air you're hearing escape is likely from the pump's chamber/hose and not the shock itself. The valve should close immediately. Either way, get the proper tool.
droo Posted August 12, 2015 Posted August 12, 2015 What I have done in an emergency out in the sticks, is use a bomb to inflate the rear shock. I use the cheap and cheerful one that allows you to turn the knob to regulate the airflow. But it takes very little air, so start real slow... It won't tell you the pressure, but it will get you home or back on the bike. The CO2 in a bomb is at 850 psi, and the maximum pressure on the shock is 300. Careful.
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