Hi collected STW wisdom

I have a Topeak shock pump that has a valve on it that is supposed to balance the pressures between shock and pump so no air comes out when you unscrew it. To say it is is useless would be kind and polite. It can easily drop 20 psi taking it off, verified with a Shockwiz. So I  want a new one that works

What would people recommend please?

Thanks

Chris

Lifeline digital works for me. Exactly the same as RS/Fox version other than having a slightly smaller connector (that may or may not be an issue)

My DVO analogue reading pump seems to lose only a few psi maximum so very impressed.

DVO also have instructions on how to sorta calibrate or minimise air loss of the pump.

Which topeak pump do you have? I’ve found the pocket dxg has the best connector of any pump I’ve tried.

OK so for clarity, are you wanting one that doesn’t leak air out of the <shock>, or are you wanting one that doesn’t leak air out of the shock OR the pump?

Literally every shock pump worth buying does the former. The escaping air is from the pump only, the shock is sealed up before you remove it. If you reconnect, then the shock releases air into the pump and equalises the pressure causing a drop in shock pressure, but the shock was at the pressure the pump said it was before you first removed it.

It’s frustrating this because most of the products sold for this reason are either a) correcting a failure that made the company’s product unfit for purpose or b) just simply misleading.

If you want something that doesn’t leak any air at all, so that when you disconnect no air escapes but also, when you reconnect you see the exact same value, I don’t think that exists. No matter what, the shock will always equalise pressure with the pump (and hose and gauge), it’s going to be at atmospheric pressure til the valve opens. The amount could be big or small but it’s going to exist, by definition you can’t equalise pressures without measuring and you can’t measure without affecting the pressure. So at best you can aim for a very low loss but even the valve chamber etc makes some loss inevitable unless you have a permanently attached measurer, ie, shockwiz or similar.

Cheap BETO is as good as any shock pump out there. They cost about £15 usually, or you can get them branded as Halfords or RSP or many others, they make pumps for loads of others.

Thanks for the advice all I will like at the lifestyle and dvo

Lifeline digital is great

I understand that a digital pump may not show an accurate reading but at least you can get it to the same value each time, with all the tiny analogue dials that’s impossible

As Northwind says, all pumps will sound like they lose air as you unscrew them but it will be the air in the pump rather than the shock. Any time you check air pressure you will lose a small amount of air as some air has to come out into the pressure gauge to be able to take a reading.

Indeed, as above…. if you have a Shockwiz fitted you can watch the actual pressure in the shock, even with the noise, you don’t lose pressure…. well, unless it’s faulty anyway.

The next time you connect it though, it loses pressure when fitting, so looks like it’s lost pressure… it’s a bit of a catch 22 and you have to simply trust the removal pressure.

My shockwiz is confirming that the pressure is coming out of the shock and not just the air in the pump. There can also be a 20psi difference between what shockwiz thinks the pressure is and the shock pump. Ive never had a pump with that bigger difference before. It appears to be that it takes the pump along time to release from the valve before the valve pin closes the valve. I dont think its the shock as its the same on y wife’s bike too

There can also be a 20psi difference between what shockwiz thinks the pressure is and the shock pump

A man with one watch always knows the time. A man with two watches is never sure.

If that offset is repeatable then does it matter? IME the key thing with shocks is being able to get the same pressure in them after a service, so it doesn’t matter if your pump consistently reads 110 when someone else’s reads 130. After that if it’s a bit firm then I’ll drop a smidge out, if it’s a bit soft I’ll add a smidge in but I don’t really care what the actual value is. Same if the shockwiz is saying to add or remove pressure – it’s the change that’s important, not the value.