A friend has just bought a s/h Cannondale Prophet from Ebay. Great bike at a great price.

The bikes previous owner kept it in storage for some time during which the tyres lost pressure and were flat. They are now struggling to keep pressure.

They are Hutchinson something or others on Mavic 819 UST rims.

They are not going down super fast but to reguarly to make going for a ride an option at the moment!

I assume this is due to the seal between rim and tyre deforming during storage but we are both a bit clueless on the world of tubeless.

So do we squirt something in through the valve – the much mentioned sealant? And do you remove the valve from the rim? Any tools required?

In the long run is it possible to happily run tubes and standard tyres on these rims? I know from reading here that many love their tubeless setups but the tyres are a bit ££.

keppoch.

Firstly, with a true UST set up you don't NEED to use sealant. The tyre and rim bead create an air tight seal. The downside of this is that if you get a puncture you have no way of sealing it. It does sound as though you are low on sealant and there is a small hole somewhere. Unlikely to be at the bead but possible.

To put more sealant in you would either need to take the valve core out (if you have two part valves) or dismount the tyre on one side and pour some sealant in.

You can use normal tyres IME but the channel that runs down the centre of the rim can make inflation a bit of a pain. Using draft excluder from B&Q in the channel can make things easier.

Thanks for the advice.

Any recommendations on which brand of sealant and from where? How mcuh of it would be likely to solve this problem?

keppoch.

Stans No Tubes sealant. IMO the best of the available sealants. 40ml per wheel should see you right. Everything yoi need to know about running Tubeless is available on the JRA site http://www.justridingaling.co.uk …and Jon's a good bloke too.

Available at your LBS I suspect or at CRC or JRA. One bottle lasts ages.

Just check it once a month because over time it does gradually dry up.

chuck a load of conc soap solution over tehm and see if you get any bubbles – I suspect around the valve hole wether a small tear or not seated properly or leaky valve?