Bicycle tyres that last longer
I found this post on instructables that shows how to extend the life of a bicycle tyre using Neutral Cure Silicone. Parents of young children will appreciate the fact that it claims to extend the life of a bicycle tyre, which can be a costly exercise if you have two or more children riding a bicycle, so I thought what the heck... give it a try!
Not recommended for an adult bicycle, this process adds longer use to a children's bike tyre and it's very easy to do - can be done with the wheels in the bike.
It should also be noted that these tyres cannot and should not be used on wet surfaces and that the dome applied should be no more than 3mm above the original tyre profile. The treatment will also last longer if you keep the bike out of extended periods of UV/sunlight.
Measure the tyre diameter and cut out a shape as shown in the moulding template above. You can use plywood, plastic, or metal, etc., for the template
Sand or wire brush the tyre - it must be free of dust, oil etc., for the silicon to adhere properly to it.
Apply the Neutral Cure Silicone and form a proper base layer, by rubbing a thin coat into the tyre surface. Now build up layers by applying a bead of silicon all around the tyre and using the template to shape the bead - rotating the tyre by hand is fast enough.
When any excess silicone runs down the sides, wipe off or add back in the middle of the tyre, until you have reached your maximum retread thickness of 3mm.
One must work quickly, as silicon sealants tend to skin over in a short amount of time.
Once the silicon has been applied and built up to a generally nice profile, leave it to set for at least 24 hours in a preferably warm humid environment.
The thinner the retread - the faster the curing. Long cures are needed for thick retreads and in cold dry climates.
The silicone sealant sets from the outside in, as the humidity in the air reacts with the rubber. The "skin" has to harden from the surface all the way down to the bike tyre rubber. If the retread is very thick, and not enough time has elapsed for it to finish curing, you will get a hard skin, on an uncured base.
A simple poke and push test is all that is needed - to feel if the skin is solid all the way through to the tyre. If it holds fast without slipping, it's more or less cured.