By Julian Thrasher, ATG Training
This instalment of Workshop sees us tackle the thorny (pun intended – I think) issue of setting a wheel and tyre up to run tubeless.
This is the sort of workshop job that can either be really easy with a ‘pop – pop – pop’ – as the tyre inflates nicely onto the rim, or really frustrating, with a ‘pop – pop – BANG’ – sealant everywhere as the tubeless tyre bursts off of the rim, or a ‘hiss – hiss – hiss’ as the tubeless tyre refuses to seal.
We’ll walk you through a few top tips that will give you a ‘best practice’ approach when it comes to setting up tubeless.
Firstly let’s talk about the different types of tubeless you’re likely to set up. They come in three main types:
- Tubeless conversions – where a non-tubeless tyre and rim are converted to run tubeless, using a rim tape and conversion strip. This is perhaps the least consistent approach, we’ve had tyres that go up straight away on a given rim and tyres that either point blank refuse to fit or seal on the same rim.
- UST type – (Universal / Unified Sytems Tubeless) A slightly ironic tag because you have to run a UST tyre on a UST rim for best results making it not really Universal. The UST can be set up tubeless without sealant due to the heavy carcass of the tyre (though why you’d want to is a mystery)
- TLR type or Tubeless Ready type, which again requires you run a dedicated TLR rim and tyre. Unlike UST though you must use sealant to achieve the best results.
Compatibility. Mixing and matching DOESN’T WORK. Trust us on this. We’ve had some huge explosions where someone has tried to install a UST tyre on a tubeless ready rim. The beadhook of the tyre and rim are engineered to work in unison and the UST / TLR interfaces are quite different. Trying to get one to work with another will result in either blistered hands or burst earderums.
The list of possible combinations that will or won’t work on a tubeless conversion is potentially limitless. When you find one that works, write it down in your mechanics notebook for future reference.
Cleanliness is next to Godliness. Well it is when it comes to the tyre and beadhook. A little left over sealant in the carcass of the tyre is a good thing as long as it hasn’t set into a custard-like mess. Clean the rim and bead hooks until any sign of old sealant has gone. Doing so will result in a much better seal
Soapy water. The rubber carcass of the tyre is quite grippy and will do it’s best to hold onto the rim. This will result in you having to over-inflate the tyre in order to get it to seat, risking a potentially customer scaring bang if the tyre decides to give up. Use some soapy water around the bead of the rim before inflating and you should find that it slips into place at a much lower pressure.
Stretch it out. Some tyres are very tight to fit. If you have an old ETRTO type rimmed wheel sitting in the workshop then install the tyre onto this with an innertube and let it sit overnight. The tyre should stretch slightly allowing an easier fit when it comes to mounting it to the tubeless rim.
Take the valve core out. You’ll probably need to do this to install the sealant anyway, but taking the valve core out gets rid of the core restricting the amount of air that can go into the tyre quickly, useful if all you have in the workshop to seat tubeless is a stock trackpump. BTW having a compressor or one of the new tubeless track pumps makes the job WAY easier!
Grease the valves. Sometimes the tyre and tube will go up easily with that satisfying pop / snap, but then refuse to stay up over time. A majority of times this can be traced back to the valve leaking. Ensure you are using the recommended valve for the rim you are using and try greasing round the edge of the valve that will seat against the rim or rim strip. A word of warning, excessively tightening the valve nut can lead to you damaging the rim strip (if used) again, greasing the valve will help here. We’ve also found that the Stans tape is quite stiff, so instead of using a knife to pierce where the valve will go through, use a hot needle. This will cauterise the tape and give a much better seal. If you’ve tried all of this then the last ditch approach is to use clear silicone sealant around the external rim edge of the valve – we’ve done this when all else fails.
We’ll finish up by saying that some tyres are especially ‘thirsty’ and we’ll aim this firmly at the tubeless conversion and TLR type systems. This means that the tyre will absorb a lot of sealant into the carcass before holding air. Keep adding sealant and shaking the tyre to ensure even distribution around the tyre. We like to rest the wheel face down on a bucket so that the sealant can work its way into the sidewalls of the tyre, flipping every half hour or so to ensure even distribution.
By following these tips you should find that your next tubeless install goes a lot more smoothly – or at the very least you’ll know what to recommend to your customers to ensure it does!