Forum menu
Seeking some STW wisdom here. Late last year I bought my first new bike in about 8 years and, as a result, I'm now running my first tubeless set up. Obviously things have moved along a bit in terms of wheel and tyre standards since the distant past of 2010 and I'm pretty much clueless now when it comes to setup and maintenance.
My wheels are DT Swiss XM1501 (27.5) with 30mm rim width and my tyres are 2.3 Minion / 2.3 High Roller II (also, if it makes a difference, I weigh 83kg). When I got the bike it was set up with the pressures at 20psi front, 25 psi rear.
I guess my questions boil down to:
- Given that it's no longer a case of reading a recommended PSI off the side of tyre, how do I decide on what pressure to run my tyres at based on rim width and tyre size? How did the people setting up the bike arrive at 20/25psi?
- What maintenance do I have to do on tubeless tyres (how often do I need to replace sealant etc) and are there some good tutorials anywhere on how to do this without spraying Stan's over a quarter mile radius?
As ever, STW wisdom is much appreciated!
I replace sealant every 3-6 months; 6 months is probably getting a bit late to leave it. I'll also do it if I'm going away somewhere it would be annoying to find I'd forgotten.
But you can just give them a shake; if you hear liquid you're good, and if you just hear balls of dried up latex rattling around, you need to replace it.
To replace the sealant, if you've got removable valve cores, just unscrew the core and then use a big fat syringe as a funnel. I used to use the syringe as a syringe, but that way you end up with latex everywhere. Just let it flow in.
If you don't have removable valve cores, get some removable valve cores.
As for pressure - lower is better unless they start burping, but I usually find they start to feel squirmy before that happens.
Tyre pressures - ride the bike. Pump to pressure to suit how you like them. A lot of people go as low as 20psi, I don't go below 30 myself. Don't like squirmy tyres, especially on hard cornering. So, you have to find what you like the feel of.
Depends on the sealant as to how often you check it or top up. Best way to top up is to squirt your jiz through the valve core.
Lotta vids on Youtoob. This fella usually is pretty good
(Cheats by using Hutchinsons in the vid - easily the most reliable tubeless tyres to set up ime 🙂 )
Pressure is largely down to preference and the accuracy of the £1 pressure gauge on your track pump 😀
psi is totally subjective and there is no general rule, it's whatever you like.
For myself any natural XC which can involve some road or hard pack I like about 25 front 30 rear but if on a Trail centre I prefer more like 18 front 22 rear.
I top up my selant every 6 months or so using a big syringe and pumping it in through the valve.
Also - for valve cores - I'd recommend a metal tool, the plastic ones round off with any slightly tight core! I think you can get screwdriver style ones, but I got this little thingy for a quid http://www.chainreactioncycles.com/lifeline-valve-core-remover-tool/rp-prod155551
i tend to let air out until i feel roll under hard cornering ( front ) or the rim on heavy landings ( rear ), then increase it a bit and call it done.
replenish the spaff when you can't hear it splosh about inside the wheel. do it by removing the valve core. i use a small stan's bottle ( the white one ). put the valve at about 7 or five o'clock, squeeze the tyre a bit and hold, start squirting in the spaff, then as the stuff goes in release the tyre so it helps draw the spaff in.
refit the valve and re-inflate.
if you don't have a trailside repair kit such as the weldtite or genuine innovations one, get one.
There is a rule of thumb formula out there but I cannae recall it...Anyhow, the way to really do it is to ride and see what works for you. 20 / 25 would be on the softer side for me, but I'd run something like that if I was doing technical stuff, not too rocky, that needed a lot of grip - I am heavier than you, though. For more general riding my preference would be closer to 30 / 35. You just need to ride and see what you like and basically set a lower [too soft mate] and upper [rock hard lad] limit.
I don't do any maintenance on my tubeless tyres. I believe the more diligent cyclist tops up or adds sealant periodically - you can do this with a tube of some sort through the valve by taking the core out, or simply unseat the tyre and change it the obvious way.
Psi - your starting pressures are not unreasonable.
Stans used to say weight in lbs/7 = psi then +/- a few psi from there. So 183lb = 26psi.
I think this is about right for a 2.25 tyre. Yours are slightly bigger so you can go a bit lower, eg 25psi. It's only a starting point though so experiment a bit around this.
How did the people setting up the bike arrive at 20/25psi?
20/25 I would have thought is a reasonable middling pressure for those rim widths/tyre sizes, assuming average weight/gnar rider. I weigh a bit less, but have slightly higher pressures on slightly narrower rims.
If you've had it a year I'd expect your sealant would need a bit of a top-up. I let the pressure out, take out the valve core and inject it into the stem of the valve, which generally leaves the beads still in place. Some people favour popping the bead off the rim in one spot and just pouring it in.
Tio- sealant can get out and cause your valve stem nut and the thread holding the valve core in to seize up (annoying if the first time you find out about it is out on the trail when you have to resort to fitting a tube). Grease both threads when you re-assemble.