Tubeless fitting help!

Trying road tubeless for the first time. Aerocoach Aeox wheel with a Conti 5000 TL tire. Tightest fit of any tire I’ve ever installed, getting the thing on took every ounce of experience and cunning I’ve acquired from 25 years of cycling, and was the closest I’ve ever come to going to a bike shop to install a tire. Eventually it was on, and when I pumped it up there was a satisfying pop as the beads seated and I was able to pump it up to ~100psi. It was losing a bit of pressure over a few hours, but no problem I thought to myself, this is where the sealant comes in. So took out the valve core and put in the 30ml of caffelatex recommended by my LBS, gave it a gentle spin and re-inflated it. Came back after work and it was pretty flat again. Uh oh I thought. Gave it another spin and re-inflated. Same thing again so I added another 30ml of sealant, taking it up to the recommended dose for a MTB tire. Still the same thing.

Any ideas? The fact that it will hold 100psi suggests to me the beads are seating properly. There is no sealant coming out anywhere. So it seems there is a small leak somewhere which the sealant isn’t getting into. But if double the recommended sealant isn’t doing anything then I can’t see how adding more will make any difference. Maybe take it for a few rides (on flat safe roads in close proximity to a car with a track pump…) to see if that somehow kicks it into place? Given what a nightmare it was getting that tire on in the first place, I suspect if I have to go through the pain of taking it off again then the thing will be going in the bin and be replaced with a trusty regular tire and latex tube…

Use soapy water to see if you can find where the leak is coming from. My guess is it’s the rim tape. Look for bubbles forming around the spoke nipples.

You also need to shake the wheel pretty rigorously to coat the inside of the tire with sealant. A gentle spin is not sufficient.

Another thing to try is to bounce the wheel on the ground rotating a few degrees between each bounce. Do a few times. This splashes the sealant up on the rim tape and can help seal any leaks through the rim tape.


All of the above, plus riding it is also a good idea. No need to go anywhere, just up and down your street will do it.

Its pretty normal with new tyres/rims to leak a little bit at first.

Thank you both, gave it a good old shake, some bouncing and a short ride. Will see how it holds up now! Must have read a dozen articles on tubeless, lots of advice on how to seat beads and inject sealant, nobody mentioned taking time for a new tire to bed in!

Mine usually need a couple of days to bed in. Or at least they do often enough to make me think about when to change them.

The sealant foams up when in motion to seal so as above you may need to go for a ride

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Yup, I use the “Stan’s Shake” after initial install. I do this with every tubeless setup.

Hold the wheel vertically with hands on the 3 and 9 o’clock positions. Then rotate the wheel at the wrists so it move the lower part of the wheel back and forth.

You should hear the sealant splashing around in the wheel. Rotate the tire about 1/8 turn, reposition hands and repeat until you get the whole wheel done.

It’s useful to start with the valve stem as the bottom for an easy way to track progress.

Ha! Welcome to tubeless! :wink: Time to break out the soapy spray and see where the leak is.

If you’re not seeing any sealant coming out I’d first suspect that it’s leaking through the rim (maybe need an extra layer of tape?) or at the valve stem. Try jiggling the valve stem a little to see if you can hear air coming out there. Anyhow, once you figure out where the leak is move the tire around and get some sealant over there.

Anyhow, this is a big part of tubeless…pfaffing about with your tires.

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Not directly helpful, maybe, but I’d suggest that you don’t rely on sealant to create the initial seal. Sealants job should be purely for puncture repair/prevention rather than as an integral part of the installation.

Great in theory.

In practice, the simple process variability from making rims and especially tires… leads to situations and combinations of components that don’t always seal “perfectly”. The sealant is a necessary part of the tubeless picture for some (but not all) setups.

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Most manufacturers of wheels either make their own tyres, test their wheels with certain (officially recommended) tyres or just test with as many different tyres as possible.

With this in mind, there’s not much reason to put up with a sub-optimal setup where the reliability (the whole reason people choose to use tubeless) is diminshed due to relying on some sticky liquid rather than a proper mechanical join.

I think the reason is cost. The wheels on my mountain bike are carbon DT Swiss and are awesome for tubeless. Swapping tires is a piece of cake, and sealant isn’t needed for the tires to keep air.

The aluminum Bontrager wheels on my road/gravel bike is a different story. Changing tires is a pain, as the rim tape/strips need to often be redone, and the sealant is needed even to get the tires to initially inflate. Once the tires are seated with the sealant, everything’s fine. Yes, I could replace the wheels for a better set, but that costs $.

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I see what you’re saying but I’m not sure that’s the case. I’ve had cheap rims and tyres, some of which mount up great and some which are a total pain in the neck.

Are you using bontrager tyres with your bontrager wheels?

I certainly don’t think that the only way to guarantee a good setup is to buy more expensive wheels. I’m just saying that a setup is likely to give you much less hassle if it’s a “recommended” or well tested setup. And neither of those should require sealant on initial setup.

Not using bontrager tires. Every tubeless tire I’ve tried - Hutchinson, WTB, Schwalbe - has the same issue. I think it’s because the OD of the wheel is too small, making the initial seal difficult.

Agree, ideally the wheel/tire combo would not need sealant, but practically speaking this is not always the case.

And yes, it does not require an expensive wheel - just a well designed one. I picked up a bontrager aluminum rim for my fatbike for $100 that seals fine with 45Nrth tires.

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I’ve had difficulty seating tyres on bontrager rims too. But for best results, using a Bontrager tyre should be the obvious choice.

I realise in the real world that not all tyres will fit all rims, but PRACTICALLY speaking, surely the most practical thing is to choose a rim and tyre that are best suited to each other? Makes a lot more sense to me than choosing any old combination and then just plugging holes in the mating surfaces with sealant. That will be very impractical when the rim and tyre prematurely part ways because of a poor join.

I am in the same boat. I have a set of ENVE 7.8s. I did the front wheel zero issues was shocked actually how easy it was.

Back is another story ended up putting a tube in it because I tried multiple times over 3 months to get it to seal no dice.

I will work at it this winter to get it figured out. (I don’t use the wheels often is why it isn’t pressing but sure does suck lol)

That ignores the reality of tire preferences in the form of tread pattern options, performance characteristics, and even size options. Sometimes, brands don’t offer the particular combination that a rider wants or needs. The need to mix and match brands (wheel vs. tire) is very likely and even essential for some riders.


In practical terms, I’m choosing the rims I already have, and a tyre that is right for the conditions I want to ride in. I’m not buying new wheels just to run a different tyre!

Also in practical terms, what difference does it make if the sealant also seals small imperfections in the rim, the tyre, or the interface? I’m putting it in there anyway, as long as it seals all the little holes, it’s doing its job.


The issue i think is with this specific set of wheels. They’re supposedly tubeless, but they are not well designed. Eg the there’s a reasonably deep channel in the rim making it difficult to get an initial seal - some part of the tire ends up sitting in the channel, and not on the shoulder of the rim, so air just escapes.
And the spoke holes are offset in the bed of the wheel which makes them difficult to seal with tape (the deep channel exacerbates this issue).

The next tire I’ll try is the Bontrager GR1 - very similar to the schwalbe g-one I currently have, but was not available at the time. Maybe this will be better, but I’m guessing not.

@DaveWh, This may well not be true for all Bontrager wheels, but many (most?) are designed to use their plastic tubeless rim strip insert. They have a very specific design that includes sizing and features specifically for tubeless use. The molded rim strip replaces a generic rim strip that may ship stock with some tubed setups.

If you are using tubeless tape rather than the intended insert, this may be causing the issues with your setup.

I highly recommend checking to see if your wheel should be using these instead of simple tape. If so, I would change that at the same time you redo tires the next time you tear it all apart.