somebikeguy 

Hi all

I have installed a fair number of tubeless tires recently and never had an issue. Contis, and a whole mess of Gravelkings. In a variety of widths from 30-40mm. I took a Gravelking 38 off a 20mm ID rim a few months back then installed it on a different 20mm ID rim (both Pacenti Forza) tonight. No matter what I did I could not get it to seat. In all instances I am using a compressor. I turned the pressure up and up and nothing doing. I used a new valve core, same.

Is it common to have trouble re-seating a tubeless tire after its been mounted, removed?

In the second pic I'm using barely any finger pressure to show how far the bead is from seating. I really can't recall if it felt/looked the same when the tire was installed for the first time.

Shadco 

Valve core is out for th initial seating right?

.

somebikeguy 

No because my automotive inflator needs an adapter to the presta and will not attach directly to the valve body without the core

chaadster

I don’t know how much of the issue is due to the tire being used and how much is just the typical vagaries of wheel and tire compatibility, but there may be some tricks you can use to get it on.

It’s not clear what the problem is, but it seems like the bead may be too loose when in the center channel of the rim. Ironically, you mistakenly used “ID” when referring to the inner width (i.e. IW) of the two rims, but it is in fact a wheel-tire diameter mismatch that causes a slack fit.

Something to try is wrapping the circumference of the mounted tire with a strap or towel in order to press it more snugly to the rim when inflating. A cargo tie-down strap would work, for example. Don’t lock it down tight, just hand hold it so you release the tension as it inflates.

Similarly, you may be able, using a work surface and your hands, to just apply some compression to the tire as you inflate, pressing the tread into the rim to slow the air loss and let the air do the job of pushing the up onto the rim shelf. It might take a little futzing and rotating of the tire, but I’ve had success with that type of manipulation.

staehpj1

That doesn't help. It reduces the air flow. Personally I use adaptors only for an emergency when out somewhere away from the shop. For at home why not upgrade to the prestaflator with swapable heads or the one with a head that does both? Or do as I do and have a schrader inflator for cars and a presta one for the bikes. You could upgrade the head on yours or buy another.

masi61

The remnants of seals may be hanging up enough on the bead/bead shelf that it resists moving outward at the pressure you are subjecting it to. I agree with staehpj1 that having the presta core in there is restricting flow.

The Airshot canister that I use comes with a high flow adapter that you thread onto the presta valve body (with the presta core removed. The added airflow (with the presta core removed) when you open the Airshot canister valve enables a more forceful tire mount that gives you the satisfying “pop, pop, pop” that you need to hear.

Kapusta

Is the problem that the fit of the bead is too loose? This can happen as tire get used. If so, you need to do one of two things:

1- Improve air flow. Without the valve core removed, you’re just not gonna get very much airflow, even with the pressure turned up.

2- Tighten up the fit. Might try Another layer of tape.

MattTheHat 

Can you use the adapter and just hold the locking hose end in place instead of locking it down?

somebikeguy 

Thanks for the advice. Will something like this seat on the body of the valve with no core installed? https://prestacycle.com/products/pre...le-presta-head

I'd like to buy as little as possible as the Hazet shraeder / automotive inflator is "the good stuff" and does not need upgrading.

staehpj1

Yes, I have one like that and it works fine with the core out.
The issue might be does it fit on your inflator hose? Ideally you could swap between schrader and presta on your existing inflator, but they are different brands and may not be compatible.

Dino_Sore

I have had problems with the type of presta adapter you are using. I use the Prestaflator with their big presta head, and that appears to allow more airflow. And, yes, there may be wheel/tire combos that require you to remove the valve core.

Also try using more lubricant when seating the tires. I can usually get away with a spray bottle of soapy water. However, if I have a very difficult tire, I will put soap in a bucket and fill the bucket with a high pressure hose. Get the soap as foamy as possible and brush it on the beads and rims. Be generous; you want the soap to look like shaving cream. This has always worked for me. (Over time, however, I have figured out what tires work best with my wheels, and I can usually get tires to seat with a floor pump).

staehpj1

By the way... I found that the cheap ($8.99) Harbor Freight inflator isn't bad and I use it for car tires and other shrader stuff. I use a Prestaflator for bike tires (all my bikes are presta).

somebikeguy 

Managed to get it done with another Hazet friend

unterhausen

I came here to mention blow guns, but OP beat me to it. That looks like a really nice one. I got a cheap one from Home Depot and opened up the tip so it just barely fit inside the presta valve. Seems to work okay.