Few basic hookless rim questions

I picked up a new set of 29er wheels for my Cutthroat and they’re hookless. I’ve looked around for answers and everything seems to just explain what hookless is. Any help is appreciated!

  1. If you lose pressure on a hooked rim, the tire stays in place with the hook. What happens on a hookless rim? For example, on a hooked rim I add sealant through the valve stem but often lose a bunch of pressure. How do you add or top off sealant if the tire loses pressure and comes out of contact with the sides of the hookless rim?

  2. For difficult to mount tires (e.g Rene Herse in my experience), I’d have to install with a tube then break the bead on one side of the tire and remove the tube. An Airshot canister would then be needed. Any tips for hard to mount tires on hookless? Should I get a small compressor? Is a CO2 trail side enough to inflate usually?

Frank,

There is still a “bead seat” for-say so its not like the tire is trying to latch/hold onto a flat wall.

This is one of the best articles you can read and I think it will educate you very well and explain why the “industry” is so confused right now (uhumph specialized)

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My N=1 is that the tyre stays in place just like on a hooked rim. And that hookless rims and hookless compatible tyres are made to tighter tolerances and with less variation between manufacturers so to date with 3 different rim-tyre combos I haven’t really had any issues mounting or removing tyres. Airshot canister is recommended though, I have had tyres that I couldn’t get to seat initially without one. My usual sequence is remove valve core, blast it with a canister to seat it, deflate, add sealant, reinstall valve core and then inflate.

In terms of road or trail side repairs I haven’t yet had to reinflate a tyre that has become unseated. It’s either stayed seated and I’ve got it to seal or put a plug in there and reinflated. Or if it’s not going to seal or plug I’ve put a tube in there. Carrying CO2 probably a good idea though.

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This is a key point, also keep in mind the max pressure ratings for tires on hookless rims can be lower than with hooked rims. I don’t remember the exact number, but it is on the low end for ‘road’ tires.

Thanks all I really appreciate the help!

@teddygram. This is the best one I’ve read yet!

@cartsman I’m glad to hear this has been working well for you…gives me a confidence boost!

@toyman I’m sure you’re right about the pressures. I’m running 29x2.2 tires so I won’t be anywhere near the max.

The hook is a lot of noise and not a lot of difference. The “Hook” on a rim is a .5mm - 1mm bump that your bead never really touches and that .5mm bump doesn’t really stop anything from happening. As such, it doesn’t change anything you’re doing.

Now how hard is a tire to mount on a given rim?? No one will know, but here’s a tip -
Mount the one side of the tire and have the bead sit in the valley. When you go to mount the 2nd side, grab a fist full of the tire and pull the entire tire flat + away from the lip in the area you’re working with. That give you the most slack. If its an asymmetric rim, both side won’t mount as easily, so try the narrow side first, then the wide side.

I dont think the tube method is the best way to go.
-Get the beads in the gutter, make sure the beads are going round the valve hole, push down on the tire around valve, wet around the bead.
-Remove the silver valve, inflate it without the valve in place, it should set pretty easily. you can either deflate it slowly or try to get the valve replaced while the air is streaming out. I usually let it all come out so I can inject goo in there afterward.

I was able to mount Conti Race Kings by hand but needed an Airshot to seat them. They held perfectly over night. So far I’m sold on this whole hookless business!

I had trouble getting tubeless tyres inflated with just a track pump, until i tried this:

Basically magic as far as i can tell

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If both the rim and the tire comply with the standard, tolerance is very tight. So if you lose pressure the tire will probably stay on. If you lose pressure & jam a tire iron in there to pry the tire off…it will probably stay on. If you jam a second tire iron in there and try to pop the bead over the rim…it will probably stay on. If you leave the wheel sit in the hot sun for 20 minutes and then jam two tire irons under the bead and try to pop them over the rim…the tire will probably stay on.

You get the picture.

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I thumbs-upped your post but am making an explicit comment about that link you posted, if you’re having tubeless issues read then reread that article, specifically the ‘sealing a rim’ section.

I was having issues with a square-shaped rubber grommet, swapped over to a muc-off valve with round and problems disappeard (am not associated with muc off, but their valves are super great). Even other tips such as ‘hole should be minimal and let valve push through’ are invaluable and will save you hours and sealant.

A tip I would add is “inflate and bead the tyre with no sealant, let it sit for 2+hrs. If it holds air it’s probably good. Listen closely to all parts of the tyre/valve for leaks. If it looses any air at all in that time, do not try put sealant it, rip tyre off and inspect valve+rim tape