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Hookless rims...how?
 

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RCoapman
Joined: 09 Feb 2005
Posts: 5137
Location: Back in the snowy homeland

7/26/22 11:14 AM

Hookless rims...how?

I've been searching and I haven't found a good explanation- how to tubeless tires stay on hookless rims?

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Sparky
Joined: 08 Dec 2003
Posts: 19068
Location: PDX

7/26/22 11:26 AM

Best Data I've seen is ENVE.

Given hoe fussy ENVE hooked rims are with tires, I'd be reluctant to go the hookless path myself.

But, at least ENVE states what tires to use on their rims.


https://support.enve.com/hc/en-us/articles/360039656291-Hookless-Beads-Explained

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RCoapman
Joined: 09 Feb 2005
Posts: 5137
Location: Back in the snowy homeland

7/26/22 3:48 PM

This is effectively the same that I've read elsewhere...doesn't address my main question- how does the tire stay on the rim and pressurized without a hook to 'catch' the bead?

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Sparky
Joined: 08 Dec 2003
Posts: 19068
Location: PDX

7/26/22 3:53 PM

I think the teams racing then use the foam vitt locking anti pinch inserts. I seem to recall Roubaix had a lot of rider finish on the velo well flattedon the foam things...

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Brian Nystrom
Joined: 26 Jan 2004
Posts: 5096
Location: Nashua, NH

7/26/22 5:29 PM

Rob, it's the same way they stay on the rims of motorcycles, cars and trucks. You have a strong, non-stretch bead that fits tightly on a bead seat with a slight rib on the inside to prevent the tire from unseating. If the fit is correct, a hook on the rim isn't necessary because the tire bead can't expand enough to unseat itself, let alone climb over the rim bead.

Here's a version of the Enve article with images:

https://www.gravelcyclist.com/bicycle-tech/the-hookless-bead-rim-how-it-works-who-theyre-for-by-enve-composites/

When problems occur, it's inevitably because the rim and tire are not designed to the same specifications or deviate from them. It's a ridiculous situation that was solved with MTB tires decades ago with the UST standard. I have no idea why road rim and tire manufacturers can't get their shit together, but that's where we are. For now, you have to limit yourself to tires that the rim manufacturer says will fit properly. Otherwise, you're on your own.

This is much less of a problem with gravel tires due to their lower pressures. A less than perfect fit may result in seating difficulties (too tight) or burping (too loose), but it doesn't seem to be common to have a tire blow off a rim.

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dddd
Joined: 11 Jan 2004
Posts: 3345
Location: NorCal

7/27/22 6:04 PM

It strikes me as odd that pressures specified with hookless rims in mind would focus solely on tire pressure, to the exclusion of the tire's width as a consideration.

Doubling a tire's width doubles the tension in the tire casing, which is the force that pulls the tire bead outward away from the rim's bead-seating "shelf".

So it seems like "inflation pressure times tire width" is the parameter that might better define the upper inflation limit of a tire on any given hookless/tubeless rim, no?

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Brian Nystrom
Joined: 26 Jan 2004
Posts: 5096
Location: Nashua, NH

7/27/22 6:28 PM

Actually, Enve's pressure chart includes rider weight, tire width and rim width:
https://www.enve.com/learn/tire-pressure/

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RCoapman
Joined: 09 Feb 2005
Posts: 5137
Location: Back in the snowy homeland

8/8/22 10:09 AM

Ok, so I really wasn't getting it until this weekend when I finally mounted a set of tubeless tires for the first time. I've always been a visual/hands-on learner so nothing really made sense to me until I futzed around with these things until it literally clicked, or popped as it were.

I am so used to thinking about lateral (parallel to the axle) pressures keeping the tire hooked onto the rim I was struggling to get that it's radial pressures, i.e. the exact fit of the bead to the rim, that maintain the seal and prevent blow off. It was all explained rather clearly, in retrospect, I just needed to see and feel it.

I also made an absolutely bloody mess with the sealant, lol. Lessons learned for next time.

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Sparky
Joined: 08 Dec 2003
Posts: 19068
Location: PDX

8/8/22 3:24 PM

"made an absolutely bloody mess with the sealant"

More of that potentially to come. When you get good cut and the bike, brake, clothes, shoes get bathed.

The more PSi you run, the faster atmosphere differential helps the juice get out on non sealed punctures/cuts etc.

Bring some sorta mopping cloth, tube and a boot in case of the worst case scenario.

I've decided more than 55 PSi it is not for me...

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dan emery
Joined: 11 Jan 2004
Posts: 6884
Location: Maine

8/8/22 4:30 PM

My $.02

Not really sealant related, but at this point I’d rather use tubes than tubeless. Now that I use wider tires at lower pressure, I basically never get flats. Except on my one pair of tubeless tires, which periodically leak air form the rim or something, and have to be refreshed. etc. And I did get one puncture that didn’t seal. I don’t have to refresh anything with tubes. And I’ve never been unable to replace a tube on the side of the road. I dunno about tubeless if it doesn’t seal and I need to take it off and put it back on.

I’ve been reading Bicycle Quarterly and I notice that Jan Heine, of Rene Herse, whom I think knows a thing or two, chooses tubes for his epic gravel rides.

YMMV, obviously

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Brian Nystrom
Joined: 26 Jan 2004
Posts: 5096
Location: Nashua, NH

8/8/22 4:32 PM

I probably shouldn't say this, but...

I've never cut a tubular, clincher or tubeless tire to the point that it sprayed sealant. In fact, the only flats I've had were from small punctures when I went too long between refreshing the sealant. In each case, I added sealant, pumped the tire up, it sealed and I was back on the road or dirt. I always carry a small bottle of sealant, a tube, and a chunk of old tubular casing to use as a boot, if necessary, but they rarely get used. Perhaps decades of riding tubulars made me hyper aware of road debris.

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Brian Nystrom
Joined: 26 Jan 2004
Posts: 5096
Location: Nashua, NH

8/8/22 4:42 PM

Dan, gravel tubeless tires are pretty easy to get on and off and the most you'll have to do is remove one side. It's really no big deal. The major issue in many cases is getting the right size rim tape and getting a proper seal when you initially set them up.

Now, if you really want to have some fun - or you truly hate yourself - try tubeless fat bike tires!

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Sparky
Joined: 08 Dec 2003
Posts: 19068
Location: PDX

8/8/22 6:15 PM

"try tubeless fat bike tires!"

Do you have to put a band around those to seat them like a car tire??

I am also using more tubes than not again. Including in TLR tires. And using tubulars too..

Have not yet delved into hookless.

I ran some new gravel tires Sunday, on some small gravel, tiny.. [read sand]. Pirelli Cinterato H, these roll well on everything I note.



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Brian Nystrom
Joined: 26 Jan 2004
Posts: 5096
Location: Nashua, NH

8/9/22 6:40 AM

The issue with fat bike tires are twofold:
- Positioning the beads so you can get the tire to inflate when initially installing it can be a real headache, though I manage to do it on my own using a compressor.
- Even worse is unseating a bead when you need to. This generally involves laying the wheel down, protecting the underside of the rim, then stepping on the tire as close to the rim as possible to pop the bead free. Sometimes it takes several attempts.

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Sparky
Joined: 08 Dec 2003
Posts: 19068
Location: PDX

8/9/22 7:59 AM

Sounds like MC tires..

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KerryIrons
Joined: 12 Jan 2004
Posts: 3234
Location: Midland, MI

8/10/22 9:36 AM

Cuts


quote:
I've never cut a tubular, clincher or tubeless tire to the point that it sprayed sealant.


It obviously depends on where you ride, but even here in Michigan with our 10 cent bottle deposit, there is still sometimes glass on the road. And sharp rocks. And road debris. Sidewall cuts are not a regular thing, but I get one every 20-30 thousand miles and there is no way sealant would deal with it. I always carry some Tyvek for a boot and have used it many times.

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Nick Payne
Joined: 10 Jan 2004
Posts: 2625
Location: Canberra, Australia

8/10/22 4:04 PM

So far as fixing punctures in tubeless that are too large for the sealant to cope, I carry a tyre worm kit with me. I've had to use it twice while out on the road, and it's a really quick fix, as no dismounting of the tyre/beads is needed - put the puncture uppermost, bung in the worm, spin the wheel, inflate. The worm seems pretty much a permanent fix unless the casing is cut to the point where it starts bulging, in which case the tyre gets replaced when I get home.

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Sparky
Joined: 08 Dec 2003
Posts: 19068
Location: PDX

8/10/22 7:23 PM

I have a mini plug kit as mentioned a few times.

Not used it on the road yet, so can't suggest one way empirically just yet...

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