Racing Dan

Read carefully ;-)

The tyre/rim combinations in the Mavic chart are the ETRTO/ISO standard, but the pressure is Mavic recommendations. Presumably NOT ETRTO/ISO, or it would say so. No mention as to why they deviate, but a safe bet is to not have tyres blow off Mavic wheels and deal with the fallout from that.

Sy Reene

Understood, so does this mean if ETRTO were to do their own version of this chart, would they really plop the 72psi value into every yellow box on this chart that's in a hookless column? That doesn't seem rational.

Racing Dan

I dont know for sure. I cant find the current ETRTO or ISO standard chart. I do agree its weird having the same max pressure for every imaginable combination, and I bet its not the case either. I just cant prove it right now.

Racing Dan

This is the Schwalbe special chart for tubeless tyres on hookless rims. Their recommendation for a 30mm tyre is 4.5 bar max. That is 65 psi. Also not 72 psi, but closer.



https://www.schwalbe.com/en/tubeless...e-requirement/

SoSmellyAir

Iffy as in a tire with a nominal width of 28 mm is barely wider than the 25 mm internal width of the wheel; I would not install narrower than a 30 mm wide tire on those wheels. Yes, I also feel that hooked is safer than hookless, especially for a chubster like me.

PeteHski

I think the ETRTO standard max pressure on hookless rims is 73 psi for tyres up to 28 mm and 65 psi for 30 mm and above. But the various tyre manufacturers don’t necessarily comply with the ETRTO standard. For example Conti state a max 73 psi for all widths of their GP5000S TR. They say that they test their tyres at 110% of this max pressure on the widest rim allowed in the ETRTO rim/tyre width chart. Other tyre manufacturers use slightly different methods, so there is no real standard here.

79pmooney

Not a hooked vs hookless issue but tire types in general. Today's Itzulia Basque Country stage race, a rider slid out on a corner with pavement buckled by tree roots. Odds are what? 95% that he was riding tubeless, 5% clincher and 0% tubular? My experience is with tubular and clincher. Even using the exact same tires, clincher and tubular (Vittoria G+) I find the grip on iffy surfaces with tubular rules. I hear that sidewalls on tubeless are in general, stiffer than needed for clinchers. (And the classic tubulars I raced had sidewalls that almost weren't.) I wonder if this rider had simply been riding the old stuff perhaps Jonas Vingegaard, Primroz Roglic and Remco Evenepoelmight have avoided ugly crashes that may well affect their rides in big races later this season. That's a lot of high priced athlete to sacrifice for the glue free tubeless ride.

https://www.cyclingnews.com/news/tour-de-france-champion-jonas-vingegaard-remco-evenepoel-primoz-roglic-injured-in-serious-crash-during-itzulia-basque-country/

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Fredo76

I don't know about tree roots, but when I see a disc-wheel team time trialer's wheel slide out from under him for no apparent reason on a sharp corner, I figure he'd have been better off running small-flange Record hubs, laced three-cross, and tubular rims and tires. Not crashing beats aero.

choddo

Tubeless and clinchers are far from mutually exclusive.

Horror crash.

Atlas Shrugged

That's a real stretch. Current premium tubeless tire sidewalls are as supple as regular clinchers, so that is not an issue, and I have never heard of a real grip difference between tubular and clincher tires. Now blaming the cash as well as the potential injury of these top athletes is over the top.

Trakhak

Or it was the merciless performance of disc brakes. That said, I'll take discs over GP-4 hard-anodized rims. That slick brake track was awful in the rain. The late Jobst Brandt despised hard anodizing of rims for that and other reasons.

79pmooney

I'm not saying anything clincher vs tubeless re: handling. I've heard some clinchers have gone to stiffer casings to be tubleless ready which strikes me as a step backwards handling-wise if true but I haven't seen this first hand. I do know that I feel more secure on poor surfaces riding tubulars than the identical clincher. And better tubulars with thinner, more flexible casings handle better.

Blaming the cash? Huh? I'm just pointing out that this crash cost bike racing a lot. (If tubulars would have made a difference, the cost of this incident would cover an awful lot of expensive tires and mechanics gluing time.)

Disc brakes? GP-4 rims? This thread is about tires, specifically tubeless tires that may have caused or at least not prevented crashes in the pro ranks.

choddo

But how did we go from hookless to tubeless being to blame? Clearly we don’t know what caused this one but there’s been no suggestion until now that tubeless are an issue.

seypat

It says hookless in the title.

PeteHski

Yeah it’s nonsense. My 30 mm tubeless GP5000S TR tyres on 22 mm internal rims at 65 psi are about as plush and grippy as it gets for high performance road tyres. These same tyres are the fastest ever recorded at Paris Roubaix and that is as challenging as it gets for uneven road surfaces.

DaveSSS 

Traction is going to be better with 28-32mm tubeless tires that are used at far lower air pressures than old school narrow tubulars. I don't know what aspect of handling you're talking about that's contingent on supple side walls. I modern tubeless with 38 psi lower pressure should be far more supple.

PeteHski

They certainly iron out a lot of the road bumps and cracks I encounter. Tyres have never been better and are probably the biggest improvement in road bikes over the last decade. Even if they were slower I would still prefer them to high pressure narrow tyres. While the pros have mostly settled on 28 mm I prefer going a step wider for my weight (80 kg) and crappy roads.

mstateglfr 

So sliding out on a corner never happened with small flange Record hubs and tubular tires glued to box rims?

Mojo31

How could it?

seypat

Probably not, definitely not with large flange. Small flange only took over because of the weight savings. Large flange were the one and only until they weren't. They used more material and that was deemed bad.

Also, if you're talking about TTs, Pelissier hubs were the way to go, not Record.

https://velobase.com/ViewComponent.a...7a9f1&Enum=110

seypat

Speaking of French, cycling, tires, safety and such........

https://www.france24.com/en/live-new...y-union-boss-1

mstateglfr 

I must not understand what 'sliding out' means because to me it seems really easy for someone to slide out in a sharp turn, regardless of hub design or spoke lacing and regardless of tire type, if the tire deflates or if the tire loses contact with the ground.
The fact that a tubular tire will stay attached to the rim doesn't mean a wheel won't slide out on a sharp corner if the tire deflates or if the rider hits a bump at a bad angle during the turn.
A shallow box rim won't keep a rider from sliding out on a sharp corner if the rider hits a bump, the wheel loses contact with the ground, and the rider is at a bad angle during the turn.
The lacing pattern of a wheel won't keep a rider from sliding out on a sharp corner if the rider hits a bump, the wheel loses contact with the ground, and the rider is at a bad angle during the turn.




I was responding to Fredo76 whose post I find to be of little value and erroneous because he attaches benefits to something that doesn't inherently contain those claimed benefits.
If someone slides out on a sharp turn using a carbon rim and disc brake, there is 0 reason to think they wouldn't have slid out on that same sharp turn using a box rim with tubular tire and traditional lacing to a low flange hub.
Like really, what does the lacing pattern have to do with anything? Why would a low flange hub stop a wheel from sliding out in a sharp turn better than the hub flange height of a modern hub?...and speaking of, why is Fredo assuming the modern hubs aren't also low flange?


I think his post was bad and contained erroneous information which misdirects the issue and frames the type of equipment he likes in a positive light. So I questioned his comment.
But since you two have responded, I am open to underswtand hat I am missing here. Why would a low flange box rim 3 cross laced tubular wheel not slide out in a sharp turn? And if that can be answered, then this can also be answered- why do carbon rim tubeless wheels with disc brakes slide out in that same sharp turn?

seypat

Maybe I was being sarcastic. I thought the rant about large flange hubs would give it away. It didn't so that means it was the perfect amount of believable. People are too serious here on BF.

That being said, I do have 3 sets of wheels with large flange hubs. They do have a better ride than small flange. I wish they were still around.

mstateglfr 

Ha, with all the bonkers claims and comments on here that are genuine, I didn't pick up on the absurdism/sarcasm.

seypat

Speaking of safety, do you remember when graphite golf shafts first came out? People were snapping them in anger and killing themselves when the jagged shaft would cut a major blood vessel.