Thomas DeGent no fan of hookless…
#251
Senior Member
You forgot about the sound. Ditch the crabon and you'll stop looking over your shoulder for that Pterodactyl that's swooping down to carry you off for dinner.
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#252
Senior Member
This, and my fat ass would have me hovering close to the danger zone. What hasn't been talked about yet is if one's weight flucuates 2 or 3lbs from day to day. The pressure and weight measurements better be precise. That 5-10lb range won't cut it.
#253
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What's a more likely scenario in road cycling: A) an impact causes tire to deflate, which could lead to tire tire unmounting from the rim and breaking as it hits pavement or B) impact causes rim to crack, which could easily lead to a tire coming off?
Seems like the people saying the type of tire retention doesn't matter are assuming scenario B, but the tire being deflated at the beginning of scenario A is a lot more likely to me, and the hooked rim by design has a better chance of retaining that tire than hookless. This is the scenario the CPA is concerned about.
Seems like the people saying the type of tire retention doesn't matter are assuming scenario B, but the tire being deflated at the beginning of scenario A is a lot more likely to me, and the hooked rim by design has a better chance of retaining that tire than hookless. This is the scenario the CPA is concerned about.
#254
Senior Member
What's a more likely scenario in road cycling: A) an impact causes tire to deflate, which could lead to tire tire unmounting from the rim and breaking as it hits pavement or B) impact causes rim to crack, which could easily lead to a tire coming off?
Seems like the people saying the type of tire retention doesn't matter are assuming scenario B, but the tire being deflated at the beginning of scenario A is a lot more likely to me, and the hooked rim by design has a better chance of retaining that tire than hookless. This is the scenario the CPA is concerned about.
Seems like the people saying the type of tire retention doesn't matter are assuming scenario B, but the tire being deflated at the beginning of scenario A is a lot more likely to me, and the hooked rim by design has a better chance of retaining that tire than hookless. This is the scenario the CPA is concerned about.
#255
Senior Member
Increasing the total bike/rider weight from 260 to 270 pounds only increases the recommended tire pressure by 1.3 psi. If I weighed that much I'd be on 32mm tires where there's a significant safety margin, not 28mm.
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I've had a few sudden deflations while riding GP4000 and GP5000 tires. Never once did the tire bead come off the rim.
You either believe that DeGent's tire spontaneously blew off the rim, causing the crash (and rim damage occurred during the crash) - or you believe what Vittoria and Zipp have concluded, that he hit a rock, which damaged the rim causing the tire to deflate, which then came off the rim.
Last edited by terrymorse; 03-08-24 at 01:08 PM.
#257
Senior Member
#258
Senior Member
A few years ago on a ride, I thought I heard a flock of turkeys take flight. I looked around/behind me and it was a rider with crabon wheels whooshing instead. I'm glad it wasn't a flock of seagulls. If it had been seagulls, I would have jumped off my bike and ran. I would have ran so far away. Even then, I probably couldn't get away.
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#259
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as you'll calculate from the ETRTO chart above in post #247, a 32mm tire supposedly should only be inflated to a max of 65psi (450 x .145)
#260
Senior Member
Not very easily. I once rode on a fully deflated GP5000 clincher for a mile, because I didn't want to ruin my cleats by walking. The tire did not come off, until I worked it off with tire levers.
I've had a few sudden deflations while riding GP4000 and GP5000 tires. Never once did the tire bead come off the rim.
The makers of the tire and rim wouldn't have any vested interest in spinning the story, would they?
I've had a few sudden deflations while riding GP4000 and GP5000 tires. Never once did the tire bead come off the rim.
The makers of the tire and rim wouldn't have any vested interest in spinning the story, would they?
#261
Senior Member
The latest ETRTO guidelines limiting 30-34mm tires to 65 psi is more limiting than what's stamped on my 30 mm Pirelli tires. They say 73 is OK. I believe that ETRTO guidelines only apply to products manufactured by member companies who agree to abide by their recommendations, but I need to recheck that. Regardless, I'm going by what's printed on my tires. Weighing 135, it's not one of my concerns.
https://www.cyclingnews.com/features/changes-to-etrto-do-new-wheel-and-tyre-combination-recommendations-affect-your-safety/
https://www.cyclingnews.com/features/changes-to-etrto-do-new-wheel-and-tyre-combination-recommendations-affect-your-safety/
Last edited by DaveSSS; 03-08-24 at 03:57 PM.
#262
Senior Member
The latest ETRTO guidelines limiting 30-34mm tires to 65 psi is more limiting than what's stamped on my 30 mm Pirelli tires. They say 73 is OK. I believe that ETRTO guidelines only apply to products manufactured by member companies who agree to abide by their recommendations, but I need to recheck that. Regardless, I'm going by what's printed on my tires. Weighing 135, it's not one of my concerns.
https://www.cyclingnews.com/features...t-your-safety/
https://www.cyclingnews.com/features...t-your-safety/
My 30mm Specialized Turbo 2bliss T2/T5 are sidewall stamped as 65psi min - 95psi max. The Mavic chart above says 65.4psi max for this setup.
I run them around 55-60psi on 23mm ID hookless but I bet a bunch of folks are running these higher.
#263
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Not sure that has been established for certain. He could have had a rapid loss of pressure (from an impact, or something else), followed very quickly by tire coming off the rim.
#264
But in this particular crash the insert clearly didn’t work, which suggests that the tyre came off suddenly without warning. Whether that was from a severe impact or a spontaneous tyre blow-off depends on whether you believe the manufacturers or take a more cynical view. An impact seems more likely given the reported rim damage.
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#266
#267
What's with these ass backward poor logic posts saying "my friends and I have been riding hookless for x years and never had a downhill tire blow-off, so hookless is fine"?
The point is not how frequent downhill sudden flats are. Flats are rare and flats that just happen to coincidentally occur during a downhill are even rarer, because most of our riding minutes are not on downhills. The point is, what happens IF it occurs.
Neither you nor anyone you know have ever been in an airplane crash. Plane crashes are extremely rare, far rarer than downhill tire flats. If someone says you have a choice of two airplanes to fly in, a normal plane, or a plane with some safety features reduced because it was cheaper for Boeing to make, the world would rightly call you a moron if you chose the less safe plane on purpose.
.
Either way it doesn't shine a good light on you.
The point is not how frequent downhill sudden flats are. Flats are rare and flats that just happen to coincidentally occur during a downhill are even rarer, because most of our riding minutes are not on downhills. The point is, what happens IF it occurs.
Neither you nor anyone you know have ever been in an airplane crash. Plane crashes are extremely rare, far rarer than downhill tire flats. If someone says you have a choice of two airplanes to fly in, a normal plane, or a plane with some safety features reduced because it was cheaper for Boeing to make, the world would rightly call you a moron if you chose the less safe plane on purpose.
.
- If the two plane tickets are the same cost, then you're a moron.
- If the less safe plane ticket is cheaper and you chose it to save money, then you're tighter than a dolphin's ass, cares more about money than your own safety
Either way it doesn't shine a good light on you.
Last edited by Yan; 03-08-24 at 08:35 PM.
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#268
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#270
Senior Member
This article has the best info I've read. I will continue to use 28mm tires on my BTLOS hookless 25mm IW rims. I've tested setups to 85 psi with no blow offs. I have used early model Michelin tubeless that were not approved for hookless for this reason - they suffer from bead stretch after 6-9 months of use. If deflated to add sealant, the beads dropped off the shelf and couldn't be reinflated with valve core in place. In contrast, Pirelli P-Zero TLR tires remain tight after more than a year of service. I briefly installed an old P-Zero with a tube and had a hard time getting the beads off the shelf when I took it off.
https://www.cyclingnews.com/features...t-your-safety/
For heavy riders who can't fit 32-35mm tires, it's probably best to stick with hooked, so you won't be buying Zipp or Enve wheels. Comparing a 31mm external width BTLOS rim to a hooked version of the same rim, the Zipp pressure calculator recommends about 8 psi higher pressure with the resulting 22mm IW, instead of 25mm. At least the pressure recommendation is well under what's allowed for a hooked installation.
https://www.cyclingnews.com/features...t-your-safety/
For heavy riders who can't fit 32-35mm tires, it's probably best to stick with hooked, so you won't be buying Zipp or Enve wheels. Comparing a 31mm external width BTLOS rim to a hooked version of the same rim, the Zipp pressure calculator recommends about 8 psi higher pressure with the resulting 22mm IW, instead of 25mm. At least the pressure recommendation is well under what's allowed for a hooked installation.
Last edited by DaveSSS; 03-09-24 at 08:11 AM.
#271
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This article has the best info I've read. I will continue to use 28mm tires on my BTLOS hookless 25mm IW rims. I've tested setups to 85 psi with no blow offs. I have used early model Michelin tubeless that were not approved for hookless for this reason - they suffer from bead stretch after 6-9 months of use. If deflated to add sealant, the beads dropped off the shelf and couldn't be reinflated with valve core in place. In contrast, Pirelli P-Zero TLR tires remain tight after more than a year of service. I briefly installed an old P-Zero with a tube and had a hard time getting the beads off the shelf when I took it off.
https://www.cyclingnews.com/features...t-your-safety/
For heavy riders who can't fit 32-35mm tires, it's probably best to stick with hooked, so you won't be buying Zipp or Enve wheels. Comparing a 31mm external width BTLOS rim to a hooked version of the same rim, the Zipp pressure calculator recommends about 8 psi higher pressure with the resulting 22mm IW, instead of 25mm. At least the pressure recommendation is well under what's allowed for a hooked installation.
https://www.cyclingnews.com/features...t-your-safety/
For heavy riders who can't fit 32-35mm tires, it's probably best to stick with hooked, so you won't be buying Zipp or Enve wheels. Comparing a 31mm external width BTLOS rim to a hooked version of the same rim, the Zipp pressure calculator recommends about 8 psi higher pressure with the resulting 22mm IW, instead of 25mm. At least the pressure recommendation is well under what's allowed for a hooked installation.
#272
Junior Member
This seems like a good time to revisit Trakhak's earlier question. BTLOS wheels are available in both hooked and hookless, with the two version weighing the same and costing the same. If the hooked version gives you more flexibility with tire pressure (and therefore usable tire widths), what is the advantage of using the hookless version?
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#274
Junior Member
If they weighed the same and cost the same I'd buy hooked rims, just for that extra bit of reassurance. For lower pressure tubeless applications (MTB and gravel) I really don't think it makes much difference. I'll admit, though, that for road tubeless where the pressure might be within 10-20 psi of the rated maximum I'd be more comfortable with hooks.
#275
Senior Member
I suggest reading the info at the Giant website regarding hookless rims. Apparently, they couldn't care less what ETRTO or ISO have to say. They're confident that their wheels and tires will work at higher pressures.
At some point, users will find that sealants don't work so well at higher pressures. There's an advantage to not needing as much pressure. My 30mm tires allow 87 psi with hooked rims, but punctures might not seal as well.
https://www.giant-bicycles.com/us/hookless-technology
At some point, users will find that sealants don't work so well at higher pressures. There's an advantage to not needing as much pressure. My 30mm tires allow 87 psi with hooked rims, but punctures might not seal as well.
https://www.giant-bicycles.com/us/hookless-technology