#151
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meh, to each their own.. I like his take on most things.. he's not trying to be anything other than who he is as a cyclist/human.. so much different than many in the niche..
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#152
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In this article https://www.cyclingweekly.com/news/u...ter-of-urgency it was quoted:
Hansen said: “This crash is why the CPA are 100 percent against hookless rims. Tires should not come off a rim. The maximum PSI these hookless tires can have put in them is 73, and if you hit something for sure it goes above the maximum 73 PSI rating on impact. That is why the tires are coming off.” Is this really true? If you have a car up on a lift and inflate a tire to 35 psi and lower the car so the full weight of car is on the tires, the pressure is still 35 psi. That's because when weight is put on the tire, the casing stretches and the volume remains the same thus the pressure within remains the same. This is pretty much a static case, but in a dynamic situation like hitting a rock or pothole, does the pressure really rise like what is quoted above? |
#153
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The way I see it is if there’s a cost saving and it’s safe, especially with mountain bike prices where they are, then it’s worth doing. Every vertical is different but it’s not uncommon to hear a $1 cost saving at manufacturer level has a $5-20 impact on cost. The longer the supply chain, the more pronounced. Point being is that saving $20* at the point of manufacture on a rim could have an $800 saving for consumer on a wheelset. (To be ultra clear, if this gets read out of context from my previous comments, this view is strictly for off road application.) *I don’t know the actual saving, just noting that someone else on this thread pointed out it was $20 manufacturing saving to go hookless. |
#154
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It is hard to know if he is being quoted out of context and he is a undeniably an extremely smart guy but I’ve noticed he has a tendency to take two principles and then say “logically 1+1=2”, when things often don’t work that way and are much more complex. That gets combined with his fondness for over complicated verbiage and you get left with stuff that’s a bit nonsensical. Last edited by jimoots; 03-01-2024 at 03:36 PM. |
#155
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#156
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#157
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Well, you do have the case of Sagan's exploding rim...caused Roval/Specialized to pause tubeless for a full year.
And given how firm these tires are to remain on a hookless tubeless setup, I'm not so sure you couldn't see a instantaneous peak pressure spike. Interesting point made on Geek Warning - the "margin of safety" of these systems is to a fair extent less than the margin of error of most consumer level pressure gauges etc. If there's no benefit to me and some risk, I'll pass. |
#158
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I still say a huge point is we don't know what pressure these tires had in them.. were they following the hookless guidelines? Has there been a verified case of a tire blowing off (not just burping) that were being used as the manufacturer intended i.e. within acceptable pressure ranges?
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Be the Reason Others Succeed |
#159
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#160
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Edit: I'm going to have to verify this because I use similar width tires and I doubt I weigh less and only use 67 psi max. according to the Silca Calculator. Last edited by MikeD; 03-01-2024 at 05:07 PM. |
#161
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#162
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Burping demonstrates that the tire casing/bead have been yanked with a force of an inopportune direction and/or force. And as you say, the rush of air could create other undesired dynamics. A tire may reseat after a burp, but if there was an insufficient factor of safety (like only 10% below the blow-off pressure, as per the hookless pressure specs.), it may come off entirely instead of reseat.
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#163
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Most tire brands approve of 28mm tires on 25mm IW rims, like the ones in question. I've been running 28 on 25mm IW rims for a couple of years. A lot of them were early model Michelins that weren't even hookless approved. The beads on one of my last Michelin tires stretched so much that the beads fell off the ledge if the air was let out to add some sealant. None ever came loose while riding. I tested new setups at 85 psi.
I run nothing but Pirelli P-Zero TLR now. |
#164
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Your choices are your choices, best of luck. |
#165
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And max pressure according to this chart:
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