Velocity Cliffhanger rim bead cutting tire
07-06-21, 10:10 AM
#1
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Velocity Cliffhanger rim bead cutting tire
Anyone have this problem? 2 Marathon Plus tires ruined by the rim bead cutting the chafer strip of the tire. Velocity suggests minimal tire width for this rim be 1.75. The bike,a Periscope,takes 26x1.50 in the back because of the chainstay clearance.
07-06-21, 10:55 AM
#2
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Hmmm...
Here are a couple of threads... I'm posting double links until things settle down.
https://www.bikeforums.net/cyclocros...-rims-1109069/
https://www.bikeforums.net/cyclocros...wide-rims.html
https://www.bikeforums.net/cyclocros...e-rim-1107567/
https://www.bikeforums.net/cyclocros...-wide-rim.html
I can't say from personal experience, but the articles above recommend an "Omega Shape" Ω for the tire.
Tires are very dynamic. So, they not only flex on bumps, but also flex on every revolution. Especially on a Tandem with heavier weights. As the tires flex, it puts the flex in a pliable part of the sidewall.
Too wide of a rim would create a straighter sidewall. So rather than Ω, one gets: ∩. This would give you a wider contact patch which might be good when riding straight, but it could impact cornering. And it will change how the sidewall flexes.
As far as what to do...
What pressure are you running your tires? A Tandem may change may tire dynamics. But, apparently hookless rims are common at low pressures. A "tubeless" profile and tight fitting tires should help with retention.
Assuming you consider a non-functional rim trash, I would probably sand or grind the hook into more of a bump shape, being careful to bevel or round the upper transition. Of course the hook may help with rim strength and stability.
Here are a couple of threads... I'm posting double links until things settle down.
https://www.bikeforums.net/cyclocros...-rims-1109069/
https://www.bikeforums.net/cyclocros...wide-rims.html
https://www.bikeforums.net/cyclocros...e-rim-1107567/
https://www.bikeforums.net/cyclocros...-wide-rim.html
I can't say from personal experience, but the articles above recommend an "Omega Shape" Ω for the tire.
Tires are very dynamic. So, they not only flex on bumps, but also flex on every revolution. Especially on a Tandem with heavier weights. As the tires flex, it puts the flex in a pliable part of the sidewall.
Too wide of a rim would create a straighter sidewall. So rather than Ω, one gets: ∩. This would give you a wider contact patch which might be good when riding straight, but it could impact cornering. And it will change how the sidewall flexes.
As far as what to do...
What pressure are you running your tires? A Tandem may change may tire dynamics. But, apparently hookless rims are common at low pressures. A "tubeless" profile and tight fitting tires should help with retention.
Assuming you consider a non-functional rim trash, I would probably sand or grind the hook into more of a bump shape, being careful to bevel or round the upper transition. Of course the hook may help with rim strength and stability.
Last edited by CliffordK; 07-06-21 at 11:02 AM.
07-06-21, 11:01 AM
#3
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I put what the tire recommends in,in this case 90psi. I thought about the sanding idea but I doubt I could achieve uniformity all around the rim,there's not much metal to work with.
07-06-21, 11:31 AM
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From the Velocity website:
Other reports here of similar issues with other tires I believe have been traced to too low inflation pressures. I think 75 lbs. should work well. What's the maximum inflation pressure shown on the sidewall?
OPTIMAL TIRE WIDTH:45mm - 65mm
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