Challenge Strada 25 on Mavic Open Pro rims blow off

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roadchallenge
Posts: 151
Joined: Mon Dec 05, 2016 5:13 am

by roadchallenge

Hi,


I tried mounting Challenge Strada 25c (open tubular) tire on Mavic Open Pro ( it is 15c internal ), the front wheel sat okay no problem all throughout, however rear wheel just exploded by sitting in the room at about 100psi, and tire came off and tube has a long tear in it. Tried 2 times and it blew off each time for me, took to a shop, guy mounted and pumped with butyl tube to 100psi and i rode it was fine. Then i wanted to throw a latex in and blew off again during pumping. Concluding that most likely user error left me with some questions and fear to touch any tire with 6-7 bars in it afraid it would explode in my hand.

1. Tire was very easy to mount on Open Pros then i checked Pro 4 and Conti they as well vent on and off very very easy.

2. If it is such a delicate process to mount road open tub and make 100% sure every centimeter of tire bead is correctly engaged with rim while tire is so easy to mount, what prevents it from blowing off the rim during basic riders force or hitting irregularities on the road?

3. Is Challenge Road Open tubs and Open Pros a generally terrible idea?

4. what happens if road tire blows at 100 psi in your hand?

5. 7 - 10 bars on a sidewalls markings, 145 psi max clincher, i thought aluminum and carbon rims start to give at 125 psi, jesus...

Moving on to Bora Ones 35 and Vittoria corsa g+ tubeless 23 will still run with tubes ( supposedly double strength bead of regular open tub) hope this will be so tight it will blow sidewalls of rim first before tire comes off :twisted: .

by Weenie


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duvivr6
Posts: 218
Joined: Mon Apr 21, 2014 2:28 pm
Location: PR

by duvivr6

Seems like the culprit here is your latex tubes, since the setup worked fine with he butyl tubes.

Try mounting the tire that you had in the front on the back see if that makes any difference.

mattr
Posts: 4671
Joined: Fri May 25, 2007 6:43 pm
Location: The Grim North.

by mattr

I've had 4 or 5 sets of assorted Challenge open tubulars, mostly mounted on open pros.
Not blown any off. Mostly have used them until knackered.

Latex tubes can very very easily be installed with the tube pinched by the tyre, this might lift the tyre off the rim. Especially if you've already blown it off (that can stretch/damage the bead.)

1 Open pros generally are very easy to mount, can't recall ever needing levers. Even with steel beads and winter tyres.
2 If they are properly mounted, it's no issue.
3 No.
4. you'll lose a bit of skin and regret touching the tyre!
5. I don't run anything over 100psi these days, more like 85-90. In the olden days, i ran tyres at 150 psi on open pros.......

tubeless tyres have far far stronger beads. You won't blow them off unless they are badly mounted or damaged.

Marin
Posts: 4035
Joined: Wed Jan 22, 2014 11:48 am
Location: Vienna Austria

by Marin

Once mounted and before inflation, check both beads carefully for a pinched tube:

Depress the bead toward the center of the rim well with your fingertips and check that you can see _only_ the rim tape and no tube. I failed to do this once and had a blowoff. I run open tubulars & latex on 4 of 5 wheelsets btw.

mattr
Posts: 4671
Joined: Fri May 25, 2007 6:43 pm
Location: The Grim North.

by mattr

Which can be tricky once the bead is deformed from being blown off!

roadchallenge
Posts: 151
Joined: Mon Dec 05, 2016 5:13 am

by roadchallenge

Thanks for response guys. I agree, should be extra cautious mounting it on on Open Pros, and sure as hell that first blow off stretched tire, front sits fine. I think Open Pros are a somewhat dated design although wheelset is bomb, laced to campy hubs, i defenitely will use a tighter fitting combo from now on just to be safer.

P.s.

Measured beads length with Baby Limus, and stradas bead are larger on both tyres, so yeah gotta be surgical with challenge road tyres, they could just shrink bead a bit and it would cause less issues.

by Weenie


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