Compass Cayuse Pass real width on wide rims
Moderator: robbosmans
All this "narrower than the rim, 105% stuff" is only relevant in crosswinds or when riding sideways
Going fast in low wind only frontal area counts
Going fast in low wind only frontal area counts
Last edited by Marin on Mon Jul 09, 2018 6:35 am, edited 1 time in total.
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The tires work fine, but I'm not sure I can provide any feedback beyond that, I only did a handful of rides in dry weather after all. No noticeable feel change compared to tubeless Pro One at the same 75/80 psi pressure. Do note that 25mm Pro One measure 2mm wider. To mount Compass, I had to use a lever, but that should be partly due to tubeless rim bed profile.
Those are Extralites, you can check out scale and bike shots in my thread.
I looked through this thread and the FM079 thread for the tyre scale weight images but cannot find them. Can you please link to the post, or provide us the measured weights by reply?
Sorry for inconvenience, here are scale shots.
^That's a good weight, but why get them when Veloflex master 25's are 5 grams heavier at most and 2 1/2 times cheaper?
I have a couple of thousand km on BJP Extralites, setup tubeless on LightBicycle RRU25C02 rims (disc brake bike). I run them at ~35psi front and ~50psi rear - no problems so far. Whenever I'm setting tubeless tyres up, I always inflate them with a tube first and leave them at least overnight, and if possible longer, before dismounting the tyre and doing the tubeless setup.
p.s. Jan Heine, the man behind Compass, has an article on road tubeless here: https://janheine.wordpress.com/2017/05/ ... -tubeless/.
I've been running my BJPs tubeless without problem for quite a while now. I replaced the one I had the blowoff with because it would never fully seat - manufacturing defect maybe.
New here on the forum, running a pair of Compas (now René Herse) Barlow Pass extralight tyres mounted tubeless on 21 mm internal width carbon rims. I have about 2 k km on them.
A couple of posts that I read in this thread alarmed me:
You should under no circumstances run ANY of their tyres tubeless on a hookless rim or a rim where the G-height (distance between the interior shelf and the top of the hook) is less than 5.2 mm.
They posted (belatedly, I presume after some incidents) this info here: https://janheine.wordpress.com/2019/04/ ... rse-tires/
I started researching this after mounting my Barlow pass per the usual way (blast of compressor air to seat the bead, followed by deflation to inject sealant and then inflation to 4 bar, followed by a shake and let sit period of 12 hours). 10 minutes later, while standing quietly in a corner, the tyre (which was well-seated, I checked) blew off the rim with a deafening bang. Sealant hit the ceiling and the proverbial s***t the fan when my wife realized what had happened.
Since then I learned a couple of things:
1) No 21 mm internal width rim is designed to hold a 38 mm tyre at 4 bar. You risk splitting the rim. Even though the tyre says it withstands 6, you should never, ever go there. I ride'm at 2-2.5 bar and that's plenty.
2) I'm taking a wild guess here but I don't think any of those tyres were ever designed for tubeless use. It works with the wider ones but ONLY because those can be run at really low pressures. Compass should have been more forthcoming about this imho.
That said, after the mounting disaster I inspected rim and tyre, then remounted after everything looked ok. Haven't had any issue since and don't expect trouble, provided I never go higher than about 2.7-3 bar. Any higher looks like tempting fate to me.
The tyres behave beautifully, btw, very grippy, comfortable, nothing but praise. But I won't descend a col at 70 km/h on them, that's too rich for my blood.
A couple of posts that I read in this thread alarmed me:
You should under no circumstances run ANY of their tyres tubeless on a hookless rim or a rim where the G-height (distance between the interior shelf and the top of the hook) is less than 5.2 mm.
They posted (belatedly, I presume after some incidents) this info here: https://janheine.wordpress.com/2019/04/ ... rse-tires/
I started researching this after mounting my Barlow pass per the usual way (blast of compressor air to seat the bead, followed by deflation to inject sealant and then inflation to 4 bar, followed by a shake and let sit period of 12 hours). 10 minutes later, while standing quietly in a corner, the tyre (which was well-seated, I checked) blew off the rim with a deafening bang. Sealant hit the ceiling and the proverbial s***t the fan when my wife realized what had happened.
Since then I learned a couple of things:
1) No 21 mm internal width rim is designed to hold a 38 mm tyre at 4 bar. You risk splitting the rim. Even though the tyre says it withstands 6, you should never, ever go there. I ride'm at 2-2.5 bar and that's plenty.
2) I'm taking a wild guess here but I don't think any of those tyres were ever designed for tubeless use. It works with the wider ones but ONLY because those can be run at really low pressures. Compass should have been more forthcoming about this imho.
That said, after the mounting disaster I inspected rim and tyre, then remounted after everything looked ok. Haven't had any issue since and don't expect trouble, provided I never go higher than about 2.7-3 bar. Any higher looks like tempting fate to me.
The tyres behave beautifully, btw, very grippy, comfortable, nothing but praise. But I won't descend a col at 70 km/h on them, that's too rich for my blood.
Had this happen to me earlier this year, but with an MTB Lightskin tire while performing the tubeless dance. I'm glad none of the sealant got into eyes, but the rest was a real mess, just like you said. The rim delaminated a bit, similar to what you can do removing rim tape with a really strong adhesive.