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Old March 1st 19, 05:06 PM posted to rec.bicycles.tech
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Default Tubeless Carbon Rims Again

Bought a set of tubeless carbon rims again. I think that because the last group had so many bad reports that they worked on the construction. It was pretty plain that they had several layers of Pre-Preg and that they either hadn't put the correct resin between the layers or they hadn't allowed it sufficient time to harden under the heat lamps.

The new ones are REALLY cheap but I wouldn't expect them to stay that way for long. With the demand when the Clinchers first came out they went from cheap to almost double the price pretty rapidly. And I haven't seen any reports of the cinchers failing.

With the new Continental GP5000TL tires they went right together with only a little mounting problems. I found that letting them sit with only a couple of inches of the last mount still not in place allowed the tires to loosen up a little do that I could mount them without prying but only pushing the tire on by sliding the lever along the rim like you do when you pull a tire off.

They pump up with a regular floor pump and none of the "tubeless" pumps that are being advertised.

They immediately inflated to 80 lbs and I left them overnight. The front tire remained at or near full inflation. The rear had leaked down to perhaps 40 psi. I suspect this is because I didn't do a perfect job or mounting the rim tape which is an airproof stuff. The rear was my first try with what looked like a too-wide tape but in retrospect is probably correct.

I put the sealant into it and re-inflated the tires. Today they are both still at full pressure. And I used the Finish Line sealant which is supposed to be good for the life of the tire. This stuff has glitter or something in it to plug larger holes. But it dries pretty rapidly in open air and you can clean spills up with a broom or simply rubbing on a rim. I have a 12-29 on the cassette with a compact crank so on the Colnago I could climb the side of Mt. Vesuvius straight up. The weights are pretty light and these new rims are 10 mm even deeper than the Clincher which was 50 mm.

I dropped the o-ring of the filler valve for one of them and no amount of crawling around on the floor found it. So I went down to Ace Hardware and it turns out that they are a normal 1/4 inch over-the-counter o-ring. After getting it and installing it and putting the wheel together sure enough there was that o-ring out in plain sight.

We are supposed to have a dry day this morning so I'll try to get out on the Basso. I want to try out my new GoPro camera and see if I can get it to work. The old mount broke with I tried to fit it to the Colnago. But they are over-the-counter so I can a mount especially for the Colnago and another for the Basso so that I only have to pull one Allen head and switch mounts.

Once we get to descent weather again I'll do some very careful rides on the new tubeless wheels on the Colnago. I'm still not very confident in those wheels and now I can document any failures as they occur. But at the price of those wheels I couldn't get a pair of cheap wheels elsewhere.

Although the Basalt brake shoes on regular rim brakes doesn't seem to wear the rims noticeably I have gone through a couple of sets of shoes in the 2,000 or so miles I put in on them. This makes me think that if I have to replace shoes all the time that I would be just as well off replacing disk brake pads which wouldn't wear the rims at all. But then I would have to have a bike designed specifically for disks and the much larger axles and the much heavier forks and rear triangle seems to make them less attractive. So if you're buying a super-light you might want to get one set up for disk brakes. Otherwise you just have to make do with Basalt brake shoes. By the way - remember that carbon rims are worn mostly from heat degradation of the material so do not wait until the last second to jam the brakes on. I've very fast in descending turns and I have never found it necessary to brake at the last second and no one can keep up with me on the descents. Of course I'm barely able to hand on, on the flats. And everyone disappears up the climbs.

I wouldn't ride with Jay and then have to put up with all of his heckling here because I could stay with him on the climbs.
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