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Post by brianbutler on Nov 30, 2022 16:06:37 GMT
I'm working on a 1976 Raleigh Competition that came with tubular rims and tires. The tires were worn out and I decided to convert them to clinchers (Weinmann LP18 rims and Panaracer Pasela 27x1 blackwalls.) I carefully measured the ERD of the tubular rims and it was the same as the stated (and measured) ERD of the new clincher rims. I reused the 15 gauge Champion spokes since they are in perfect condition, but I ran into a problem after lacing the new rims to the old hubs and didn't notice it until I had finished tensioning, dishing, and truing the rear wheel.
The new rims are double wall and the problem is that the spoke ends extend beyond the seating surface, where they will puncture the tube. Only the 9 spokes on the drive side and inside of the hub are are grossly extended. The other nine on the drive side are "almost" too long. I rechecked the ERD measurements and then noticed the problem. The original spokes are actually too long for the ERD but they got away with it because the distance between the inner and outer walls on the tubulars is much larger than on the clinchers and the spoke ends do not extend beyond the outside wall, although they do extend about 3mm beyond the tops of the spoke nipples.
My mistake was assuming identical ERD's would ensure proper fit, so I did not actually do the usual spoke length calculations. Lesson learned, and 18 replacement spokes 3mm shorter for the drive side ordered. As usual, don't take shortcuts.
Brian
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Post by wheelson on Nov 30, 2022 19:46:33 GMT
Somehow mistakes seem to be the best teachers. It seems I’m still being taught after 50+ years of wheel building. I recently made the mistake of not checking drive/non-drive spoke lengths when reusing spokes. Not good when mixing spokes of 2mm difference. So it goes. Interesting thing about the bike world, things are sometimes frustrating but never boring.
Best,
John “wheelson”
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Post by cusqueno on Dec 1, 2022 10:36:14 GMT
File or Dremel?
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Post by brianbutler on Dec 1, 2022 12:27:50 GMT
Good thought and I tried but the outside hole is very small, only 7mm so not enough room for a file. I also tried a couple of Dremel tools without much luck and considerable risk to the rim. Finally, I removed a spoke, clipped off a couple mm, and tried it but the shortened thread stripped when I tried to bring it up to tension. At that point I needed to buy another spoke anyway and saw packages of 18 NOS Champion 15 gauge spokes in the right length for $19.98 so it seemed like a reasonable path.
By the way, maybe I need some lessons, but I find the Dremel tool the most frustrating device in the shop. I'm not sure I have ever used it successfully. It never seems up to the task and I almost always break the bit, wheel, drum, or whatever tool I am trying to use. Either that or damage the workpiece. I should ask triitout for some dentistry tips 
Brian
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Post by 54roadie on Dec 10, 2022 7:03:47 GMT
I'm working on a 1976 Raleigh Competition that came with tubular rims and tires. The tires were worn out and I decided to convert them to clinchers (Weinmann LP18 rims and Panaracer Pasela 27x1 blackwalls.) I carefully measured the ERD of the tubular rims and it was the same as the stated (and measured) ERD of the new clincher rims. I reused the 15 gauge Champion spokes since they are in perfect condition, but I ran into a problem after lacing the new rims to the old hubs and didn't notice it until I had finished tensioning, dishing, and truing the rear wheel.
The new rims are double wall and the problem is that the spoke ends extend beyond the seating surface, where they will puncture the tube. Only the 9 spokes on the drive side and inside of the hub are are grossly extended. The other nine on the drive side are "almost" too long. I rechecked the ERD measurements and then noticed the problem. The original spokes are actually too long for the ERD but they got away with it because the distance between the inner and outer walls on the tubulars is much larger than on the clinchers and the spoke ends do not extend beyond the outside wall, although they do extend about 3mm beyond the tops of the spoke nipples.
My mistake was assuming identical ERD's would ensure proper fit, so I did not actually do the usual spoke length calculations. Lesson learned, and 18 replacement spokes 3mm shorter for the drive side ordered. As usual, don't take shortcuts.
Brian
Why change at all? I tried tubulars again, a few years ago, and instantly knew how much better the ride is compared to the clinchers I replaced. They are not brand new Clement silks, by any means, but so much better than clinchers. I'm slowly switching most of my bikes over to tubulars.
I'm no longer worried about flats. I run Tufo tubulars, which have air-tight casings without inner tubes. They take sealant that works exactly as it does for tubeless tires. One tire has had three small punctures. Two of them let out just a few psi. One was worse, I was down to about 45 psi, but still got home without denting the rim in any way. I put in another dose of sealant, pumped the tire to 125 psi, spun it for a while, and the sealant did it's job. The tire holds air, the bike rides like a dream.
I use Finish Line, it's guaranteed not to dry out before the tire is worn out. I also use Tufo tape to mount the tires. That's a piece of cake.
Now I just need to find some decent tubular rims that are 25mm wide...
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Post by brianbutler on Dec 10, 2022 13:01:11 GMT
Very good information and no doubt tubular tires have advantages for performance cycling. For most of my routes and riding style I think clinchers are better. Probably 25% of the surfaces I ride are unpaved and many of the paved surfaces are rough because I look for routes on back roads (way back in many cases.) Some of my riding is lightly loaded touring/camping. My speeds are slow, averaging 14-15 mph. I am guessing, and have been told, that it is easier to fix a flat or change out a tire during a ride with clinchers than with tubulars, although your description sounds otherwise. I have standardized on Panaracer Pasela tires, either 27x1 or 27x1-1/8, which generally last over 3000 miles with several flats along the way, always fixable with patches and cement. I have switched a couple of bikes (1976 Raleigh Competition and Sekine SHT) from tubulars to clinchers because I was afraid that if I set them up with tubulars I would never ride them.
Based on your advice, I will give it a second thought and maybe set up a pair of wheels with tubulars to try them out. I have some nice vintage hubs and rims and winter approaching so it's time for some more projects.
Brian
Brian
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Post by brianbutler on Dec 11, 2022 0:59:18 GMT
54roadie, which Tufo's are you running? I looked them up and there is quite a variety. They all get rave reviews so I am intrigued.
Brian
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Post by 54roadie on Dec 23, 2022 4:54:02 GMT
Hi Brian, I use S33 Pro and Hi Composite Carbon. The one still holding air after three (admittedly small) punctures is an S33. Good Luck and Happy Holidays.
Frank
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