Bike Forums - View Single Post - Weinmann LP18 Geometry Causes Flats?

12-17-17 | 08:36 AM

#52

DQRider

Old Boy

Joined: Jan 2016

Posts: 2,127

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From: Minnesota

Bikes: Mostly 1st-generation, top-of-the-line, non-unicrown MTBs/ATBs: All 1984 models: Dawes Ranger, Peugeot Canyon Express, Ross Mt. Whitney (chrome), Schwinn High Sierra, and a 1983 Trek 850.

Quote:

Originally Posted by Ferrouscious

I'm gonna take a shot at this. I have a pair of LP-18's as well. I have used them with 13mm Velox rim tape with cross tyres up to "35c", but with the narrow rim, it ends up closer to 31-32c. I ran those tyres at 3.2ish bars or 50-55ish psi. I usually ride on "25c" aka 23c Paselas at 110 psi, but I weigh 140lbs. I know that is high, but I have rough roads where I live and pinch punctures are a common problem.I have never had any problems with the rims, but the '80s Weinmanns that they replaced had what I assume to be a defect. On the inside sidewall of the rim, the join/weld where the rim was joined to make it round was filed flat, but didn't follow the profile of the rim. The edges were sharp-ish. I think that the combination of this along with the wider than recommended tyres are a possibility. The aforementioned pear shape of the tubes also probably play a role. The wide rim strips may be hiding the bad filing.

Thanks for taking a shot. The inside features of the rim are sharper than on other rims I've used. I'm beginning to accept that I was using tires that were too wide - I'm not going to buy a pair of 25s just to test this theory - I would never ride them. As for the rim strips, I've tried several combinations, as you will see by reading earlier posts, all with this strange result. I mean, who ever heard of "longitudinal snakebite"?

Quote:

Originally Posted by speedevil

I didn't recall seeing this mentioned or asked - how tight are the tires when mounting? Do you always mount tires starting at the same point on the rim? Is is possible that a tight bead is pushing the rim tape over and partially exposing the nipple holes? And when the pressure is removed (by deflation) that the rim tape returns to it's intended position, hiding the cause?

I realize that this isn't what rim tape is supposed to do, but with the lack of another explanation (so far) you have to look at outliers, no?

One of the oddest things about these rims is that the tires go on ridiculously easy. I use only my hands, no tools are necessary. I always start by aligning the lable on the drive side with the valve-stem, and then start inserting the bead directly opposite that. With a bit of talcum and patient persuasion, I get tires to seat in these rims every time without resorting to tools. So I don't think the "tight bead pushing the tape over" scenario applies here.

I'm done messing with these wheels.

In the Spring I am going to sell them with the qualification that they are too narrow for the tires I use. I've got ten bikes rolling right now and haven't had any flats since I hung these wheels up on the wall. Life's too short to obsess over weird phenomena like this. I'll just be sure to buy the right rim width from now on.

Thanks everyone for trying to help!

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