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Freehand circles FTW

Riding in an urban setting, I've lost two tubes in the last week to snakebites, and it's easily the most common way for me to get a flat. I've got Gatorskin treads, which help prevent standard punctures, but don't seem to do much (read: anything) for snakebites. Wheel set is extremely similar to the Mavic Ellipse, i.e., very thin. Other than avoiding potholes/curbs/edges*, is there anything that I can do to cut down on this?

Some more information for those interested:

  • Wheel set is the Mavic Ellipse, whoops - previous owner removed all identifying labels, probably as a theft deterrent. Here's the only tag left on the tire:

Obfuscated Mavic

  • Tubes are 700x23, sometimes I cram a 700x25 in there
  • I inflate "until it feels good," usually ~110/115 psi, tire feels hard and there's no give if I push on it, usually bounces almost as high as the height I drop it from
  • Rider weight ~190lbs

*Yesterday I got bit by a patch of gravel. Seriously.

Also, no chance in hell I'm trading these rims out. They cost more than a month's rent.

Update: Yesterday's ride home

So when I left work yesterday, I pumped my tires up to 145 psi as suggested by @freiheit, and it's embarrassingly obvious that I have not been putting enough air in my tires (as in, "holy crap, this is awesome, why didn't somebody tell me this sooner?"). The ride was a little bouncier, but my acceleration and top speed were significantly increased.

That being said, I still got a flat about mile 7. Good news, it wasn't a snakebite, so that's nice for a change. Got home, put a new tube in and tried pumping to 150 psi, and the tire blew up*, and it failed suspiciously near the first flat. I didn't find anything in the tread (glass/nails/whatever) or any glaring defects/breaches, but the tread is pretty old and worn out at this point, so I ordered a new one. This of course, was before @amcnabb pointed out that those tires are slightly larger than the max recommended tire size for the wheelset.

I'll update this once I get my new tire, but it looks like not enough air + old tire might have been the source of my troubles.

*Especially embarrassing living in Watertown, MA, where my neighbors are pretty suspicious of loud noises right now. I got a few dirty looks.

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Run wider rims, run higher pressure. –  Daniel R Hicks May 1 '13 at 15:47
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What size tires do you have, and to what pressure are you inflating them? And how often do you inflate? –  whatsisname May 1 '13 at 17:04
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Don't cram larger tubes in there. They are more likely to get caught between the bead and the rim. If you have 700/23 use tubes that state 700x18-700x23, or 700x20-700x25, or anything where the tube has 700x23 in the range, don't try to use 700x25-700x28 tubes. –  Kibbee May 1 '13 at 18:11
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According to Sheldon, on 13 rims you should be running a tire width between 18 and 25. In my opinion, with that narrow of a rim, you should be running a tire pressure of about 150. And if you just inflate until it "feels right", you'll probably end up below 100. –  Daniel R Hicks May 1 '13 at 22:38
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5 Answers 5

up vote 10 down vote accepted

Inflate your tires to a higher pressure. Use a pump with a pressure gauge instead of going by "feel". Check the pressure more often. The max pressure listed on the sidewall is a good starting point, but if you're already inflating to max psi, you may want to exceed it a bit.

It's likely you have a slow leak, and you're at a low inflation pressure by the time you get the snakebite. Check the tires and rims very thoroughly for sharp bits, and use water submersion to check the tube for leaks, including the valve. A fresh tube wouldn't hurt.

If your roadside inflation is with CO2 cartridges, be aware that CO2 leaks out faster, so you'll need to top off with air the next few days.

You may want to seriously consider buying a second wheelset with wider rims for urban riding with wider tires, and keep the narrow rims and tires for races and weekend rides.

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If he's already inflating to max psi, I'd guess that there's a slow leak and he's running low by the time he's half done with his ride. –  jimirings May 1 '13 at 14:42
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check your tire pressure before EVERY RIDE! I keep a pump by the door and top it off before I head out. If you're commuting, then at least once a day. –  Benzo May 1 '13 at 14:43
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Average weight riders shouldn't need as much as the max psi on the sidewall. –  James Bradbury May 1 '13 at 16:24
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Also check the rim tape. –  James Bradbury May 1 '13 at 16:25
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When I went from 25-35 psi to 100 psi tires, my pinch-flats went away (BMX tires, so not the same requirements/capabilities as MTB/road). The problem was that I was still using nylon mags so they kept blowing the bead. Make sure your tire AND rims match and can BOTH handle the PSI you are using. –  BillyNair May 5 '13 at 5:56
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The problem may be that your tires (700x23) are too wide for such narrow rims. According to the manufacturer, on the "Features" tab for the Mavic Ellipse:

Recommended tyre sizes: 18 to 22 mm

You may find better success with narrower tires (or alternatively, wider rims), and as suggested by Daniel R Hicks, "the narrowest tube you can find that claims to fit your tire."

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Really wish I had noticed that a long time ago. :/ Thanks for pointing that out. –  mikeTheLiar May 2 '13 at 13:02
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A tire that's too big for the rim would have lateral stability (flopping to the side) issues, and maybe strain the bead seat too much. It wouldn't cause snakebite flats. 1mm above the recommended size is unlikely to cause anything anybody could notice. –  freiheit May 2 '13 at 13:15
    
@freiheit That's what I figured, I wasn't really worried about it but it's those little details that bug ya. –  mikeTheLiar May 2 '13 at 13:38
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Already suggested is trying narrower tires. Another theory I put forward is moving up to 25mm (According to Sheldon Brown Ok on this rims) would help - more volume means more load capability (for the same pressure). I am not a roadie, but MTBer's go to bigger tires so they can run lower pressures without snakebites. Surely the same mechnaics is at play here - bigger tyre same pressure = less snakebites.

Another thing to try is cheap tubes. Sounds dumb till you consider they are made thick and heavy = more pinch resistance - it does defeat the purpose of running "1 month salary" rims tough.

Edit:.... Talcum powerder - I always rub a little on my tubes before installing - it lubricates the inetrface bettween the tire and tube.

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With wider rims, I think this would be a fantastic idea. –  amcnabb May 2 '13 at 4:13
    
@amcnabb This has been suggested before, which is why I sometimes had 25's around, but I'm getting conflicting reports now. Anything out there that can definitively settle the issue for my wheels? –  mikeTheLiar May 2 '13 at 13:03
    
@mikeTheLiar I really think you need wider rims, and then you can move to narrower tires. In the meantime, all you can do is increase the air pressure as has been suggested in other answers. –  amcnabb May 2 '13 at 15:43
    
Basicly the physics of tires are such that more volume (for the ame pressure) means more load carring capacity. You get pinch flats because you ran out of load capacity, ergo, bigger tire, fewer pinch flats. Our MTB brethern worked this out a LONG time ago. –  mattnz May 2 '13 at 21:22
    
.. a wider tire is more likely to pinch if it runs out of capacity - but is less likely to run out of capacity....... –  mattnz May 2 '13 at 21:28
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My experience tells me that if you are a commuter then you should consider wider rims/tires. That said, I found Bontrager Hard Case were effective against pinch flats when I was using my road bike to commute: 23c rear, & 25c front. (Don't say it.) I used to be plagued by other types of flats on my road bike, but only in the rear. I got so desperate I tried Airless tires, which btw suck - don't bother. Also tried Slime tubes which were reasonably effective. In part to test my wider-is-better-for-commuting theory I recently bought a crossover that uses (hang on while I go look) Nimbus Flakjacket 28c tires front & rear which I mounted with liners & inflate to 120psi, 5psi under the recommended limit. Had it for oh at least 3 months. I commute every day; take longer rides on the weekends, no flats yet! My commute starts suburban & goes to urban so I've had some teeth-jarring pothole bangs.

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I never have "snake bites" in my road or ATB tubes and I've been riding for over 40 years. When you install a new tube, make sure the rim strip is centered. Coat the new tube and the inside of the tire with baby powder (talc, not cornstarch). Inflate the tube to about 30 psi. Deflate. (This removes any pinches.) Inflate to the max and ride.

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