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Technical FAQ: Wiping tires and rubber for big guys

  • By Lennard Zinn
  • Published Apr. 10, 2012
  • Updated Apr. 17, 2012 at 11:24 AM EDT

Zinn’s regular column is devoted to addressing readers’ technical questions about bikes, their care and feeding and how we as riders can use them as comfortably and efficiently as possible. Readers can send brief technical questions directly to Zinn.

Dear Lennard,
I reach around and wipe my front and rear tire to get imbedded objects out while riding, but is this worth the risk to limb, if not life?  If you roll over a glass shard will it not either cut immediately, or on the next one or two revolutions?  Obviously I only clean the tires occasionally, so it would be an incredible coincidence if I got it out just in time. People also used to sell “tire clearers” for bike tires. Is this age-old practice worth it?
— Fabio

Dear Fabio,
Funny you should ask that.

I am one who habitually wipes off my tires (road bike only; no sense doing this with knobbies!) whenever I ride through glass or come back onto pavement after riding on gravel. I think I would not have taken seriously the “risk to limb, if not life” part but for a recent painful experience with this.

I have done this tire wiping for so many decades that it’s become a practically automatic maneuver onto which I place little attention. Therein lies the problem. I always used to wipe my tires with my fingertips, but I’ve had my fingers sliced enough times by glass or metal shards stuck in my tire (which I was glad to have gotten out of my tire, by the way) that I tend to instead wipe the tires with my gloved palm. I’m right-handed, and I usually wipe the tires in an unconscious way with that hand. But on March 21, on my way to the first day of a seatpost flex test at Microbac Laboratories, I had something in my right hand when I rode through some glass, so I wiped first my front tire and then my rear tire with the palm of my left glove. No problem on the front, but big problem on the rear.

As you of course know, you need to wipe the rear tire in between the seatstays and the seat tube. Well, with a heavy backpack full of lightweight seatposts on my back perhaps pushing me down lower and using my left hand while placing very little attention on it, I put my hand on the tire behind my seatstays! You can maybe guess what’s coming. The tire pulled my hand forward, and as my hand turned, my thumb went under the brake bridge.

So there I was, riding along with my right hand on the top of the handlebar, not on the brake lever, and my left thumb caught between the top of the tire and the underside of my brake. The smell of burnt flesh was strong as my bike slowed down far too gradually from the friction of my thumb. It seemed to take an eternity for me to drop what was in my right hand, move it to the lever, and apply the brake.

The tire burned through many layers of skin. The photo shows what it looks like now, after 2.5 weeks of healing, and it is now level with the top surface of the thumb as well as has grown in from the edges. But at the time, it was a giant, oval crater in my thumb. The other two photos show the two sides of the burnt piece of flesh that was peeled off and burnt to a little crisp by the tire. Also, the pressure of the brake bridge down on the nail side of my thumb caused blood to spurt out all along the base of the nail, so I may lose the nail as well.

Many years ago, I also once let my hand slip forward between the tire and the seat tube when wiping the tire with the palm of my hand (again with the left for some reason!). That was also quite uncomfortable. I know other riders who’ve had that same experience, sometimes causing crashes.

So, “risk to limb, if not life” is not far-fetched if you’re not paying attention. I still wipe my tires, though. But for now, I’m back to wiping them with my fingertips and only with my right hand!

And in answer to your question, I do feel that I’ve avoided flats many times by doing it, but I tend to wipe them as soon as I go through something, so I hopefully catch it on the first revolution on at least one of the tires. A sharp object may cause a flat by getting into the tread and slowly working its way in. If you get it off quickly enough, it will not work its way through to the inner tube. I remember one time where I rode over a sharp, bent piece of metal an inch long or so. I felt my bike hit it and wiped the tire, lacerating my fingers. However, I stopped immediately and pulled it out, and it had not yet gone through the tire, so I rode on, albeit with blood on my white handlebar tape. Many other times, I felt big, sharp things come off of the tires under my hand that certainly would have otherwise caused a puncture.

In the 1970s and early 1980s, I and countless other riders used the Pneudan Tire Saver or the Bicycle Research Tire Saver atop our tires. If you scroll through the Flickr photos from Speedplay’s museum, you’ll see a number of other designs as well. The tire saver mounted to the brake bolt, and you would bend the thing to only very lightly touch the tire and knock off any pieces of glass or metal sticking up from it.

I think these tire savers went out of favor as 700C clinchers became decent enough that riders were willing to switch to them from tubulars for training. It was expensive and a pain to get flats on tubulars on training rides. However, once clincher rims became good enough that the wheels didn’t fall apart rapidly and clincher tires were reasonably light and fast-rolling, the cost in time and money of replacing or patching an inner tube became trivial, so nobody cared to have the whining noise and friction of tire savers on the tires any more. That doesn’t mean people stopped wiping their tires off, though!

So the takeaway is, yes, wiping off the tires saves time and money on flat tires, in my opinion. Just do it carefully!
― Lennard

Dear Lennard,
I have a Specialized Secteur Elite; the bike weight is about 23 pounds. I am a big guy: 315 pounds, and I am running Easton EC90 aero clinchers. My tires are 700x23C Specialized Armadillo all condition tires. I am feeling I have the wrong tire set up for the bike and weight. Could you give me a little insight on what tires I should be running and what air pressure. I need your help. I do ride 100-mile rides.
— Chris

Dear Chris,
I usually don’t answer the myriad questions I get about specific tire and tire pressure for a certain rider, wheel, and event, because (a) there is no hard data on this; (b) everybody rides differently; and (c) there is no way to come up with the correct pressure for yourself without experimenting (for instance, using the roll-down method I described here).

That said, yours is a special case due to your weight. And since most of the custom bikes I build are for really big guys, many of them your weight or heavier, I have a lot of experience here. If you can fit 28mm tires under your brakes, do that, and run them up near their maximum rating. While the Armadillos are not fast-rolling tires, that kind of casing durability is probably a good idea for you.

With your weight, you need the volume, but you also need the pressure to not only keep from pinch flatting but also to produce a tire contact patch that does not compress the tire too deeply. If you can’t fit 28mm, try 27mm, etc.
― Lennard

Feedback on last column:
Dear Lennard,
Your guy who wrote about his bunged up first thread in his hanger could have threaded his derailleur in from the back side to try to clean up that first thread enough to get it started cleanly, if the bolt was steel.  And make sure that if he chases the threads of the hanger with a tap, he does it from the backside where the threads are good.
— Mike

Dear Mike,
Good points! I’ve actually done that before — put the derailleur in from the back side when I couldn’t get it in due to damaged threads, and it fixed it well enough to screw in the derailleur in a hotel room somewhere so that I could go ride.
― Lennard

Dear Lennard,
FYI, Wheels Mfg. does still make their Dropout Saver kit.
— Katie

FILED UNDER: Bikes and Tech / Technical FAQ TAGS: / / / /

Lennard Zinn

Lennard Zinn

Our longtime technical writer joined VeloNews in 1987. He is also a framebuilder, a former U.S. National Team rider, and author of many bicycle books, including Zinn and the Art of Mountain Bike Maintenance and Zinn and the Art of Road Bike Maintenance, as well as Zinn and the Art of Triathlon Bikes and Zinn's Cycling Primer: Maintenance Tips and Skill Building for Cyclists. He holds a Bachelor’s degree in physics from Colorado College. Readers can send brief technical questions to Ask LZ.

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