[fish9999]

Hi. I ride a Trek 4 series with Bontrager 26x2 tires and Slime inner tubes (I like them because they lose air slowly and I can make it home). I ride on town streets which have lots of cracks in the asphalt. I'm getting 2 flats a week lately. The guys at the bike shop say that because of my weight (about 200 pounds) when I hit a crack it "pinches" the tire and that causes the flat. Is this true? I used to live in Manhattan where the asphalt was in no better condition and i didn't get this many flats. Are there tires with greater puncture-resistance? I am willing to try anything. Thanks, Stu

[LarryM]

Originally Posted by fish9999

... The guys at the bike shop say that because of my weight (about 200 pounds) when I hit a crack it "pinches" the tire and that causes the flat. Is this true?
Thanks, Stu

It certainly could be. You might consider pumping your tires up to a higher pressure, but do not exceed the manufacturers recommendation listed on the side of the tire.

From another thread, here are four sites that talk about inflation pressure as a function of tire width and total weight.

You need at least enough pressure to keep from getting pinch flats when you hit a hole, but not so much pressure as to blow the tire off of the rim, or experience an extremely rough ride.

From tire manufacturers
http://www.schwalbetires.com/tech_info/inflation_pressure
http://www.michelinbicycletire.com/michelinbicycle/index.cfm?event=airpressure.view

Other opinions:
http://www.sheldonbrown.com/tires.html#pressure
http://www.bikequarterly.com/images/TireDrop.pdf

[tomk]

Proper inflation on the tires will probably help if it is a pinch flat you are experiencing - so check out the links provided by LarryM. You could definitely check out some different tires. You might look at the Continental Gator Skins:
Continental Ultra Gatorskin Bike Tire - 26 x 1-1/8 at REI.com

Both my LBS and REI steered me away from the Slime tubes and products and suggested I go with a tougher tire. I ended up with the Specialized Armadillo Elite but that is on my road bike.

[photosbymark]

I'm not sure its a pinch flat. What valve stem type are on your tubes? With a slime to I am guessing its most likely a Schrader valve (the ones like a car tire) and one of the first things I would do is mix some soap in a small amount of water. Fill the tire with air to the proper pressure, then put some of that soapy water on the valve, especially over the top and look for bubbles. A valve stem is a common source of a slow leak and it can be removed and replaced with a proper tool.

If you are having that many flats, there is a leak somewhere. The next step Id take is to take the tire off and put some water in the bath tub. Put some air in the tube and hold the tube underwater. If its leaking, and it has to be if you are having flats, the leak will create bubbles underwater. It may just be easier to replace the tube.

While the tire and tube are off the wheel. There should be some tape called rim tape to cover the spoke holes. Once in a while a spoke will go through the rim tape and cause flats. Feel for things sharp on the wheel, then move to the tire.

Weight has nothing to do with it. I have a good 50 lbs on you and ride roads that would make a logging road seem smooth at times. I rarely have flats. It is normal when a tire sits in the garage for a few days for it to drop a few psi. Dropping pressure during the ride isn't normal and you shouldn't need slime just to get home.

[LarryM]

It looks like Park Tool added some content to their web sites over the last couple of months. fish9999 might want to check the Park Tool section on tire and tube repair for some ideas on how to autopsy and fix flats.

[Green]

Originally Posted by fish9999

The guys at the bike shop say that because of my weight (about 200 pounds) when I hit a crack it "pinches" the tire and that causes the flat. Is this true? I used to live in Manhattan where the asphalt was in no better condition and i didn't get this many flats. Are there tires with greater puncture-resistance? I am willing to try anything. Thanks, Stu

Stu,
I weigh 270 pounds and have not had a puncture or pinch flat in 3 years of riding my Surly LHT (2000+miles), and that is no joke.
In that time I have had two sets of tires on my rims, no slime, no liners, only tires.
Both sets were Schwalbe Marathons.
I also have a seldom used 27 inch Schwinn Traveller that sports a set of Continental Gatorskin ultra, again no flats in over 4 years (500 to 700 miles).

In my book, Schwalbe Marathon tires are worth every penny!

Here is the single BIGGEST reason I blieve I have not had any flats, besides tire make.

All about tire inflation.pdf

You MUST read this article. It will probably stop your flats all together.

At our weight it is extremely important to inflate your tires correctly and this article explains how to do it.
I think more than 4 years flat free speaks for itself.

[fish9999]

Dear Everyone, Hi. Well, I drove in daylight along the road that Iride at night (to avoid all the car traffic) and I saw that in spots it looks the asphalt was chewed up by mutant beavers. I went to a different bike shop and they sold me what seems to be the right tire for my street- it's a "Maxxis-Larsen Tubeless" (but they added a Slime inner tube anyway). The tread is MUCH thicker than the old tire and as many people pointed out they inflated it until it was pretty much rock-hard. I've ridden a couple of times already and it certainly rolls better than the former tire. So I hope for the best. Thanks again, Stuart Fischman

[photosbymark]

Slime is at best an opportunity to get home without walking. It's not the solution, anymore than an aspirin is the solution to a hang over. The solution to a hang over is to not drink so much in the first place. The slime is the aspirin that gets you through the next day, but it also sounds like you are making progress on the solution as well. A tire gauge is a must, though I have to admit back in my younger days I took a guess on how much air a tire could take. How it feels is a way to confirm for me, not a way to measure.

Good luck and let us know if the new tire fixes the problem.

[Saugus18]

A couple of months ago I got a flat on the back tire, fixed it, then got another flat the very next day on the front tire. Both went flat slowly over night, so when I went to ride the next day I quickly realized I wasn't going anywhere. I soon learned I was dealing with the dastardly goathead thorns, they were everywhere! Upon inspection, I noticed a couple still stuck in the tires. This was the 3rd flat in about 3 weeks, and I was tired of it so I took the bike to the LBS and they slimed and lined my Specialized Hemisphere tires. They said they would be pretty surprised if I got a flat again, and they were right. Not one problem, and I've been riding almost everyday on the same route for many weeks. So slime PLUS liners have done real good for me.

[froze]

The air pressure thing has been answered so no need to go there again.

Slime tubes don't work at all once the pressure exceeds about 65psi, the force of the air pressure just blows the slime out of even the smallest of holes and your flat again. The stuff works great in MTB tires. In addition the presta valves Slime tubes use on their road tubes are the cheapest crappy designed valves I've ever encountered. However I don't recommend Slime tubes at all! Your first line of defense against flats is the tire, find a great tire like the Schwalbes, or Specialized Armadillo and flats will be greatly reduced. Next line of defense would be a liner like the Slime liner or Mr Tuffy; the last line and least effective is the tube. But I would try a better tire BEFORE adding a liner to see it that alone will work for you. Your always going to have flats, you just want to try to reduce the frequency of such without adding weight of liners and heavy tubes such as thorn resistant tubes or Slime tubes.