tire size

[badger]

this is probably going to sound rather ignorant, but it's never too late to learn, right?

I currently have a 700x25 size tire on my bike. It's gotten 3 flats in the last month, so I'm thinking it's time to get a new one even though it's only a year old. I found the same one online but it's a 700x20. I'm assuming the last two-digits refer to the diameter of the tire? so would going from a 25 to 20 make a huge difference in riding or anything else, or none at all?

thanks!

[smilingcat]

Do you think you got the three flats because the tread is so worn that you have very little rubber left on the tire? Or is it more of bad thing come in threes. It happens!!

Years and years ago, I used a panaracer 700x18C. It was a real pain getting it on the wheel and off the wheel. The contact patch was so much narrower than the 700x25C, I would have to pump up the tire to near its max. otherwise, it was more likely to get snake bites. While on x25C, I could get away even when the tire pressure had dropped to 80PSI, that wasn't true for the x18C. I would have flatted with snake bites. Didn't care for the narrow tire.

Now to confuse, not all x25c are the same diameter I noticed.

Can't really say about the handling. I didn't try the same model of tire at different sizes.

[badger]

well, I believe there are loads of tread left, it's still as stiff as it was when I got it. I commute on it nearly every day, but distance is pretty short so I doubt it's at its end of life.

All three were nails, two were like an inch long. Today it was about a 3/4" nail smack in the middle of it. It's always my rear tire, too, which is why I'm thinking it needs to be replaced.

Or, like you said, it could simply be just bad luck. Don't know, but not having had any flats for over a year and all of a sudden getting 3 within a span of 5 weeks makes me wonder.

[nscrbug]

I'm gonna say it's "bad luck"...especially if all the flats involved nails. Are you riding the same route everyday and flatting in the same area? Is there any construction going on along your route...or maybe a house or two getting a new roof? I'm always cautious riding down a street where I see a house getting a new roof...roofing nails find their way into the street and just about everywhere else.

As for the tire size...I went from riding 700x23 on my previous bike to riding 700x25 (stock tires that came on my bike) on my current bike, and I can't really tell much of a difference. However, with going from 700x25 to 700x20, I'm guessing there would be a fairly noticeable difference...mainly being a harsher ride due to the need for max air pressure in the narrower tire. But in all fairness, I've never ridden on anything narrower than a 700x23, so I may be wrong.

[withm]

If I had 3 nail punctures in the same tire, I'd be inclined to replace the tire regardless of the amount of tread left. Going to a narrower tire is probably not the best idea - a 20mm is really for racing and will not give you any maneuverabilty if you encounter sand or gravel on your commute, or support increased loads assuming you are carrying clothes, computer, lunch, etc. to work.

If anything, I'd suggest you switch to 700Cx25 and keep them inflated to the max. This will help to avoid pinch flats and increase the probability that nails, glass, or other debris will bounce off the tire rather than penetrate it.

[pinkbikes]

I recently got a new bike and had four flats in my first five rides. And I nearly never get flats, so I was NOT happy!

But perhaps you need to look at the type of tyre you are using? The tyre that came as original equipment on my bike was as soft as butter and was ideal as a race tyre but no good at all for everyday use.

I replaced it with a tyre of the same size (700x25) but in a more robust structure. I personally have a liking for kevlar bands in a tyre that is going to be used for everyday. No flats since.

Perhaps if you don't like the behaviour of the tyre you may need to look at an alternate instead of replacing it with the same (and not a narrower one) to get different behaviour.

Oh - and sometimes it really is bad luck (or a big nail) and you would get a flat no matter what tyre you had!

[BleeckerSt_Girl]

I commute on it nearly every day, but distance is pretty short so I doubt it's at its end of life.
All three were nails, two were like an inch long. Today it was about a 3/4" nail smack in the middle of it. It's always my rear tire, too, which is why I'm thinking it needs to be replaced.

Are you able to ride on your commute less on the shoulder or near the gutters? I find the further into the shoulders of a road I ride, the more nasty debris there is there, like glass and nails and sharp metal objects. Can you ride maybe a foot closer to the white line and still feel safe?

After three nail punctures, I'd get a new tire regardless of tread. Too much chance of a sudden blowout, and that could be really dangerous in traffic.

700x20 tires will get more flats than 700x25. Can you get some heavier tread tough kevlar tires for your commuter bike? My brother in NYC only rides mtn bikes with massive tread tires because of all the metal and glass there. Since you have a short commute is this an option?

[badger]

thanks for your input, ladies. you all have valid points!

My tire is a Specialized Armadillo, which is kevlar lined, and have had no issues with it for the 12+ months I've had it. I normally get flats in the winter after a sudden snow and the melt afterwards.

I did get all my flats in the same area that does have construction - it's the coliseum that we had our opening/closing ceremonies for the 2010 Olympics. Didn't think they used conventional nails but they must?!

I called the City to have the area swept more regularly, and I might alter my route to one that adds about 5 minutes longer to my commute. I'm just so sick of getting these flats.

And I was just thinking this morning as I rushed out that I should inflate my tires, so I wonder if I would've avoided it if I let myself be late by a minute or two to pump them up? (probably, and it's not like it was under-inflated, I just like them really inflated).

I'm going to look for the same tire again, or another similarly re-inforced one cheaper than my LBS ($60 each!) but will put a new inner tube for the time being.