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What size tire?

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Before you get too excited it’s not for you, and it’s probably not even a bike you’d want anyway. My wife and I know someone who wants to get started in triathlons but doesn’t have a bike. We were entrusted with this virtually brand new 1986 Trek Elance 310 and this just seemed like a good opportunity to spread a little love. I gave it a full overhaul. I cleaned, repacked, and adjusted all bearings, lubed chain and freewheel, trued both wheels, taped the bars, and threw on a computer. It still needs a seat post though. I tried to throw on one that I had sitting around but It won’t come close to going in. My cheap digital caliper seems to indicate that it might be a 27.0 rather than a standard 27.2. Is this possible?

It also needs new tires which leads me to the real purpose of this thread. The rims are 27” x 1” that measure about 19mm outsde. The tires that came stock on the bike were 27x1” skinny little guys that measure a little more than 21mm across. The young lady riding the bike probably weighs in the neighborhood of 120lbs. Should I replace the tires with the same skinny little 27x1 (which are actually more like 21mm) or move up to the next size option 27x1 1/8” which is more like 28mm wide. Which size do you think would be more appropriate for said beginning triathlete? I don’t know about you, but those 21mm wide tires just look like a pinch flat waiting to happen. By the way, the cycling portion of her first event will only be six miles. :)

Thanks,
Ken
 

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I'm 5' 120lbs and have never pinch flatted anything in 5 years of riding (including mtb); well ok, I've pinch exploded tubes trying to change flats/tires, but that's it... I also get far less than my fair share of glass, rocks, snake bites, etc, and even managed to ride unfathomed distances (at minimum 5+miles, probably more) with a blown sidewall without flatting the tube!!!! (and I'm not that great at maintenance...maybe it's luck, but I think "tiny" might have a little bit of something to do with it)

Since she's thinking tri I'd go skinnier rather than 28's personally; unless she's never been on a road bike and has some mental hurdles with tiny tires.

Can't find a 23 around anywhere? Unfortunate. It's a very cute little bike; hope she enjoys it!
 

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tire brand gurus needed

This is a question for the tire-brand gurus. The 1" should be closer to 25 mm. I would look around for a 1' that was supposed to run true-to-size or a 1.125 that ran "small." Maybe you should re-post this question in the wrench section.
 

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If she's a new cyclist I'd go with the 1 1/8". It'll give her a little room for error as far as potholes and the like. Once she's got a coupla miles under her belt she can always re-tire it.
 

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the seat is too....uh...um....it needs a seat and post
 

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Ken from Fresno said:
I don’t know about you, but those 21mm wide tires just look like a pinch flat waiting to happen.
It's not the size of the tire that determines its susceptibility to pinch flats, but inflation pressure. The smaller the tire, the more pressure it needs to become "rigid" enough to resist pinching. Since very narrow tires are often underinflated and larger tires are often overinflated, tire size has erroneously been connected directly to pinch flat problems or the absence of them. I'd go with the 1" tires (less weight, slightly livelier feel) and inflate them to the recommended maximum.
 

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Choices

Ken from Fresno said:
The tires that came stock on the bike were 27x1” skinny little guys that measure a little more than 21mm across. The young lady riding the bike probably weighs in the neighborhood of 120lbs.
At 120 lbs, she can ride really narrow tires without much of an issue. However, it's quite unlikely that a tire you buy today that is labeled 1" will be as narrow as what you have. Besides, you don't have a lot of choices in 27" tires these days and I would be surprised if you could find one that narrow. A true 1" tire will be 25 mm, which is massively wide for this person.
 

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Hey, I had one of those! 1986 Japanese-made Trek 310, made with Ishiwata EX triple-butted tubing. Good bike that served me well for some time.

Replace the tiny tires. I think 27x1 tires are usually undersized -- more like 7/8, really. The 1 1/8 are probably smaller than indicated, too. The Harris Cyclery website (you know how Sheldon was about tire sizes) says the Panaracer Pasela 1 1/8 measures 25.5 mm, which is just a tenth of a mm more than an inch.
 
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