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I recently bought a Mavic A 319 rim with ETRO 622 x 19C and Schwalbe Marathon 28" tire with ETRO 32-622. Based on the tire sizing chart found at Sheldown Brown (https://www.sheldonbrown.com/tire-sizing.html) and the recommended tire width by Mavic of 28 to 47 mm, I thought that the 32mm would fit for sure. However, it requires enormous strength to pull the tire onto the rim. Much more than any tire that I have changed in the past. Because of the very tight fit, my tire was pulled down slightly on one side, making it run unevenly. To correct for this I had to pull and push on different parts of the tire to make it fit evenly. Also, something I never needed to do on a bike.

Is this expected, because the 32 are on the low end of the spectrum or did I read the numbers wrong?

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    OJS's answer gets it right, but to clarify, the Schwalbe Marathon tyres are renowned for being slightly on the small side. They're an utter pig to put on a rim that may be even half a millimetre larger than another. Perseverance is good,. as are four hands and a nice warm day. I think there's a fresh question here, worth asking, of "what tips and tricks are there for fitting Schwalbe Marathon tyres ?" Its also possible you've moved the rim tape a little, with all the effort required to get the tyre onto the rim without pinching. – Criggie May 8 '19 at 8:10
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    Did you make absolutely sure (through use of a helper person if necessary) that when you were fitting the tire as much of it as possible at any one time was in the center groove of the rim, and none of it was riding up on the inner tube, and you were working towards the valve? Do you have abnormally thick rim tape? – Caius Jard May 8 '19 at 9:07
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    Trying to fit a Schwalbe Marathon is one of those life changing experiences. Once you've completed the task you will have grown as a man, and all the worlds problems seem just a little bit smaller than they were before. – Andy P May 8 '19 at 9:59
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    What @CaiusJard said. When fitting a tight tire, make sure the portion of the bead already on the rim is in the middle of the rim. Most rims have a smaller diameter in the middle of the rim than they do near the sidewalls, and getting the tire bead into the smaller-diameter portion can make fitting the tire much easier. – Andrew Henle May 8 '19 at 10:39
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    @AndrewHenle indeed, that's why rims are shaped thus. Take a car tire for example, the rim is shaped like this and if you don't push the tire so the bead you just pushed on, is right in the depth of the valley in the rim, then you get about 3/4 the way round and reach a hard stop (and if you're using a tire machine you will definitely rip the tire and ruin its ability to hold air). Bigger diameters are easier; most bicycle tires I've changed I didn't even use levers for – Caius Jard May 8 '19 at 13:34
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You have the correct tires.

This does not have anything to do with tire width. The diameter determines whether tires will fit or not, unless there is a huge width mismatch. Rims and tires are both made to a tolerance, and you just happen to have an unusually large rim and small tire. I have had the opposite problem with some Schwalbe tires, they were so loose that they kept slipping off the rim when installing.

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One word: oven. :)

  1. Twist the tire once to fold it into a double loop that will fit in the oven. Consider using a nylon “zip” tie or two to hold the tire from unfolding
  2. Bake the tire at 200 degrees for ~30 minutes
  3. Wear a pair of work gloves to remove the tire and install it on the rim. (200 degrees won’t bake cookies, but it’s too toasty to handle while installing.)

It’s still not easy, but it’s definitely more pliable and easier then at room temperature.

-David

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    Hi, welcome to the website. Your method is definitely unusual, but let's say risky. Not only because it may destroy tires, but it may also damage the oven, or even worse. Definitely a serious warning needs to prepend the answer . By the way, 200 degrees Celsius or Fahrenheit? What will happen with the zip-tie at such temperatures? – Grigory Rechistov Jan 18 at 22:16
  • 200 degrees Celcius is excessive and will damage your tyre in short order. Simply leaving the tyre in a sunny window will bring it to a good working temperature of about 40 degrees C without risk. If you're suggesting 200 degrees fahrenheight, that's 94 degrees C which is still hotter than anywhere the tyre would get, and decrease its service life. – Criggie Jan 18 at 22:26
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    Also, 200C will have zero effect on the steel bead wire, which is the actual part that is difficult to get over the rim. – Argenti Apparatus Jan 19 at 23:05

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