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This is very similar to this question.

When I fill my tubes up to about 85 psi the tire pops off the rim and the tub gets caught on the rim and blows up. I have gone through 4 tubes in two days at this point and the only thing that seems to help is to inflate them to about 60 psi. Even putting pressure on the tires so they seat correctly (not sure if that is the correct term, I am quite new to cycling) only works until I put weight on the bike, and then the tubes blow.

For some info, I frankensteined a bike together out of used/old parts so my rims are quite old (although relatively true after ~8 hours of work) but the tires are falling apart. The rims are 27's (inches?) and there were really no options for newer ones at the place I put my bike together at, only 700's.

Could replacing the tires fix this? I would like to get the tubes to around 90 psi since at 60 they are quite flat when riding.

Edit: Some details on the tire, tube and rim.

Rim: ~1 Inch wide at the top, ~25 1/2 inches in diameter
I couldn't really figure out how to check the bead. Rim tape looks fine, it is some hardish plastic covering the spoke screws.

Tire: See these images of the tire.
Supposedly a 27 x 1 1/8 tire that holds 90psi. Not sure what else is helpful info other than the pictures of the deteriorating side walls (and the lip at the bottom that catches the bead)

Tube: 700x18-23 27x1 48 mm presta valve. I can't find max pressure, but I am sure it is in excess of 90 psi.

  • Do you have the right tube for the type of rim and tire you have? Is the rim tape properly applied? Is the tire right for the rim? – Batman Aug 19 '14 at 3:49
  • It's possible that the rims are worn out to the point that the rim is spreading under pressure (especially likely with older non-box rims). It's also possible that the rim is simply too wide for the tire. – Daniel R Hicks Aug 19 '14 at 11:52
  • @Batman, how would i determine the correct tube size? I have been using the 27x1 tubes. – Chris Aug 19 '14 at 12:19
  • Are you sure the rim is a 27? What kind of tire do you have on it? – Batman Aug 19 '14 at 12:31
  • @Batman, question has been updated. – Chris Aug 20 '14 at 3:59
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Three things to check:

1, Is the bead seated correctly. It's pretty common to get tyres blowing off the rim if they're not seated correctly. That said, this usually leads to an exploding tube rather than the tyre just coming off 2, As Daniel R Hicks said, are the rims so worn they're expanding? 3, Check the rim for dings and warping as Malarky sort of says, but not just the area for the bead. You may have a bent rim

Chances are, though, that the tyres are done. The pictures would make me think they're on their last legs. I had a pair of 20+ year old ones recently that ended up in the bin as they just weren't reliable enough for me. Some things aren't worth saving a few euros/pounds/dollars over, and the contact points on a bike are some of those things for me. If the rims seem fine new tyres are where I'd go.

  • 1
    I think there were a couple issues here, my tires were crap, and i wasn't fully seating the bead. I bought new tires and went around the rim pushing the bead down a few times and it seems to have worked. I still can only seem to manage around 80 Psi before the tires pop out, so my rims are probably on their way out too. – Chris Aug 21 '14 at 0:03
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Would you really want to ride on these tires that are falling apart?

You need new tires. You may have to order. Biketiresdirect.com has 27s.

Make certain the rim has no defects that prevent the tire bead from holding. Make certain the tires are seated all the way around the rim (pay particular attention to the area around the valve) and the tube is not caught under the bead.

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    Are you affiliated with that website? If so, you should declare it – Batman Aug 19 '14 at 7:09
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    I agree I need new tires, but I am trying to determine if that will fix it, or if I need new rims as well. I will probably go with 700's because they seem easier to find, so I don't want to waste money on tires that I can't use if I determine the rim's are worthless. – Chris Aug 20 '14 at 3:59
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I've had this issue with some inexpensive 27" replacement rims and some 27" tires (hard to get good 27" stuff these days!) My parts were new. If your tire is in poor condition, you should replace them...brakes and tires are the only parts of the bike that HAVE to work properly ALL THE TIME.

What I did to work-around this issue is inflate the tire slowly and when I saw it pop out of the seat, deflate and reseat it... Repeat until tire got up to pressure. Once mine were inflated fully, they would stay seated just fine.... but if I let them leak down... had to be careful when I was inflating them... This was usually only an issue the 1st time the tires were inflated after they were removed from the rim.

And replace the tires if they are bad. Check the rim sidewall for thickness too. If the rim is worn out, it should be destroyed and not re-used... it'll get someone killed.

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Are those non hook edged steel rims? They can't keep high pressure tires on. Get some hook edge rims or accept low pressures.

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I looked at the picture of your tire. It's flaking apart. Your tire is obviously the problem. You need a new tire.

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