tire and rim compatability

[Wild Dave]

well i got a used set of schwalbe marathon (kevlar guard wire bead) tires from a neighbor who was throwing them away, they barely have any wear on them for that i feel very lucky. i'm starting to get the impression they won't fit my mavic X517 sup rims. the tires are 26x1.75 so i bought new tubes to fit the narrower tire but the tire keeps coming off the rim as i pump it up. the rim (which i have always believed to be a 26" rim that always took 26" tires) has these other numbers on it (559x17) and the tire has these numbers on it(47-559). i suspect this may be where the problem lies, am i correct in assuming this?
 jeez, i never knew riding a bike could get so complicated, whatever happened to the good old days?
thanks for any and all imput

[SweetLou]

That tire width is fine for those rims. Mavic's tire recommendations for their 17mm mountain rims is 2.1 inches or about 53mm. Your 47s fit within Mavic's specs.

Good old days? I have to disagree, using the old sizing is much more troublesome. 26x 1 3/8 is not the same as 26x 1 3/8 S-6, and these aren't the same as the 4 or 5 other 26" size. The ETRTO system is much more clear.

[Wild Dave]

thanks lou.
  guess i just need to focus my brain and carry a metric/inch combo tape measure.  i'm thinking maybe i just need to be more careful to see that the tire is seated evenly on the rim, the tube was squeezing out between the tire and rim. seems the tires have been sitting around without being mounted so maybe they need a little more attention initially while pumping them up.
thanks again

[Pat Lamb]

You might try pumping the tire up to 15 psi or so, then disconnecting the pump and checking all around the tire, on both sides, to make sure the tire is seated evenly.  Manhandle it a bit if necessary to get the bead even, and the same amount of tire showing all around.  Once it's all even, then pump up to full pressure.

[DaveB]

The critical number here is the "559" which is the rim's bead seat diameter in mm.  Since both your rim and tire are 559, they are compatible and if the tire won't stay put at any reasonable pressure, something else is wrong.  I agree that you have to be certain they are seated properly and that the tube isn't caught under the tire bead.   

BTW, why was your neightbor discarding them? Any chance the wire beads were broken or badly kinked?

[Wild Dave]

The critical number here is the "559" which is the rim's bead seat diameter in mm.  Since both your rim and tire are 559, they are compatible and if the tire won't stay put at any reasonable pressure, something else is wrong.  I agree that you have to be certain they are seated properly and that the tube isn't caught under the tire bead.   

BTW, why was your neightbor discarding them? Any chance the wire beads were broken or badly kinked?

my neighbor had some stuff curbside with a free sign, there was an old univega mt. bike and other stuff. i not sure he knew or may not have valued them for what they were, on a whim i went over and grabbed them because i was looking for tires and don't have alot of $ at the moment. i too didn't know their value until i brought them home and googled them.
     eventually, hopefully by next spring i'll be able to either justify buying a touring bike, surly l.h.t., soma saga, or velo orange, (i don't know enough about them at the moment) or try and turn my mt. bike into a touring bike by making some small adjustments and pulling a trailer. any and all suggestions/help/info, on the subject will be very much appreciated. i'd love to do some l.d. touring, as i've done plenty of l.d. hiking and have traveled to many places on the planet, bike touring just seems to be calling me at the moment.
thanks for everyone's help

[John Nelson]

My best guess is that you're pinching the tube between the tire and the rim.

[SweetLou]

One thing I do when putting a tire on a rim, especially if it is a difficult fit, is to pump up the tire just a bit. I then go around the rim, pushing the tire in so that I can see if any of the tube got pinched between the tire and the rim. Once I am satisfied that the tube is in the tire and nothing poking out, I will add a couple of more pounds of pressure. I check both sides to see if the tire is seating correctly. If everything looks good I will put more air in and check the seating as I go.

This isn't always needed and often I don't do it this way. I only do it on difficult tire/rim combinations, and all kid tires, those are the worse.