I purchased a new stead a while back. The wheels came equipped with 700C Alexrims DP17 (622x17) rims. After a few hundred miles I started getting punctures in the cheap tyres and replaced both with 700*32 Marathon plus tyres. I chose there because I wanted the ultimate puncture protection.

When fitting the M+ tyres I had problems, the tyre as I was levering the tyre on one side, it would pop off the other. Also one of the tyres blew off overnight after I had fitted it, I think the other blew off a few days latter.

That was 6000 miles ago, and the rear is in need of replacement, and it is getting urgent.

I bought a 700*28 Marathon plus tyre two months ago, and tried fitting to the rear wheel, and it will just not stay on the rim. If I get it onto the rim, then it pops off as I inflate it. So I went back to the old tyre. Last week I tried fitting the new tyre to the front wheel, and had the same problems. After about 90 minutes of messing around, it stayed on whilst inflated. I then took the bike out for a test ride, and within a mile or so, it came off the rim on both sides.

I really want to use M+ tyres, but this is unsafe. Are there any recommendations about what I can do?
I am thinking of replacing the rims, but am hesitant in case I encounter the same problems, are there any disc rims with very tight fitting suitable?

Both 700x28 and 700x32 are within the specs given by Sheldon Brown, and I am happy to rebuild wheels myself.

There is a far larger range of actual rim circumfrences the that of tire bead ones. Tires are moulded by the thousands in one mold. Rims are rolled and cut to size in batches of 10+. Also when using a tire that is much wider then the rim's interior width expect more fitting challenges. Andy.

I had trouble with the Marathons so I bought this tool to mount them. I won't buy the tires again so I gave the tool to a friend who has MS and needs the leverage. Bike Tools Etc. - 1000's of bicycle tools and parts for the home mechanic!

Quality control just doesnt seem to be what it used to. I never had the problems with tubes and tires when I was young compared to now!

Best advice I can give to get those tires on properly and stay on, (despite them being too big..!) is to air them up a little at a time and "move" the bead until it centers the tire on the rim.

Good luck!

-SP