Tyre/Rim Compatibility

[Hacienda71]

I had a slightly disconcerting experience this afternoon. Shortly after a fairly rapid descent I noticed when braking something on the front wheel was rubbing. As I was only a couple of miles from home I rolled back and took a look. I was shocked to see about three inches of tyre had come of the rim.
The rims are 1980's Mavic MA40's the tyres are cheapo 23c Vittoria Zaffiros. I had ridden about 35 miles on the tyres with no issues they are at 110psi which is within the recommended limits.
Have I, just not fitted the tyre right 35 miles ago or is there a problem that may recur? I don't want a blowout on a 40mph descent.

 

[fossyant]

Some rims tyres don't get on but I have never come across any. Re fit them but talc the inside of the tyre and the tube before fitting. Hopefully it was a fitting issue or trapped tube.

 

[goody]

Surprised the tube didn't blow.

 

[Cycleops]

It is quite easy when fitting the tyre for the bead not to seat fully in the rim, this can cause the the tyre to ride up and come out of the rim. When fitting quarter inflate the tyre and push it down making sure it is properly seated before fully inflating.