Equipment Safety Question
 

I have some Metro Duro's (26X1.5) on my bike. They are great tires...kevlar belts...carbon fiber sidewalls (I read that on one site but can't find it now) and a steel reinforced bead. Anyway, the tires are now about 7 years old and the side walls in particular have been giving me problems. I tossed another tire because there was a huge bubble in the sidewall that looked like it was going to pop any minute. I replaced it with the same kind of tire off my wife's bike. Everything was going fine (300-400 miles) then I noticed a very small bubble forming on the front tire again last night. I rode it today without problem, but I checked when I got home and it was not huge...but noticeably bigger. The fibers in the side walls are starting to split. Is it worth chancing for another day or is this not something you would risk? The other bubble was huge and didn't pop.

Also, do you think this has more to do with the age of the tire than over inflation? I inflate to 85 PSI...the tire is rated for between 50-100 PSI. Thoughts? I hate missing a commute day! Argh! Lastly, does it help to 'condition' the sidewalls with Armor All or something like that? Would that have prevented this break down of the material?

Your tires (and your wife's) seem OLD. Go ahead risk it, but expect a Blowout.
sounds like the material is already deteriorated.
GOOD LUCK

Check whether your brake pad is rubbing the sidewall of the tire at that spot. I see this frequently when someone's wheel has a flat spot, a dent or a dip... the wheel dips towards the brake pad and thus the tire ends up rubbing the brake pad, wearing through the sidewall.

To do the check, spin the wheel and view it from the side where it passes through the brakes. Do you see any noticeable dips and jumps? Apply the brake and rotate the wheel so the bubble in the tire is between the brake pads... is the brake pad touching the tire there?

If that's the cause, then the solution is to fix or replace the wheel, then replace the tire.

I don't think that's the problem but I will check. I think I'm going to throw on some duct tape (it works for everything, right!?!?!?) for extra support. Then I will get some new tires tomorrow when I get back from work. Just wondering how dangerous this tire is now. Anyway, thanks for the advise.

If the fibers in the sidewalls are starting to split then tire is history. Armor All might have helped the tire last a little longer, but 7 years is plenty of life from a set of tire.

If the sidewall is bulging,for any reason,I wouldn't chance them. I have too many steep hills and bad roads. And 7 years is a long time for a tire.