Schwalbe Marathon Plus recurring puncture - options? Does anyone have any experience of using puncture resistant tyres when they have been cut so badly as the object pierces the tyre right through?

Being Mr. Unlucky, 2-3 months ago I managed to get a puncture on my Schwalbe Marathon Plus'.

I changed the tub initially. When the second, third puncture happened, I started looking closer. The object (what I am guessing was a piece of glass, from memory) cleanly cut straight through the "SmartGuard layer". 





My guess was the object was still embedded in the tyre as it took 1-2 days after fixing punctures 2, 3, 4 for next puncture to flatten the tire completely. 

I examined the site, and tried to clean it out with a pair of tweezers, narrow knife, etc.

What are my options to continue using this tyre? I have (rightly or wrongly) applied some patch adhesive to the outside of the tyre on the puncture site, to see what happens.



Or should I stop using it?
If I understand correctly, you continued to get punctures until you found the embedded object which you dug out with a knife and tweezers.  

I have been in a similar situation many times and I suggest you try again. Punctures 1-4 where likely caused by the same object, which you hopefully removed this last time.  Does the tire have a small weakness at that hole, yes. But, the casing on these types of tires is incredibly tough. That is why they roll like bricks.  The tough casings however let you continue riding with small weaknesses without issue.  

Just inspect it after inflating, and for a while afterwards, to see if the hole gets larger or the tube starts to breach (you usually need a larger hole for that to happen).  I personally haven't had any problems with these small holes enlarging or new debris entering the hole.  That said, there is a non-zero probability than an object could pass through the whole and cause more problems.  If you know the tire contact patch size and you measure the area of the hole you could even compute that probability for bravado.

My only other advice is getting more practiced at finding and removing debris. I usually keep the tire oriented so the tire label is over the valve stem.  That way when dealing with a flat I can track the tube flat back to the tire location quickly.  Then I running my bare hands around the inside found tire until I find the sharp that penetrated the tube.  Once you find it flexing the tire casing can often be enough to help loosen an embedded object so you can pull it out with your fingers, avoiding other tools such as pliers, tweezers, and knives.  

Finally, stop riding over the sea of broken glass and all will be well!