Should i change this tyre pre-emptively?

[cyclintom]

If the tire you showed in the top picture is a Continental they have some "wear dots" that will show when they should be replaced. Seeing a flat spot on top of the tire isn't of much help since when you are riding the bike the tires are compressed into a flat spot at any angle of lean.

If the tires are those which do NOT have double or triple cords to prevent bad-road flats its difficult to judge. In California cities the roads are so bad that you can't use the cheaper tires and hope to get more than 500 miles out of them. I get perhaps 1200-1500 out of Gatorskins or Specialized Armadillos. These strong tires are beginning to be made by other manufacturers but I don't know them and always hesitate after getting such bad mileage out of other tires.

 

[doctorold]

Froze is correct in that tread patterns are of no consequence. The issue is whether you think the thinning will cause a flat and that you'd be OK to be on the side of the road fixing it. If you're OK with that, then leave it on.

 

[sgcyclistsg]

If the tire you showed in the top picture is a Continental they have some "wear dots" that will show when they should be replaced. Seeing a flat spot on top of the tire isn't of much help since when you are riding the bike the tires are compressed into a flat spot at any angle of lean.

^ Thanks for the info. I have more peace of mind now (about the flat spot), but seems my conti tyre doesn't have a wear indicator.

 

[cyclintom]

In your photo it appeared to have them. If you look at a new tire you will see them plainly enough and know what to look for. They are dots that go to the bottom of the recommended wear.