Schwalbe still makes such claims. Under the section
“What does EPI mean in relation to the carcass?” is written among other things:
“But be cautious when comparing EPI indications, as often the number of strands of all carcass layers are added together. An indication of 200 TPI results e.g. from 3 layers of 67 EPI each underneath the tread. With all EPI numbers above 150, it should be assumed that the figures have been calculated by adding up the strands in all layers. Schwalbe only indicates the material density in one carcass layer. Commonly, there are 3 carcass layers underneath the tread.”I just counted the cords in a Schwalbe One (HS 448) tyre. This was difficult because the rubber coating partially obscures them and I don’t have a linen tester or even a magnifying glass. I made it about 110 TPI, which is close enough to Schwalbe’s claim of 127 TPI. About every 4 mm runs a supporting perpendicular cord (the warp to the weft, so to speak).
If I can get my hands on a linen tester I’ll attempt a more precise count of the threads in a Veloflex Master open tubular.
By the way, I think some of the open tubular designs have only two casing plies under the tread but then have a third strip of the same fabric glued beneath the tread as a rudimentary puncture strip. By counting only the plies of the casing itself the manufacturer would have an excuse for doubling the tread count (rather than tripling it) in the interest of making the TPI claim more plausible than Continental’s brass-necked exaggeration.
