I wrote to Schwalbe about the apparently excessive weight of their Marathon
700x28 (510g) and Marathon Slick 700x30 (500g). Of all the tyres I've
considered they're the only ones in the 500g+ range. This is the bulk of
Schwalbe's swift response. I think it makes for interesting reading, both
about their justification for the weight (they claim 6,000 to 12,000km for
the Marathon) and about how Continental calculates their TPI:
"You are right if you say our Marathon tyres are mostly heavier than other
high performance tyres. Reason for this is, that the Marathons are made for
long life, low wear and safe riding. All tyres you are mentioning are light
weight skin tyres with thin tread and without sidewall rubber.
The Marathon, as well as Marathon Slick are very strong due to a special
sidewall rubber film reinforcement and long lasting because of a thicker
tread with special compounds. I think this is a key for our success all over
Europe, as bicycles purpose here is mostly everydays use.
We can of course also provide real lightweight tyres. For example our
Stelvio 28-622 is only 325g with Kevlar breaker.
Please be advised, that the TPI's mentioned by Continental can not be
compared with TPI values from other manufacturers. Conti adds up the TPI's
of all carcass layers of one tyre. If we would do so, our Marathon would
have 150 TPI whereas Marathon Slick would be 201 TPI. Stelvio is at least
335 TPI as there are two additional carcass layers (overall 5) for puncture
resistance."
I haven't found an Australian price for the Stelvio but Performance have
them for USD39.99.
--
"I'm proud that I live in a country where witnessing two hours of bloody,
barbarous torture in gloating detail is considered indicia of religious
piety, whereas a mere second gazing upon a woman's breast is cause for
outraged apoplexy."
Betty Bowers, http://www.bettybowers.com/melgibsonpassion.html