Auto tire designers , including designers of tires for sports car prototypes and Formula 1, obviously believe the tread makes a difference, as they design rain tires with much deeper tread than dry tires, which are often slick, or nearly so. Maybe Jobst is arguing that motorcycle and bicycle tires are fundamentally different than auto tires, but I don't see the basis for such an argument. Jobst wrote a really good how-to book on wheelbuilding, with useful illustrations, but I find most of his theories, even some of his theories about wheelbuilding, to be totally unsupported by any facts that I can discern. I remember once questioning Bob Lickton about why he built some wheels for me with some detail that was counter to a Jobst theory. Bob replied Jobst should stick to computer programming and leave wheelbuilding to those who do it for a living every day. The same probably applies to designing tires.
Regards,
Jerry Moos Big Spring, Texas, USA
John Barry <usazorro@yahoo.com> wrote: Sounds like another shot-from-the-hip Jobst theory.
Anyone who has driven on good tires on a wet road, and then driven on bald ones on a wet road and not noticed a difference, would have to be either very distracted, or borderline comatose.
Hydroplaning is a very real phenomenon, and to suggest that tread pattern could not have some bearing on how severely hydroplaning affected a tire just doesn't have their facts straight. I'll leave the posting of citations on the topic to the engineers here.
John Barry Mechanicsburg (where bald tires wouldn't be a good idea tonight), PA, USA
>
> Anyway, here's Jobst on the subject (found on line).
>
> *snip from Jobst*
>
> * Tread patterns have no effect on surfaces in which
> they leave no
> impression. That is to say, if the road is harder
> than the tire, a tread
> pattern does not improve traction. That smooth tires
> have better dry
> traction is probably accepted by most bicyclists,
> but wet pavement still
> appears to raise doubts even though motorcycles have
> shown that tread
> patterns do not improve wet traction.*
>
> */snip Jobst*