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$1,000,000.00 Tire question(5 posts)

$1,000,000.00 Tire questionPhatMatt
Feb 28, 2003 7:07 PM
What is more important spinning weight or rolling resistance? For instance;
Tire 1 180pis 230g
Tire 2 125psi 155g

What do you all know or think.

Matt
Depends on the type of riding you want to doAhimsa
Feb 28, 2003 7:17 PM
...and even then it's subjective to a degree.

A brief and general "For instance":

Perhaps in a crit I might want to go with the lower spinning weight so that I might get up to speed quickly.

Perhaps for touring I may prefer a lower rolling resistance over the long haul at relatively moderate speed.

That help?

Cheers!

A. (Personally I choose durable, comfortable, nice riding tires over all else)
I second that... andrwbadley
Feb 28, 2003 8:13 PM
I think a 220g 23mm tire at 115psi is a nice combo of wear, comfort and traction for most road riding.
The unanswerable tire questionKerry
Mar 1, 2003 4:09 PM
Tire rolling friction is mostly about the casing and how supple it is. Secondary factor is the possibility of squirming between tread and casing. Tertiary factor (only with tubulars) is about squirming of the tire against the glue bond. Casing/tire weight is a VERY minor factor. The amount of deflection of a tire casing is a factor of inflation and rider weight. Tires will deflect enough to create a road contact patch equal in area to the rider+bike weight divided by the tire pressure (200 lb bike + rider with 100 psi tire pressure = 2 square inches of contact area, about 1 square inch per tire). In most cases, rolling friction does not decrease significantly above pressures of 130 psi or so becuase the tire is not deflecting much anyway. Within all this, the amount of energy in deflecting the casing (some would call this casing stiffness) determines the rolling friction of a tire. This cannot be deduced from tire weight or tire pressure ratings.
agree with Kerrycyclopathic
Mar 2, 2003 6:43 AM
it is not clear which tire would have higher rolling resistance. To make things a bit more complicated the rolling resistance depends on shape of contact patch and on type of road surface. On coarse pavement running higher volume tire at lower pressure not only reduces amount vibration transferred to frame but actually reduces rolling resistance.

With respect to weight the effect.. Extra weight on tires only doubles when you accelerate/brake. Otherwise it has same properties as anywhere else on bike. Someone commented on this being important for Crit still I would take extra grip offered by wider tire any day over 2/3lbs weight save.