Wow. Using that chart, figuring total weight for bike and rider as
Wayne indicated, pressures for me are about 88 psi front and 109 psi
rear!
My riding is strictly fast road for short duration...mostly 1 to 1.5
hour rides, with some 2 to 3 hour spins on weekends. So I'm not looking
for comfort, speed is my demon, so I like tires hard and fast.
These numbers are so far below the range imprinted on the tire casing.
What am I missing here? Seems like such a soft tire would put the rims
at risk of damage on road hazard impact.
That chart is shooting for 15% vertical deflection of the tire sidewall, which is not a whole lot. That should optimize your contact patch, therefore your rolling resistance should be optimized as well, IIRC (I probably don't).
Wayne Pein 26 September 2007 18:43:21 [ permanent link ]
joseph.santaniello@gmail.com wrote:
Yes, and too hard particularly on less than perfect surfaces will
perhaps actually increase rolling resistance, and probably reduce
traction.
This is what the testing in Vintage Bicycle Quarterly (now Bicycle Quarterly) showed. If the tire is supple and the inflation pressure lower, the tire absorbs the imperfections rather than the bicycle and rider and thus rolls faster. With a stiff casing and hard pressure, the bike and rider bounce vertically and are slower.
Dan Becker 27 September 2007 14:02:29 [ permanent link ]
In article <1190877346.182206.4180@22g2000hsm.googlegroups.com>, <"joseph.santaniello@gmail.com"> wrote:
On Sep 27, 3:01 am, Dan Becker <No...@address.invalid> wrote:
In article <1190790537.536299.247...@g4g2000hsf.googlegroups.com>,
With a TT setup you will probably have a differnt weight distro than
suggested on the chart. You might want some more air up front as a
result.
I took that into account and adjusted the pressures accordingly.
Agreed. Just noting that a "vertically compliant" (man, I'm getting
tired of that phrase) ride is not a major factor to me in my riding
style and choice of machines or tires. But if this approach doesn't
have a speed penalty, then I'm certainly not opposed to less shake,
rattle, and roll.
Buzz is no good, and if the road is rough, not too much air might be
faster.
That's what Wayne's post lead me to believe; I should have chosen my words less pejoratively than saying "doesn't have a speed penalty." What you guys are clearly saying is that it is rather a case of having my cake and eating it too.
I'm appreciative to all for the replies. This is a fascinating, counter-intuitive discussion for me.
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