Re: 1.25" Slicks ==> Real Road Wheels?

[Michael Press]

In article <[email protected]>,
"(PeteCresswell)" <[email protected]> wrote:

> When I went from WTB Mutano Raptors (55/55) at 35 psi to 1.25" slicks at 90 psi,
> I think I picked up at least 2 mph average speed on my commute.
>
> Not really knowing anything, my guess is that most of that came from decreases
> in both "barn door" wind resistance and aerodyne effect (i.e. no lugs whipping
> the air).
>
> Guy on a road bike passed me today, but he was young, more aero, and working at
> it - while I was running just a little beyond cruise mode - i.e. not consciously
> trying, but somewhat beyond my normal aerobic pace enjoying a little bit on an
> endorphin rush.
>
> He got a hundred yards or so ahead and then the space between us remained
> constant for quite awhile after that.... So I'd say that a couple-two-three mph
> would have evened us up.
>
> Now I'm wondering if I'd get anything like that increase by going from the
> inch-and-a-quarter slicks to "real" road wheels - as in 700 or 29" or whatever
> the standard size is... and the skinniest tires that will let me ride without
> obsessing about the quality of the road surface. Since it has disc brakes, I'm
> pretty sure my frame would handle the diameter.
>
> Somewhere in the back of my mind my real agenda is the thought of starting to do
> group rides and being able to keep up with riders of similar ability (or lack
> thereof...) on road bikes.
>
> Anybody been there? Is this wistful thinking?

Inch and a quarter slicks at 90 psi are almost optimal.
Slightly narrower and higher pressure will give a
measurable decrease in rolling resistance, but will not
make you faster in the real world.

Do you remember the buzz that those knobby tires made on
the pavement? That is where the 2 mph was going.

--
Michael Press

 

[[email protected]]

Pete Cresswell writes:

>> Do you remember the buzz that those knobby tires made on the
>> pavement? That is where the 2 mph was going.

> Between their center ridge and the fact that they're *really* worn,
> I don't feel any buzz with the Mutano Raptors.

> OTOH, from the relatively-new 1.25" Hutchinson cross tire I've been
> running on the front wheel of the commuter bike to save me from my
> own stupidity I get considerable buzz. I've eaten it a couple of
> times from losing the slick rear wheel... but haven't done any face
> plants yet. Hopefully I'll develop a "Slick" mode and an "MTB"
> mode... currently though, I just forget sometimes.... --

I think this falls out in the wash if you consider what causes rolling
resistance. That it was caused by tread scrub on the road was long
believed until Specialized marketed their raised center ridge tire
with a quarter inch flat rib down the center. That left a quarter
inch wide wet track after riding a wet section of pavement, yet this
tire had relatively high rolling resistance compared to slicks that
were introduced at that time.

http://www.sheldonbrown.com/brandt/rolling-resistance.html

Jobst Brandt

 

[(PeteCresswell)]

Per Michael Press:
>Do you remember the buzz that those knobby tires made on
>the pavement? That is where the 2 mph was going.

Between their center ridge and the fact that they're *really* worn, I don't feel
any buzz with the Mutano Raptors.

OTOH, from the relatively-new 1.25" Hutchinson cross tire I've been running on
the front wheel of the commuter bike to save me from my own stupidity I get
considerable buzz. I've eaten it a couple of times from losing the slick rear
wheel... but haven't done any face plants yet. Hopefully I'll develop a
"Slick" mode and an "MTB" mode... currently though, I just forget sometimes....
--
PeteCresswell