[Yak] BF PL or me?
lenw at eskimo.com
lenw at eskimo.com
Wed Oct 1 15:53:31 CDT 2008
There are several things working against you with this bike. First of all,
you are seriously under geared. A 53/11 with 406 wheels is about equal to
a 53/19 with 700 (27 inch) wheels. If I recall the math correctly,at a
typical 80 rpm for a road rider, you will be going about 18.5mph in top
gear. If your buddies are doing say 22 mph on the flat, you would have to
be turning almost 100 rpm to stay with them - possible but difficult for
an untrained rider.
If you are not spun out on the flats, then you are just not developing
enough power, but see below.
Another factor is rolling resistance: rolling resistance is relatively
small but still significant compared to aerodynamic resistance, especially
at moderate speeds and slower. Rolling resistance increases with
decreasing wheel size - everything else being equal. Most of BF's
performance bikes are sold with 451 wheels for this reason. Rolling
resistance cannot account for a 15% difference in performance, but it is
another handicap that you have to overcome to stay with your buddies.
Finally, weight. the weights of your friends bikes are probably several
pounds lighter than yours. This will have some effect uphill. For a given
power output, speed uphill is related to total weight - you plus your
bike. A five percent increase in total weight will result in a roughly
five percent decrease in speed. Not worth 15%, but coupled with increase
rolling resistance, another handicap to overcome.
There could be other bike-related things affecting your performance. Do
the obvious things like make sure the brakes aren't dragging, make sure
the wheels spin freely, etc.
My guess is that the biggest reason for your getting dropped is that you
can't match the power output of your friends; sounds like they are
probably more experienced and fit than you are. The only cure for this is
to keep riding.
Finally, if you really think that the problem is the bike, trade with
someone about the same size as you, make sure the saddle height is the
same, and ride a few miles with your friends.
> Drag? Tires? Chain?
> Can't figure it out.
> My PL just can't keep up with my buddies' road bikes, by a big margin
> Yeah, I'm probably physically a bit slower than them, but they are WAY
> busting my butt up hills and on the flats. They've ridden my bike and they
> say they can't put their finger on it, but it feels just a little
> I've got Kenda Quest 32x406 at 90psi on Rolf super-light wheels (bike is
> about 22 pounds)
> I'm running 53/38 dual on the front and 11-34 cassette.
> What other factors?
> Any thoughts/help much appreciated.
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