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Zach Kaplan
zakaplan@earthlink.net
Mon, 15 May 2000 17:36:53 -0700
Bill (and HPV list, this is too important not to post there):
Ron and I completed the CCD Saturday. We are still the only two recumbent
riders to have ever completed this ride, this was my 4th time and his 3rd
time. The ride started at 5:40. I believe Ron finished around 22:15, I
finished at 11:52p because I lost over an hour due to a sudden air loss on
the rear tyre going down the fastest descent on the ride at 90 km/h. The
bike started fishtailing at that speed but I was able to apply the brakes
and get stopped in a straight line. When I came to a stop I could smell the
burning rubber from the pads. I had to sit down across the street in the
shade and calm down for approximately half an hour before I could repair it.
A SAG driver stopped and I discussed dropping out with him but his Toyota
Tundra 4-door pickup had only a 6 foot bed and although he had a blanket for
the fairing and rope it seemed like a big hassle and the fairing might get
damaged so that was incentive to keep going. He had a HAM radio and said
when he got to the top of the hill he'd ask about having my headlight
batteries forwarded from the 179 mile rest stop to the 145 mile rest stop as
it was looking like if I went on I wouldn't make it to the stop my batteries
were at. He was also going to come back in 20 minutes and would pick me up
if I was still there.
So I went back across the
street when my heart rate got back down to normal and figured out what
caused the sudden air loss. As you recall I mentioned on the way to the GPC
that the remote valve control didn't have enough of a grip on the valve to
open it when a self-sealing tube is used. On Friday I removed the valve
extender and opened the valve with a needle nose pliers then reinstalled the
extender and left it in the open position. At high speed the centrifugal
force caused the remote valve control to press down on the open valve
releasing all the air.
As a result I think I'm
going to stop using the Spinergy rear wheel on the GR on long rides and save
it only for short rides where a self-sealing tube isn't so important since I
have learnt the hard way the self-sealing tube isn't compatible with a
closeable valve extender. I have a wheel here with a Ritchey OCR Pro rim,
1.8-1.6-1.8 spokes and an XTR hub which I will use instead and it will be
lighter and easier to repair on the road. The aero advantage of the Spinergy
on the rear isn't much and certainly not worth the price of not being able
to use a self-sealing tube. Besides their remote valve control does not make
it obvious when the valve is open or closed as it is just a sliding rod with
a gripper at the base so even if I wasn't using a self-sealing tube I could
still have accidentally left the valve open.
I told Gardner about what
happened and he was familiar with this problem. He said they've had several
HPVs lose their air this way in races. He says it happens over 50 mph when
the valve is left open. This means one doesn't even need to have a remote
valve control pressing down on the open valve to lose the air at speed, just
an open valve is enough. So for bikes that go really fast down hills all the
aero wheels that require valve extenders are unsafe unless it is a closeable
extender like what Spinergy uses and even those are potentially unsafe as
they are easy to leave open without knowing it.
I'm also probably going to
stop using the HED front wheel on long rides both because it requires using
a valve extender and the spokes are hard to replace should one break as the
tyre, tube and rimstrip need to be removed and then a special thin socket
must be used to loosen the nipple. Also those bladed spokes have a tendency
to twist which may make them less aero than conventional round spokes and
having just 18 spokes isn't much of a reserve in the event one breaks. With
28 spokes I could continue riding with the wheel just slightly out of true
if one spoke breaks while with 18 spokes the wheel would go wildly out of
true if one broke requiring opening up the brake and possibly risking having
more spokes break. I once had a 16 spoke 369mm front wheel break a spoke so
I know what happens when a low spoke count wheel breaks a spoke although
that spoke breakage was clearly due to a spoke that had been damaged. When I
told Gardner about not using the HED wheel he said Easy Racers don't often
have front wheel problems unless someone hits something. The final problem
with the HED wheel is it was full of water after the rainy Grizzly Peak
Century, a problem I experienced on a rainy 600km brevet last year.
The wheel I plan on using
instead for long rides will be based on a Schmidt dynamo hub laced to either
the 24 or 28 hole Bontrager Maverick lightweight rim I showed you (need to
find out if Schmidt does 24H) or a Velocity Aeroheat AT 32H rim which has a
more aero shape but may be slower overall due to the extra air drag and
weight of 4-8 additional spokes. With the Schmidt I wouldn't have to be
concerned with making it to a certain rest stop by a certain time and won't
have any worries about battery charge states or carrying enough batteries.
This will be quite nice to have on a ride like BMB. My test with the Excess
Access bar shows the Lumotech headlights will work quite nicely behind the
fairing. I may have one 15W NiteRider mounted to the Excess Access bar as
well for high speed descents. This would be powered by the 4.5Ah NiMH
battery that runs the NiteRider taillight and NiteRider 5W helmet light. My
experience with the Schmidt-Lumotech equiped Stratus is that the two 3W
Lumotechs produce enough light for most level ground riding and one of them
is plenty for climbing. The lens and reflector is much more efficient at
putting light on the road than the MR11 bulbs used by NiteRider.
The distinctive looks of
my bike made it easy for the SAG driver coming from the 179 mile rest stop
to spot me on the road and give me my batteries approximately 20 minutes
before sunset. This was good as there was about half an hour of night riding
before I made it to that stop. I definitely got a lot for my $45 for this
ride. There was an excellent meal at the finish with vegetarian enchiladas,
rice and beans. Also at that 179 mile rest stop there were soy hot dogs. I
had two of these on buns, then when they ran out of buns had two more, one
straight and the other on a bagel. This rest stop closed about 5 minutes
after I left. The salt in these things really hit the spot and I remarked
that last time I had soy hot dogs was a year ago at this same rest stop. I
was told that comment had been heard a lot.
Here are the ride
statistics for this year on the Gold Rush: Distance: 335.0 km (207.7 miles)
Average rolling speed: 22.2 km/h (13.764 mph) Maximum speed: 90.1 km/h
(55.862 mph) Rolling time: 15:03:53 Elevation gain: 4180 metres (13,730')
Maximum elevation: 835m (2750')
And last year on the
Festina 20/20 prototype: Distance: 337.96 km (209.535 miles) Average rolling
speed: 23.4 km/h (14.508 mph) Maximum speed: 79.0 km/h (48.98 mph) Rolling
time: 14:23:08 Elevation gain: 4305 metres (14,120') Maximum elevation: 835m
(2750')
Note the course appeared
to be the same both years so the cyclecomputers must be calibrated
differently and the greater climbing last year may be due to different
atmospheric conditions.
In looking at the
statistics for both years I conclude at very high speeds (the sort of speeds
I don't like going in part to avoid getting into situations like what I got
into on this descent) the Gold Rush is 14% faster than the Festina. However
at normal cruising speeds the Gold Rush speed advantage is no where near
this great, probably more like 5% which is still significant on a long ride.
My other conclusion is that I'm not in as good shape this year though some
of this may be due to the Festina having a higher first gear forcing me to
go harder on the climbs with it. That prototype Festina with 3x7 hub had a
22" first gear while the Gold Rush has a 14.7" first gear which I made use
of on several climbs. I was also carrying more weight on the Gold Rush such
as the fairing, rack, Nightsun Tri-Light on the bike at all times, heavier
batteries, a Gortex jacket, additional gloves, more Cliff Bars, a bag of
salted almonds, full size frame pump, twice as many tubes due to two
different size wheels and so on. It would be interesting to see how speeds
compared on specific parts of the courses. Going on memory I think I was
cruising on level ground faster on the Gold Rush but climbing slower with
it. In both cases I finished the ride with plenty of energy left and no
pains which is the way I like to finish a long ride.
Interestingly on the rough
descent down Santa Rosa Creek Rd. to Cambria on the coast I saw numerous
road bike riders stopped repairing punctures. At a rest stop later on I was
talking with one who punctured both tyres on a big crack in the road just
prior to entering a corner. He went down at speed and had lots of road rash
but I think he completed the ride. While I was talking with him I heard a
loud explosion coming from the Rolf front wheel of another road bike.
Apparently this was due to a pinched tube from a repair he did due to a
puncture on Santa Rosa Creek Rd. I took it very easy down that descent and
as you know I don't like going really fast on descents in general but going
down Jolon Rd. it was a straight, smooth descent so conditions were right
for just letting it go without using the brakes which is how I ended up at
90 km/h. The bike was actually only half way down the hill and still
accelerating when I detected the air loss in the rear tyre. Considering what
happened it felt surprisingly stable with no air in the rear tyre at that
speed, I think the inherent stability of the long wheelbase helped here but
when I told Gardner that he thought it was mostly luck that kept the bike
upright. In any case it is not an experience I want to go through again and
by going back to a conventional wheel without a valve extender while keeping
the relatively puncture resistant Ritchey Tom Slick 37-559 tyre/Wrench Force
self-sealing tube combination I think the odds of a sudden air loss at speed
from happening again will be low though not low enough and I'm eagerly
waiting the introduction of tubeless road tyres which will eliminate most of
the tyre problems which cause crashes.
This incident also may
have put the final blow to the presta valve with me. For a while now I've
been admiring schrader valves because they are a standard used on cars,
trucks, motorcycles, air shocks and low-end bicycles all over the world and
I like the concept of settling on the most widely used standards (metric
system, 406mm and 559mm wheels, International English, etc.). Bike snobs
seem to prefer presta valves and look down on schrader valves but the only
logical reasons I can see for this are the presta valve being narrower and
thus slightly lighter and more aerodynamic and the presta valve not needing
as large a diameter hole in the rim which may be a strength issue on very
narrow rims, you know the type of rim that doesn't handle wide tyres well
and handles poorly in an air out condition. The main reasons people have for
prefering prestas seem to be looks and tradition. Presta valves were
something passed down by road bikes. At one time it was mostly road bikes
and higher end mountain bikes that had presta valves. I remember once
wanting 406mm presta tubes just for this reason, because it was something
used on higher quality bikes. That was in the early 1990s when presta 406mm
tubes were not available outside of the very expensive somewhat unreliable
AirB latex tubes. Now many high end downhill MTBs are using schrader valves
just like the motorcycles they were derived from and many MTBs and
recumbents are equiped with schrader valves on their air shocks. The world
is figuratively smaller now and I think settling on the lowest number of
standards is even more important now. It is time for the presta valve to
fall out of favour just like 451mm tyres and inches and miles. The roadies
can keep their presta valves if they want them. Now that I won't regularly
be using deep section aero wheel I have no more need for those valve
extenders that are only available for presta valves so I have no reason not
to use presta valves except for a few "stock" bikes that come drilled for
prestas only. 406mm rims like the Velocity Aeroheat AT and Bontrager
Maverick are wisely drilled for shcrader valves requiring one to use a
spacer if they want to run presta valves. This way even if you are using
prestas if you need an emergency replacement tube you can go into a
department store anywhere and find one rather than have to be drilling out
your rim on the road to take one of these tubes. The Festina is the next
bike to make the transition to self-sealing tubes and since the 406mm
version of this tube is only available with a schrader valve I'll simply
remove the spacers from the Velocity rims and run them that way. The high
speed air loss incident would not have happened with a schrader valve. The
fact the presta valve has a loose part which can be accidentally left open
and ridden that way only to press down under centrifugal force at high speed
is reason enough not to use presta valves.
Zach Kaplan Cycles
Alameda, CA 94501 USA
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