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· No Crybabies
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Discussion Starter · #1 ·
Mentioned this in another thread, but someone suggested doing a separate report.

Ok, I get a little bored once in a while and try different things. A few years ago, it was doing double centuries in the mountains on fixed gear. Lately, it's bombing down mountains as fast as I can, sort of at the other end of the spectrum.

Here's the report, with the SRM data graphic, on my website:

http://www.midcalracing.com/downhill/dhtt051808.htm

Any suggestions to go any faster, other than getting a bigger chainring? The 67 already cost $200, and while they make them up to 110 teeth (would probably drag the ground), the cost goes up to $700. I'm not *that* crazy. ;-)
 

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Crazy, crazy

Wild stuff. Remarkably consistent speed, to average 49.6, and only top out at 57.5 . I've been at or barely over 50 mph a few times -- that's plenty, and I can't imagine sustaining it for 10 miles.

I suspect, as you note, that you'd get a higher average by coasting more, assuming you can get more aero in your tuck. 2 scary suggestions for modified position:

-Superman. Modify your aero bar setup so your arms are stretched out straight, as was done for some hour records a while back before they changed the rules. Handling might be fatally compromised, but you're not scared of that, are you?

-full "egg" tuck. Get rid of the aero bars altogether. Use the drops when you're pedaling, and when you go into coasting mode, move the hands to the tops next to the stem, get your chin down on the bar, and tuck the elbows in against the chest. I've seen the pros do it in the Alps, and I've done it for 30 seconds at a time. It's wicked aero. Handling? Well . . .

Crazy, but impressive, man.
 

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Maybe you should hold off on your quixotic quest for higher speeds until the kids are grown up and moved out.

BTW it ain't often one can write a sentence with 2 consecutive "Q" words. ;-)
 

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Let me get this straight--- you are flying down the mountains on a bike with a rear disc and a +50mm front? On aerobars? (Of course, I first was thinking you were riding fixed) Seriously, how does that bike handle?




Fixed said:
Mentioned this in another thread, but someone suggested doing a separate report.

Ok, I get a little bored once in a while and try different things. A few years ago, it was doing double centuries in the mountains on fixed gear. Lately, it's bombing down mountains as fast as I can, sort of at the other end of the spectrum.

Here's the report, with the SRM data graphic, on my website:

https://www.midcalracing.com/downhill/dhtt051808.htm

Any suggestions to go any faster, other than getting a bigger chainring? The 67 already cost $200, and while they make them up to 110 teeth (would probably drag the ground), the cost goes up to $700. I'm not *that* crazy. ;-)
 

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MB1 said:
quixotic quest
BTW it ain't often one can write a sentence with 2 consecutive "Q" words. ;-)
I quickly question qualified queries about your assertion.

"Quixotic quest" is almost redundant, isn't it?
 

· No Crybabies
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11,692 Posts
Discussion Starter · #8 ·
solid

filtersweep said:
Let me get this straight--- you are flying down the mountains on a bike with a rear disc and a +50mm front? On aerobars? (Of course, I first was thinking you were riding fixed) Seriously, how does that bike handle?[/IMG]
Actually, it's rock solid, until there's a cross wind. By way of context, I rode this bike nearly all last summer preparing for the Furnace Creek 508 in October. I've done solo double century training rides on it. I rode it for most of the 205 miles, until I abandoned, in the 508, then. There were some wicked winds that day, which were mostly head winds, but when the road turned, I'd get a push sideways like someone yanked on the bike with a rope. But, it was always manageable, even if difficult.

When I switch from this bike back to back with my Bianchi 928 SL, a 13 pound bike, the Bianchi feels so nimble it's almost unnerving at first. It makes the Cervelo feel like a truck.

One problem, though, is the 82 mm deep front wheel on the Cervelo. I have found that on mountain descents over 40 mph, starting a few hundred yards behind trucks, I'll get some nasty buffeting. Front wheel wants to jump all over the place unpredictably. I either have to back off or pass them.

So, bottom line is that I have a *lot* of experience on this bike, and on bikes with aerobars generally. Training for and doing ultra rides almost requires it, so you get very used to it. Also, it's hard to describe adequately, but this particular road is very suited for doing this. It has a relatively constant grade, big, wide sweeping banked turns that I probably could take flat out at 80 mph, a wide shoulder and 4 wide lanes, new, clean, smooth pavement, and not much traffic at most times. Could not possibly find a better place, short of a closed road.

Actually, I feel safer doing this than on my 13 mile commute to work.
 

· Shirtcocker
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you need a steeper hill...I'm surprised you couldn't go over 60 with that combo. I've coasted down plenty of CO passes at over 55--then again I was tucked and not pedalling.
 

· No Crybabies
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Discussion Starter · #10 ·
yes

Bocephus Jones II said:
you need a steeper hill...I'm surprised you couldn't go over 60 with that combo. I've coasted down plenty of CO passes at over 55--then again I was tucked and not pedalling.
There certainly are steeper roads around. There is one only 10 miles from my house that I have hit 56 mph on, but only instantaneously, and this is a 2 lane road with tight turns. Far more dangerous. Also, not exactly a "time trial" kind of effort -- more like a strap on your big cajones and take your chances kind of thing.

I hit 64 mph descending into Death Valley from Townes Pass several times, including in the dark after riding 220 miles, and without any aero antics. Sustained over 50 mph there for a very long time.

This isn't so much about a top speed, though, even though that's really the highlight of the effort. It's a high speed time trial. The goal was to find a relatively safe place to sustain a high speed effort for a substantial period of time, where pedaling, not a suicide tuck, would get you to the bottom the fastest. I'm confident that here, tucking and coasting, is not the fastest way. I've tried that a hundred times here. Some combination of tucking, which is difficult on a time trial bike, or just getting very low on the aerobars (Superman, as someone mentioned), plus power, is probably fastest, unless someone gets a chain ring well over 67 teeth.
 

· Knives, Guns, and Booze
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2,942 Posts
Wow, and I thought I was the schniznit back in 1994 when I popped a 56 toother on front and a hard-to-come-by 12 tooth cog on the rear (needed a slightly longer chain as well), since I would draft behind semis whenever possible on Highway 32 in between Chico and Orland. Of course, regular downhill spurts in high cadence on Skyway was fun, especially when the cars weren’t gaining on me.

But now I’m much older, and much wisdom has been gained. I suddenly realised that I wasn’t immortal.
 

· No Crybabies
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11,692 Posts
Discussion Starter · #15 ·
gravity

threesportsinone said:
Strap a pulse jet engine to you bike for your next attempt, once you get bored with that strap it to your chest and jump out of a plane. You can find the video of him riding it on youtube, as well.
Think I'll stick with gravity and leg power. Not quite that bored or crazy. ;-)
 

· Unlabeled
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3,729 Posts
More weight

Fixed said:
Mentioned this in another thread, but someone suggested doing a separate report.

Ok, I get a little bored once in a while and try different things. A few years ago, it was doing double centuries in the mountains on fixed gear. Lately, it's bombing down mountains as fast as I can, sort of at the other end of the spectrum.

Here's the report, with the SRM data graphic, on my website:

http://www.midcalracing.com/downhill/dhtt051808.htm

Any suggestions to go any faster, other than getting a bigger chainring? The 67 already cost $200, and while they make them up to 110 teeth (would probably drag the ground), the cost goes up to $700. I'm not *that* crazy. ;-)
If you add weight and don't increase the wind resistance you'll increase your speed. Adding non-rotating weight will be most effective for hitting the highest speed. Adding rotating weight will store energy from steeper parts of the descent, giving a lower maximum speed but a higher average speed.
 
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