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My bike was -TWO- Wheels!
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Discussion Starter · #1 ·
Me and a friend have a little competition going on. Who can get the highest top speed...

Me and him both have exactly 41mph

This is on a FS rig with knobbies. What can i do to get that extra little 2 mph?

I am now running like 55/50 psi im in as much of a tuck as I can be in on a MTB and I am spinning out obviously. So the hill is getting me from about 30mph to 40

What can I do to get teh extra mph, I was thinking of cranking up the preload on both of my shocks to get rid of bob, but then though, I could lower both to get a lower stance, and be a little more aerodynamic.

So what are your suggestions to get that extra little bit?
 

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Do like Lance...

summitlt said:
Me and a friend have a little competition going on. Who can get the highest top speed...

Me and him both have exactly 41mph

This is on a FS rig with knobbies. What can i do to get that extra little 2 mph?

I am now running like 55/50 psi im in as much of a tuck as I can be in on a MTB and I am spinning out obviously. So the hill is getting me from about 30mph to 40

What can I do to get teh extra mph, I was thinking of cranking up the preload on both of my shocks to get rid of bob, but then though, I could lower both to get a lower stance, and be a little more aerodynamic.

So what are your suggestions to get that extra little bit?
Get one of those time trial hats, or a skin suit. At those speeds, baggy clothes will make some drag.
 

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summitlt said:
Me and a friend have a little competition going on. Who can get the highest top speed...

Me and him both have exactly 41mph

This is on a FS rig with knobbies. What can i do to get that extra little 2 mph?

I am now running like 55/50 psi im in as much of a tuck as I can be in on a MTB and I am spinning out obviously. So the hill is getting me from about 30mph to 40

What can I do to get teh extra mph, I was thinking of cranking up the preload on both of my shocks to get rid of bob, but then though, I could lower both to get a lower stance, and be a little more aerodynamic.

So what are your suggestions to get that extra little bit?
Easy:

Calibrate your computer so that actual tire diameter is smaller than what's input in computer. Get 2, 5, 10 mph extra with no extra effort. :D

I guess a serious answer would be to crank up the preload and just pedal like mad.
 

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My bike was -TWO- Wheels!
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576 Posts
Discussion Starter · #6 ·
Seems like that 41mph is terminal velocity. Must take a lot to get over that.

I dont want to "cheat" I want to do it for myself too. Guess Ill just crank the preload.
 

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I once hit 57.4 mph with semi-slicks while on a paved downhill road. the front end started to shimmy so bad I had to slow down.. imagine grabbing a fist full of front brake going that fast.. serious pavement crayon!
 

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roadiegonebad said:
actually, you want to take the air out of your shocks so that the bike drops lower and gets more aero with speed (like those old illegal Lotus F1 cars). and put 80psi in your tires
Actually I don't see how reduced drag will ensue from bike being marginally lower. I think you are talking about downforce not drag with Lotus cars. Better try aero tuck, zip up your jersey, get some lycra shorts (if you haven't already) but bump up the preload to reduce bobbing.

Also note that increasing pressure in your tires will whack your speedo out of calibration and it will read speed lower than it actually is. This effect is not negligable and you'd want to recalibrate your computer using the actual tire diameter at 80 PSI or whatever you'll run them at if you want accurate reading. Also don't forget to bring into question your buddy's speedo calibration if he does indeed beat you.

Another thing I remembered is that when doing top speed runs with a car you easily approach certain high speed (~180 kph) but to get to actual top speed (the last 20 kph or so) it takes ages. When applied to bikes this means that you rarely reach your actual top speed as you inevitably get tired before you hit the actual max as you can't sustain such power long enough.

What you can then try is conserving energy at the start and buiding up your speed slowly and then giving it all once you hit say 25 mph or some other suitable speed. The idea being that you conserve sprinting power (which is limited) for reaching top speed instead of fast acceleration at the low speeds. Good luck and hope you kick his butt.
 

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My bike was -TWO- Wheels!
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576 Posts
Discussion Starter · #11 ·
Boj said:
What you can then try is conserving energy at the start and buiding up your speed slowly and then giving it all once you hit say 25 mph or some other suitable speed. The idea being that you conserve sprinting power (which is limited) for reaching top speed instead of fast acceleration at the low speeds. Good luck and hope you kick his butt.
I think that is my tiket right there, usually a I sprint the whole way untill im not helping anymore.

Ill have to do that, ill report whenever it happens...
 

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Land speed records.

endurowanker said:
what are these bikes for? is that bottom guy riding on snow? :eek:
and yes, he is on snow. A perfectly groomed ski resort with some steeeeeeep hills. The top speed record is in the 127mph range. There are a couple of crazy french brothers that have been pushing that record for a few years.
 

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Yep, that's the fastest way to ride a bike. Down a sky course. They don't even pedal cause it's pretty much useless.

One thing that might help you go faster is making your bike and youself heavier (armor might come in handy, both for making you heavier and safer at the same time; a Full Face helmet, will do both, plus making you more aerodynamic), and/or more aerodynamic. It's no coincidence DH bikes are usually over 40 pounds.

You can also try putting 1' tires on your bike (less ground friction, if you're going DH on asphalt), that will give you some extra speed, but BEWARE it will also mean you'll need more distance to stop!

Godspeed.
 
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