# Re: OT Back on the Track

On Sep 13, 12:39 pm, Jay Beattie <jbeat...@xxxxxxxxxxxxxxx> wrote:
On Sep 13, 9:58 am, "Kerry Montgomery" <kamon...@xxxxxxxxxxxx> wrote:

"Frank Krygowski" <frkrygowREM...@xxxxxxxxxxx> wrote in message

news:j4npbh\$l1g\$1@xxxxxxxxxxxxxxxx

Michael Press wrote:
In article
<5560b2f2-1954-4c54-ba4f-7c4ab62bd...@xxxxxxxxxxxxxxxxxxxxxxxxxxxx>,
Jay Beattie<jbeat...@xxxxxxxxxxxxxxx>  wrote:

On Sep 12, 7:54 am, "dustoyev...@xxxxxxx"<dustoyev...@xxxxxxx>  wrote:

How fast do you have to go to stay up on the banks?

I started on the rental bikes at Alkek. Yes, the banking (only 33.3)
was truly a thrill, the first couple of corners (i.e., the first lap)
was a thrill I will never forget<g>!
--D-y- Hide quoted text -

- Show quoted text -

12mph depending on conditions (wet/dry).
http://www.flickr.com/photos/bikeportland/142592414/
I was always a crappy track racer, but I raced in San Jose and at
Alpenrose, and the deal with Alpenrose is that it is much more 3D.
You look up, you look down -- not just across.

bank angle:    a
speed:         v

We want the speed for which the tangential force at the contact patch is
0.

First, I think you mean lateral friction force, not tangential force.
Tangential refers to the direction of motion.  However, see my comment

vv
g.sin a = ---.cos a
r

vv = g.r.tan a

For a 40 deg bank and a 15 meter radius
v = 11.106 m/sec = 40 km/hour.

Alpenrose at 43 deg, 16.6 meter is a 27 mph turn by this method.
How do you get 12 mph? By setting a maximum tangential force at
the contact patch?

I'd assume 12 mph is a rule of thumb, coming from experience.  It may take
into account that the track may be wet sometimes in some places. It may
take into account that if you go too slowly, your outside pedal may hit
the track, since you'd be nearer to vertical.  And of course, it may be
wrong.

I'm trusting your number crunching on the 27 mph, but it's really not
applicable in any case.  There is no requirement that the lateral friction
force be zero.

--
- Frank Krygowski

At this distance in time my memory may be imperfect, but the Raleigh pros
were at Alpenrose 40 or so years ago, and I seem to recall one of them
riding at well under 12 mph at the very top of the track, where his outside
pedal would have more clearance from the track.
Kerry- Hide quoted text -

- Show quoted text -

It doesn't take much speed to stick to the sprinter's line, but up
bank, you have to keep your speed up -- but not a lot.  I follow the
12mph rule of thumb because I don't want to test the lower limit.http://www.youtube.com/watch?v=R8eVHE1kcuU

Corresponding action with motor, without helmet:
Cyclists are wimps.
DR
.

## Relevant Pages

• Re: OT Back on the Track
... was truly a thrill, the first couple of corners (i.e., the first lap) ... Alpenrose, and the deal with Alpenrose is that it is much more 3D. ... into account that the track may be wet sometimes in some places. ...
(rec.bicycles.tech)
• Re: OT Back on the Track
... was truly a thrill, the first couple of corners (i.e., the first lap) ... Alpenrose, and the deal with Alpenrose is that it is much more 3D. ... You are off on a different tangent. ...
(rec.bicycles.tech)
• Re: OT Back on the Track
... was truly a thrill, the first couple of corners (i.e., the first lap) ... Alpenrose, and the deal with Alpenrose is that it is much more 3D. ... You are off on a different tangent. ...
(rec.bicycles.tech)