Burgundy Street Climb on a fixed gear (Melb)

I was feeling a bit energetic this morning and decided to ride all the way
up Burgundy St (Heidelberg) on my fixed gear roadie instead of turning left
onto Studley Rd at the hospital. I am running 45/16 gearing with 170mm
cranks on the fixie and was going great guns until about the pedestrian
overpass where I really started to slow down and feel the low cadence a bit.
By the time I got to the last 20 metres or so where it kicks up and turns to
the left I was going really really slow and it was lucky that I managed to
score a green light because I don't think I would have been able to get
going again from a standstill!!!

I have only just put a speedo on my fixie and I managed to hit 50km/h going
down the hill past Ivanhoe Cycles and using the following logic I think that
this is about 135 rpm or so........

50,000 m/h / 60 = 833.333 m/min
0.7m x pi = 2.199 m/revolution (for 700c wheel)
45 / 16 = 2.8125 wheel revolutions per pedal revolution
2.199 x 2.8125 = 6.185 m / pedal revolution
833.33 / 6.185 = 135 pedal revolutions per minute (give or take)

Let me know if anyone picks any mistakes in my calculation.

Gags

Gags Wrote:
I was feeling a bit energetic this morning and decided to ride all the
way
up Burgundy St (Heidelberg) on my fixed gear roadie instead of turning
left
onto Studley Rd at the hospital. I am running 45/16 gearing with 170mm
cranks on the fixie and was going great guns until about the
pedestrian
overpass where I really started to slow down and feel the low cadence a
bit.
By the time I got to the last 20 metres or so where it kicks up and
turns to
the left I was going really really slow and it was lucky that I managed
to
score a green light because I don't think I would have been able to
get
going again from a standstill!!!

I have only just put a speedo on my fixie and I managed to hit 50km/h
going
down the hill past Ivanhoe Cycles and using the following logic I think
that
this is about 135 rpm or so........

50,000 m/h / 60 = 833.333 m/min
0.7m x pi = 2.199 m/revolution (for 700c wheel)
45 / 16 = 2.8125 wheel revolutions per pedal revolution
2.199 x 2.8125 = 6.185 m / pedal revolution
833.33 / 6.185 = 135 pedal revolutions per minute (give or take)

Let me know if anyone picks any mistakes in my calculation.

Gags

Calc is ok, but measurement isn't. A 700C wheel is not 700mm
diameter... it is 622mm and then there is the width of the tyre to add
on.

Put the calcs aside though: 45/16 up Burgandy St?!?!?! That's crazy
talk!

Ritch


--
ritcho

On 2008-02-05, ritcho (aka Bruce)
was almost, but not quite, entirely unlike tea:
Gags Wrote:
50,000 m/h / 60 = 833.333 m/min
0.7m x pi = 2.199 m/revolution (for 700c wheel)
45 / 16 = 2.8125 wheel revolutions per pedal revolution
2.199 x 2.8125 = 6.185 m / pedal revolution
833.33 / 6.185 = 135 pedal revolutions per minute (give or take)

Let me know if anyone picks any mistakes in my calculation.

Gags

Calc is ok, but measurement isn't. A 700C wheel is not 700mm
diameter... it is 622mm and then there is the width of the tyre to add
on.

If I remember correctly, 25x700c is pretty darned close to 2000mm
circumference, rolling. Which puts 45/16 at 70.5 gear inches.

And 140rpm. Unless your speedo has 2100mm dialed into it, in which
case the rpms are still good.

P.S. Spin faster, bucko! I want 180rpm by next week!

--
TimC
Usage: fortune -P [-f] -a [xsz] Q: file [rKe9] -v6[+] file1 ...

On Feb 5, 8:33 pm, TimC -
astro.swin.edu.au wrote:
On 2008-02-05, ritcho (aka Bruce)
was almost, but not quite, entirely unlike tea:

Gags Wrote:
50,000 m/h / 60 = 833.333 m/min
0.7m x pi = 2.199 m/revolution (for 700c wheel)
45 / 16 = 2.8125 wheel revolutions per pedal revolution
2.199 x 2.8125 = 6.185 m / pedal revolution
833.33 / 6.185 = 135 pedal revolutions per minute (give or take)

Let me know if anyone picks any mistakes in my calculation.

Gags

Calc is ok, but measurement isn't. A 700C wheel is not 700mm
diameter... it is 622mm and then there is the width of the tyre to add
on.

If I remember correctly, 25x700c is pretty darned close to 2000mm
circumference, rolling. Which puts 45/16 at 70.5 gear inches.

And 140rpm. Unless your speedo has 2100mm dialed into it, in which
case the rpms are still good.

P.S. Spin faster, bucko! I want 180rpm by next week!

--
TimC
Usage: fortune -P [-f] -a [xsz] Q: file [rKe9] -v6[+] file1 ...

You can calculate it all on Sheldon Brown's website ... sniff.