Tuesday, May 16, 2006



Refinement
Yesterday I fixed up the 2 biggest problems with Whoops.

  1. Calf catching the derailleur as I push forwards
  2. Knee hitting the handlebar as I recover my leg

You can make these things out on the left... There's not too much spare room in there once the cover's on! So, I made a few changes to the mid drive....

The Mid drive is a step up gear arrangement. As it was, the initial drive was geared, and the final drive was single speed. You see, there are 2 chains in there.

So, now, I modified the mid drive & the wheel.

I shifted the multiple gears down to the wheel, along with the derailleur. The mid drive is only 2 cogs now. So now I have a much straighter hip to ankle line & I can push harder.

I'll give you some numbers. Front chainring is 52 teeth, Mid drive is 15 & 32 teeth. Wheel cogs are 28 through 11. In the biggest gear, 1 turn of the pedals rotates the wheel 52/15 x 32/11 = 10.08 times. So, at a pedal speed of 100 revs per minute (fast but not extreme), we'll be sitting on 1607 m/minute, or 96.5kmh. Push up to 120 rpm, and we'll be riding at 115kmh.

I also cut the handlebars a bit narrower, which should prevent the knee banging. I will eventually install a second brake, but not sure where I'll put the lever!

2 comments:

Anonymous said...

Hi Timbo - I've been reading your Blog with great interest and just wanted to send a reply in case you don't get too much feedback. It sounds great and I wish you guys all the best. How many KMs a week are you doing in test and training?

Team Captain Tim said...

Hi John,
Currently riding Whoops at least once a week, for an hour at Darebin Velodrome. Very spooky riding through 42deg. turns in a recumbent! Probably doing 40km in the hour I reckon. Otherwise, just riding a recumbebt to get my legs used to the different riding position.
BUT, I've given Whoops back to Ben for 2 weeks, so I'm going to miss my big Orange Egg!
See ya.
Tim