Originally Posted by
alfa111
Looks like TrackHackSolutions on facebook is selling these for $250 each. That seems a little steep.
I'm going to modify the bearing pressfit dimensions and send the drawing back to my machinist, then I'll see how much he'll charge for 5 or 10 of these.
The typical road skewer works fine, all it needed was two spacers from a leftover fixed gear hub, and I cut down the sleeve from the original shimano freewheel setup (seen in black on the spindle).
https://photos.app.goo.gl/FoxdaLWSLG7OYVLD2
https://photos.app.goo.gl/x2jErEB3q7NtNMik2
chainline looks perfect:
https://photos.app.goo.gl/quD6ssJacoKbbyoq1
As far as standing starts, I'd say it'll work fine. It has a lot of intertia, but not as much as a 220lb guy on the track, so to mimic that I would run a larger gear than on the track for standing starts. I'll try some starts on it tonight and see how it goes.
Looks awesome!
One good thing is that since you are using a proper track cog on the rear, you could rig up a way to put the speed sensor next to the flywheel that would have a magnet doube-sided taped to it. And that would get you speed that might be close to real world simulations. It would a nice bonus to find that it's calibrated to provide exponential resistance based on the speed of the flywheel and having it match the real world for a given generic CdA.
Also, maybe engage a chain tensioner on the drive side before doing starts. The skewers may allow for slipping.
One more question: Does the fan have some sort of gate on it to allow you to fine-tune resistance like the Wattbike does? Are you doomed to have to switch chainrings/cogs to get different resistance levels?