ISIS spider?

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Timelord   1 W

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ISIS spider?

Post by Timelord » Dec 25 2017 12:54pm

Helping someone who wants a Bafang Ultra Max drive. Since he can't weld this into a DIY aluminum frame, he's planning to bolt the mounting plate in the middle of a DIY steel recumbent frame as an intermediate drive. But that means he'll need an ISIS spider without a crankarm to attach to the Ultra Max to use as a timing sprocket to the front crank. Anybody know of any armless spiders? I know Maxarya has a similar spider since their bikes use a similar layout, but that one is square taper, not ISIS.

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spinningmagnets   100 GW

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Re: ISIS spider?

Post by spinningmagnets » Dec 25 2017 3:58pm

Best of luck wishes on your search. If you find this, please post a link for the benefit of others who are searching for the same thing. However, I fear you are looking for the proverbial left-handed green-eyed Unicorn...

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amberwolf   100 GW

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Re: ISIS spider?

Post by amberwolf » Dec 25 2017 11:19pm

Why not take an ISIS crankarm with spider, and cut off the crankarm part? (and then grind away any remnants to smooth it into whatever shape you might want)


I did this with square taper types years back when I built CrazyBike2's various middrives, though most of those were swaged-on chainrings, IIRC, the same would work with the bolt-on-the-spider type.

12-C   100 W

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Re: ISIS spider?

Post by 12-C » Jan 01 2018 12:59am

I have designed this in CAD in the past.

I did not make the spider part was intending to use it for a very similar purpose. I followed the ISIS white paper to the best of my ability and I believe that I did it correctly but have never CNC'd a component from the design. So there fore I can not confirm that it is true.

The reason that I decided to design from scratch is because all the CAD drawings/free files I could find on the web (ex. Grabcad etc..) did not actually adhere to the design specifications according to my evaluation. And I didn't want to risk CNC one off prototype a paperweight in the end....

From memory, CNC a custom part like this would run a couple hundred $

The white paper
http://www.isisdrive.com/isisdrive/ISIS ... t_revD.pdf


here is a pic where I incorporated a 6 hole disc/cog spider
ISIS spider to fit 6 hole rotor single cog.jpg
ISIS spider to fit 6 hole rotor single cog.jpg (73.85 KiB) Viewed 171 times

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