Dimensions of BCD's and interfaces, ENO/Kart/etc

[spinningmagnets]

I've been wanting to do this for a while. The 5-hole interface for the sprockets that attach to the popular FLANGED ACS-Crossfire and White-Industries ENO freewheels are likely to be adopted by anyone who wishes to make an adapter or sprocket for the E-bike market:

Pic and dimensions here thanks to ES member DanGT86

http://endless-sphere.com/forums/viewtopic.php?f=28&t=47618&start=250#p831386

 

[spinningmagnets]

Karts occasionally use a shaft adaptation spider instead of a solid sprocket, this allows inexpensive and rapid tooth-count changes by having a chainring instead of a sprocket. Chainrings can be found in steel, aluminum, and composite materials...also using a chain pitch of #25, #219, #35, and others...The decision to have 6-holes in the mount was made in order to allow the option of having two "half moon" chainring sections, which allows the chainring set to be changed to a different tooth-count without needing to remove a wheel from the Kart

The standard Kart spider interface is 6-holes/6mm diameter each, in a Bolt-Center-Diameter (BCD) of 5.250-inches

 

[spinningmagnets]

Sometines it's useful to be able to attach a sprocket or chainring onto the left side of a bicycle wheel. The common disc brake ISO standard is BCD-44mm, bolts are 5mm X 0.80 (common M5).

Pic shown is an adapter to connect a 44mm BCD disc brake flange to a common 130mm BCD chainring, made by ES member recumpense (Matt).

 

[spinningmagnets]

ES member LightningRods found many inconsistencies in the standard BSA bottom-bracket thrreads, It was sometimes listed as 1.38 X 24, 1.375 X 24, or 1.37 X 24. Flanged freewheels (ENO, ACS, etc) and BB components are now sometimes used for jackshafts in non-hub drives.

BSA stands for "Birmingham Small Arms", a military firearms company in England that established many machining standards in the early days of the mechanization of industry.

Here is the discussion about finding the proper exact dimensions:

http://endless-sphere.com/forums/viewtopic.php?f=2&t=54237
1.375 X 24, ISO 6696 thread standard, 2008

 

[spinningmagnets]

Good pics (don't miss page-2):

http://www.bikeman.com/bicycle-repair-tech-info/bikeman-tech-info/1599-bottom-bracket-types

 

[spinningmagnets]

(I have not personally verified these dimensions yet)

The BBS02 sprocket is listed as having an 60.4mm BCD, and the five bolt hole diameters are 5.2mm. The center hole is 50.2mm in diameter.

The BBSHD is different, and it is__________
[insert image of blueprint here]

 

[spinningmagnets]

Shimano 9-spline freehub (Thanks to John Bozi for the pic)

 

[amberwolf]

If you really want to save that reference image, you need to upload it as an attachment, or if the source site goes away, so does the info.

Feel free to remove this post as irrelevant if you do upload it as attachment.

 

[spinningmagnets]

Good idea. I hear there will be a software upgrade and ES migration soon. I will take a screenshot and then upload (when I get home from work), then delete these last two conversation posts.

 

[amberwolf]

Why not just right click on the image displayed in the above post, then "save as"?

 

[spinningmagnets]

Huh...I always wondered what "save as" was for...