Chainring bolt spacers

Joined
Apr 25, 2014
Messages
2,768
Location
Sausalito
Can I use 4mm spacers to get a better chainline? For pedal bikes no problem but wonder if a motor ok.
 

Attachments

  • B1148DB5-2581-4248-BF0C-A267B8AEA8DA.jpeg
    B1148DB5-2581-4248-BF0C-A267B8AEA8DA.jpeg
    3.4 MB · Views: 206
  • E291FB52-23AD-4523-A8E6-F82B76EF85F0.jpeg
    E291FB52-23AD-4523-A8E6-F82B76EF85F0.jpeg
    3.4 MB · Views: 206
  • 2571D691-F916-4CC3-8B90-492E46C59818.jpeg
    2571D691-F916-4CC3-8B90-492E46C59818.jpeg
    3.6 MB · Views: 206
  • EC260431-A372-464E-9097-6A2762A99E4D.jpeg
    EC260431-A372-464E-9097-6A2762A99E4D.jpeg
    3.7 MB · Views: 206
Hummina,

Yes, you can even use individual bolts with standoffs to separate motor driven sprockets laterally. Three bolting points (a minimum) determine a plane, but 5 or more bolting points will give added torsional stiffness to the hub. I use class 12.9 high strength bolts for the bolts going through the spacers as they can be tightened somewhat more than generic bike bolts.

It looks like you are using a one-piece spacer which is likely better than a group of standoffs but it can be more difficult to fabricate.

F6F74029-73A6-46F5-B4A9-2BC56251F9E2.jpeg

The above sprocket is spaced by both a concentric spacer ( 2.25” exhaust pipe) and 5 bolt through standoffs. I just used generic bolts here as they and the concentric spacer make for redundancy of torsional rigidity.
 
DingusMcGee said:
Hummina,

Yes, you can even use individual bolts with standoffs to separate motor driven sprockets laterally.

It’s hard to see what’s in ur pic and maybe it’s not a jackshaft, but if it is a jackshaft, isn’t it rough on the bearings to have the chainring so distant from the bearing and not have the chainrings over the bearing? I can use the 4mm spacers or machine the carrier for the rear sprocket and straighten the chainline that way if worth it but more expensive/work.
 
“ isn’t it rough on the bearings to have the chainring so distant from the bearing and not have the chainrings over the bearing? ”

Some dual bearing forms are designed to handle eccentric loadings. They each have a “V” shaped race.

Note that this cantilevered sprocket is stiffened and supported by both bolted standoffs and a short piece of round exhaust pipe centered and acting as another spacer. This redundancy of spacers gives the projected forms additional torsional rigidity.

5EE9F007-9003-4F34-B135-01438693815A.jpeg



The chainring on the sprocket & mount are subject only to human pedal forces since the motor has a separate chain drive.
 
Back
Top