Shimano I-Spec B bar clamp

I bought some shifters which use the I-Spec B mounting interface, but I don't have the accompanying brakes. Part of…
6h 7m
1× print file
0.05 mm
0.40 mm
12.00 g
9
76
2
792
updated March 3, 2024

Description

PDF

I bought some shifters which use the I-Spec B mounting interface, but I don't have the accompanying brakes.

Part of this was an experiment to see if 3DP plastic could repeatably stretch over the bar & still adequately clamp. This would enable users to fit & remove accessories, like shifters, without access to the end of the tube or bar. In practice, this worked wonderfully well, with some revs, like rev 3, outperforming rev 7 because more of the arc length is available to flex. The clamp is strong enough, although it is certainly weaker than the stock metal solutions.

  • therefore, I made my own clamp
  • rev 3 & 4 both leverage cast aluminum fittings that bridge between the shifter & the bar that came with my shifters
  • M5 bolts & nuts required
  • rev 3 has the shifter bolt coaxial with the bar clamp bolt, which puts the shifter vertically too far down for ease of each -- hence, rev 4 where it's the shifter mounting bolt axis is 4.5 mm below the bar axis
  • printed in PLA just fine

I will likely no longer be updating this model any more since I got shifters with a dedicated bar clamp (not I-Spec)

  • printed in Clear resin on Form 3, seems fine so far though I thought it might be too brittle

Rev 3

Screw lengths

  • for rev 3, it's important to use M5 x 10 mm socket head cap screws for the bar clamp & M5 x 20 screw for the shifter mount, plus M5 nuts to fit everything together

Rev 4

  • Don't use this one
  • See the Make for more details.
  • Intended to entirely replace the cast aluminum intermediary piece.

Rev 7

  • best working one so far
  • doesn't use the cast aluminum intermediary piece -- to remove this piece, disassemble the shifter from the bottom; don't try to rip it out like I did, because there is a captive pin riding in a slot (SL-M670-B)
  • not adjustable -- make the adjustments in CAD for drop from the bar axis, fore offset from bar axis, & side offset (left/right)
  • light interference fit, probably because I mismeasured something, but it works to one's advantage so that there is no play between the mount & the shifter body
  • doesn't cover the adjustment slider slot in the shifter, so rain & mud could get in
  • files provided for front/left shifter, simply mirror it to get the other side
  • uses an M5 x 8 countersunk bolt for mounting the shifter
  • M5 x ~12 socket head cap screw for clamping the band

Rev 8

  • best lateral offset so far
  • vertical drop from bar perfect
  • didn't adjust the fit to the shifter, but there's some undesirable play, gonna try to get rid of this in the next version by lengthening the grab around the sliding plateau
  • covers up the adjustment slot better
  • uses an M5 x 8 countersunk bolt for mounting the shifter
  • M5 x ~12 socket head cap screw for clamping the band

2023-09-13: rev 9

  • beefed this one up since rev 8 broke on me
  • longer engagement on the “rails” on the shifter body
  • had to cut a literal corner off the piece due to an interference, will try to fix in future rev so no cutting is necessary to fit

2024-01-19: rev 11

  • way more beefy
    • resulting thickness means the clamp can no longer mount without removing brakes, grips, etc.
      • however, after a few months of testing I think this might be the minimum 1-piece solution that will survive indefinitely
  • the clearance bite is now part of the model which avoids the end of the channel on the shifter body
    • in a previous revision, this had to be manually cut off or otherwise removed
  • printed in Tough 2000 resin on Form 3
  • nut pocket was really tight to insert, but was totally fine after
  • I think it was an M5 x 20 CSK
  • bolt going to shifter is the same as before
    • 2024-02-05: actually, it's now more like an M5 x 10 if I had to guess, up from what looks like an M5 x 6 CSK

2024-03-02: rev 11

  • this iteration finally failed, & now the failure is not in the band clamp area
  • printing again in Bambu PA-CF, 50-70% grid infill to see if that's any better
  • this has been a great lesson in this peculiar load scenario

Tags



Model origin

The author marked this model as their own original creation. Imported from Thingiverse.

License


Highlighted models from creator

View more