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