I finally had a chance to work with some of the new OnePointEight head parts. These are being rolled out for heavier eBikes.

Matt has a Transition Repeater 29″. He was ‘upgrading’ from a RS ZEB R 160mm to a Fox 38 Grip 2 Factory 180mm. The ZEB that the bike came with has a 46mm crown race, the Fox has a 40mm crown race as there are few 1.8″ options in the aftermarket.

So, Matt had to solve a problem, how to convert from the ZS66 lower that the Transition has to the 1.5″ steerer?

Currently, there are just a couple of options to do this. In this case we used the Arcos ZS66/40 will replace the ZS66/46 unit. These have a cool seal above the bearing that more headsets should have. Rusted out lower bearings are a real problem.

The taper length of the fork we removed was about 80mm long. fyi

Here are some more detailed specs on a ZS66/46 system.

While we don’t have any formally published numbers or tools for small builders but it looks like the size and tolerances are:

Head Tube Bore: 65.95mm, +0mm, -0.05mm Token (or 65.95mm,+0, -0.1mm FSA)
Head Tube Bore Depth: 15.0mm, +0.5mm, -0 Token (or 16.0mm,+0.5mm, -0 FSA)
Crown Race Seat Diameter: 45.78mm, +0mm, -0.10mm Token (or 45.8mm,+0, -0.1mm FSA)