thru axles? E thru?!


Senior Retro Guru
Hi. So I've just bought a frame from here which is going to build my special bike. It's designed for a spec beyond anything I've ever built so this is a learning curve for me but I want to build something out of my comfort zone.

Anyway it uses a thru axle and I've got the details from the old skewer but I will need a new one. The details printed on it are '12-178-P15-20'. Basically deciphered - 12mm axle, 178mm length, p15 I'm guessing means pitch is 1.5 (looking at the derailleur hanger being designed for that I would say so anyway) and 20mm thread length.

So I think I've found an axle for it but it says it's only designed for E-thru. What the hell is E-thru? I'm used to good old fashioned quick release, E-thru sounds like some sort of electronic gizmo (I know it's not by the way :facepalm: )

Does anyone have any idea on this modern day witchery :LOL: How do I tell if it's an E-thru or not. Yes before anyone says it I know this is going to be an expensive build but I'm building it over the next 6 months buying parts as I can afford them. I wanted something special to get me to the races and this is definitely going to be special to me.


Retrobike Rider
The E-thru thing is just Shimano's name for their 1.5mm pitch axles, to distinguish it from the 1.0 and 1.75 Maxle ones from SRAM/Rock Shox.
(And it's not even anything specifically to do with e-bikes, just to add to the confusion :? )

As long as the diameter, pitch and length are right, (ie 12-178-P15...the new axle should slip in fine). The end length is pretty flexible given that it's a through hole 18-22mm will be fine.

There's a useful printable guide sheet available from the RobertAxle Project here: ... ide_A4.pdf

All the best,


Gold Trader
GT Fan

It is all getting a bit confusing. I just bought an e-bike saddle. Don't have an e-bike, wasn't aware they needed anything special or specific, never seen an e-bike seat post but maybe I need one to mount the saddle to, and maybe the post only fits an e-bije frame.

Or maybe it is all just marketing bs?

Hopefully I live to tell the tale after fitting the e-bike saddle to a normal bike and pedal using my own legs!