Shimano Altus Rear Hub (FH-CT90) - Axle Swap

[Afasoas]

Hello Hive Mind,

I'm looking at putting a wider solid (non-QR) threaded axle into the rear hub of the Gas Pipe Hybrid.
I've been out and measured the hub three times.
As far as I can make out:

• OLD / distance between inside edges of dropouts: 135mm
• dropout width: 6mm
• outer locknut width: 14mm
• total axle width: 175mm

At the moment, the outer lock nuts that secure the wheel in situ sit flush with the end of the axle, which is nice and neat.
Not great for attaching the hitch for my Carry Freedom trailer, hence looking at the axle swop.

I found this data sheet which suggests Shimano would have originally supplied the hub with a 185mm axle.
And, for some reason, probably an OEM decision, mine has a 175mm axle? (or perhaps the bike has been converted to 7 speed at some point, but the shorter 174mm 6 speed axle from an original 6 speed hub has been re-used, like this, for example?


Before I go ahead an order a 185mm axle, does the assumption above RE shorter axle sound reasonable?
I also need to double check the diameter. It looks like 9mm to me; measuring 9.5mm with my vernier gauge over the threads?

Thanks

[Afasoas]

I took the plunge and ordered a pair of NOS front and rear hubs  - identical part numbers.

And the great news is they've turned up with a spacer and a 185mm axle making them both suitable for 135 mm OLD spacing and suitable for use with the Carry Freedom trailer hitch. Looking forward to getting the axle swapped out and then storing the hubs safely away until it's time to get a new set of wheels built up, giving the bike another lease of life.