Just got a set of A2Z Components disc brake hubs for my next wheel build.
Model number XCFI, weight 115g:
Front hub with end caps removed:
Front hub end caps - these caps weight 15g. It seems possible to convert these hubs to 15mm through axle but some spacers would need to made up on either end and possibly some different seals would need to be used:
Front hub dimensional data (in mm)
|WL, width from center to left flange||22.5|
|WR, width from center to right flange||34.0|
|dL, left flange diameter||56.5|
|dR, right flange diameter||39.5|
|S, spoke hole diameter||2.4|
Model number XCRI, weight 247g:
The hubs have 2 sets of sealed cartridge bearings in the front and 4 sets in the rear. The cassette freehub is made from aluminium so it should really only be used with cassettes that have the big cogs on aluminium carriers like XTR, XT and SRAM PG990, PG1090, PG999. Running a cassette that uses separate cogs could result in the steel cog gouging the freehub body.
Rear hub dimensional data (in mm)
|WL, width from center to left flange||34.8|
|WR, width from center to right flange||19.8|
|dL, left flange diameter||56.0|
|dR, right flange diameter||59.8|
|S, spoke hole diameter||2.4|
A2Z Rear Hub Deconstructed
There has been some talk on the forums about rear hub drive failures on similar hubs - primarily the Rotaz hubs. I don't have a Rotaz hub to compare the A2Z to, but here are a series of pictures showing the A2Z rear disassembled:
Rear hub pawl system:
Close-up of rear hub pawl system with one pawl removed:
Freehub body - has 15 points of engagement and rear hub engages with 5 pawls simultaneously:
Rear axle and end caps - made from aluminum with an OD of 15mm and ID of 10.5mm:
Axle almost fully re-inserted into hub - shows end cap on axle and seal - seal seals against outer edge of bearing when axle is full inserted:
Axle end cap close-up:
You can dismantle the rear (and front) hubs for inspection and repair without tools. For the rear, just pull on the freehub and it will come out with the axle. This makes is very easy to keep an eye on the pawl mechanism, clean, regrease etc.
Rear Hub Update
I've been keeping an eye on the hub engagement mechanism and am sorry to say that it seems to be flogging out. The hub still functions perfectly, but on close inspection you can see that the freehub engagement teeth are wearing unevenly, this puts uneven pressure on the pawls and they in turn are damaging the aluminium hub shell.
I'm not sure what has caused what, but probably the soft aluminium of the hub shell has given way first, allowing the pawls to tilt sideways in their slots and in turn putting uneven pressure on the freehub teeth.
It also looks like the freehub teeth have made contact with the hub shell on occasion. If I had to guess this has probably been off some larger landings where flex in the aluminium axle has allowed this contact to occur.
I wouldn't really recommend this hub. The pawl support in the aluminium hubshell is an inherent design weakness. I've used these hubs for somewhere between 5000 and 7000km, mostly offroad. The hubs are relatively cheap, but I'd really expect to get 10 times the service length out of my next rear hub.
I'm going to replace this hub either with a DT Swiss 240s or a Tune Kong.