[Closed] 142x12 and boost 148 quick question (actual facts required!)

The syntace standard was the initiation of the 142 format, they called it X12. Obviously as you say other makers then designed other axle thread types but 'most' should have followed the basics for hub dimensions.

https://www.syntace.com/index.cfm?pid=1&pk=1314

As for 148, youd think they would follow same principle dimensions, just wider, but not found any published docs for it yet.

Thank you, just what I needed

If I'm reading between the lines right... I don't think you can just space out the end caps like you could going from 135 to 142 despite the 148 end caps being the same OD (presumably - as they'd need to have the same clearance for casssette/disc lockrings)

142 end caps sit into the frame, leaving the cassette and disc in the exact same relative location to as 135. That's why you could space out or swap end caps on 135 hubs for the 142 standard.

As far as I can tell 148 equipped bikes have the same/similar frame insertion depth as 142 - the flanges of the hub are wider apart - so if you were to space out a 142 hub by 3mm a side your cassette and disc will be 3mm too far away from the derailer and caliper.

Sounds like the realised that the new 142x12 'standard' didnt require the purchasing of enough new kit

llatsni - Member

As far as I can tell 148 equipped bikes have the same/similar frame insertion depth as 142 - the flanges of the hub are wider apart - so if you were to space out a 142 hub by 3mm a side your cassette and disc will be 3mm too far away from the derailer and caliper.

Though you can space mechs and either discs or sometimes calipers around.

llatsni - Member
If I'm reading between the lines right...

Depends what you're reading but yeah 148 is a different kettle of fish, more specifically it would need spacers as mentioned, easy enough if the frame were
i.s. mount but of course it won't be because post mount is [s]less compatible[/s] progess.

Though you can space mechs and either discs or sometimes calipers around.

You cant offset a mech -3mm tho can you ;0)

You could dish the hub across to the right to align the gears, space the rotor out 5mm (hope sell 5mm disc spacers) and have a 6mm axle spacer integrated into left/disc side of the hub axle.

Would be easier to just swap out the hub for the correct one tho.

STATO - Member

You cant offset a mech -3mm tho can you ;0)

Sure you can. That might actually be a small enough amount to do entirely with the mech's adjustment but failing that you can stand the entire mech off the hanger.

I didn't explain that very well, spacers won't work unfortunately: on 148, the hub flanges are 6mm further apart - therefore the caliper and derailer are 6mm further apart. Putting spacers on the end of 142 caps would put the cassette and disc out of reach. 3mm is a lot.

The extra 7mm going from 135 to 142 was made up "inside" the dropouts of the frame - the effective width between the caliper and derailer are identical.

Just read what STATO posted - you'd need a very accommodating wheel builder! 😯

Sure you can. That might actually be a small enough amount to do entirely with the mech's adjustment but failing that you can stand the entire mech off the hanger.

'-' as in MINUS 3mm, as in further to the centre, not +3mm which would be your stand off.

Just read what STATO posted - you'd need a very accommodating wheel builder!

No you wouldnt. Moving the hub 3mm towards the drive side would actually reduce the dish in the build and deliver more even tension to the wheel, this has been done on many many frames over the years, specialized are a particular fan of the concept with the old Big-Hit being the obvious one, but also in the specialized 142+ (yes thats a different standard again!) hubs that come on many current bikes.

If your wheelbuilder cant work that out, walk away!

3mm is a trivial amount to spacer parts around- I made 20mm spacers to fit a fireblade wheel into my suzuki, frinstance. It's fiddlier to make such small spacers than large ones, ironically. But certainly no challenge.

But, I had a brain fart and thought the mech attaches to the inside of the hanger, when of course it's on the outside! So spacers would make that worse not better. So that bit was total bollocks.

I believe the mech's own adjustment would be adequate- I can certainly adjust my mech to be more than 3mm too far towards the wheel, in a normal setup, you find that much variation between 2 different frames. But you're basically using the mech's margin for error, which assumes the frame doesn't already need it.

Or offset the whole wheel, as stato describes.

But the disc, no problem. Or IS adaptor if you have one of those.

Nothing to add to this except that I opened this thread to make a comment about 142x12 being one hell of a drive ratio 😯

But, I had a brain fart and thought the mech attaches to the inside of the hanger, when of course it's on the outside! So spacers would make that worse not better.

A 3mm spacer in between the mech cage and the main body would probably be enough to do it if you made sure the contact area was large enough to maintain stiffness.

Some of the chunkier mech hangers (I'm thinking of my Commencal) could probably lose getting on for 3mm without much harm. It also probably wouldn't be beyond the wit of man for someone to design an offset upper link (B link?) for shadow mechs which would shift the whole thing in a bit.

There are certainly a few options available if you really want to go that way

I may be missing something here but the original post asked about the OD of the hub ends being a certain size. Now being a pedant, OD To me means outside diameter and there fore the round bit around the aperture in which the axle passes.
Having done a fair, too much, amount of research into hubs and standards etc there aren't any, I've found, which specific the outside diameter of the flange. It's getting better for the front as many manufacturers are putting recesses into the forks to hold the hub in the right place for making fitting easier.
The rear often doesn't get this luxury, although it needs it.
If you're asking about the overall width of the hub then everything above this post makes sense.

OD To me means outside diameter and there fore the round bit around the aperture in which the axle passes.

As opposed to OLD which would mean then length of the axle?

OLD is how I feel! Just going on standard engineering abbreviations. OD outside diameter, ID internal or inside diameter.

Having done a fair, too much, amount of research into hubs and standards etc there aren't any, I've found, which specific the outside diameter of the flange. It's getting better for the front as many manufacturers are putting recesses into the forks to hold the hub in the right place for making fitting easier.
The rear often doesn't get this luxury, although it needs it.

If you click the link in my first response you will find links to the technical drawings which define the 142 dimensions, including hub end cap outer diameter, which is what the OP asked for.

It's all the subsequent response which are speculating why he wanted them and then suggesting things which make no sense