SRAM MTH 746 148x12 BOOST hub - service?

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SRAM MTH 746 148x12 BOOST hub - service?
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flag Dazn
Posted: Feb 29, 2016 at 12:16 Quote
Hi,

I have just taken delivery of my new Bronson and within 20 miles the rear hub feels like it has play in it already, so I had a look to see how to take it apart and it's not obvious, also there's nothing on SRAM's website showing how it's done.

On the non-drive side there's a 19mm outer nut and then another 19mm inner, which would need a 19mm cone spanner to attach, but then in the end of the axle there's a hex key which looks like 12 or 14mm.

Question is if I buy a 19mm cone spanner is it just a simple case of holding the inner nut and then un screwing the outer, assume it's a normal thread and not left handed?

Any help / diagrams / guidance would be much appreciated.

Thanks!!
flag HindlePie
O+
Posted: Mar 14, 2016 at 13:16 Quote
Hi

Did you get anywhere with this?

Mines' started doing the same after just a couple of rides. I've tried tightening the outer nuts but the little 'knock' is still there. I'll try and investigate further next week.

Mark
flag jkgamble
Posted: Mar 15, 2016 at 12:29 Quote
Had same problem on my Nomad. It's been a while but as I recall you hold the axle with the large Allen key then tighten the inner cone to set tension. The outer cone is to tighten against the inner to lock it in place. As to whether the threads are left hand or not I can't remember. There may be an arrow on one of the cones but I may be thinking of a different hub. Just be gentle and don't force anything. Also do not make the inner nut too tight. You want the play to just be gone but you want the bearings to still be smooth. I would hold the axle with the Allen key and loosen the outer nut first to discover how it's threaded. You're least likely to over tension bearings that's way.
flag Dazn
Posted: Mar 16, 2016 at 8:57 Quote
Hi,

I worked this out, you either need an allen / hex key in the non-drive side and then loosen the outer nut (standard thread) or the way I did it was to buy a 19mm cone spanner and hold the inner nut with that, then loosen the outer one with an adjustable spanner. Same result.

The axle comes out very easily and is simple to clean and grease.

Putting back together was the same, I did up the inner nut and then held that while tightening the outer one up to it. I had a little bit of play so I just tightened the inner nut slightly each time until the play had gone.

Very simple job.
flag Replicon
Posted: May 27, 2016 at 3:31 Quote
Hi,

Same issue with my Bronson; small play in rear MTH 746 hub after about 200km. Aim to adjust the preload this weekend. Found this diagram on the internals:

http://www.veloruf.de/n/shimanoteile.html?id=50191219

Quick question; when you remove the lock nut and inner cone nut (and freehub), is it possible to use the axle to tap out the bearings? Have bought some replacement bearings (SKF 61903-2RS) just in case the current ones need changing but if I can't use the axle to tap out the bearings I'll need to invest in a blind hole bearing puller. Unless I can bodge it somehow....?

Cheers.
flag Replicon
Posted: May 29, 2016 at 23:47 Quote
Just to update for anyone who might find it useful.

Adjusting preload is easy, insert 12mm hex/allen key in the non-driveside axle end, then use 19mm spanner and 19mm cone wrench to adjust.

Also, axle does slide out when locknut and inner cone nut are removed.
flag sensai-miagi
Posted: Feb 1, 2017 at 1:11 Quote
One year on and your post and informative response is still making happy riders, thanks Danz for this Smile

Dazn wrote:
Hi,

I worked this out, you either need an allen / hex key in the non-drive side and then loosen the outer nut (standard thread) or the way I did it was to buy a 19mm cone spanner and hold the inner nut with that, then loosen the outer one with an adjustable spanner. Same result.

The axle comes out very easily and is simple to clean and grease.

Putting back together was the same, I did up the inner nut and then held that while tightening the outer one up to it. I had a little bit of play so I just tightened the inner nut slightly each time until the play had gone.

Very simple job.
flag johnniewalker
O+
Posted: Feb 24, 2019 at 15:21 Quote
Make it 3 years on!

sensai-miagi wrote:
One year on and your post and informative response is still making happy riders, thanks Danz for this Smile

Dazn wrote:
Hi,

I worked this out, you either need an allen / hex key in the non-drive side and then loosen the outer nut (standard thread) or the way I did it was to buy a 19mm cone spanner and hold the inner nut with that, then loosen the outer one with an adjustable spanner. Same result.

The axle comes out very easily and is simple to clean and grease.

Putting back together was the same, I did up the inner nut and then held that while tightening the outer one up to it. I had a little bit of play so I just tightened the inner nut slightly each time until the play had gone.

Very simple job.
flag ronnikn
Posted: Mar 24, 2019 at 11:15 Quote
Thanks!

Noticed a little play on my Bronson v3 after two rides!!
flag asoto746
Posted: Apr 7, 2019 at 15:53 Quote
Found Diagram for the rear hub on SRAM. It was a PAIN to find.

Anyways, this post has been helpful for all of us! Look at Page 36, it shows the hub assy.

https://www.sram.com/sites/default/files/techdocs/2016_sram_spc_reva.pdf

In there you can find replacement parts for the whole hub.

Don't f*ck up the axle end caps like I did, or you will end up buying the whole axle... they don't sell the caps alone.
flag Jmyrick100
Posted: Oct 26, 2019 at 18:03 Quote
Current/direct link, still page 36.

https://www.servicearchive.sram.com/sites/default/files/techdocs/2016_sram_spc_reva.pdf


asoto746 wrote:
Found Diagram for the rear hub on SRAM. It was a PAIN to find.

Anyways, this post has been helpful for all of us! Look at Page 36, it shows the hub assy.

https://www.sram.com/sites/default/files/techdocs/2016_sram_spc_reva.pdf

In there you can find replacement parts for the whole hub.

Don't f*ck up the axle end caps like I did, or you will end up buying the whole axle... they don't sell the caps alone.
flag mtbpadrino
Posted: May 2, 2020 at 5:12 Quote
Cheers all for the infos and the links. Been a while since this thread been started and can say that today, 02.05.2020 still provides quality help.

I did swap the shimano HG type freehub to an XD type. Been a pain in the b*t to try and figure it out which XD will match to my MTH 746 hub.

No point getting in touch with Sram as they're useless and clueless...

Anyway, once you managed to get the axel out you'll need a mallet to gently tap the freehub of the axle. It's just pushed on the axle and nothing else holding it. A few gentle tap and the freehub will fall of. Then you need to regrease everything and slide the new freehub on the axle.

All done and good to go.
flag p0is0n0ak
O+
Posted: May 2, 2020 at 6:55 Quote
bikerxaba wrote:
Been a pain in the b*t to try and figure it out which XD will match to my MTH 746 hub.


This is the XD driver for the 746.
flag Burfield642
Posted: Feb 9, 2021 at 4:09 Quote
This was so helpful thank you. Bronson V3 same issues. Hoping to upgrade sooner than later. ????????????
flag Sladey404
Posted: May 10, 2021 at 14:42 Quote
Whats the current XD drive for the 746 hub pls
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