Changing headset bearings, any wiring in the way?

steve_sordy

Wedding Crasher
Nov 5, 2018
8,362
8,590
Lincolnshire, UK
Focus Jam2, Acros headset. lower headset bearing is grumbling, sounds like rusty balls!

It is not too bad, but I might as well replace them sooner rather than later. I'll do top as well as bottom and use Endura bearings. I have read that the ones used by Acros are carp!

Apart from pulling out the two leads going into the display, are there are any hidden wires I need to be aware of?

I know about the ones under the grips hiding in the creased bar, but I won't be touching those. I plan to remove the bar and stem and leave them dangling while the work gets done.
 

Peaky Rider

E*POWAH Master
Feb 9, 2019
821
520
Derbyshire Dales
No, there's nothing in the headtube.
Just a Di2 cable running inside the handlebars to the display and one from the display to the side scoop, which you are already aware of. I didn't even bother disconnecting mine.
The old bearings and cups were a bugger to get out though.
 

steve_sordy

Wedding Crasher
Nov 5, 2018
8,362
8,590
Lincolnshire, UK
The bike is a 2019 Focus Jam2 9.6 NINE

I believe that the headset is an Acros AZX-212 AH, 1-1/8", tapered, HSZS 44/286-ZS56/40 W

I understand the "1-1/8", tapered" part of the description, but what does the rest of it mean?

What size bearings do I need to order that fit with that? Are they plain roller bearings, or is either of them an angular contact bearing? What width are they?

Any help would be appreciated. :)
 

S D

Active member
Mar 26, 2019
191
124
Shelley
I wish I could help with the bearings but unfortunately I can’t and would like to know the answer also.
PS I changed my handlebars some time ago and found to my cost how easy it is to trap the control button wire in the stem clamp as it passes the stem to the display.
It’s tricky to repair ?
 

Si1

Member
Jun 6, 2019
23
35
OX18
The bike is a 2019 Focus Jam2 9.6 NINE

I believe that the headset is an Acros AZX-212 AH, 1-1/8", tapered, HSZS 44/286-ZS56/40 W

I understand the "1-1/8", tapered" part of the description, but what does the rest of it mean?

What size bearings do I need to order that fit with that? Are they plain roller bearings, or is either of them an angular contact bearing? What width are they?

Any help would be appreciated. :)


@steve_sordy did you ever get details of the bearings?

I have a Jam2 9.6 which I'm having problems with very slight play in the headset, which I can't seem to get rid of no matter how much preload I apply.

I'm not sure whether I need to try new bearings.
 

steve_sordy

Wedding Crasher
Nov 5, 2018
8,362
8,590
Lincolnshire, UK
@steve_sordy did you ever get details of the bearings?

I have a Jam2 9.6 which I'm having problems with very slight play in the headset, which I can't seem to get rid of no matter how much preload I apply.

I'm not sure whether I need to try new bearings.
Nope, apparently those details are all you need!

My long term LBS guy must have been a bit busy because he would not order any bearings and let me bring the bike in once they arrived, he HAD to see them. I wasn't happy at leaving my bike for a week when it was rideable, so I called in at the bike shop at Sherwood Pines the next time I was there. He didn't ask what the bearings were, he said go get a coffee and come back in 20 mins! I brought him a Kit-Kat to show that I appreciated his service (I paid him as well). :)
The point is that the sizes and types of the bearings were kept in stock. So they cannot be unusual.
 

Si1

Member
Jun 6, 2019
23
35
OX18
Nope, apparently those details are all you need!

My long term LBS guy must have been a bit busy because he would not order any bearings and let me bring the bike in once they arrived, he HAD to see them. I wasn't happy at leaving my bike for a week when it was rideable, so I called in at the bike shop at Sherwood Pines the next time I was there. He didn't ask what the bearings were, he said go get a coffee and come back in 20 mins! I brought him a Kit-Kat to show that I appreciated his service (I paid him as well). :)
The point is that the sizes and types of the bearings were kept in stock. So they cannot be unusual.

Thanks, I think I've sussed it now. The 2020 Focus website details the headset for the carbon framed models. Out of that I've worked out that the bearings are these: (is42/28.6 is52/40).
If you Google them, they do appear to be quite common and available.
 

steve_sordy

Wedding Crasher
Nov 5, 2018
8,362
8,590
Lincolnshire, UK
Thanks, I think I've sussed it now. The 2020 Focus website details the headset for the carbon framed models. Out of that I've worked out that the bearings are these: (is42/28.6 is52/40).
If you Google them, they do appear to be quite common and available.

Those are different to the ones I posted* (which was from the Focus spec). You are making me wonder whether the size I gave was for the alloy version whereas my bike, like yours, is the carbon fibre version. ooh err!

Note* See post #3 above.
 

Si1

Member
Jun 6, 2019
23
35
OX18
Those are different to the ones I posted* (which was from the Focus spec). You are making me wonder whether the size I gave was for the alloy version whereas my bike, like yours, is the carbon fibre version. ooh err!

Note* See post #3 above.
I have a screen grab of the 2019 Jam 9.6 from last year which doesn't refer to the headset at all. However, I noticed on the spec for the 2020 carbon framed bikes (which I'm 100% sure are the same frame as they still use the Shimano motor), there are details for the headset (as per attached image).
I've ordered some replacement bearings (as I'm having this issue with some very slight play in the headset that I can't dial out no matter how much preload I put on), so I guess I'll find out if they're the right ones!

Screenshot_20200421-002906_Samsung Internet.jpg
 

Si1

Member
Jun 6, 2019
23
35
OX18
I have a screen grab of the 2019 Jam 9.6 from last year which doesn't refer to the headset at all. However, I noticed on the spec for the 2020 carbon framed bikes (which I'm 100% sure are the same frame as they still use the Shimano motor), there are details for the headset (as per attached image).
I've ordered some replacement bearings (as I'm having this issue with some very slight play in the headset that I can't dial out no matter how much preload I put on), so I guess I'll find out if they're the right ones!

View attachment 29470
As an update, and for anyone's future reference, the bearings I mentioned above are correct for the Jam2 9.6 (carbon frame).
I used these :
Headset Bearings | Tapered Headset | 1 1/8" - 1.5" | IS42/28.6 & IS52/40 | eBay

I still have a very very slight bit of play in the headset, so I'm guessing the bearings weren't at fault!
@steve_sordy sorry to bother you but I know you have the same bike as mine. If you hold the front brake and put your hand on the top headset bearing dustcap, whilst rocking the bike with quite a bit of force, can you feel a very slight bit of movement?
I'm not sure whether what I'm experiencing is within acceptable limits and I'm chasing my tail, or there's a more serious issue!
 

steve_sordy

Wedding Crasher
Nov 5, 2018
8,362
8,590
Lincolnshire, UK
..............
@steve_sordy sorry to bother you but I know you have the same bike as mine. If you hold the front brake and put your hand on the top headset bearing dustcap, whilst rocking the bike with quite a bit of force, can you feel a very slight bit of movement?
I'm not sure whether what I'm experiencing is within acceptable limits and I'm chasing my tail, or there's a more serious issue!

With bare fingers (I normally have gloves on when doing this), I could persuade myself that there is something there, but it may just be a slight rotational movement of the spacers vs the frame. I'm happy with it anyway. I have felt loose headsets before and mine isn't.

PS: Thanks for confirming the bearing sizes on your 2020 bike. Mine is the 2019 and I have only two explanations of why your spec and mine differ. One is that Focus changed the spec from 2019 to 2020. The other is that the spec for the alloy version, differs to that for the carbon version. I may have picked up the alloy version by mistake.
 

Si1

Member
Jun 6, 2019
23
35
OX18
With bare fingers (I normally have gloves on when doing this), I could persuade myself that there is something there, but it may just be a slight rotational movement of the spacers vs the frame. I'm happy with it anyway. I have felt loose headsets before and mine isn't.

PS: Thanks for confirming the bearing sizes on your 2020 bike. Mine is the 2019 and I have only two explanations of why your spec and mine differ. One is that Focus changed the spec from 2019 to 2020. The other is that the spec for the alloy version, differs to that for the carbon version. I may have picked up the alloy version by mistake.

Thanks for responding Steve, I think I've sussed it now.
It appears to be a problem with the top compression washer. I put it together without the dust seal and could see play between the steerer tube and the inner of the bearing race no matter how much compression I dialed in.
Tried another compression washer from my other bike and I can easily dial out the play.
The factory fitted one is made of plastic which seems a poor design choice to me!

Regarding the bearing type, the number you was given started with ZS which is zero stack. The carbon Jam has an integrated headset so it needs the IS bearings. (I reckon the ZS ones are for the aluminium frames).

Incidentally I have a 2019 Jam2 9.6 too, not the 2020 one (although I'm absolutely sure the 2020 carbon framed one is exactly the same frame).
 

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