Headset Bearings, are these the right ones

[kidloco]

Hi oh wise cycling folk,

I am trying to source some replacement bearings for my BMC Roadmachine.

I took them out and took some pics.

I asked BMC as well, and they originally tried to sell me a whole headset assembly which includes a new top cone for £105. When pressed again they gave me this info.

Top:
MR155 {870/DJ-RS}
41.8*6.5*45°/45°

Bottom:
MR019 {073/DJ-RS}
51.8*7.5*45°/36°


I just wanted to double-check with someone more mechanically minded than me (my cat qualifies as this) before I order and potentially waste any cash.

Are these the correct bearing sizes?

FSA Bearing 36 x 45, 1.5" TH073/DJ - MR019

Contact Angle: 36°×45° Height: 7.5mm ID: 40.0mm OD: 51.8mm

gearmechhanger.com

FSA Bearing 45 x 45, 1 1/8" MR155,TH-870DJ

gearmechhanger.com

 

[Berger]

Looks fine, the codes are all you need MR040 etc.

I think these are FSA codes but the rest of the information is the bearing size internal chamfer and external chamfer etc

 

[jamest23]

@kidloco Did these non-BMC replacement bearings work for your headset?. I’m having exactly the same issue for my Roadmachine 01 Three and looking at options. However I just read elsewhere that with the BMC Teammachine that the Top bearing is proprietary and a standard replacement won’t marry with the BMC ICS (See below). As I have the ICS on my Roadmachine I wondered if you also encountered this compatibility problem?


“Disappointingly, the top headset bearing is of a proprietary size. BMC say that it is a 1 1/8 but it mates perfectly with the ICS cover, preventing you from using anything else. I upgraded to a Chris King Dropset and the dimensions were perfect but the bearing will not sit in the cover. After contacting their support, they confirmed the bearing has to work with BMC’s cover. Other after-market options also won’t work. BMC also charge an exorbitant amount for a spare headset, which isn’t the best quality, so you will want to be religious in keeping this area maintained. Clearly, they bought a load during manufacture. Watch out for this nasty surprise!”

 

[Saytan]

Fortunately top bearings tend to last absolutely ages, it's bottom ones that die easily, so you may get away just replacing the bottom one.

 

[kidloco]

@kidloco Did these non-BMC replacement bearings work for your headset?. I’m having exactly the same issue for my Roadmachine 01 Three and looking at options. However I just read elsewhere that with the BMC Teammachine that the Top bearing is proprietary and a standard replacement won’t marry with the BMC ICS (See below). As I have the ICS on my Roadmachine I wondered if you also encountered this compatibility problem?


“Disappointingly, the top headset bearing is of a proprietary size. BMC say that it is a 1 1/8 but it mates perfectly with the ICS cover, preventing you from using anything else. I upgraded to a Chris King Dropset and the dimensions were perfect but the bearing will not sit in the cover. After contacting their support, they confirmed the bearing has to work with BMC’s cover. Other after-market options also won’t work. BMC also charge an exorbitant amount for a spare headset, which isn’t the best quality, so you will want to be religious in keeping this area maintained. Clearly, they bought a load during manufacture. Watch out for this nasty surprise!”

Yes, I ordered the FSA parts listed above and they fit perfectly. I'm also running an ICS stem as well (ICS2, they new one).

 

[jamest23]

@kidloco Thanks and good to know! I'll give it a try...