ChuckD6421 

Hiya,
I need to replace the lower headset bearing on my 2013 Trek Domane 5.2 and not finding clear answers to what works.
I did find lower headset bearings for "2010+ 5 Series Madone frames". Does anyone know if this would work?
Or, does anyone know exactly what the specs are for this part so I can match it up somewhere?
Thanks.

jimc101

https://www.canecreek.com/headset-fit-finder - IS 52/40

Any good LBS should stock these, have you tried your local Trek dealer?

ChuckD6421 

Yes, have been to Crane Creek and I see that result. But if I'm not mistaken, this is an integrated crown race and that result is for a press fit. When I switch to integrated it then opens up 2 more fields for "Bottom" (not sure what they're referring to but my inside diameter looks to be more like 39.8), and for "Bearing seat angle" which I do know what they're referring to and by my eyeball looks more like 36 degrees than 45. So with those uncertainties I tried emailing them and neither the email link on the Finder page works for me, nor did they answer my separate email with an inquiry.

So that's what led me here looking for someone who might have access to the actual specs.

And btw, my nearest Trek dealer is 27 miles away and my last encounter with them led to my vowing never to set foot there again.

Thanks.

Krijsh

I have used this bearing - "Wheels Manufacturing 1.5" 36 x 36 degree Stainless Steel Angular Contact Bearing 40mm ID x 51mm OD x 6.5mm wide" cut and paste into Amazon

I would recommend getting a bearing that has a black oxide finish to resist corrosion a little more than the standard.

In the Enduro bearings catalogue look under headsets. You'll find the bearings you're looking for near the bottom of the last page. Yes it says they're for Madone but they fit. Make sure you get the year of manufacture correct.

Here is another page from edgesportsuk that clearly outlines the sizes etc:
Google - " trek-madone-headset-bearing-kit-2011-and-later-acb3645-and-acb6808ss" it will be the top result.

I also recommend spreading a liberal amount of clear silicon grease (any waterproof carbon-safe grease really) on and around the bearing when installing. Especially in the gap between the crown and the lower part of the headtube to slow the ingress of water and dust. It will require cleanup but has helped get more life out of the lower bearing.

These are not really "press fit" and can be changed by hand usually. An old tire lever sharpened to have a screwdriver-like flat end might be needed. When using any tools around carbon, be gentle. Just in case you didn't know, also be aware that the angles quoted can be for the physical tapers on the external race surfaces and also the "angular contact" angles of the bearing innards.

Some guide specs for the job:

Always, always check your own bike for the correct specs
- Steerer tube compression nut 9-10 NM
- Steerer tube top cap nut 5 NM
- Stem to steerer tube 5.2 NM
- Stem to handlebars 5.2 NM

Good luck

ChuckD6421 

Thanks very much Krijsh, great info there.
I'm good with the procedure, mostly wasn't sure the Madone's and Domane's were compatible.
Tx again.

SquidPuppet

$25.00 for a single bearing? Ouch.

ChuckD6421 

Right?
Only consolation is it'll hopefully last as long as this original part has, >4 yrs.
But gouging is the nature of the industry.

fietsbob

Try to keep the crud out.. add an O ring or a sleeve section of inner-tube before you put the fork back in..

to cover the gap.