Taper roller bearings

[Guest machinman]

Hi all, i think its time for new headstock bearings. Has anyone tried tapers or should i go OE. 

I have the castellated socket, and i'm ok for tools.

Any thoughts?

Cheers.

[embee 7,288]

Up to you really. There are pros and cons with both.

Personally I think the std  cup&cone ball bearings are fine if adjusted correctly. They need to be well greased and have a significant amount of preload (designed to take it), then they'll last fine. I find the preload specified in the workshop manual is excessive (forget what, is it 15Nm?), and use something more like 10Nm before tightening the locking ring, but you need to feel the resistance to decide exactly what is appropriate. They do give a value for the force at the handlebar end to turn the steering, but that's getting a bit fussy IMO, yo can feel what is too loose or too tight.

 

Taper rollers need almost no preload but no slop, so potentially more fussy on adjustment and need to be monitored to ensure they don't develop any slack. If set correctly they'll offer potentially slightly less friction (if that's really an issue in practice) and in theory longer life than cup&cone, but in the real world on a road bike I personally don't think there's any real clear cut advantage.

[Guest machinman]

Thanks Embee, ive gone with a genuine set, bit pricier than the taper set. 

The originals are approaching 40,000 miles. I regreased at 20,000 miles, and they are a little bit notchy now, so i figured if i pull it apart i may as well replace.

Thanks for the torque tip.

[embee 7,288]

Just checked the manual. It says apply 23Nm preload, as said I find this too much. Might be worth working up to that after fitting new bearings just to make sure they're settled, but I'd suggest then backing off and gradually work up again by feel. Bear in mind when you tighten the locking nut it can apply extra load depending on the thread clearances, so feel your way. I find around 10-15Nm then nip the locknut and see what it feels like works for me.

[DaveM59 1,603]

I wouldn't say tapers are an upgrade. The taper bearings on the X9 certainly don't last that long, the rollers create 'dents' in the outer race that then make the steering notchy usually in the straight ahead position that gives a very weird sensation when cornering. They also as stated take very careful adjustment, as if loose they knock over bumps, and if tight give a squared off tyre like feeling as if the bike won't lean into corners, then falls suddenly.