"These headsets last forever"?

For discussions about bikes and equipment.
Brucey
Posts: 42272
Joined: 4 Jan 2012, 6:25pm

Re: "These headsets last forever"?

Postby Brucey » 22 Jun 2020, 7:56am

Samuel D wrote:A swing in length of 0.2 mm is equivalent to a 72° turn of the M6x1 preload bolt. That’s huge.


it is and it isn't. In Nick's example the length change is a slight overestimate, but the gist of the argument is on the face of it fair.

However it should be noted that the bearings are sensitive to load, not free head tube length, in other words the stiffness of the assembly is what changes the preload in the bearings when the free length changes.

If the bearings are set at ~20C then the possible temperature excursion is +20C or -30C. This corresponds to free length changes in the head tube of ~ +0.072mm or ~ -0.108mm.

The stiffness of the head tube vs the steerer tube will likely vary from one frame design to another, but it is likely that the changes in free length are comparable with those experienced when the preload is applied. If so, in hot weather the preload might increase from (say) 200kg to 400kg and in cold weather you might lose the preload entirely, and experience movements in the bearing of ~0.1mm or so. Neither thing will give the headset bearings the kiss of death immediately, but if the preload is wrong (too high or too low) to start with, it might help cause damage.

FWIW I have long thought that it could be a good idea to include a wave washer in an Ahead headset build, just above the wedge; something that squashes flat @ ~400kgf load and 0.5mm travel would be about right I think. Setting the headset bearings would then become a matter of feeling the torque ramp up as the washer was squashed flat, and then backing off 1/4 turn. Preload wouldn't vary with settling/temperature excursion so much. A potential downside is that the wedge might move around more than it does anyway; it might be that the wedge could benefit from having its own sleeve against the steerer, such that the wedge always moved against the sleeve not the steerer. CF steerers commonly suffer worryingly in this respect and this approach would be of benefit anyway.

cheers
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reohn2
Posts: 40711
Joined: 26 Jun 2009, 8:21pm

Re: "These headsets last forever"?

Postby reohn2 » 22 Jun 2020, 9:22am

pwa wrote:Either I have a magic touch with an allen key or I've been really lucky, because the move over to threadless headsets brought me no problems.....

Nor me,including tandems.

......... I regard threadless headsets as one of the least troublesome components on a bike.

Me too.

The Hope headset on my Sala Vaya has well in excess of 30,000miles and I haven't touched it other than swapping stems and adjusting during the process.
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jb
Posts: 1044
Joined: 6 Jan 2007, 12:17pm
Location: Clitheroe

Re: "These headsets last forever"?

Postby jb » 22 Jun 2020, 10:31am

I think some people could find problems with a door stop.
Cheers
J Bro

mikeymo
Posts: 1888
Joined: 27 Sep 2016, 6:23pm

Re: "These headsets last forever"?

Postby mikeymo » 22 Jun 2020, 12:53pm

Thanks for all the feedback folks.

So the answer to my original question, which was something like:

"If the cartridge bearings are the important bit, does the rest of the headset matter?"

seems to be yes, because of design, especially seals. But the cartridges bearings matter too.

I'll carry on with the caged ball headsets that came fitted, and put my new Grade 10 balls and Comma grease in when I've got the urge. I suppose I should at least open them up to find out how terrible these bearings are, or aren't.

In the meantime, I think I've found the headset I'll fit, next time I need one:

https://shop.fullspeedahead.com/headsets/road-mtb-urban-commuting/the-pig

Loose balls (or could be), which is what I want. And 8/32" balls in the bottom race, phwoar!!

Though to be honest, tracking down loose ball headsets, actually for sale, is a bit of task. At least ones from a manufacturer I've heard of.

Samuel D
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Location: Paris
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Re: "These headsets last forever"?

Postby Samuel D » 22 Jun 2020, 1:25pm

pwa wrote:I regard threadless headsets as one of the least troublesome components on a bike.

I’m sure plenty of them are (expensive cartridge models, mudguards, good-weather riding anyway, five bikes to spread the load, knowledgeable set-up?).

But my observations of riding companions’ bikes tell me it’s also one of the most commonly misadjusted components of a bike. Too tight or rattling loose is depressingly common. It occurs to me that the owners probably think their headsets are fine, which just goes to show you … something.

mikeymo wrote:https://shop.fullspeedahead.com/headsets/road-mtb-urban-commuting/the-pig

Loose balls (or could be), which is what I want. And 8/32" balls in the bottom race, phwoar!!

Now we’re talking! I think those are 16/64" balls, though. Which numbers suggest it’s twice as good again as you thought.

mikeymo
Posts: 1888
Joined: 27 Sep 2016, 6:23pm

Re: "These headsets last forever"?

Postby mikeymo » 22 Jun 2020, 1:42pm

Samuel D wrote:
pwa wrote:
mikeymo wrote:https://shop.fullspeedahead.com/headsets/road-mtb-urban-commuting/the-pig

Loose balls (or could be), which is what I want. And 8/32" balls in the bottom race, phwoar!!

Now we’re talking! I think those are 16/64" balls, though. Which numbers suggest it’s twice as good again as you thought.


LOL, you noticed. Just converted to point how much more biggerer they are than the usual 5/32" balls in caged/loose ball set ups. 60% more biggerer.

Brucey
Posts: 42272
Joined: 4 Jan 2012, 6:25pm

Re: "These headsets last forever"?

Postby Brucey » 22 Jun 2020, 3:41pm

if you want a loose ball headset and it is threadless 1-1/8" for a bike with mudguards that sees the weather then this

https://www.sjscycles.co.uk/headsets/sun-1-18-inch-aheadset-with-steel-cups-black/

might be the best seven quid you have ever spent. The rubber compression ring should mean that water is less likely to run down into the top bearing and you can replace with loose balls to your heart's content.

There are also steel 'Ritchey Logic' models which use a 'semi-cartridge' approach; again not expensive and I think you can fit loose balls in these too.

FWIW most headsets can be made to last well, all it takes is a little grease, keeping the water out, and some good adjustment. I can usually manage it, so It should be simple, right? Funny how often it all goes horribly wrong for other people....?

cheers
Last edited by Brucey on 22 Jun 2020, 3:56pm, edited 1 time in total.
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~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~

mikeymo
Posts: 1888
Joined: 27 Sep 2016, 6:23pm

Re: "These headsets last forever"?

Postby mikeymo » 22 Jun 2020, 3:51pm

Brucey wrote:if you want a loose ball headset and it is threadless 1-1/8" for a bike with mudguards that sees the weather then this

https://www.sjscycles.co.uk/headsets/sun-1-18-inch-aheadset-with-steel-cups-black/

might be the best seven quid you have ever spent. The rubber compression ring means that water is less likely to run down into the top bearing and you can replace loose balls to your heart's content.

There are steel 'Ritchey Logic' models which use a 'semi-cartridge' approach; I think you can fit loose balls in these too.

cheers


Thanks Brucey, I'll bookmark that. Interesting the way Google works. I twigged that people selling them often call them "semi-cartridge", presumably to try and lure people in with the word "cartridge", when really it's just ball bearings.

I've got lots of Grade 10 balls and a massive tub of that CV grease we talked about. So at £7.49 a throw it's barely costing me anything. Well, apart from not getting the warm glow of spending a small fortune on a very simple component of course ;-)

Of course this will all be moot once I get Bob Jackson to build the frame of my dreams with a threaded steerer.

seph
Posts: 160
Joined: 3 Sep 2010, 8:22pm

Re: "These headsets last forever"?

Postby seph » 22 Jun 2020, 5:13pm

I’m currently trying a messy compromise with my Campagnolo Record and changing the grease often. That hasn’t stopped the familiar witness marks from showing up on the races.

For whatever reason, I have not had this problem to the same extent with threaded headsets. Why might that be? (I’ve had other problems with those.)


I had a similar problem with mine.. (Campagnolo record 1’’ ahead) as it was relatively expensive (previously I have tended to buy cheap steel ones for other machines) I let my lbs fit it. It was notchy within 400miles... I thought Ill of the shop at first, but their other work has been spot on, they actually have a torque meter (unlike me!) so I don’t think that was fair..
I replaced the caged bearings with loose and it was ok for a little while, but then got worse quite quickly, so I replaced with a cheaper steel one.

reohn2
Posts: 40711
Joined: 26 Jun 2009, 8:21pm

Re: "These headsets last forever"?

Postby reohn2 » 22 Jun 2020, 5:14pm

jb wrote:I think some people could find problems with a door stop.

It would appear so. :?
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