Bluesguitar

I've stripped down a 1985 Trek 720 that has what I believe to be its original Stronglight A9 roller bearing headset. The components look pretty good now that I've gotten rid of all the old hardened grease, so I'm inclined to just put it back together again. My question is about the four convex/concave rings and where the lubrication should go relative to them and also the bearing races. I'm assuming the rings are supposed to stay put in their cups and cones while moving over the bearings but I'm not sure. Two of the surfaces are black plastic and in good shape where the ring contacts them.

Would anyone recommend replacing this headset while I've got it disassembled? I'd need to have the pressed pieces removed and replaced by a mechanic if I got a new headset.

HillRider

If the rollers and the races are in good condition why replace headset? Clean off all the old grease, lubricate with new fresh grease and put it back together. I expect a Google search will give you a parts diagram and assembly instructions.

Bluesguitar

OK thanks
I'm wondering now if I have a mixture of parts since the plastic parts are just the two cones - the one on top of the fork crown and one on top of the headtube. These look OK where they contact the rings but the one on the fork crown is superficially chipped outside that contact area.
Does lubrication go on both sides of the metal rings?

mpetry912 

these are phenomenally durable headsets. the two metal "plates" function as cones. I do put some grease on both sides of them. then just clean the rollers and re-install.

parts are available but post a pic if you have questions.

Mark Petry
Bainbridge Island, WA

dsbrantjr

Never Fix A Running Piece. If the parts look unworn, lube it up and reassemble it. I would not be too concerned about getting lubricant places it doesn't belong, it will get all over everything with use/time anyway. Just make certain that the rollers have plenty.

JohnDThompson 

IMO, those Stronglight roller bearing headsets are the best threaded headsets ever made. They combined durability, lightness, and affordability in a way that has never been matched. If your headset has plastic cups, it's B-10 rather than an A-9. The conical metal pieces are the races on which the rollers run. They are intended to "float" inside the cups to accommodate for minor misalignment. Grease them up, and the roller assemblies, re-install and it should be good for anther couple decades.

N.B. as an experiment, in 1988 I installed an A-9 headset on my commuter bike and rode it for twenty years with zero maintenance. I opened it up in 2008 to see how it was holding up, and only found some slight discoloration on the lower stack races. I reassembled it, putting the former lower stack rollers and races in the upper stack, and vice-versa, and will check on it again in 2028.

dedhed

Replacement bearings are out there should you need to replace them.

https://www.benscycle.com/Strongligh...SABEgK2NPD_BwE



https://www.peterwhitecycles.com/str-hs.php

reconnaissance

I've been running the same Stronglight headset in my Cannondale mountain bike since 1986. For giggles and a nod to the Moly DiSulfide grease thread, that's what kind of grease I put it together with and it is smooth as...well, you get the gist.

Cheers.

Bluesguitar

Ok thanks will put it back together and see how it works out!

CyclingFool95 

My 96 Colnago that I bought last year came with a Strong-light. It looked remarkably good when I disassembled it, but I just couldn't get the load on it right - no matter what i did it was either too loose or too tight. Finally, I gave up and put a Chris King headset on it.

JohnDThompson 

A roller bearing headset will always have more drag than a ball-and-cup headset, but since, unlike hubs or bottom brackets, headsets are not in constant rotation when in use, that increased friction is irrelevant. Jan Heine of Bicycle Quarterly suggests that it may actually be a benefit in dealing with high-speed shimmy.

If your headset was binding at a particular spot, rather than just exhibiting consistently more drag throughout rotation, that is an indication that the head tube and/or crown race seat is not perfectly perpendicular to the steering axis. Re-machining the head tube and/or fork crown race seat would address that problem.

WizardOfBoz

Agree with Mark: grease the side touching the rollers like you would ball bearings. Enough to cover and lube. Cover the other side, and mating surfaces thinly to prevent water getting in and rust/corrosion forming. Quick question: are the "rollers" really cylindrical or are they slightly tapered?

Here's a pic from the retro-grouch site.

Andrew R Stewart 

I expected that John would chime in on this thread. We have both used many Stronglight roller bearing headsets but have rather different opinions.

If you have plastic head tube cups/cones then you have the lower cost version, uses the same rollers and conical contact surfaces. After 6+ on personal bikes and many more installed for customers I find they have some differences from balled headsets that bare notice.

First is the lack on open interior volume. What? Well this speaks to how much grease one can trap inside the headset. Less space is less grease. less grease is less "oil" (remember bearings quickly plow a trough through grease and push most all aside, from then on then the oil in the grease feeds the bearings). I found, unlike John's experience, that these headsets likes more frequent servicing.

next up is the adjustment. The many parts inside the headsets make for a lot of possible slop/movement. While I hate stiff turning headsets I ran these with a bit more preload then I would with a balled design. I also found that I usually went back to a recently serviced unit and increased the preload after initial use.

Last on my list is the tall stack height. A couple of MMs more then a Campy NR/SR. So when retrofitting a Stronglight roller bearing unit to an existing bike care needs to be taken in the prior to purchase measurements. When the top/lock nut doesn't have many threads of engagement it can strip, a steel nut was a common upgrade on customer installs.

At one time the bearings were available as a kit independent of the complete unit. The 4 conical contact surfaces and two plastic retainered roller elements. Every so often these can be had on E bay. The NIB (as in "bag") A9 I have on my shelf waits for the right project. Andy

mpetry912 

I have these A9s installed on most of my vintage bikes, however I'm running the lower unit only. Upper bearing is usually Campy.

The stronglight top nut and cup are alloy and pretty easy to round off Plus running the lower unit only puts the stack height back to what it should be.

I have a limited supply of parts and bearings, PM me for info

Mark Petry
Bainbridge Island, WA USA

Road Fan

Trek sourced those headsets with the plastic and metal parts in those days - one came to me new on my 1984 610. Yours is probably original. If you keep it lubed it should last numerous more decades. I think it's called A10. Originally the locknut was (at least mine was) marked "Bernard Hinault."

I lube the rollers and the bearing ring faces that will face the bearing. I don't lube the other faces, but oil will seep into those interfaces, over the years. If you're going to toss it, PM me first, please!

JohnDThompson 

The Stronglight rollers are cylindrical, not tapered. This means there is some sliding contact as the bearing rotates, but as noted above, headsets are not in constant rotation when in use, so the added friction was felt to be an appropriate compromise in keeping the cost down and accommodating minor misalignment.

Stronglight did make a special wrench for these headsets to minimize the risk of damage to the soft aluminum parts, much like the Shimano scalloped headset wrenches.

Bluesguitar

Thanks to all for the info!
I'll put it back together with lube as you all suggested and see how it works-
It came apart pretty easily with an adjustable wrench on the top and a thin Park wrench on the bottom but the softness of the material is noted.

WizardOfBoz

That's too bad - tapered roller bearings would seem to be the perfect setup. None of the sliding issues that your note mentions. Another issue with the design is the spacer - one could make the roller spacing smaller.

On edit, I spoke to an expert at SKF bearing about this. He mentioned that standard taper bearings have a radial thrust that has to be resisted by a lip. So my idea of a tapered roller thrust bearing would have some impracticalities. He mentioned that the cylindrical roller bearings, while they have some "rub", do not have the issue where the bearings are forced out. In his words, the Stronglight design is probably the best design possible. And had a bike with these bearings installed (and had built unicycles, recumbents, mountain bikes, and road bikes - a real bikie!) so I trust his expertise. At least, I was impressed.

He did mention that Harley and I think BMW use tapered rollers on their motorcycle headsets. Had a great conversation with the guy - a real expert.

mpetry912 

oh gosh, don't let the "tapered vs cylindrical" discussion put you off these - as John said above, given how the bearings are loaded and the low rotational speeds, these A9s (and the related Miche unit) are really the ideal design, far more durable than any spherical bearing headset.

Never seen those Stronglight tools Thanks for posting those. t I have the Park HW-2 headset wrench which absolutely will not slip. However, used A9s frequently show evidence of crescent wrench / channel lock usage by "expert mechanics".

Generally I just use the bottom cup assembly. Like the Phil bottom bracket, a classic bike component that will last a lifetime.

Mark Petry
Bainbridge Island, WA USA

WizardOfBoz

Mark, to be clear, after my discussion with the SKF guy (who was a SERIOUS bikey) I understand now why the roller is superior to a taper roller for this application. So I agree with you: no one should take my speculative musings seriously enough to forgo purchasing a bike with these bearings. Surprised, with the high end bike parts people addicted to novel/different designs every year to give them marketing advantages, that no one's resurrected this design.

mpetry912 

I agree, why has nobody resurrected this design ? It is simple, I think cheep to manufacture (no precision grinding / hardening) and super durable.

maybe that's the problem ? Anyway, get 'em while you can, they do pop up on ebay. I just use the lowers on my vintage bike - so as not to need a Campy crown race every couple years.

There is the Tange / IRD headset with a similar lower roller assembly (upper is conventional cone and ball design).

I run heavy Moly D grease (Wurth CV joint grease in a handy tube) on these. I have a small stock of spares, PM me off list

Mark Petry
Bainbridge Island, WA USA

dsbrantjr

Do you have a source for that grease? Is this a rough equivalent? https://www.amazon.com/Sta-Lube-SL31.../dp/B000CPAWOC it is a lithium-based grease

mpetry912 

yes, that is probably the same stuff. Any molybdenum disulfide grease with an "EP" rating will be an excellent grease for headsets.

Now, don't bust my chops 'cuz I mis-spelled it. I got my tube of "Wurth" grease from Pelican Parts (german car parts) but yes, the Sta Lube product is probably the same stuff.

Tube is nice, it's super messy.

Mark Petry
Bainbridge Island, WA USA

Andrew R Stewart 

One aspect of roller bearings is the force the rollers see that pushes them lengthwise. In a well designed balled bearing the curve of the races trap the balls in a "just right" location. With a roller design no top to bottom, of the race, curve exists so the rollers want to find the greatest distance from the virtual point of the cone that the race surface is part of. In the Stronglight units the rollers would migrate towards the larger end of the race. The plastic retaining/locating ring keeps the rollers in place with little (but not "no") added friction. How to balance the wish for more rollers against the need for this retaining/locating plastic ring and it's strength/cost to make is the question. I just counted the number of rollers in my old A9s, it's 20. Andy

dsbrantjr

Thanks for the info. Yes, moly is messy stuff, I have a bottle of the powder and it is more tenacious and messy than graphite, tough to get out of clothes.