univega.duder

Dear Bike Forum Mechanics Community,

After purchasing the incredible, 1995 STUMP JUMPER M2 FS Comp in the very sweet "Grunge grape", I have come to the realization there is too much play in the headset. I’ve loosened the stem bolts, and I’ve thoroughly tightened the adjusting bolt. Alas no matter how much I tighten the adjusting bolt, it does not get rid of the play in the headset.

Today I took off the top cap, and admired the rusty star nut, but soon realized I don’t know what the next step is. The headset appears to be the original Tange-Seiki S&-3 Aheadset. The fork is a Rockshox Judy. I’m wondering if the headset needs replacement, or is there a repair that can remedy this issue. Can I replace or repair myself? I don't have any of specific tools for headset repair.

I’m open to any suggestions that gets me jumping stumps again soon.

Grunge grape!

cxwrench

Your stem and/or spacers is most likely stuck to your steerer tube. There's plenty of room between the top of it and the top of the stem. Remove the spacers and clean them up then grease them. Make sure the split compression ring is not stuck either. Oh...flip your seatpost q/r so it wraps around the clamp before you skewer the **** out of your leg. It's not supposed to be point back like that.

Andrew R Stewart 

I'll also add that fork slop can mimic headset slop. Andy

ShannonM

On the headset:
It looks like the star nut has a broken tine. I don't know if this will cause the headset to not hold adjustment, but it very well could... everything all has to work, from steerer tube to star nut to stem to top cap. Which is why I wouldn't ride it as it sits. Removing star nuts from steerer tubes is a pain, because they're engineered to never come out. Unless they break, which this one already has. If the star nut fails completely, the entire front end of the bike falls apart.

Another possibility... bent steerer tube on the fork.

After you've replaced the star nut, take the headset down to the cups, clean, inspect, replace as needed, repack, reassemble. Check the races carefully. If they're pitted or not-quite-round-anymore, replace the headset. If they're good, replace the bearings. If the ball / race interface is wonky, the headset can't stay in adjustment. Also, good headsets aren't expensive... replacing the whole thing isn't a terrible idea.

General-Purpose warning with Specialized M2 frames:

They are quite prone to cracking at or near the welds. The metal-matrix composite tubing that Specialized used on the M2 frames was an aluminum alloy mixed with aluminum dioxide ceramic particles suspended in the metal. The AlO2 ceramic increased the strength of the aluminum tubing quite a bit, so the tubes could be drawn thinner than non-composite aluminum, and thus be much lighter. All in all, a great idea. Except for the fact that, when the stuff was TIG welded into a bicycle frame, the aluminum oxide particles migrated away from the weld zone, leaving un-reinforced aluminum at the joints, which was too thin to take the strain by itself.

When I worked at an ex-Specialized shop in the early 2000s, I saw a bunch of cracked M2s. If memory serves, most broke at the seat stay / seat tube junction, followed by the chainstay / bottom bracket. All of the failures that I saw were ridden broken and didn't cause a crash, (they were all brought in for tune-ups, and "inspect every weld" was SOP for any M2 frame,) but that was 10 years after the bikes were made, and 15 years ago now.

I'm not saying, or even implying, that your bike is unsafe. But it's a thing that you need to be aware of, and be regularly checking for.

Really, the whole story is a total bummer. Metallic composites have enormous potential as a bicycle material, and almost entirely because Specialized didn't understand them and used the wrong one, the M2 fiasco killed them off so thoroughly that, even 25 years later, nobody in the industry has ever even experimented with them again.

--Shannon

dsaul

It looks like the star nut is not set deep enough in the steerer tube. The top cap could be hitting the top of the star nut and not allowing you to preload the bearings. It could also be that the lower bearings are bad on a bike of that age, but I'd try setting the star nut a bit deeper first.

dedhed

Once the stem is tightened, the star nut does absolutely nothing, and you could remove the top cap if you so desired.

Bike Gremlin

Some stupid questions, but at least I would check and confirm that:

Is the play you can sense coming from the steerer tube (bearings not being pre-loaded properly), or from the fork "legs", i.e. stanchions to lowers (slides) connection having play?

If it's the headset, it seems rather rusty, so I'd first remove the fork, check on the bearings. Clean and lubricate (or replace the headset bearings) as needed. Just to confirm that, when tightening the top cap, the preload is being put on the headset bearings, not just against the (stuck) spacers.

Also, as someone noted, check if the top cap bottoms out against the star nut inside. You can easily test that by removing the stem, then tightening the star nut to see if it can go all the way to the fork. If there's some room, and that's more than your fork is beneath the top of the stem (when the stem is in play), it means your top cap is not able to provide the required headset bearing preload when you mount it all. In that case, think it's easiest to just knock the old star-nut deeper inside, then install a new one - at the optimal depth.

No other ideas.

Relja

cyccommute 

+1. An improperly adjusted hub bearing can also feel like a loose headset as can a sloppy brake arm. I isolate the fork by grabbing the wheel and/or the fork bridge while rocking the bike to feel if the headset is loose.

70sSanO

If the spacers don’t easily slide up the steerer, it is the rust on the steerer tube as already noted in a previous post.

Remove the spacers. You may have to spray some WD40 or liquid wrench and then tap the top steerer tube to get them to move. This isn’t that much different than a stuck seatpost, except you could cut the spacers off if needed. Clean them up, grease the steerer tube and re-assemble.

Your star nut has pulled to the top and should be replaced. Just pounding it back down won’t keep it in place.

John

univega.duder

Hi everyone - I can't thank you enough for all the excellent suggestions! The spacers were indeed stuck to the fork steerer tube. I was able to unstick them with some WD40 and vise grips. I also realized the plastic top cap seemed to be bottoming out on the star nut and had become a bit mangled. When I replaced the top cap I used a slightly shorter top cap allowing the bolt to better tighten into the star nut. At least that's what I think happened. In any case I'm happy to say the play is gone from headset!

Thanks cxwrench You were correct my spacers were indeed stuck. I also fixed the seatpost q/r so I can hopefully avoid any skewering of my legs!

Thanks ShannonM Woah I had no idea about the frames being prone to cracking. I haven't noticed any cracks but I'm going to look in more detail at the areas you mentioned.

Thanks dsaul The top cap was indeed hitting the start nut. I switched to a shorter top cap which didn't extend so far into the steerer tube and that seems to have allowed me to preload the bearings properly.

70sSanO Thanks John! Great suggestions.

cyccommute 

Do yourself a favor and replace the spacers with plastic ones. While you are at it, grease the steer tube to avoid corrosion.


The M2 Metal Matrix frames cracked at the chainstay welds. But I seem to recall that Specialized used the M2 designation on other frames that didn’t use the metal matrix allow.

That’s only a bandaid approach. You need to replace the star nut. It’s not difficult. In your case, you may be able to remove the threaded nut and just use a screw driver to bend the star part of the nut out of the steer tube. If you can’t do that, just use a long punch (or screwdriver) to drive the star nut down into the steer tube and then install a new star nut.

univega.duder

Thanks cyccommute I'm going to try and replace the star nut. I appreciate all the suggestions!