aaronrob222

I'm having a very hard time finding out for sure if how my headset and stem are currently set up is going to kill me or is merely a faux pas. I'm using the cable guide/collar on the bottom, no spacers, and my new VO stem thusly attached directly to my long (white) steerer tube. Sorry I don't have a better pic on hand.



In short, are spacers vital? The spacers I ordered are still being delivered from Ebay. It felt secure after the initial installation and I rode the bike 5 miles to work. But then I googled around and there's some consensus that spacers are vital and incredibly important; that is simply not jibing with the reality of my bike right now, so I'm very confused. Everything feels sturdy.

If I understand correctly, I'm just doing what Sheldon had done:
"Using the separate collar allows you to mount the stem anywhere on the extended steerer, without any need for spacer washers, and without any need to re-adjust the headset every time you raise or lower the stem."

PatrickGSR94

DO NOT RIDE THE BIKE THAT WAY!!! See this post and others below.

Yes, you must use spacers. The stem clamps to the steer tube and keeps the fork from dropping out. Without spacers between the stem and the headset top bearing, your fork can drop down by the amount of steer tube exposed, which can make things really sketchy when riding.

As you show it now, your bike's front end is not secured properly at all. And the front end is most critical to prevent crashing.

wphamilton

I don't use spacers on mine either. There is no issue AFAIK, though one of the companies - Trek maybe - wants you to have at least one spacer on the CF steer tube.

*I don't know what you mean by "collar guide" - I'm talking about a regular fork, headset and stem.

tyrion

Note that if you go over some bumps, the whole fork + bars assembly can slide down, and if it somehow sticks in the slid down position, you have no front brake.

edit: OOPS, wrong: the bar/fork sliding down will activate the front brake!

PatrickGSR94

You can run no spacers if your stem is slammed down directly against the headset top cap. The OP's photo shows bare steer tube visible below the stem, which most would indeed consider to be dangerous. As tyrion said, if the stem/bar/fork assembly slides downward, it will potentially lock up your front brake and almost certainly cause a crash.

wphamilton

I don't see his picture, maybe fire-walled off at work, but if the stem is tightened down with enough tension on the headset bearings it won't be loose, no matter how much steer tube is showing above the stem. You don't need the spacers, nor even the cap, which are all non-functional except for tightening it up when you put the stem on. Maybe the picture shows something amiss - tube below the stem would be absolutely wrong - but not having spacers is not dangerous. Just make sure you install it right.

PatrickGSR94

no no, he's got exposed steer tube BELOW the stem!! Above the headset top cap and canti brake hanger, but below the stem. The whole assembly can drop down, if the front tire is off the ground, which would then lock up the front wheel/brake since they're canti brakes.

wphamilton

Geeze @aaronrob222, loosen up the stem, slam it on the headset, put some blocks or something on top to tighten with the star nut (get one first if you didn't install one), and then tighten up the stem bolts. Any play, as people have said, is a non-starter.

lostarchitect 

The reason it felt OK to you on your 5 mile ride is the brake cable guide is holding the whole thing in place. You were lucky. The cable guide is attached with one small bolt and is not secure enough to hold permanently. You need the spacers and the stem pressing down on them, and you should not ride it until this is fixed. If you can lower the stem enough that it is touching the cable guide, you can ride it that way until you get the spacers. If not, do not ride it.

CliffordK

What kind of a stem do you have?

• Threaded steer tube/headset + threadless adapter?
• Standard Threadless?

The spacers are not needed if you're using a threaded steer tube/headset + threadless adapter. Otherwise you should have them.


Perhaps you can add tension, clamp down the brake adapter, then release the tension, but the device isn't designed to clamp as hard as a typical stem.

aaronrob222

Yikes, I think I understand now. Many thanks for the warnings, all.

That any of this was dangerous was not even on my radar until I Googled. Granted, I think part of my ignorance is coming from the fact that I went from a Jamis/ATS shim set up, which doesn't really show you how a threadless system is supposed to work. I just tightened everything up, did a couple hard brakes in front of my apt., and thought it was good to go. Couldn't detect any play at all.

But, can anyone explain what Sheldon Brown is getting at here: https://www.sheldonbrown.com/handsup.html#threadless

I had this article somewhere floating around in my mind, which was also reinforcing that no spacers can be okay in a pinch. Is it that the brake cable guide vs. seatpost collar that he uses can withstand different stress?

lostarchitect 

Yes, exactly. He says he has used "a separate clamp to secure the headset, rather than using the stem". Your brake cable guide is serving this purpose now, but it's not secure enough to use long term (or at all, IMO). His clamp is much more robust.

CliffordK

Many seatpost collars have a ridge which would have to be removed if you were to try to use one.

It is hard to say. The top collars are designed for that purpose. As the Sheldon Brown website suggests, only use them on Steel or Aluminum (narrow force distribution). I have see setups for folding bikes which I think also has an additional adjuster in there somewhere, and didn't use 3 feet of spacers.

Anyway, the collar is designed to take more force than your brake guide likely is designed to take. However, you do have the benefit of getting some extra tension from the brake cables.

As far as "danger"... probably not that dangerous, although you could damage a headset if riding loose.

I suppose, also keep in mind that most of the force on your headset is on the crow race and lower cups, and not greatly affected by the upper tension. Your steer tube is unlikely to suddenly fall downward.

PatrickGSR94

Note that you can't just "tighten everything up" and then ride it. You need to load up the headset bearings to remove all play, but not bind them. This is done by tightening the stem cap bolt with the stem bolts loose, but of course the stem has to be able to press down on the headset top cap (either with spacers, or with the stem slammed down onto the headset cap). Once the bearing play is removed, then you tighten the stem clamp bolts. I also like to loosen the stem cap bolt and then just snug it down, so that only the stem bolts and stem are putting the preload onto the headset bearings, and no force is on the star fangled nut inside the steer tube.

tyrion

The seatpost collar there does what spacers normally do, keep the steering tube from sliding down in the head tube. In smooth riding gravity will keep the head tube down on the steering tube where it's supposed to be, but if things get bumpy...

lostarchitect 

100%. OP this is what you gotta do. The brake cable guide bolt should also be loose when you have the stem bolts loose for this, and tightened at the end when you tighten the stem bolts.

lostarchitect 

No, there is more danger than this now. If the brake cable guide came loose and the frame and fork moved apart, the brake cable would be pulled and the brakes would slam shut on the front wheel. This could be very serious.

Brian Ratliff

People are overreacting. It's not great though, since you cannot preload the headset bearings. Long term, this will thrash the bearings since the steering tube is rattling around between the bearings. Even if you have the clamp arranged to preload the bearings, without a top cap this preload will eventually disappear. Sheldon knows what he is doing and probably used a temporary stack of spacers with a top cap to gain the initial preload before tightening a steel seatpost clamp with high torque to keep that preload. When he was around, he rode mostly steel stuff and had tons of old components lying around his shop to rig up something durable.

Forces on the headset are mostly against the lower bearing; your weight on the bike will keep the system together. The cantilever is pulling the headset together, so that force is in the right direction. If you crash the bike, you will likely loosen the system up enough for the cantilever brake to get weird. As the clamp loosens, your front brake will likely get pretty grabby and chattery as it relies on bracing against a sturdy fork-to-bike connection for braking power, more so than caliper brakes.

If you don't understand my discussion about forces and preload, don't ride your bike this way. If you do ride your bike this way, pay attention before every ride to how loose your headset is. If it loosens, fix it right away.

So, it's not fatal, but it's not good... why don't you just spend $5 to buy a few generic spacers from your local bike shop? It's such a small thing and it'll do a ton to keep your bike riding well.

dabac

Thing is, what Sheldon used to maintain preload was something as rugged as a seat post collar/clamp.
You’re using a brake hanger.
It’s unlikely to be as strong.

wphamilton

I wouldn't use a seat post clamp either. It would be OK for a little while but then work loose.

Bike Gremlin

Top cap is used for easier tuning of the preload. As long as a clamp is tight afterwards, the top cap can be thrown away (though rain will get into the fork that way, but as far as holding it all in place goes, it's no longer needed).

For holding the things in place, stem is usually used (with spacers beneath it to reach the top bearing). Alternative to that could be using some other type of clamp, that sits just on top of the bearings (without spacers, or using just one spacer beneath it - whichever helps you achieve the right preload) - that way stem can be fixed at any point above it, without the spacers, since it is no longer needed to hold the preload. Tyrion's picture demonstrates that nicely:



The thing I don't like with the setup above is that only one bolt is used. If it snaps for any reason, you're left with no proper preload. So if going with such setup, I'd get a clamp with two bolts, or put another clamp above the first one.

Same goes for the stem in the pic. I prefer stems with two bolts for attaching on the steerer tube and four bolts for holding the bars (not the two bolt ones, like the stem in the picture).

dabac

I dunno.
I’ve done plenty of XC MTB miles, and I can promise that I haven’t always managed to go light over roots and rocks. And I’ve been caught out by potholes ever so often on the commuter. And the saddle has always stayed put on the bikes with Allen key clamps.
While I do brake more often than I hit pot holes, I do think hitting a pot hole seated puts more stress on the clamp.

wphamilton

You're probably right. I'm only worried about it slipping fractionally over time like my seatpost clamps and damaging the headset,

Now that I see his picture it isn't as bad as I thought - I thought there was exposed seat post under the clamp, able to flop loose.

HardyWeinberg

And the Sheldon Brown's of the world don't mind checking that before each ride...

PatrickGSR94

That seat post clamp hack looks like something one might use temporarily when initially setting up and fitting the bike, to get the stem at the right height, so that they can determine after the fact how many/size spacers need to be used. I would never ride a bike with the fork and headset secured with a seat post clamp only.