Installation of Edge Composites compression plug
 

I'm looking for installation instructions for Edge Composites compression plug that ships with their forks. The instructions on their website apparently are not up-to-date, because they refer to a conventional type of compression/expander plug that fits fully down into the steerer tube. This new type appears to actually rest *on top* of the (cut edge of) the steerer, with the compression plug itself positioned down into the steerer as one might expect. I'm wondering about the proper installation of this type of plug, concerning positioning relative to the stem, the spacer on top of the stem, the top cap, etc. Particularly, it's unclear to me if the unique, conical top cap is actually supposed to come in contact with the compression plug, given it's unique design. If so, this means that the top cap is not interchangeable with "normal" top caps (Chris King, etc.).

There was another thread in this forum about the same issue, but it seems to have been refering to an older, conventional type of expander/top cap.

It's just not like any compression plug/expander bolt I've ever seen before.

Thanks,

Dave

Here is a picture that I've edited, showing the design. You can see there is a "lip" on the top of the plug (just below the top cap in this picture) that rests on top of the steerer tube.

The expansion plug should not come in contact with the top edge of the steerer tube. Doing so would prevent it from being able to preload the bearings. It appears as though you either need to cut the steerer tube considerably shorter than the top of the stem (highly NOT recommended) or use a spacer on top of the stem that is taller than the depth of the lip on the underside of the plug to keep it from touching the steerer.

Yes, I should mention that Edge *does* recommend installing a spacer on top of the stem (as do, apparently, many carbon fork manufacturers), but nonetheless the plug *must*, by design, rest on top of the steerer (see picture). I agree that shortening the steerer is not the way to go.

My guess is that the top of this 'compression plug' (as Edge calls it) must follow the usual rule of being several millimeters (2-3 according to Edge) below the surface that the top cap rests on. In this case, that means 2-3mm below the spacer. BUT, if I do that, then the conical Edge top cap comes into contact with the plug! It's a Catch-22 if I follow their instructions.

What I don't have an image of is the Edge top cap, which is strongly conical - it has a funnel shape on the underside. As crazy as it sounds, this unqiue shape seems to suggest that contact is desireable.

Post some pictures of the plug assembled and disassembled, preferably with a scale in the picture. Actual dimensions of the components would be even better.

You're thinking way too hard.

The purpose of that is to set preload, which means if the top cap contacts the top of that compression plug it's useless. Slap on a large enough spacer so that this does not happen when you tighten the cap as much as needed. Problem solved. Whether this be more than 2-3mm is irrelevant. Some topcaps require more clearance from the top of the plug than others to not contact when the plug when tightened.. It depends on the exact cap. Once the preload is set you can toss the extra high top spacer and reset it. Also there should be a *minimum* stack height of 5mm worth of spacers for most forks.


That edge design for a compression plug is dumb as hell. Go buy a $10 FSA one.

It's irrelevant.

The OP needs to stack as many mm's worth of spacers as it takes to make sure the top cap does not contact the plug before achieving proper preload on the headset. This is one of those situations where realizing the written instructions has no relevance to reality is important.

I heard back from Jack at Edge Composites. The compression plug does rest on the top (cut) surface of the steerer tube, which is their way of guaranteeing that the expander is positioned sufficiently far enough down in the steerer. Then, as everyone has of course indicated, the spacer on top of the stem has to be sufficiently large enough to ensure that the top cap does not contact the plug (Edge suggests 10mm!). So I'm using the Edge plug but with a King top cap, so I can use a 5mm spacer.

As I previously mentioned, I think one thing that is somewhat unusual is that Edge (and others) definitely wants their steerer tubes to extend up beyond the stem a bit, necessitating a spacer on top of the stem (regardless of the type of expander plug). I see a lot of carbon forks, but I don't recall seeing spacers on top of stems before (maybe I've just never noticed!).

The spacer on top of the stem thing is the new and right way to do it. Up till a couple years ago nobody really paid attention, including myself!

Hate to drag this post up again but I have the same problem.

This is the first fork that needs a spacer on top of the stem to be flush.

I like my top cap even with the top of the stem. To do so on an Edge/Enve fork requires the fork to be cut about 6mm down into the stem.

That just doesn't seem safe. Is there another plug to use on this?

I'd recommend the spacer-on-top-of-the-stem approach, it's going to be the safest way to go. Especially with forks as light as those. I also like their plug; the lip on the end means there's no ambiguity about where it should be located, and if someone does get aggro about clamping their stem onto the end of the carbon tube, the plug's lip will help keep the stem from deforming/cracking the steertube.

Here are the exact instructions. They seem a bit contradictory.

See the 2 marked in red.

It looks like they say to cut the steerer tube 1-2mm above the top of the stem. Then say that it should be 2-3mm below the top of the stem.

Preparing the Fork

• Avoid scratching or scoring the steerer tube surface. Any damage to the steerer tube could cause failure.
• Apply a small amount of grease to the fork crown race seat. Do NOT make any modifications to the crown race area of the fork. Only use a headset race with the correct inside diameter for your fork steerer tube.
• Hold one leg of the fork securely and, using an appropriate race seating tool, install the headset crown race. Do not place the fork on the dropout tips or crown while installing the race. Doing so can damage the fork and could cause failure.
• Assemble the fork, headset and any spacers in the head tube of the bicycle and slide on the stem.
• The spacer stack below the stem must not exceed 50 mm (2 inches).
  
• A carbon steerer tube should extend 1-2 mm above the top of the stem clamp and have a 5 mm spacer installed between the stem and the top cap.
• Carefully measure and mark the amount of steerer tube that you will need to remove. Remember that, when cut, the top of the steerer tube must be 2-3 mm below the top of the headset/spacer/stem assembly.
• Remove the fork from the bicycle.
• Make absolutely certain that you do not cut the steerer tube too short.
• Using a new fine tooth hacksaw and proper cutting guide, cut the steerer tube to exact specifications.
• Carefully sand or file the rough edges until smooth.
• Clean the steerer tube and inside of the stem clamp with alcohol to remove grease and dirt; then let dry.

What they're basically saying is that the top of the steerer tube should be about midway up the 5mm spacer that's sandwiched between your stem and your top cap. That ensures that the stem's got 100% grip on the steer tube and not gripping the end of it, and also leaves the necessary "air gap" under the top cap so you can preload the bearings.