rodey

Picked up my Orbea Orca Aero yesterday. It was built by my LBS with a spacer above the stem (picture linked below). I don't know a ton about building bikes. Is this spacer necessary? I don't see anything in the manual.

Not really a huge deal at all, I'm just kind of anal and it's an aesthetic thing.

https://imgur.com/a/ccGMd0x

tyrion

You probably need that spacer - you need enough spacers+stem so that the top cap isn't resting on the steerer tube (steerer tube is part of the fork and what the stem clamps to).

The bike shop probably left the steerer tube a little long just to allow you to move the stem up a bit if you decide to. If you know the exact height you want the stem, you can cut the steerer tube to the appropriate length and not have any spacers on top of the stem, but don't cut the steerer tube until you're sure.

Andrew R Stewart 

Add to the aboved is that carbon steerer's are more likely to crack is compressed near an edge. So by raising the steerer's end/edge further above the stem's upper pinch bolt the less likely this is. Andy

alcjphil

Think about it. Your stem is compressing a steer tube made of carbon fiber. If the top of the stem is above the top of the steer tube, pressure on the steer tube exerted by the top pinch bolt will not be evenly distributed at the top of the steer tube. There are expansion plugs that can mitigate this uneven compression, but if your bike manufacturer does not provide such a component you can take it for granted that they might not honour a warranty if you stray from their recommendations. I own a couple of Look bikes that require a spacer above the stem, but the spacer they provide is tapered providing a smooth transition into the top cap which I find to be quite appealing visually. That spacer above the stem on your bike is probably there for a reason. Before trying to rearrange it, make sure that the modifications you want will not void a warranty or, more important, put you in danger

rodey

Thanks for the info. A review for the bike that I read had a picture of the same stem like so...

https://keyassets.timeincuk.net/insp..._290116001.jpg

That'd look better to me. At the end of the day it's not like it's a game changer or anything, but I would like that flush look more.

Would I just need to remove the top spacer and trim down the steerer tube that amount?

Not sure I even feel confident enough to do that, so I'll probably just leave it, but just would like to know the process.

curbtender

You could find some of those wavey spacers and put them underneath.

tyrion

Take your time, get a stem and handlebars you know you like, then cut the steerer tube.

CliffordK

I agree..

Teardrop aero spacers.
Then a round spacer on top... just looks funny.

As @tyrion said, get the spacing right the first time. Up/down adjustment? Then cut to length.

What you do want is the steer tube to fully support your stem, not to be cut off halfway up the stem.

rodey

Given the initial position, I can't imagine I'd ever want to raise the stem more than it is. I'll wait a few rides though.

If I want to get it flush, I just need to mark the top of where the steerer tube is poking out and make the cut, correct?

WizardOfBoz

Yes, but do a little research - carbon fiber is a bit difficult to cut and special blades work best. There are stem-cutting guides available to ensure that the cut is square on the end but you can wrap the bar with tape to guide you in hand cutting.

If you are handy, do your homework first, and have the right tools, probably not a big deal. If not, should be pretty cheap at the LBS.

rodey

Ah, so you think the LBS would cut it down? That'd probably be my preference. I guess for some reason I didn't know if they'd do it.

gregf83 

It's not difficult to cut a carbon steerer. A 32tpi hacksaw blade will make a nice clean cut. You can buy a guide to ensure a square cut or fashion something yourself with a pipe clamp or similar.

Before cutting I would get the correct instructions from Look or the stem manufacturer. Recommendations are not universal so best to get the actual instructions from the manufacturer.

rodey

Do you know if those materials are usually readily available online? I can't find any specific specifications from Orbea anywhere in the manual.

gregf83 

Sorry, for some reason I thought it was a Look bike. If you can't find the instructions via a google search I would contact Orbea directly. I have an older Orbea MTB and needed some custom suspension parts and Orbea customer service was excellent. Just contact them through their website and they should be able to help you out.

WizardOfBoz

Yeah, pretty sure that they would if you asked. As Greg points out you could use a fine-tooth hacksaw (or a carbide-grit hacksaw). A stainless pipeclamp or two (one on each side) works great. But if you don't have experience or a comfort level with a hacksaw then starting your hacksaw career on an expensive carbon fork is probably suboptimal. I suspect that the LBS will charge less than what it costs to buy a good hacksaw, so there's that.

rodey

Cool. I'm going to give it a few more rides this week and the call to ask if they'll flush it out with the stem. I'm sure I could do it and be fine as long as I was cautious, but I'd prefer they do it.

conspiratemus1

The steerer is supposed to be cut so that it is a bit shorter than flush with the top of the stem, usually 3 mm but no more. This is so that when you preload that vertical stem screw the stem cap will for sure bear against the stem (thus holding the head set snug) and not just press uselessly against the top of the steerer and never clamp down the headset. At least those are the instructions that came with my old Alpha Q.

Also, manufacturers of carbon forks vary in whether they say, "Always put a spacer above the stem" or "Never put a spacer above the stem." Just wanting to prepare you for the shop possibly saying they have to leave it as it is.

rodey

Yeah, I already kind of thought of the scenario of the LBS coming back and saying that. I also emailed Orbea so I'm going to see what their recommendations are.

However in all the pictures from Orbea I can find with the standard stem, the steerer tube is sitting flush. Granted, they probably wouldn't want a 5mm spacer in marketing materials.

Sy Reene

I'm wondering, from one of the linked photos you provided, if there isn't pre-fabricated minimal spacer designed for this stem/bike.. basically providing the 2-3mm that typically gets recommended for how far below the cap the steerer tube should be. What is that hairline gap showing at the top of the stem clamp area that seems to go all the way around? I'm guessing the idea is you cut the steerer tube to fall where that hairline is?

rodey

Interesting. That seems like it could make sense.

rodey

Here's the response I got from Orbea. Bolded is the most relevant. Does the sentence regarding the top of the stem not extending above the top of the steerer tube mean having it flush like in the photo I linked is not recommended? Or am I missing something?

rodey

Found another image of an Orca Aero with the same stem as I have: https://cdn.road.cc/sites/default/fi...?itok=m1zyHf3C

To me this image makes it seem like I may be out of luck in terms of getting a flush look, given Orbea's response?

AndreyT

It is as "necessary" as the top cap is "necessary".

When you are just assembling your headset and your stem bolts are still loose, this spacer is necessary, of course. This spacer is what transfers the pressure from top cap to the stem to preload the whole assembly. If you remove the spacer, the top cap will simply rest on top of the steerer and will not be able to preload anything. The whole principle on which the assembly/adjustment procedure for a threadless headset is based makes no sense without that spacer.

However, once you finished assembling your headset, i.e. once your stem bolts are already tightened all the way to spec, the top cap and the spacer are not necessary anymore. They are basically tools, which are used temporarily in the course of headset assembly/adjustment. After that they may remain there essentially "for storage", for aesthetic purposes and as a dust cover. You can remove them both, if you so desire, but I see no reason to do so (weight weenies might, though).