Looking on EBay for a longer stem for my CX bike, I noticed that there are a lot of cheap CF ones that cost less then some AL ones. Couple of questions here:

1) do you get what you pay for? Cheap = cheap quality = broken after a few rides?
2) is CF superior over AL?
3) what are these CF/AL combination stems? Clamps are AL and stem is CF? Are these joints compatable and strong?
example:


4) should I worry about 10s of grams weight wise?
5) would you purchase one of these cheapies?

TIA...

What you posted is aluminum with a carbon fiber wrap for visual appeal.

Look up the term "black aluminum". Since carbon is highly anisotropic, when making a component that experiences forces in all directions, the final product ends up about as heavy as aluminum. Stems are one of those applications.

Look up UNO stems. They are a light aluminum options, pretty high quality. I have a couple.

1) Yes
2) Not in this application
3) Junk
4) I wouldn't
5) No


Strong / Light / Cheap: Pick any two...

If your stem breaks while you're riding, you're going to lose a lot of teeth.

2) only if you get the whole one piece stem and bar combination from a prestigious Italian company..

Don't even go there. EBay is not the place to go bargain shopping for something as mission critical as a stem. Well, unless you're actually looking for cheesy carbon wrapped junk. And seriously, you're not going to use weight as an argument for an el cheapo eBay stem?

Buy quality. Ride with confidence. Shave the 10 grams somewhere else -- try wearing different socks.


-Kedosto

If you want to go budget on a stem, look at Nashbar or Performance at their low priced stems. If you go that route, at least you know it has to be of a reasonable quality.

I've ridden low priced stems from both without any concerns.

"But I like my teeth..."

Okay I get it. Lucky I asked first so thank you for saving my teeth.

So what makes a good stem?

1) AL seem like the best option for now. What type of AL alloys should I look into? Any thickness specs to look for or just base it on weight?
2) Road or mountain stems?
3) Name brand or not? Any vendors come to mind?

I want a good value for all my purchases. That means a good quality product for a good price. There is always going to be "name brand" items that can charge more because they can. I try to stay away from these if possible. There are tons of other vendors to choose. Should I stick to name brands?

Do you have a road or mountain bike? First thing is you need a stem that will fit your frame and handlebars. Next thing, it should be the right length and angle to put the bars in a place that's comfortable to reach.

I've never heard of anybody crashing after their stem broke in use. It might have happened and I didn't hear about it, it might not have happened. But it would be impossible to recover control of the bike without crashing if it happened, and that's not a risk I'm willing to take. (The most expensive carbon stem is maybe $250, my life is worth more than that.)

Aluminum is a better value, unless you just really want carbon for some personal reason. A stem isn't a part of the bike that benefits much from using CF and for various and boring reasons you don't wind up saving much weigth at all, sometimes it's the opposite.

It doesn't matter how thick the walls are or what type of aluminum it is, or even what brand. Just get a reputable brand, from a reputable store. Anyone who will be in business next year will not sell you a crappy one.

You can probably get a "take off" stem for $10 at a bike shop. Somebody will buy a fancy bike, and buy a CF stem to go with it, so they'll leave the original one with the store. This is a regular thing. People buy "take off" stems because it's a cheap way to experiment with different sizes and angles and find the best fit, and for other reasons.

I saw someone who that had happened to a few months ago. I was hanging out in an LBS and this guy walks in with blood on one arm, slinging a grocery store bag of ice on his shoulder, and he's carrying his bike. The stem had snapped very cleanly, one cylindrical aluminum tube becoming two shorter aluminum tubes. He walks up to the mechanic's counter and asks if they have a stem that could be swapped in, preferably not the same brand. Pretty quickly he was riding home.

I have a carbon-wrapped aluminum stem, and I'm happy with it but totally understand it's faux-carbon for looks and has no advantage over a good aluminum stem. It's a Ritchey so I'm confident of the quality. Normally I would just have an aluminum stem, but this carbon wrapped one came more or less free with a Ritchey CF bar I bought a while ago. I've never had a matching stem and bar before and it kind of looks nice, enough so that I'm OK with the fact that stem is kind of a fraud.

It's only a fraud if it claims to be something which it isn't.

Ebay is a great place to get stems. Just stick to known brands and avoid the cheap junk. Tons of good options from the likes of Bontrager, Specialized, Cannondale, FSA. Many people swap stems so there's plenty of decent ones. Use a little common sense and there's nothing to fear.

The other option is ask your LBS. They usually a pile of take-offs from people's bikes. You can usually find something in the $10-20 range.

Shimano PRO Vibe or PLT. Lots of length and angle options, they're affordable, and they just plain work. I'm on my 4th stem due to fit changes, and every one of them has been a Shimano PRO.

If you want one of the best values, i.e. lowest weight per money spent, go with the UNO stem (by Kalloy) as suggested. About the only reason to go with something else is if you are dead set on matching your seatpost, handlebar, and stem. I was already buying Ritchey stuff for my new build so I went with a Ritchey WCS C260 stem. A little tiny bit lighter than the Kalloy for about 2.5X the price (from Merlin Cycles), but it does come with a better handlebar clamp arrangement in my opinion.

Works for me. A stem is about the last thing to take a chance with.
And you don't need to spend $100+ to get a good one.

Check this out (jump to 0:57 if it doesn't do it automatically):
Many pros use aluminum stem and bars because they are more durable without a significant weight penalty (especially when you consider that weight sometimes needs to be added to hit the 6.8kg minimum). Team mechanics are frequently pulling the bikes off and on the team cars - which means stems take more of a beating than the typical weekend warrior dishes out.

In any case, the video illustrates a catastrophic stem failure...

Yea, poor choice of words. There was no misleading, and I knew exactly what I was getting. I was using the word in the sense of the casual observer might be "impressed" by my matching CF bars and stem, when the stem is just made to look like CF. Regardless, it looks nice, works well so I have no problem with it at all.

Thats a helluva crash! I watched it in high def, super slow mo and couldn't say if it was his stem or not....but looked like his steer tube to me.

We don't know their reasons, but you'll have to explain to me (us) how taking a bike off a rack has anything to do with the bars/stem.

Lots of pros use carbon bars/stems. The best cyclocross racer in the world used a carbon bar/stem combo. No problems to speak of (but counter to my point he is actually back on alum this year). With that said, there are several CX guys I race with that don't use carbon, when you crash, you bars can spin and slam into your TT, I've heard of (never seen) carbon bars break this way. Alum may not have.

I'd wager a guess the real reason is that since carbon stems offer minimal weight savings, are MUCH cheaper and the weight limits of a bike are easily met without them, whats the point?

I'd have no problem riding a carbon stem from Enve, 3T, FSA etc. I wouldn't touch one from a no-name manuf. To much at stake if it breaks and tolerances are questionable. I would (and do) trust inexpensive Alum ones though.