Direct mount stems - good or bad idea ?
- Thread starter jungle
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Meh, I'll risk the cost of a set of crowns for all the benefits I get running an integrated stem. No more tweaked stems in minor crashes, less weight, lower stack height, stiffer... Those benefits alone make the slight risk of breaking a crown not enough to persuade me otherwise.
I'm pretty sure people running steerer-clamp stems can and will break crowns too.
I'm pretty sure people running steerer-clamp stems can and will break crowns too.
I think its worth it just so that you don't have to spend 15min squinting trying to see whether your 50mm stem is on straight, and then realizing 2 weeks later that its not. 
ink:
ink:
or halfway down a run.dante said:I think its worth it just so that you don't have to spend 15min squinting trying to see whether your 50mm stem is on straight, and then realizing 2 weeks later that its not.
dante said:I think its worth it just so that you don't have to spend 15min squinting trying to see whether your 50mm stem is on straight, and then realizing 2 weeks later that its not.
The hardest part of building a bike, making sure the stem is straight.:wonky2:
So, DW, what are your thoughts on this? Having designed the e13 stem im sure you know about the forces involved more so then others in this thread.Cave Dweller said:
Does running a bolt on stem increase the chances of damaging your fork.
Why not make a "bolt-on" stem truely integrated by incorporating the lower half of the bar clamp right into the upper crown? Saves the weight of 4 bolts, way stronger, lighter and lower.
Hmmm, me thinks I see a new viable aftermarket product.
Hmmm, me thinks I see a new viable aftermarket product.
Well you still need 4 bolts to attach the top of the stem down...EVRAC said:
or just glue it on. Elmers wood glue is best :hot:Transcend said:
I have heard pritt stick is pretty good tooatrokz said:
Transcend said:
Not to mention that it would be impossible to adjust the length /reach either !
Naw they got that covered. They'd just sell you a new crown for $99 everytime you wanted to change the reach.DIRTWRKS said:
... thought about this a bit more. The advantages of the direct mount stem have been thouroughly discussed, so I won't mention them. With the direct mount stem you don't have the secondary release (slip) mechanism you do with the clamp on stem, so I'd say that is one advantage for the clamp on stem. At it's greatest, the clamp on stem is capable of transfering the same load / energy as the integrated stem (i.e. no slip). If the clamp on stem does slip a little, that could be a positive aspect as it relates to "potential" damage. But again, there is a heck of a lot of energy transfered thru both. I can agree that the integrated stem should in theory be a little more unforgiving...
Now, let's start breaking $hit and see what happens... Volunteers?
Now, let's start breaking $hit and see what happens... Volunteers?
wasn't sic working on this?EVRAC said:
I just don't think that's a very practical idea. For one, like stated above, you'd need a new crown to run a different length stem. Plus, you couldn't run a regular stem if you wanted to. I guess for an aftermarket crown it wouldn't be a terrible idea but I don't see any advantage, other than saving the miniscule weight of 4 bolts (although then, if you want to get into that, you don't have the holes in the crown so you gain weight there.)
Bump it up for an answer...........Cave Dweller said:
'Cave Dweller said:
Something tells me you're not going to get a straight answer here.
Dave works for e13, e13 make integrated stems, and not regular ones...
ink:I think we've already found our answer here. When you crash and your regular stem twists on the steerer it is taking away some of the force that would otherwise go into the fork. Exactly how much will depend on clamp surface area, stem bolt torque, etc etc...
My feeling is i will get no answer, if it increases the chances of damage your fork im doubting e13 will say anything........Udi said:Something tells me you're not going to get a straight answer here.
Dave works for e13, e13 make integrated stems, and not regular ones...
Already answered, read back. We (e13) have toyed with standard type stems in the past, but made a conscious decision to concentrate on chainguides. The direct mount stems were designed at a time when we were thinking of expanding, hence the existence.
Anyone who tells you that your stem is going to "slip" on your steerer and somehow reduce forces is confused. Rock Shox developed the bolt on standard with stem makers becuase the engineers involved realized that a bolt on stem makes for a stiffer, stronger, and lighter interface. Same with Marzocchi.
As a rider and bike parts buyer you have the option of believing that or not, but dont think for a second that any of these companies are going to build something that they dont truly think is an advantage on the trail.
Thats all
Dave
Anyone who tells you that your stem is going to "slip" on your steerer and somehow reduce forces is confused. Rock Shox developed the bolt on standard with stem makers becuase the engineers involved realized that a bolt on stem makes for a stiffer, stronger, and lighter interface. Same with Marzocchi.
As a rider and bike parts buyer you have the option of believing that or not, but dont think for a second that any of these companies are going to build something that they dont truly think is an advantage on the trail.
Thats all
Dave
Confused how? you seem to be dodging the issue here by not explaining it. We already realise integrated = stiffer and stronger, lighter is debatable with thomson offerings, however none of those factors are being discussed here.dw said:
I for one DO run a direct mount stem on my downhill bike, but being open minded about the matter I can see (and have seen) how a regular stem can exert less twisting force on a fork when the handlebars and wheel take an impact in a crash. Something's gotta give.
Dude if you clip a tree at full race speed, your bars twisting your crowns is the least of your worries.bushrider said:
I have been waiting a week for someone to say it! These guys are talking like they clip a tree at race speed and keep on going with twisted bars, get real.Echo said:
I'm picturing some dude laying on the ground with a crushed hand, separated shoulder, broken frame, tacoed front wheel, and cracked helmet, saying "dang, I cracked my lower crown!"Transcend said:
Confused in that its not realistic. If your stem is twisting, its not tight enough. That simple. If it is tight enough, then its diretly linked to your lower crown through your steerer.Udi said:
Like the other guys said though, If you crash that hard, that fast, you are going ht have a LOT more to think abou than if something is twisted.
Dave
Well, I suppose it depends. I hit many trees (and other objects) during race runs. And yep - most put me down hard. And usually twisted the stem as well. And without tools, I wasn't putting it back straight... but the fork survived unscathed... I'm not convinced a direct-mount stem wouldn't have twisted the fork to the point of breaking... IMO it's less about continuing with the race run and more about surviving to race another day with minimal damage to the bike. The "backmarker's motto."Transcend said:
I think I wrote this before somewere , sorry if that is the case
I see convensional stems as a "Fuse" for the time you crash, the energy of the impact gets disipated on rotational movement as oppose to harsh impact that can bend and mangle parts,this is specially dangerous in the case of a double triple clamps fork were the fork legs are in iminent contact with the frame when they reach the maximun turnung radius,,,,a.k.a. you frame will get a Big ouch on the down tube and top tube near the headset, just remenebr most bicycle frames do not have "STeering stops" like most motorcycle do, to stop the forks from rotating into the frame......
I hope I'm clear in the concept, but then again is also the case of the Sponsor racer that does not care if the frame get damage and the only goal is to finish that particular race were a crucket handlebar can diminish the performance and then fix stems to the fork are the best way to go...
I see convensional stems as a "Fuse" for the time you crash, the energy of the impact gets disipated on rotational movement as oppose to harsh impact that can bend and mangle parts,this is specially dangerous in the case of a double triple clamps fork were the fork legs are in iminent contact with the frame when they reach the maximun turnung radius,,,,a.k.a. you frame will get a Big ouch on the down tube and top tube near the headset, just remenebr most bicycle frames do not have "STeering stops" like most motorcycle do, to stop the forks from rotating into the frame......
I hope I'm clear in the concept, but then again is also the case of the Sponsor racer that does not care if the frame get damage and the only goal is to finish that particular race were a crucket handlebar can diminish the performance and then fix stems to the fork are the best way to go...
I guess I'm just blissfully confused. True story: my clamp-on stem slipped on my (single crown, bla bla bla) fork due to a spill. It was pretty tight to begin with, but I figured hey, if it slipped it must not be tight enough. So I tightened it a bit more. Strangest thing happened: the treads in the stem stripped... And it wasn't some pos, I think an arguement could be made that Deity makes some good stuff. (I'm not mentioning them as a slam, because I was a return customer even after that happened. I'm just carefull now when it comes to tightening a stem up. I know that I can't hulk out on it like I can on my heavier Standard (bmx) stem.)dw said:
See, there is limit on things such as torque on bolts and the connected material. I'm fairly certain that if we asked (all the folks manufacturing a clamp on stem) if we should just arbitrarily start clamping down on their stems (past say a certain percentage above their recommended torque) they'd say do so at your own risk. So no, the blanket statement that if your stem slips it is not tight enough is, well, to use your term, confused. For the atypical crash that is hard enough, it's very likely that, you will a) twist your stem, b) bend your bars, or c) a combination of both, not to mention the world of other things that could happen to the other components as well as your body. I suppose I really shouldn't just add to the drama by taking such a dismissive and wiseass tone, but it's annoying when someone else does it to you. Mount up a clamp on stem to the manufacturers recommended torque spec to see what happens first: stem slips or bars bend. More than once my real world experiences have revealed it to be the prior, not latter. DW, I truely respect your opinion in nearly every case because it is always well thought out and grounded in the sciences. But in this case I'm pretty certain I'm not confused.
Now (for the others), it seems to me that the general discussion of most of the posts did not indicate that if you hit a tree or fall to the ground the only thing you have to worry about was your stem slipping. Yeah, high five guys, no one else had that one figured out. On the contrary, only ONE small aspect of an impact was being debated, and most of the folks were sticking to the subject at hand. Get really real.
Transcend said:
But thats not what the question is, please read back.dw said:
Its been covered already like udi said, no doubt they are a stiffer and keep your bars straight for RACING and im not doubting you in any way, but thats not what is being asked, not everyone races, some people just like to ride bikes fast with their mates, like their bike to perform to a top level but not at the expense of potentially breaking stuff. I am one of those people.
Im with udi, it seems to me the issue is being dodged, i don't at all feel the question has been answered, a simple yes or no would do it.
How many people here tighten up their brake/gear levers so much they can't move in a crash?
It sounded to me like the answer is that they are a good idea, and the people with actual knowledge about the subject tried to dispel some of the questionable theories being thrown around by people who are convinced that because their stem moved in a crash, they somehow avoided cracking their fork lowers. Sounds like people aren't getting the answer they want to hear, so they keep arguing.Cave Dweller said:
If personal experiences are what determines the answer, I crashed hard enough this year to trash my wrist and take me off the bike for a couple months, my bike has an integrated stem, and my fork didn't break.
I do. And I crash.Rik said:
Nah, answers have been slanted towards them being a better idea for stiffness and keeping bars straight for a race run, nothing i didn't know already. From what i have read jungles original post is still to be answered.Echo said:
Im not arguing, nothing wrong with asking for a straight up yes/no answer without any poly waffle.
I like my bars straight whether I'm racing or just riding.
A lot of it is emotional comfort level, pure and simple, which is rarely based in logic. Let's face it, if the decisions were based on some logical determination of which bikes performed best, we'd all be riding the same bikes.Echo said:
Example of emotion over logic: I'm not fond of long travel, single crown forks. I know there's plenty of data that says they're as stiff and strong as a dual crown. I don't really care... they don't give me warm, fuzzy feelings...
The direct-mount debate is academic to me as I run a 90mm stem.
So you think some of these theories are questionable? Seriously, how would you know? Is it that because the answer you believe comes from one certain person do you just blindly take it as Truth. Did you ever think that maybe the people who's theory you question may know something about the issue? This isn't something that you have to be a bicycle engineer to figure out. It's pretty basic stuff. Friction versus direct. How exactly can you tell who has the knowledge to dispel the subject at hand? That sucks that you broke your wrist, and believe me many of us have been there; it's great that the fork didn't break. Unfortunately, I'm certain that's not the issue. The issue is: Is it possible that a direct mount stem could theoretically cause more damage than a clamp on stem in certain crashes? Some say no, there is no way that can be the case, both are exactly the same. What is being argued is that the are not both exactly the same.Echo said:
I used to have direct mount before, now I have a stem and kinda like it better.I get a better press on the headset...and Im not the only one who switch back to a stem where I live(Whistler).Easy solution for the bar,dont crash, problem solve....hehe just kidding 
trust4130 said:
if i were to guess yes it would be safer against breakage to run a regular stem (...but i for one like my integrated better). it just makes sense that since nothing is giving then all the forces will get transfered directly into the part.