carbon steerer alloy stem ?

ellerino
ellerino Posts: 37
edited May 2014 in Workshop
Fella in local bike shop advised against alloy stem on carbon steerer tube, is he right ? as the stem that came on the bike is alloy and im just swopping it for an older shorter one

Comments

  • sungod
    sungod Posts: 17,181
    there're no issues using an alloy stem with cf steerer, it's probably far more common than a cf stem
    my bike - faster than god's and twice as shiny
  • Bozman
    Bozman Posts: 2,518
    At a guess I'd say that most of the peloton use an alloy stem on a carbon steerer.
  • Monty Dog
    Monty Dog Posts: 20,614
    Complete fiction - in the words of Father Jack, your lbs bike fella is an ar$e
    Make mine an Italian, with Campagnolo on the side..
  • andy_wrx
    andy_wrx Posts: 3,396
    Or he might just be trying to sell you a carbon stem...


    ...which is a complete waste of money !
  • ellerino
    ellerino Posts: 37
    andy_wrx wrote:
    Or he might just be trying to sell you a carbon stem...


    ...which is a complete waste of money !
    Funny you should say that ! saved me ££££££££'s thanks
  • brownbosh
    brownbosh Posts: 602
    just follow torque setting advice and all in order.
  • BenderRodriguez
    BenderRodriguez Posts: 907
    One tip. Often the internal edges of an alloy stem can be rather sharp. This can cause scratching as the stem is turned and and those along the opening where the pinch bolts are can dig slightly into the carbon when the stem is tightened. I always dress the internal edges with a needle file and some emery paper to avoid this happening.
    "an original thinker… the intellectual heir of Galileo and Einstein… suspicious of orthodoxy - any orthodoxy… He relishes all forms of ontological argument": jane90.
  • ugo.santalucia
    ugo.santalucia Posts: 28,310
    My experience is negative. I never managed to get a good grip between the two and the headset always lost tension within 100 miles or so from re-tensioning it. This is partly due to the carbon steerer/stem grip and partly due to the compression plug being unable to hold firm when the stem begins to put pressure on it, as it also struggles for grip. They are the two main drawbacks of carbon steerers as well documented and I had both big time. I have tried Finish Line assembly paste as well (an overpriced gel containing some fine sand), but it didn't make any difference, predictably. Eventually (luckily?) the steerer cracked at the base (nothing to do with the clamp), so I got a fork with an alloy steerer which works a treat and doesn't have any of that.
    I would rather wax my legs and chest than getting another carbon steerer... :evil:
    left the forum March 2023
  • BenderRodriguez
    BenderRodriguez Posts: 907
    I too had a problem finding a headset compression plug that would hold firm in a carbon steerer. I did find one that holds with no problem, mainly because the external 'teeth' at a little sharper and the stem longer. Can't recall the make though!

    Never had a stem slip, perhaps because I always clean the external part of the steerer and the inside of the stem with alcohol before fitting, just in case there is a smear of grease on them after fitting the headset.

    To my mind, from an engineering point of view a one piece carbon construction must be better than having an alloy steerer joined to a pair of carbon forks. I have certainly seen examples of an alloy steerer becoming loose or coming away from a carbon fork crown.
    "an original thinker… the intellectual heir of Galileo and Einstein… suspicious of orthodoxy - any orthodoxy… He relishes all forms of ontological argument": jane90.
  • ugo.santalucia
    ugo.santalucia Posts: 28,310
    BenderRodriguez wrote:
    To my mind, from an engineering point of view a one piece carbon construction must be better than having an alloy steerer joined to a pair of carbon forks. I have certainly seen examples of an alloy steerer becoming loose or coming away from a carbon fork crown.

    I have had three carbon forks with metal steerers (both alloy and steel) and they have been absolutely fine. The only full carbon one has been short lived, gave me plenty of headaches (as described) and ended like this, with a nice hairline crack at the base. Will never ever touch another one again
    DSC_2655.JPG
    left the forum March 2023
  • desweller
    desweller Posts: 5,175
    My all-carbon fork & ally stem has been fine and untouched since mid-2011, when I built it. And I don't use a torque wrench :-P.
    - - - - - - - - - -
    On Strava.{/url}
  • robbo2011
    robbo2011 Posts: 1,017
    The carbon steerer/alloy stem combination is so common that if it was troublesome, there would be loads of threads on here complaining about it. There aren't, so it isn't.

    (10,000km here with no issues whatsoever)
  • dennisn
    dennisn Posts: 10,601
    BenderRodriguez wrote:
    I too had a problem finding a headset compression plug that would hold firm in a carbon steerer. I did find one that holds with no problem, mainly because the external 'teeth' at a little sharper and the stem longer.

    Am I reading this wrong? To my mind the compression plug is of no use other than to allow you to put the proprer pressure on the headset bearings(which isn't much). After that you tighten the stem bolts and that's what holds everything together. You could take the plug out once you've tightened the stem bolts. Of course if you have spacers above the stem then the plug will hold them in but that doesn't require any real pressure. So I don't follow what sort of problem you have with plugs.
  • ugo.santalucia
    ugo.santalucia Posts: 28,310
    dennisn wrote:
    BenderRodriguez wrote:
    I too had a problem finding a headset compression plug that would hold firm in a carbon steerer. I did find one that holds with no problem, mainly because the external 'teeth' at a little sharper and the stem longer.

    Am I reading this wrong? To my mind the compression plug is of no use other than to allow you to put the proprer pressure on the headset bearings(which isn't much). After that you tighten the stem bolts and that's what holds everything together. You could take the plug out once you've tightened the stem bolts. Of course if you have spacers above the stem then the plug will hold them in but that doesn't require any real pressure. So I don't follow what sort of problem you have with plugs.

    in the real world my plug didn't even allow me to put enough tension in the headset in the first place, as it worked itself loose while tightening.
    left the forum March 2023
  • The Mechanic
    The Mechanic Posts: 1,277
    robbo2011 wrote:
    The carbon steerer/alloy stem combination is so common that if it was troublesome, there would be loads of threads on here complaining about it. There aren't, so it isn't.

    (10,000km here with no issues whatsoever)

    +1 ^^^ What there are loads of are threads complaining about carbon forks with alloy steerers and the potential dangers thereof.
    I have only two things to say to that; Bo***cks
  • ugo.santalucia
    ugo.santalucia Posts: 28,310
    The Mechanic wrote:
    +1 ^^^ What there are loads of are threads complaining about carbon forks with alloy steerers and the potential dangers thereof.

    There are plenty of threads complaining about pretty much everything. Based on MY experience and that of the people I know, carbon steerers have a couple of issues as I described above. If other folks have a different, more positive experience, that's great for them.
    left the forum March 2023
  • majormantra
    majormantra Posts: 2,094
    The Mechanic wrote:
    robbo2011 wrote:
    The carbon steerer/alloy stem combination is so common that if it was troublesome, there would be loads of threads on here complaining about it. There aren't, so it isn't.

    (10,000km here with no issues whatsoever)

    +1 ^^^ What there are loads of are threads complaining about carbon forks with alloy steerers and the potential dangers thereof.

    1. Where?
    2. He said carbon steerer/alloy stem, not carbon fork with alloy steerer.

    This thread has become silly.
  • The Mechanic
    The Mechanic Posts: 1,277
    1. Now you've got me. I can't find much just now but I remember a thread not long ago that scared the life out of me. The general concensus was that alloy steerers on carbon forks were the spawn of the devil and almost everyone in the world has a near fatal accident with them. I checked the ones on my Spesh as a result. I will keep looking and if I find it I will link here.

    2. I was responding to Mr Ugo's comments that carbon steerers are the spawn of the devil.... :D
    I have only two things to say to that; Bo***cks
  • ugo.santalucia
    ugo.santalucia Posts: 28,310
    The Mechanic wrote:
    1. Now you've got me. I can't find much just now but I remember a thread not long ago that scared the life out of me. The general concensus was that alloy steerers on carbon forks were the spawn of the devil and almost everyone in the world has a near fatal accident with them. I checked the ones on my Spesh as a result. I will keep looking and if I find it I will link here.

    There is a lot of nonsense on the web. You will find that most carbon forks fitted with metal steerers on those Look frames of the early 90s are still around. Most of the carbon forks up to 5 years ago had a metal steerer and they are absolutely fine.
    There is nothing wrong in joining metal to carbon, plenty of frames with carbon rear triangle that have no reported problems.
    On the contrary, there are a lot of reports of people who don't seem to get a good grip between the stem and the steerer. I frankly don't understand the reason why sometimes things don't clamp properly to a carbon steerer, but it's a fact.
    left the forum March 2023
  • majormantra
    majormantra Posts: 2,094
    The Mechanic wrote:
    2. I was responding to Mr Ugo's comments that carbon steerers are the spawn of the devil.... :D

    Ok, but it wasn't Ugo you quoted.

    When carbon seatposts started to appear people were convinced they were lethally dangerous. A few years on, there hasn't been an epidemic of impaled roadies or inexplicable failures.

    It's very hard to imagine a product achieving the level of mass market acceptance that carbon forks with aluminium steerers (or full carbon forks) have, if they were inherently flawed. They just aren't. There are less good designs out there, and manufacturing defects are possible as with any product, but fundamentally they are as safe as any other type of fork if they are installed correctly.

    A typical carbon/alu fork has an aluminium crown that 'plugs' into the fork legs. Only the legs are actually carbon. It's not rocket science, and it works well.
  • The Mechanic
    The Mechanic Posts: 1,277
    Well that is good to know that I don't have to buy new forks for my Spesh after all. I still can't find the thread but it did preach alarm about failure of alloy steerers, due, IIRC, to corrosion. I hereby withdraw my previous comments. My new bike has all carbon forks and I haven't noticed any stem slippage but will keep an eye open for it after Ugo's experience..
    I have only two things to say to that; Bo***cks
  • ugo.santalucia
    ugo.santalucia Posts: 28,310
    The Mechanic wrote:
    My new bike has all carbon forks and I haven't noticed any stem slippage but will keep an eye open for it after Ugo's experience..

    It's a common problem, but it doesn't affect all steerers or steerer/stem combinations. Problem is, if you have it there is no cure for it... I was really lucky to crack my steerer under warranty, so I could get rid of the damn thing
    left the forum March 2023
  • The Mechanic
    The Mechanic Posts: 1,277
    OK, here is the discussion on hte CTC forum on the merits or otherwise of alloy steerers.

    http://forum.ctc.org.uk/viewtopic.php?f=5&t=24386
    I have only two things to say to that; Bo***cks
  • ugo.santalucia
    ugo.santalucia Posts: 28,310
    The Mechanic wrote:
    OK, here is the discussion on hte CTC forum on the merits or otherwise of alloy steerers.

    http://forum.ctc.org.uk/viewtopic.php?f=5&t=24386

    A nasty accident, but nothing to do with the carbon-alloy interface. It is only due to metal fatigue at that particular point of the metal steerer. If the guy had periodically checked and serviced the headset, he would have noticed the crack developing... he probably never bothered and amen...
    I am fully aware of metal fatigue and I don't think metal is any better than carbon in that respect, my point is that there is nothing wrong in joining metal to carbon and a metal steerer clamps to the stem a lot better
    left the forum March 2023
  • slowbike
    slowbike Posts: 8,498
    With an 'ahead' sysyem, all the pulling / twisting force applied by the rider at the handle bars, will be transmitted to the steerer and applied at just one point to this 'thin walled aluminium tube'.
    It's funny when people who have no concept of engineering start jumping to conclusions...

    Pulling? Not much pulling going on - often a reasonable bit of weight on the bars, sometimes pulling (up hill or sprinting) but not huge forces. I bet if you took an aluminum pole the same dimensions of a steerer tube and tried to bend it with your hands - even around a fixed point - you'd really struggle.

    twisting force? Eh? Just how hard do you have to work to twist the steerer? It should be smooth as silk - even if the bearings are ceased it's not going to be that tough - just rough.

    There are a lot of forces going through the steerer tube - mostly just compression along it's length, but breaking or hitting bumps will create a lateral force that, if extreme could damage the tube. The other area is repetitive stress that will cause fatigue and eventually failure. However, the manufacturers know about this and will have designed the steerer tube to cope with this - be that steel, aluminium or carbon so failure will likely be down to exceptional force, a fault in the material or manufacture or just excessive age.

    With regards to carbon steerers and alloy stem. I've got no problems with two bikes we own with that combination. I've not experienced the problems Ugo had.
  • drlodge
    drlodge Posts: 4,826
    I've got full carbon forks and not had this problem either...perhaps I am lucky. Its Ritchey WCS forks and Ritchey WCS alloy stem. I don't use carbon paste nor a torque wrench. Perhaps its my gorillia hands that are the cure for slipping stems :roll:
    WyndyMilla Massive Attack | Rourke 953 | Condor Italia 531 Pro | Boardman CX Pro | DT Swiss RR440 Tubeless Wheels
    Find me on Strava
  • Matthewfalle
    Matthewfalle Posts: 17,380
    EC90SLX forks, Ritchey WCS ally stem - absolutely no problems at all in 3 years of riding it practically everyday in all weathers over a variety of road surfaces from smooth tarmac to pavé.

    When I put it together naturally I made sure that everything was nice and clean, no sharp edges, popped together, torqued. Job jobbed.

    No problems ref headset tension either - using some random bung (no idea what the make).
    Postby team47b » Sun Jun 28, 2015 11:53 am

    De Sisti wrote:
    This is one of the silliest threads I've come across. :lol:

    Recognition at last Matthew, well done!, a justified honour :D
    smithy21 wrote:

    He's right you know.
  • keef66
    keef66 Posts: 13,123
    My Scott bung sits securely inside it's carbon steerer and the alloy stem, the cheapest Deda job I could find on Ribble, has likewise been secure since installation last year.
    Since the bung sits in the steerer in the zone clamped by the stem, both can be tightened to the recommended torque settings without fear of damaging the carbon.
  • proto
    proto Posts: 1,483
    It's possible that some problems may be attributable to the quality of the stem, or more specifically the size and shape of the hole through the stem where it fits onto the steerer. The steerer tube will be very close to 28.6mm in diameter, probably something like 28.6/28.5mm

    The hole through the stem should be nominally the same, but will be a plus tolerance, something like 28.75/28.65mm. If the fit is a close match then very little force will be needed to clamp the stem onto the steerer.

    However, some stems have through holes much bigger than this, they feel 'sloppy' when you slide them down into position, and then when clamping, greater force is needed to get the stem to clamp. The bigger the difference in sizes the more the stem has to be distorted, and even when done up tight, there is less surface to surface contact between the two parts.

    I've actually experimented with this in the past. Clamped a 3T Arx aluminium stem onto a carbon steerer, tightened just one of the two clamp screws to a set torque figure and could not physically get the stem to slip or twist no matter how hard I tried.

    Repeated the experiment with another very popular brand and even with two screws tightened to the same level, on the same steerer, I could still get the stem to slip. t took a lot of effort to budge it, but budge it did.

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