DT Swiss Thru Axle coming undone

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  • DT Swiss Thru Axle coming undone
  • Premier Icon nickdavies
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    It’s a right hand thread, so if a wheel bearing seized onto the axle I guess it’s normal rotation could do that. You’d have to be going some to get it seized on in normal use, I had a superstar steel bolt through seize to an alloy hub once but it was out of action for months beforehand. It would be so obvious i’d have thought if that had happened.

    I reckon user error is more likely to blame here – was the wheel off for transport etc and not done up properly?

    Premier Icon Simwit
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    I’ve had problems with this happening on both a set of DT forks & on the rear of my bike when it was brand new & it definitely wasn’t user error in either case. At the end of the day the DT axle is just a large screw and doesn’t have a cam style lock like Rockshox & Fox axles. After it happened twice on my new Turner I sacked it off and bought an old stock maxle affair, it hasn’t come undone once.

    Premier Icon gpsBRM
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    One of our riding group had a mechanical last night where his rear thru axle undone itself mid ride. This resulted in the wheel coming out, ripping the derailleur apart and bending the brake disc. On closer inspection it looks like the rear wheel bearings are a bit shot which intern has undone the axle. To me the setup looks wrong, but not having a rear thru axle myself I don’t know. Is this normal behaviour or is the thread on the axle the wrong way round or some other problem entirely? It looks to me like a bit of a design flaw if the rotation on the wheel can undo the axle

    Cheers

    jimw
    Member

    For the wheel rotation with sticky bearings to make it have come undone, surely the axle end caps would have to rotate in the frame as well as these are the only parts in full contact with the bearings and wheel axle, or I suppose the axle could rotate within the endcaps. at least thats how it is on my mavic wheels. The thru axle is only a tensioning device, the endcaps/dropout interface are the weight/load bearing parts. the wheel axle is usually stationary at all times.
    that would make a mess of the endcaps and the droputs or the endcaps and the axle if the endcaps remain stationary and the axle rotates within them very quickly. Is there evidence of this?

    More likely to have vibrated loose? I must say that has never happened on either of the two bikes I have with a DT Swiss x-type 142×12 setup

    nikk
    Member

    jimw wrote:

    For the wheel rotation with sticky bearings to make it have come undone, surely the axle end caps would have to rotate in the frame as well as these are the only parts in full contact with the bearings and wheel axle

    Correct, but for that to happen, the thru axle would have to be loose.

    Nick Davies wrote:

    It’s a right hand thread, so if a wheel bearing seized onto the axle I guess it’s normal rotation could do that.

    Yes, but on the forks, the thread is on the left hand side, and on the rear, it is on the right.

    simwit wrote:

    I’ve had problems with this happening on both a set of DT forks & on the rear of my bike when it was brand new

    So first, I have run DT Swiss forks for years, doing very long days and big millage, and not had that problem ever.

    And second, if the rotation of the wheel was doing it, it would tighten up the thru axle on the fork, as the thread is on the left.

    simwit wrote:

    it definitely wasn’t user error in either case.

    I find it hard to believe. Something else is going on. Forgetting to tighten it up is a possibility. Once these things are tight, they won’t come loose.

    Premier Icon Simwit
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    Nikk, I know many if not most people who run DT thru axles never have this problem but I can assure you I know how to tighten a bolt. Bolts can & do vibrate loose. I got to the point where I was uncomfortable with how tight you had to do up these axles as at the end of the day there’s only a plastic spline inside the handle & people have stripped them. As I said earlier I’ve not had a single problem with any axle with an over centre cam action.

    Premier Icon nickdavies
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    I’ve switched all my bikes to DT RWS, thru and QR, I find it much more secure than a cam action. I’d replace the maxles on the front forks with it if I could. I’ve had back wheels rattle loose with cam locks and front maxles that needed tightening mid ride – horses for courses I suppose, but I think you can get a tighter clamp with RWS as all the cam does is expand the wedge in the axle and it doesn’t totally lock it. Have no idea if this is correct or not though!

    I really can’t see how they could work loose under normal use from tight given the size of thread and the amount of compression they’re under, not so say they couldn’t though.

    OP did your friend buy the RWS as a retrofit or was it on the bike from new?

    Premier Icon adsh
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    My Turner’s DT rear maxle has a tendency to loosen too. I do it up tiiight but it still loosens.

    Premier Icon gpsBRM
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    Cheers for the replies.

    The axle was with the bike from new. Its a Mondraker Foxy Carbon R. Ever since he’s had it (which isn’t that long) its never looked likes its done up tight enough, ie its seems to get to the end of the thread as opposed to actually tightening against the wheel, whether it should or not I don’t know.

    Certainly after this happened and we put it back together (bodged single speed) to get home (well pickup from the pub), you could see the wheel turning the axle when you spun the wheel (due to the shot bearings).

    Premier Icon gpsBRM
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    By the way the bearings in the rear wheel aren’t seized, they are just sticky.

    Also when we rode Dyfi weekend before last it undid, at that point he thought it may have been user error, ie not done up. But on the last ride it was definitely checked.

    nikk
    Member

    simwit wrote:

    Nikk, I know many if not most people who run DT thru axles never have this problem but I can assure you I know how to tighten a bolt.

    Fair enough mate, just checking 🙂

    simwit wrote:

    I got to the point where I was uncomfortable with how tight you had to do up these axles as at the end of the day there’s only a plastic spline inside the handle & people have stripped them.

    The early ones were plastic and some people stripped the teeth. The later ones are all metal and seem bombproof from my experience. Tighten em up!

    Adam H wrote:

    My Turner’s DT rear maxle has a tendency to loosen too. I do it up tiiight but it still loosens.

    That sounds bad, something isn’t right.

    gpsBRM wrote:

    The axle was with the bike from new. Its a Mondraker Foxy Carbon R. Ever since he’s had it (which isn’t that long) its never looked likes its done up tight enough, ie its seems to get to the end of the thread as opposed to actually tightening against the wheel, whether it should or not I don’t know.

    All thru axles should be tight. The axle should hold the hub end caps tight against the frame drop outs. The point of the thru hub is it makes the whole thing (frame and axle) close to being one unit, so making it stiffer.

    gpsBRM wrote:

    Certainly after this happened and we put it back together (bodged single speed) to get home (well pickup from the pub), you could see the wheel turning the axle when you spun the wheel (due to the shot bearings).

    That is not right at all.

    Something is badly wrong.

    There are a bunch of different axle standards. Just see http://www.extralite.com/Products/Black%20Lock.htm for a lot of the different standards. I think that the wrong thru axle has been specified, or the wrong wheel maybe? Or there is missing spacers / adapters or some such.

    Premier Icon nickdavies
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    ^ That was what I was getting at – if it’s a 12mm bolt thru there are 3 different standards so the wrong one could have been bought. If it was specced from new though and it’s wrong (or hub/spacers etc) somebody wants shooting. Definitely doesn’t sound right from what you’ve said, you can definitely tell when they’re done up properly. If it felt like it wasn’t tightening or there was any play it’s not right. Back to the LBS or wherever it came from i’d say to get it looked at.

    Premier Icon adsh
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    adsh » My Turner’s DT rear maxle has a tendency to loosen too. I do it up tiiight but it still loosens.

    That sounds bad, something isn’t right

    I just put it down to not having a cam action like most other axles. Now I realise it’s tendency to loosen I’m doing it up tighter and check occasionaly – it’s been OK. It is not IMHO the best design.

    nikk
    Member

    I just put it down to not having a cam action like most other axles. Now I realise it’s tendency to loosen I’m doing it up tighter and check occasionaly – it’s been OK. It is not IMHO the best design.

    I don’t think that is the reason. It is possible to apply more pressure with the DT system than a cam system. People prefer it over the cam systems because of that.

    Premier Icon davosaurusrex
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    For a bit of balance the DT axle on my 2012 Turner has been rock solid, carrying plenty of battle scars on the lever too.

    andysredmini
    Member

    Mine rotated 1/4 of a turn once but ip put it down to hitting it of something, not doing it up tight enough or the fact that everything was new and had bedded in a bit. I check it every now and then if I remember and since that once it hasn’t moved again in around 6 months.
    It doesn’t explain your situation or help you but I thought I would share it anyway.

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