Author Topic: Skewers: cam vs hex  (Read 8173 times)

Skewers: cam vs hex
« on: 15 July, 2012, 11:06:17 pm »
Just looking at different QR skewers. I note that there are these new fangled hex key ones, which dispense with the lever and cam and you simply tighten up two nuts on the skewer. To begin with I though, hmm, might as well have solid axles then, but for hollow axles, is there any advantage over cam types? Firstly, does tightening the skewer with a small hex key provide more clamping force than a conventional QR (as the sales guff claims, for some of them), and how do you judge when they are tight enough?

Kim

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Re: Skewers: cam vs hex
« Reply #1 on: 15 July, 2012, 11:28:45 pm »
I believe it does.  Certainly more than the naff external cam type, probably more than the internal cam type, too.

Some people may find the lower absolute force required to turn an Allen key compared to operating a QR to be a significant advantage.

And of course, they require a tool (possibly an obscure one, for security types) to remove the wheel.

Re: Skewers: cam vs hex
« Reply #2 on: 16 July, 2012, 12:25:46 am »
I've got them on a handful of bikes for those two reasons.  On a couple of bikea, because it provides marginally better security than a QR skewer (but can be dealt with using fairly easily available tools).  On a single speed bike, because the QR skewer does have a tendency to move slightly, and I know the hex non-QR version can't easily loosen off.  I have less faith in relatively cheap QR skewers.
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Re: Skewers: cam vs hex
« Reply #3 on: 16 July, 2012, 12:29:52 am »
Nothing new about them, my Schmidt SON hub came with a hex key skewer 6 or 7 years ago. FWIW, the hex key skewer that came with my SON is a touch lighter than the titanium skewer that I bought to use on the SON. So, lighter weight, a little more security and (possibly) more clamping force.

PaulF

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Re: Skewers: cam vs hex
« Reply #4 on: 16 July, 2012, 06:40:44 am »
I'm slowly switching over, partly because they may provide more force! Partly for the security benefit but also for less possibility of an accidental release.

frankly frankie

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Re: Skewers: cam vs hex
« Reply #5 on: 16 July, 2012, 07:59:37 am »
I have hex key skewers dating back over 25 years.

And there is such a thing as over-tightening, by the way - QRs should only be 'tight enough' not 'tight as possible'.
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Re: Skewers: cam vs hex
« Reply #6 on: 16 July, 2012, 09:53:10 am »
Definitely seemed to provide better clamping force here.  I had a front wheel which was moving slightly in the dropout under disc brake squeal.  Hex skewer (which I happened to have already) cured it.

I didn't have to crank down hard on the hex either.  And because you have to spin a QR in the front anyway then iteratively find the right tension, it's not really any slower to use the hex.

Re: Skewers: cam vs hex
« Reply #7 on: 16 July, 2012, 10:20:04 am »
Thanks for all the info. I see the Halo ones specifiy a torque of about 9 Nm which is a fair old tension.

Slight thread drift: my reason for looking at skewers was that I find it difficult to get my rear wheel out due to interference between the QR nut on the drive side and the derailleur. I was looking around for QRs that had a nut that was more conical to see if I could get round this.

tiermat

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Re: Skewers: cam vs hex
« Reply #8 on: 16 July, 2012, 11:39:10 am »
Thanks for all the info. I see the Halo ones specifiy a torque of about 9 Nm which is a fair old tension.

A word of warning

DO NOT buy the Halo ones.

If you tighten them up to the recommended tension the grip washer compresses then you get a skewer that slips in the drop out.

They also do not have a cut out in the ends, so if you are using them on a steel framed bike (i.e one with thinner than is the norm now dropouts) they bottom out on the axle end first before gripping.

They are cheap (I paid ~£8 as set from Tredz) and when you use them you find out why.
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Re: Skewers: cam vs hex
« Reply #9 on: 16 July, 2012, 11:41:55 am »
In terms of ability to clamp, I'm happy with Shimano skewers. I think I might just stick to what I know and just pull the skewer out when I take out the back wheel.

PaulF

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Re: Skewers: cam vs hex
« Reply #10 on: 16 July, 2012, 11:52:49 am »
Thanks for all the info. I see the Halo ones specifiy a torque of about 9 Nm which is a fair old tension.

A word of warning

DO NOT buy the Halo ones.

If you tighten them up to the recommended tension the grip washer compresses then you get a skewer that slips in the drop out.

They also do not have a cut out in the ends, so if you are using them on a steel framed bike (i.e one with thinner than is the norm now dropouts) they bottom out on the axle end first before gripping.

They are cheap (I paid ~£8 as set from Tredz) and when you use them you find out why.

B*gger I wish this thread was up yesterday as I ordered a set last night :(

Re: Skewers: cam vs hex
« Reply #11 on: 16 July, 2012, 12:39:41 pm »
Definitely seemed to provide better clamping force here.  I had a front wheel which was moving slightly in the dropout under disc brake squeal.  Hex skewer (which I happened to have already) cured it.

I didn't have to crank down hard on the hex either.  And because you have to spin a QR in the front anyway then iteratively find the right tension, it's not really any slower to use the hex.

I've filed off the 'lawyers lips' on three bikes, but hesitate to do the same on the disc-braked mtb.

Re: Skewers: cam vs hex
« Reply #12 on: 16 July, 2012, 12:42:42 pm »
I've filed off the 'lawyers lips' on three bikes, but hesitate to do the same on the disc-braked mtb.

Likewise. Given that I need to loosen off the skewer anyway, thus rendering it not-very-QR, this led me to consider the hex alternatives. I'm not convinced, so far, that they are a better job than a good Shimano internal cam QR.

Cudzoziemiec

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Re: Skewers: cam vs hex
« Reply #13 on: 16 July, 2012, 01:01:29 pm »
I've not heard that they're tighter on the dropout than QRs, though that doesn't mean they aren't. I've got some 'hex' key skewers which are actually pentagonal - a security feature. Whether this is worthwhile for you depends on things like where you leave your bike.
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Re: Skewers: cam vs hex
« Reply #14 on: 16 July, 2012, 01:07:56 pm »
Just looking at different QR skewers. I note that there are these new fangled hex key ones, which dispense with the lever and cam and you simply tighten up two nuts on the skewer. To begin with I though, hmm, might as well have solid axles then, but for hollow axles, is there any advantage over cam types?

1. They provide a tad of security since not every scrote has an allen key.  A bit more still if you opt for pentagon rather than hex ones.
2. They are lighter in some cases.
3. More convenient fine tuning of clamping force.

Quote
Firstly, does tightening the skewer with a small hex key provide more clamping force than a conventional QR (as the sales guff claims, for some of them)

They can provide less, the same, or more clamping force, depending on the model, use, and lubrication.  Lube = greater ability to tighten.  You can easily get more force with Tranz X ones if you want, for example.  Remember that overly tight clamping can be bad for the bearings.  Tightening the skewer compresses the hub axle, which in turn affects pressure on the bearings, with all type of bearings.  Readjust the bearings in preparation for a change in clamping force, when possible.

Quote
and how do you judge when they are tight enough?

- With a conventional (cup and cone) bearings: when the play in the bearings just disappears.  Set QRs like this as well.
- With cartridge bearings: you just have to guess when it feels right.  QR levers aren't pre-set precisely either, as you adjust the nut to provide the desired force before first use, using your own judgement.

I use hex and pentagon skewers, including Tranz X (available under various other brand names too).  I'd only prefer QRs now if I was racing.
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Cudzoziemiec

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Re: Skewers: cam vs hex
« Reply #15 on: 16 July, 2012, 01:36:34 pm »
1. They provide a tad of security since not every scrote has an allen key.  A bit more still if you opt for pentagon rather than hex ones.
And if a regular pentagon isn't secure enough for you, there are unique polygonal ones for £60 or more.
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Re: Skewers: cam vs hex
« Reply #16 on: 25 January, 2022, 09:39:34 pm »
Interesting old thread. I've just lost one of the hex nuts off the skewer on the SON dynohub on my Brompton. I've ordered both a new hex skewer and a 74mm internal-cam Q/R skewer to experiment with. It wasn't till I read this thread and another that I came across the idea that hex nuts might achieve more torque. Maybe I didn't do it up tight enough, but it's lasted some years.

Re: Skewers: cam vs hex
« Reply #17 on: 25 January, 2022, 10:17:21 pm »
I got the allen key skewers on a chromed horizontal dropout, I was surprised how firmly they hold the wheel considering the "nut" is aluminium.

Re: Skewers: cam vs hex
« Reply #18 on: 26 January, 2022, 07:03:31 am »
Quote
considering the "nut" is aluminium.
Yeah.. I had one strip. Fortunately in the workshop. Replaced with a spare steel Shimano nut. Front wheel, would not have been nice out on the road.

Re: Skewers: cam vs hex
« Reply #19 on: 26 January, 2022, 09:01:04 am »
I have an internal cam QR on my Shimano dynamo hub disc braked front wheel. It hasn’t loosened at all. Maybe I don’t death grip the brakes enough?

Re: Skewers: cam vs hex
« Reply #20 on: 28 January, 2022, 01:11:03 pm »
The nut thread was a rim brake wheel.  I have a disc with internal cam skewer as well...
They are OK in the right hands. Problem is people who cannot set up a QR and external cam skewers.

Re: Skewers: cam vs hex
« Reply #21 on: 28 January, 2022, 01:26:04 pm »
Given that the Brompton has rim brakes (and I think has slotted drop-outs to hold the wheel in the correct orientation), I'm thinking that I'll try the Q/R skewer first. They should arrive tomorrow.

Re: Skewers: cam vs hex
« Reply #22 on: 30 January, 2022, 03:48:12 am »
Thinking about this further, I'm trying to work out why we get so worried about people who do up their Q/Rs by screwing them tight, instead of using the cam, when that's exactly what happens with a hex skewer. OK, traditional wheel nuts have been a good method for over a century. But that's not usually considered to be the case on a skewer. Maybe you'd have to grab the Q/R nut with pliers to get the same torque?

On the Brompton in particular though, there are various bits of wire under the nuts, to do with the mudguards and so on, so contact is not necessarily directly with the drop-out, and there's less potentially less friction to hold the torque. I think I'm happier with my Q/R, given that I've just proven that the Allen-key nuts don't necessarily stay secure. Of course, even a Q/R ultimately relies on torque to hold the tension.