SON 28 Klassik Wheel Torque Setting

[StuntPilot]

Can anyone confirm the correct torque setting for the SON 28 Klassik dynamo hub (quick release type)? I understand that over tightening can damage the bearings.

Also can anyone suggest a small reasonably priced torque drive or set (not a workshop sized one)?

[Danneaux]

Can anyone confirm the correct torque setting for the SON 28 Klassik dynamo hub (quick release type)? I understand that over tightening can damage the bearings.

Hi Richard!

Yes and yes.

From Schmidt's own downloadable PDF data sheet for the Klassik: http://www.nabendynamo.de/produkte/pdf/english/Montage_SON_28_klassik_e.pdf ...

The hub is secured using the included skewer set. It fits the same way as a quick-
release, but fastens with a 5 mm allen key (recommended torque moment
6 - 8 Nm).
Apply a little grease on thread and screw-head but not on the shank (to
prevent clogging up the pressure compensation system leading into the hollow axle).
If the skewer tension is too low, the axle may move inside the fork end causing a
rattling noise.
Alternatively a lever-type quick-release may be substituted, or a proprietary security
fastener such as Pitlock.

Best,

Dan. (...who uses shop-grade torque wrenches on fasteners at home and substituted a q/r for his SON's bolt on skewer to prevent loosening in use, which occurred on the rough roads he travels even at the SON's recommended torque settings)

[StuntPilot]

Dan Hi! I have not yet taken the leap yet in purchasing the whole front wheel build (Andra CSS rim/DT Swiss Competition spokes/SON 28 Klassik Silver) as it is a big outlay. I have been contemplating it for a while. Hopefully soon! I am getting a bit fed up with the rim dynamo for power generation via The Plug II (it is fine for occasional night time lighting though).

Thanks for pointing out the torque settings. I should have looked at the manual. Hopefully this post will act as an easy source of information for other forum users.

Interesting that you have found that the SON skewer can come loose on rough ground. I am using Pitlocks and have had no problems with loosening so hopefully all will be well with the SON Klassik in place.

One torque set I have found is from BBB and it looks good ... review here ...

http://road.cc/content/review/73163-bbb-torqueset-adjustable-torque-tool

Expensive but you can find it for about £40 if you shop around. Madison do one too that looks very similar ...

http://www.madison.co.uk/products/cycling/tools-maintenance-repair/multitools-torx-hex-wrenches/torque-wrench/

It would be a useful addition to the tool box. I am sure that a cheaper handle only wrench can be found in local hardware shops but I like all the fittings it comes with to correctly set all bolts on the bike.

I am not sure what settings to use on other bolts on the bike though!

Richard

[Danneaux]

Quick link-back to Andre's post regarding appropriate/suggested torque wrenches here: http://www.thorncycles.co.uk/forums/index.php?topic=7815.msg50319#msg50319

I've got to do some other things ("work" rears its ugly head) for a bit, but will return to the topic with some further thoughts later when I can devote a bit more time.

Best,

Dan.

[StuntPilot]

Dan

Could be useful to have a new post with recommended torque settings for ALL bolts on Thorn bikes. I say that as I have stripped a couple of bolts in the past.
I have no idea what the torque settings should be for other bolts. I see that there is a device available for bolt tightening here ...

http://www.cyclesurgery.com/pws/UniqueProductKey.ice?ProductID=CBON008300&gclid=CN7rgtiF9LoCFQjKtAod-WQAfg&gclsrc=aw.ds

This and similar devices seem to be set to 5Nm so I assume that is recommended setting for bolts on a bike, Non?

Cheers

Richard

[Andre Jute]

Ah, thanks, Dan. It looks like Richard has already arrived at the BBB torque wrench kit I generally recommend, among other reason because with the addition of a T20 and a few additional hex bits for the Rohloff, and an 8mm socket as an emergency gear changer if you have the EXT box, and a half inch socket if you have a twin rail Brooks saddle, it soon builds up to a very complete toolkit replacing a huge toolbox. I've had mine for about ten years, and wouldn't be without it.

[StuntPilot]

Andre - looks like you have already started the topic of how tight the bolts and fasteners should be on a bike ... 

http://www.thorncycles.co.uk/forums/index.php?topic=7821.msg50325;topicseen#msg50325

[Danneaux]

Richard,

A Real Kwik Response™ 'cos I've got other matters on the boil...

A bicycle's fastener torque ratings are generally determined by the bolt diameter. A quick check of typical ratings is here: http://www.parktool.com/blog/repair-help/torque-specifications-and-concepts

Most well-designed threaded fasteners will achieve full strength when 5 threads are engaged. A glossy response (which I'll regret later so I'll call it a "rough rule of thumb") is to torque to the fastener diameter with materials in mind. Depending on the materials in use, go here: http://yetmans.mb.ca/kohler/page3/page3.html ...and select the chart for "noncritical fasteners into aluminum" for a rough guide that will largely keep one out of trouble. That said, I'm more specific than that.

This and similar devices seem to be set to 5Nm so I assume that is recommended setting for bolts on a bike, Non?

Nope. One size doesn't fit all! Note the 4mm hex key included is not a 5 or 6mm key.

Don't forget, not all recommended ratings are in the same measurement system. My favorite site for quick and accurate conversions is here: http://mdmetric.com/tech/tech4/torqcalc3.htm

Best,

Dan (...both hurried and harried at the mo')

[StuntPilot]

Thanks Dan! Great info as always! Off to digest now ...

[Andre Jute]

Andre - looks like you have already started the topic of how tight the bolts and fasteners should be on a bike ... 

http://www.thorncycles.co.uk/forums/index.php?topic=7821.msg50325;topicseen#msg50325

Yes, in the hope of not derailing your specific-problem threads, I started a more general thread to hold an aside I edited out of a reply to one of your posts. I don't mind my threads being hijacked and seeing where they go but many people have tidier minds.

[Danneaux]

I may try to do a merge later if I can keep the threads coherent. Otherwise, it may well be worth a sticky or some such.

All the best,

Dan.