The end of (some) DT Swiss blues

[Johan Bornman]

DT Swiss is a strange company in a way. It produces some excellent products and then every now and again it produces a lemon and keeps on manufacturing it year after year. At least Shimano abandons its flops and supercede them with something better.

 

A case in point is the DT Swiss roller bearing freehub body. Absolutely poor.

 

Another case in point is the hub range with the clutch - the ones they bought over from Hugi, IIRC.

These hubs have freewheel mechanisms that don't have pawl like most other hubs, but a clutch. Two serrated, hard steel plates push against each other with a spring. In one direction they engage, in the other they make a noise and freewheel.

 

The innermost plate of this clutch fits into a threaded ring. This ring violates one of the big engineering No-Nos - never support a rotating load on a thread.

 

The harder you pedal, the tighter the ring goes. This in itself isn't bad, but this ring holds the right side bearing that supports the hub. To replace the bearing, you need to get the ring out. To get the ring out you need a special DT Swiss tool and a bodybuilder.

 

The official DT Swiss tool (I wish I had one for a photo, but I don't) is made from Swiss cheese. It deforms in use, inevitably destorying itself and the fragile aluminium axle that acts as its support and guide.

 

Enough is enuff, I said and redesigned the tool. Here it is.

 

 

 

Pictured are two of them, so you can get a better view. The ring is the culprit. This tool fits securely inside the ring's splines.

 

Instead of using the hub's soft alu axle to secure the tool in place, it now features its own guide that fits securely in the bearing's hole. The splines engage perfectly and the flattened end goes into a vice. Your wheel is your lever. The tool is made from tool steel and is solid.

 

The official tool from DT is hollow, brittle and unstable under high torque. It is made from Swiss cheese. I've destroyed several.

 

Now my next mission is to find a cure for that piss-poor seal on the roller bearing freewheel mechanism.

 

Edit: I can't seem to get the picture where it is supposed to go - above its caption.

[ichnusa]

Awesome! Best post on the tech section in weeks!

[Capricorn]

hotdamn, luv the macgyvering. well done JB.

[brussel]

shot - good work...how did you machine those puppies, you'd need a mill with a dividing head I would think?

[Johan Bornman]

shot - good work...how did you machine those puppies, you'd need a mill with a dividing head I would think?

 

A very good machine shop did it for me. The body of the tool was created with standard lathe work. The splines were created by spark erosion. They followed the entire length of the tool and the superflous bit was turned down - you can still see the evidence of the long splines on the rear section.

 

I'll take a close-up of the splines in the ring and you'll see how nicely they match.

[Johan Bornman]

[goatman]

Beautiful!

 

Hope it will pay for itself over time.

[brussel]

wow! nice. Does the process use some sort of a follower that patterns off the ring? or did they CAD it up first?

[AndreZA]

Good work JB. I still think you should bring out your own line of tools. Starting with the Chain drop.

[Master216]

are these problems etc on the DT240 hub as well?

[flogster]

What Johan says is quite true, it takes very little peddling force to make that threaded insert so tight its almost impossible to loosen, even with DT swiss tools. Even greasing and regular removal wont make that any insert any easier to remove. The bearing is help "captive" underneath this insert so it has to be removed at some stage to replace the bearing.

 

The way I solved this was to locate a discarded spline or rachet gear from the 240 and found a 1/2 inch socket which fitted neatly into the inner diamter of this spline and welded it on. Use this modified socket with an impact wrench and Bobs your aunty, the insert comes out easily. Cost 20 bucks to make

 

 

In my opinion the 240 must be one of the best hubs available, dont let this little problem put you off! What other freebody can be opened and fixed on the trail without tools?

[Bat-ass]

i sell a Loctite product called "Loctite 8040 freeze and release". its a light release lubricant, that is ice cold. you spray it on the inner metal section, which contracts, and makes releasing a bit easier. Perhaps it would help Johans tool with seriously tight threads in there?

[Gert Janse v Rensburg]

are these problems etc on the DT240 hub as well?

 

Its only on the 240 Hub as far as I know....

 

the other hubs use pawls.....

 

Doug from DT Swiss also gets his own tool made from a shop.... he sells these to the mechanics that buy from him.

Dont know where JB got his from but I assume, that if it was directly from the distributer then he would have gotten the more durable one.

 

JB Im only assuming so please don't rip my head off if im wrong.....

 

 

 

[The techguy]

Well done, you've just done something Doug Patterson did 3 years ago...

[DawieO]

techguy why so aggro?

[SwissVan]

Good work JB. I still think you should bring out your own line of tools. Starting with the Chain drop.

 

Excuse the ignorance (it must be all the swiss cheese) but Whats a chain drop