Philly Tandem

Can anyone here clue me in on how to take apart a DT/Swiss 540 rear tandem hub (Co-Motion puts these on many of their tandems and also some single bikes like the Pangea)? I've Googled around and found conflicting info. The official DT manual lists all these special tools you need to buy, suggests using a bench vise, etc., while other user postings I've seen extoll the fact that you can take apart the hubs without tools, even in the field.

Looking at the hub I can't figure it out. Maybe I do need the special tools, which would be a bummer as I want a hub that can be maintained in the field or on a tour if a problem arises. (And I also don't want to shell out money on special tools if I don't have to.)

Any help is most welcome! Thanks.

waynesulak

I replaced the bearings on a pair of those a few years back and recall finding substitutes for their special tools. The bearings are pressed in so I would have trouble serving in the field but managed to do so in my garage. On tour I would have to find a competent shop to do it. I believe that the ratchets can be greased easily. I have attached a PDF for that.

Philly Tandem

Thanks Wayne. I'm not looking to remove/replace the bearings (at least not yet), rather just want to be able to pull the axle and the freehub off in case I need to grease the pawls, replace a drive-side spoke, or (more likely) take off the cogs to make packing in an S&S bag easier. The PDF you attached is helpful, thanks. Looks like I basically just need to pull outward on the cassette and the whole thing will come off?

PMK

I have a bunch of experience with these hubs.

The process is simple and can be made easier.

To remove the right side axle end cap, yes you can use the axle clamp and vise as shown. What works equally well is the chuck of a drill. Clamp the three jsw chuck onto the axle stub. Using a wiggly movement and pulling out, the end cap will come off with a bit of effort.

Once removed, look inside the axle end cap. There is a tiny thin O ring. remove it. This is there to keep the end cap and free hub together when the QR is removed. Under normal situations, the QR is always installed unless you plan to go into the hub.

Roving the O ring allows the entire drive system to slide off with no tools. The cassette can remain installed.

All of our DT hub tandems have no O ring. Off-road, if the chain mis routes and gets trapped into the spokes, within seconds it is free. On road, we did an event, noticed the freehub was dragging a bit. Removed the wheel, removed the QR, slid the drive assembly off the axle, wiped clean, relubed and reinstalled. Simple 15 minute job. Ironically a few other captains came by concerned, they were surprised at how easily it was done.

FWIW, you can buy and use the Molykote special lube they sell and recommend. I have some, but often just prefer Mobil 1 140 wt gear oil. The gear oil does not have consistency concerns and especially for our off-road tandem, we get a faster and more solid engagement every time.

Also, make sure you remove the spacer on the axle. They slide off easily, but sometimes because people do not lube the axle and spacer ID, they can get slight corrosion and get stuck.

FWIW, we also have a spare axle, not a common problem but they are inexpensive and relatively easy to replace if broken. More a just in case, since the travel and expenses would be a bigger loss than having a spare axle and riding all weekend at an event.

All the best with it.

PK

Philly Tandem

Thanks for the help everyone! Just finished pulling it apart and cleaning it up. The wheels were on on a used Co-Motion I just bought. Took a pretty good yank to get the cassette side off (doesn't look like they have been apart before), but then everything came apart pretty well (with some light hammer taps to get the axle out). It really is a pretty nice design. Very simple. I like it. I have some Chris King freehub lube in my toolbox, which is kind of like an oil. Might try that for the engagement parts in the freehub.

racefacelefty

Apologies for calling up an old thread, I cannot find the information I need.

Are the bearings in the freehub/rotor replaceable or does one have to buy a new freehub/rotor body?

If bearings are replaceable does one use the same tool as used on the hub body to remove the ring?

PMK

The bearing can be removed, however there is risk involved. You must be super careful to properly support the freehub body when working on it. The bearings will be removed via shifting the crush spacer to the side and tapping the bearing out. Once the first is removed, the second will not have the crush spacer to deal with.

Reassembly is done via finding a socket or similar to tap the outer race in until seated. Do not forget the crush spacer.

Honestly, most would just buy a new freehub that comes complete with bearings installed, because the cassette will have notched the freehub body anyway.

PMK

I thought the ring can remain installed. However, the tool for freehub ring removal is the same.

You tested my memory. Had to have a look at one I have apart. I did not recall removing the drive ring, and honestly do not know if it can be easily removed from the freehub.

On the aluminum freehub body I have with both bearings removed, the drive spline ring, if it is even a separate item is still installed, the inboard bearing was removed via the outboard end of the freehub body.

reburns

Have you looked here?
https://www.dtswiss.com/Resources/Su...chnical-Manual

racefacelefty

Yes, nothing in the technical manual about changing bearings in the freehub or rotor as they call it.

racefacelefty

I have both an Aluminium and a steel freehub/rotor. On the Alu the bearings are inserted from cassette lockring side and go flush against the drive spline ring behind a plate which appears to be solid.

On the steel rotor there is a plate on cassette lockring side that appears to be part of the construction and the bearings are behind the drive spline ring so the only way out is through the drive spline ring. The drive ring ID is 25.76mm, the bearing is 26mm.

reburns

Starting page 46 of the DT link above is the process for changing bearings. On page 48 is explained how some bearings may clear the ring and others may not:
"Some hubs from model year 2015 on, are using ball bearings with a smaller outer diameter on the drive side. The bearing on the drive side can be changed without dismounting the ring nut (see
section „Dismounting the Ring Nut“, page 48).
On all further hubs, the ring nut must be dismounted the change the bearing."

racefacelefty

And on page 46 it says: 5. Pull the rotor (fig. 4-6/12) off the hub.

Even re-reading the manual I see no reference to the rotor/freehub bearings. Just the actual hub bearings.

Turns out on the green Alu hub, left in picture, the bearings come out past the lock thread. On the black steel hub, the bearings come out the other side after the removal of the lock ring.

PMK

Agree, there is no mention of freehub disassembly. The references quoted are in regards to the hub, hub drive ring and hub bearing.

I believe the black item under the lockring for the cassette is plastic and comes out. There may be an O ring that friction holds it in place.

I do not have a 540 apart at this time. I do have an aluminum freehub removed and disassembled previously from our Ventana mountain tandem, and I have an earlier Hugi version.

Pretty certain the disassembly is the same. If that ring under the lockring was ridid, as the drivering tightened with use, the bearing preload would destroy the bearings.

PMK

My aluminum freehub has a black ring that was removed. This went under the lockring. No O ring as I mentioned, that is incorrect.

The black item is a machined washer, stepped on the inside to allow clearnce for the bearing race. It will remove easily as you tap the outer bearing out.

On a side note, are ou replacing bearings or cleaning and regreasing? The oem bearings I believe are stainless and seem to be high quality. If going to ceramic, you will need to heat and slip fit the bearings after deep freeze or cooling with dry ice and alcohol or liquid nitrogen. You might get away making special outer race drivers, but they need to go in straight and true from the start.

PMK

Looking at this closer, and seeing your photo, I think the step is posioned out and towards the lockring.

Road Fan

@PMK: This is a great post in a really informative thread. I've never owned a DT hub (or a tandem!) until recently. Now I'm building up the bike. The rear wheel has a DT Hugi rear hub with a Shimano-compatible freehub (Dyad rims, FWIW). I bought it with the frame; my bud had been stocking up nice parts to build the bike and has had these wheels in storage for several years.

The problem that brings me here is that when I spin the wheel while holding the freehub with a medium-sized cassette on it, it feels draggy and slows down quickly, like the grease is dried up. I'm sure it needs some level of rebuild. I expect the kind of free spinning I find with a Campy or Shimano hub in good condition.

The OLD is 145 (Meridian steel frame), so I assume the servicing instructions are as given in the DT Service Manual that is linked in this thread.

Anybody know if this is correct, or is a Hugi a special model with a unique design? I'd hate to suddenly lose a bunch of little ratchet parts from following the wrong procedure, or just not knowing something crucial.

Riding season is only a few months away, in Michigan!

Added info: Reading the rest of the thread, I see there may some difference between the Hugi and the newer DTs, and I may have to improvise a bit about accessing the freehub bearing.

Thanks, all!

PMK

Go back and re read my mention to remove the O ring that retains the right side axle end cap.

You will then remove the hub drive rings and springs, plush the crush spacer.

With the O ring permanently removed, maintence is easily performed without tools. The QR will keep all assembled when the wheel is removed, also, there are no small internal parts to get lost. Only 5 internal parts. 2 drive rings, 2 springs, 1 spacer.

If you do have an early tru Hugi, disassembly is different. Hearing Dyads, I expect you have 540 model hubs.

Post a photo so I can tell for certain as those are worked on / come apart differently.

The drag in the freehub is common. Most people never accomplish maintenance on hubs and let them fail before working on them. Even Chris Kings have a maintenance schedule / program to keep them operating correctly.

DT lubes the hubs drive rings with a product called Molykote. I forget the actual grade, but with time it does become stiff and wax like. This is possibly the drag you feel. Does the wheel spin freely without holding tne freehub? If so, it is an easy job, and low cost to accomplish maintenance. Once diassembled, and no need to remove any wheel or freehub bearings, clean the internal items of the drive system. Take extra focus on cleaning the splines inside the hub and freehub.

Reassemble a spring and drive ring into to the freehub and hub without grease. Ensure they slide easily and freely the entire movement until bottomed and return without isse.

Once satisfied, reassemble with new Molykote and enjoy. Do not use a lot of Molykote, a skim coat is best.

Often it may take a few miles for the hub to get that swarm of bees sound, totally normal.

The proper Molykote comes in a small tub about the size of a quarter and 3/4 inch tall. Enough to maintain the hub for a long time, just stir gently before using.

I have tried other lubes to replace Molykote. I saw mention the one person plans to use Chris King drive lube. I have tested that with less than great results. Overall, for most folks, Molykote is good, but must be maintained each year.

On both of our tandems, and rest assured the mountain tandem is harder on hub drives than the road tandem ever will be, I am testing a new drive lube. So far so good, but several times more expensive than the DT Molykote.

reburns

I started to have problems with a 540 hub dragging, especially noticeable in big ring/small cog combinations. I switched to this: https://www.lubriplate.com/Products/.../Low-Temp.html
Have had excellent results for 5+ years. Hub always spins freely and does not need frequent service.

PMK

I have never tried Lubriplate.

I have used Mobil 1 rear end oil. That definitely does not thicken with age. Pretty quiet also.

Products too viscous will not let the drive rings engage well and can slip.

reburns

The low temp Lubriplate has a consistency similar to sunscreen or hand lotion. It's just viscous enough to stay where you put it, but not so thick that it gets sticky or tacky. Good for high pressures and waterproof, it seems ideal for the DT star ratchets. I apply it in a thin glaze using a toothbrush, and have been very happy with the performance.

racefacelefty

@PMK Thank you for the input. I have come right with your help.

PMK

Sounds like you are getting good results with it. The viscosity is listed as a 1.5 rating. So yes, about sunscreen ish in viscosity.

Wanting more extreme than both the Molykote and Mobil 1 gear oil, I have gone with a Moly D fortified product. The off-road tandem is far more intense on drive train pressure than the road tandem. Off-road was the focus, but I carried it over to the road hub also.

Based on color, I think it is possible the Molykote has Rulon added as a friction reducer and also why it is the price it is.

PMK

Dare I ask, what was your ultimate decision? If you wanted new bearings, I hope it was replacement of them as you started and not freehub replacement. However, freehub replacement does allow for a spare to be built up.

racefacelefty

In the end I left the steel 10 speed freehub as is without opening it, it's only done 253km.

I changed the bearings in the Alu 11 speed to suit a QR axle at 10mm. The bearings I needed were 16100 10 x 28 x 8. In the process I converted my wheel from a 10 speed 11-25 to an 11 speed with a 10-25 cluster.