Tandem Cycling - What size Hub for 2007 Cannondale Road Tandem?

Hi guys, some of you may have been following my earlier thread about a sticky bearing. Anyway, I took the hub apart.....DT Swiss 540 disc and found that the axle had broke in half.... no wonder I had a sticking chain. Anyway, I am trying to decipher the correct hub to order. The Cannondale archives do not give the specs, the 2010 specs say a 140 rear dropout. So if the dropout is 140, I assume a order a 140 hub. Can anyone enlighten me on this issue.? I am all set to order but unsure of what size hub to order. Thanks for reading.
Pledge

You should be able to buy just an axle.

The best check would be to take the broken axle and measure it if possible, then there are no doubts.

The comment to buy an axle is assuming the remainder of the hub isn't damaged. Sorry if I missed reading a post describing the exact details.

PK

hockey , the dt axle is 145 mm .

have the same cdale . 07 rt 2 . dt hubs .

replaced bent axle after 1 yr

OK , I measured , the axle is 145 mm

145 over lock nut

Thanks. One last question. Would the dropout spacing be 145?
Hockey

One other thing. None of the builders/suppliers I called had an axle in stock nor did it seem likely they were able to get their hands on one in the immediate future. It seems rather strange that a user friendly hub can be so hard to find parts for. I am looking at buying Velocity Tandem disc hub. Just not certain whether to order the 140 or 145.
Hockey

One other thing. None of the builders/suppliers I called had an axle in stock nor did it seem likely they were able to get their hands on one in the immediate future. It seems rather strange that a user friendly hub can be so hard to find parts for. I am looking at buying Velocity Tandem disc hub. Just not certain whether to order the 140 or 145.
Hockey

In the past, when I converted a set of 140mm DT hubs to 145mm width, I used the DT website to research the part number needed and ordered direct from DT. Cost was reasonable.

I went looking for the PN for you. While reading the manual, I noticed in the specifications table, it listed the rear axle as being made from aluminum. In the past, the axles I removed and swapped to were steel. Can you verify the material of the failed axle?

BTW, here is the manuals link if you don't have it already.
http://www.dtswiss.com/getdoc/48524cfe-6b7c-428c-86d0-56eaf43be23b/Datasheet.aspx

PK

Hi PMK. How do I tell what the material is made of? I wrote a note to DT Swiss, but no response and I'm not sure I have confidence in this hub after talking to one of the other posters. My question still remains, what hub do I order for the 2007 Cannondale. Looks like a 145
Hockey

How do I tell what the material is made of?

Use a magnet.

As for the replacement axle, you might try giving Co-Motion a call to see if they have any replacement axles in stock or if they can recommend the best way to find one. No need to volunteer that your DT hub is on a Cannondale instead of a Co-Motion... just tell them that you're looking for a replacement axle for a 145mm DT 540 tandem hub.

Good advice. I tried Tandems East and MBS tandems and neither have the part or can get it readily. I'll give Co-Motion a call. I'll use the magnet test when I bang out the rest of the axle.
Hockey

let us know . I will want a spare for myself . thx

Yes this has concerns for us also. Our latest tandem build is a 29r off road Fandango hardtail. I built the wheels with DT hubs, specifically a 540 rear.

We are not a light team and have had no worries about riding the bike hard until reading the few posts with failures.

Bottom line, if a road tandem can break a 540 axle in short mileage, can it last off road. Especially if it's aluminum.

Guess I need to give ours a close look as it has about 1000 miles of off road use.

In regards to DT drive ring design and reliability, our three tandems all have DT hubs front and rear. A previous Cannondale rounded the drive rings engagement points but was caused from lack of maintenance where the Molykote grease had somewhat hardened and slow the engagement.

It may be a bit before I pull our axle, but I will keep you informed.

PK

Quick followup, pulled the freehub body / cassette off our 2010 DT540 145mm hub on the Fandango 29r. (5 minute job)

Confirmed the axle for us is steel in this hub, I will have the hub apart on the Co-Mo soon, but I'm pretty certain that one is steel also.

Visually checking for runout, I spun the axle and did not see any wobble at this time that may indicate bending. Speculating, and having seen the unbroken axles on my own stuff, the place of failure is possible where the step is cut to seat against the bearings, but could be between the right hub bearing and inboard freehub bearing.

Either way, this may be a difficult crack to see with the naked eye unless the axle is bent.

Additionally, from a quick search of previous posts, it seems many of the failures, both on Cannondales and a Co-Mo were about the same calender time. Possibly a bad batch of axles? Again I don't know this for certain, but will plan accordingly.

PK

One other thing. None of the builders/suppliers I called had an axle in stock nor did it seem likely they were able to get their hands on one in the immediate future. It seems rather strange that a user friendly hub can be so hard to find parts for. I am looking at buying Velocity Tandem disc hub. Just not certain whether to order the 140 or 145.
Hockey

145

Thanks for all the help. I am going to order a backup set of wheels for now, and hopefully source a new axle to repair the DT Swiss Hub. We miss the Tandem too much to let it sit until the snow flies.
Hockey

OK , I measured , the axle is 145 mm


one thing i forgot to mention .

While the replacement axle IS 145 mm , the OLD is also 145 mm , there is an additional piece of hardware that slips onto the end of the axle at the freehub side .

This adds to the total length of the axle to achive the correct OLD of 145 mm . Plus the requisite 5 mm per side that locates the hub in the drop-outs .. 145 mm OLD + 10 mm

I dismantled my hub . My previous posting seemed out of whack . [ 145 mm axle on 145 dropout did not jive]

Hey All,
I'm tuning in quite late. But we have just encountered the same sticky hub problem on our 2007 ? (exact year not known) Cannondale road tandem with DT Swiss 540 hubs. I appreciate the posts and will be checking the axle for run-out and cracks.

(I just had it apart and checked and lubed bearings and pawl rings, nothing seemed wrong so I reassembled it and hoped I somehow fixed it.) Not sure yet what the material is of the axle. May have to have a steel one made up by a machinist if it is aluminum and bent.

Any news on the subject for me?

Thanks!

A final follow up. Believe it or not DT Swiss sent a replacement axle at no cost. Hub is up and running again. Hopefully we will not have another issue. The axle was sheared in half.