14 Aug 2014

14th August 2014 Athena 3x11 triple front changer.

Thursday 14th 60-65F, 16-18C, breezy and sunny. A pleasant morning so far. The wind picked up but it was still quite warm. 3 mile walk. Rode to Assens. I noticed a huge ship crane in the harbour so eventually managed to get a picture without loads of street furniture getting in the way. My guess is that it is a specialist crane for erecting offshore windmills. Hugely impressive in real life! It was mostly sunny all morning with a fairly strong crosswind. Though it tried to spit with rain from a huge black cloud towards the end it soon gave up. 20 miles.

My 3x11 Campag Athena front changer has arrived at the end of the rainbow. I had to buy a new 31.8mm clamping ring for it but could only get a Shimano locally. This proved to be a deliberate mismatch. I could either take a large file to the top of the brand new Campag changer casting or attack the rear of the Shimano clamp. I chose to attack the clamp with a combination of a large reground drill and a small grindstone to tidy up.

The problem was with the cylindrical form where the two units join. The fixing hole for the Campag shifter was pushed 1/8"/3mm down and out of alignment by the overhang on the Shimano clamp. I suppose I could have filed the clamp hole oval but chose to raise the hidden shoulder instead. Once achieved I could mount the new changer squarely and firmly.

Campag Athena 3x11 triple front changer. Note slight geometric mismatch between the cage and chainwheel. This is due to the aggressively angled, 76 degree, seat tube.

I was determined to be rid of the useless Ultegra triple changer without the further expense of a new quick link. So I took a Dremel and small round stone to the back of the cage rivet. Soon the riveting was dished so thinly that it quickly gave up with a pull and twist from a pair of nail pincers.

Campag front changers have a CSK screw at the bottom rear of the cage. This allows the cage to be opened and lifted clear of the chain without having to break a link. 10 speed chains aren't a simple matter of half pushing out a rivet with an extractor and then pushing it back in again afterwards. There is far too little plate material to achieve a safe riveting. As I discovered while 25 miles from home on a ride. I dropped the chain right in the middle of the road! Fortunately I carry a compact Park chain tool with me and was able to repair it well enough to get home.

The Campag shifter's cage is about a third of the depth [front to back] of the triple Ultegra. This resulted in much more positive upward changes but left little room for even the slightest chain skew.

Athena triple changer from the rear. I've just noticed the cable is badly frayed from my"Hubub" cable realignment experiments on the Ultegra!

Unfortunately the sharply indented middle ramp of the cage is too low to push the chain off the middle ring onto the inner one. At least it is when in a lower gear. On smaller sprockets it is fine but who wants to be limited to changing down by changing up first?  This is rather odd considering the tooth count of the Campag triple chainsets: 50/39/30. So it ought to work reasonably well on my 48/38/28 Stronglight chainset too, but doesn't want to. I'm completely ignoring any differences between ramps and pins on the competing maker's chainsets.

Of course Campag warns of non-standard set-ups as its standard get-out clause. Quite fairly in may case! So I have to set the inner limit screw too far out with the risk of the chain derailing. That is only likely when it finally gets the right idea and stops grating noisily on the cage to fall limply off the middle and onto the inner ring.

To be fair to Campag I am using a 10sp Sram chain when they specifically demand their own 11 speed be used. However, I felt unable to order a 10sp Campag triple front changer because I am running with their excellent 11 speed Chorus levers and wanted a better match.

The Athena and Chorus 11sp should work better together than the Chorus with the Ultegra. Two different kinds of cheese must surely be better than chalk and cheese. I have only tried gear shifting with the trike up on the workstand so far and haven't tried it on the road.

If I raise the changer to bring the lower cage ramp up to meet the chain on the middle ring it may make everything else much worse. I could bend the remaining edge backwards to match the rest but that might get in the way of the chain on the large chainwheel. I will need to look at the geometry very carefully before deciding to modify anything. I certainly shan't be claiming under their guarantees so Campag need have no sleepless nights on my behalf. I just want it to work better than the Ultegra never did.

It occurs to me that I could file the clamp, or the changer, to improve the tilt of the cage relative to the chainwheel. The steep seat tube angle made it far worse on the laid-back Ultegra. The Campag Athena is obviously designed for steeper, more modern [?] seat tube frames.

I could also widen the cage slightly for a bit more chain clearance. First I shall try it on the road. It can't possibly be worse than the Ultegra triple changer! Though you never know!

Click on any image for an enlargement.

No comments:

Post a Comment