I know there are people on here who rate the Lefty fork. I wondered any of you have experience of servicing/repairing them also. My normally buttery smooth lefty on an old Cannondale Jeckyl has started to have a little “knock” under compression every so often. Has anyone any experience of this?
I have found a link showing how to service the newer carbon ones. Is this valid for the older variants? Would be nice if they were just in need of service.

It sounds like your needle bearings are out of alignment and need resetting. It’s quite an easy job on newer Lefties as you’ve seen. Is there a PDF manual for your fork on the Cannondale site?
http://www.cannondale.com/manual_headshok/

Cheers Angus. There is a manual on the site but there is not a description of the resetting process on there. Do I assume the process is the same? Has anyone got experience of doing this on an older fork?

Know nothing about Lefty’s but there’s a guy on mtbr.com, mendoncyclesmith who seems to be a bit of Lefty guru

FWIW, I had a similar problem on a 29er lefty a year or so ago. From memory, I let all the air out, took off the rebound and lockout dials, a nut, then took off the top cap. I seem to remember that it could be undone with a bottom bracket spanner or something. Anyway, once it was all undone, I compressed the fork quite hard a couple of times, and then rebuilt. This was on the advice of my LBS and it seemed to work. Like I say, it was a while back. I think I kind of used the manual from the cannondale site.

If it’s just a bearing reset, this is easy enough and pretty much as nickdt describes.

If that doesn’t sort it, a full service costs about £100; one of the great beauties of Lefties is that they’re pretty much completely rebuildable unless you snap them.

Andy

Like most have said If you havent done a bearing reset start there, lefty’s need it regularly.Also if the damping oil runs low you can get a knock…look for oil around the bottom of youre fork boot

I’m relatively new to Leftys but that doesn’t sound like a reset to me. AFAIK reset is just to correct bearing migration and the usual symptom of needing a reset is reduced travel. Worth trying that first, though.

Also are you telling me you’ve never reset it?!? Mine needs a reset about every 20 hours of riding. Very easy to do, as described above (though I always pull / extend the fork rather than compressing it) If it’s a few years old it’s probably worth sending it to TF tuned or Thumbprint (presuming you are in the UK) for a service anyway – Lefty’s last a long time if you look after them regularly.

I would look here for the best info:

http://forums.mtbr.com/cannondale/

As Drofluf said, post your issues in a thread there and Mendon will usually give you some helpful advice.

One thing about Leftys is that they last forever. My ‘main’ bike has a 100ELO Lefty on it that I have had since 2005. Once a year it gets a Thumbprint service and once had bearings etc replaced but you can replace every single bit inside it so short of snapping it in half, it is always repairable.

First class fork, so light, so stiff, so lockable, I love mine.

C

From the Cannondale tech manual;

‘indications of migration are: an unusual top out noise, reduced travel’.

On that basis I suspect the knock under compression that uphillcursing is experiencing is the bearings. As you say Jim, a reset is the best place to start.

What variety of lefty is it?

If it’s a knock on compression, I’d suspect the damper. If it’s a sealed damper like the DLR, then it may just need bleeding.

Thanks guys. I think I shall try the bearing reset. Can’t do any harm to have a quick look at what goes on inside before trying to find somewhere in Aus that services Lefty.

Looks like the bearing reset has done the job. Thanks everyone.