Mavic Cosmos Freehub Service
Late model (2006) Mavic Cosmos wheels are fitted with the FTS-L
freehub, the same as Ksyriums. Service instructions for these
wheels used to be available on Mavic's website at
Free wheel body, EASY maintenance
But that link's broken and I haven't been able to find the document again.
So here's a copy
that I found.
And Lennard Zinn gave an
of the design and operation of the FTS-L freehub in VeloNews.
The gist of Lennard's article is:
- The freehubs are great but they need regular servicing,
according to use.
the nylon bearings are low friction and light weight.
- Problems are a consequence of the freewheel pawls
'clattering' against the inside of the freehub body.
This generates fine metal filings
that mix with the oil and, if not cleaned out,
will cause excessive wear of the
nylon bearings or, worse still, the freehub to become 'sticky'.
- If you often ride in hilly areas,
i.e. lot's of high-speed freewheeling,
service should be more frequent.
- Thoroughly clean the hub and body.
Use oil, not grease,
to lubricate inside the freehub body,
the pawls and the hub boss that the freehub runs on.
Too much oil is better than too little.
A little pool in the freehub body is fine.
Mavic mineral oil may be difficult to obtain; specialist road bike
shops and then only to order.
- To reiterate,
you must use oil and a very thin oil at that.
I find sewing machine oil an acceptable substitute
but it may void your warranty.
Never use grease.
Earlier Cosmos wheels were fitted with a more conventional
freehub in which the body is supported on traditional ball
This is normally a very reliable freehub but it is suceptible
to water entry.
A periodic strip, clean and lubrication is therefore recommended.
Remove skewer and cassette.
Pull end collar from left-hand (non-drive) side of axle.
Unscrew and remove bearing adjuster coller from hub using
the Mavic adjusting tool that came with the wheel.
Hold the axle by inserting a 5mm hex wrench (Allen key)
into left end and unscrew nut from right-hand (drive) side of axle.
Pull axle out of hub from left side.
Press out left-hand wheel bearing using a suitable bar
inserted through the centre of the freehub.
Unscrew and remove freehub retaining sleeve using a
12mm hex wrench inserted through the wheel hub from the left.
Remove freehub body from wheel collecting seal and spacer.
Prise dust cover from freehub by inserting a flat bladed
screwdriver between dust cover and outside of bearing
(don't push against rubber seal).
Press the bearing from the freehub body using a suitable bar.
Unscrew and remove lockring / outer bearing race from inside
A suitable tool can be fashioned from a piece of
5mm thick by 25mm wide steel bar, cut to length so
that it engages in the cut-outs in the lockring.
The lockring has a left hand thread.
Knock the freehub centre from the splined outer.
Perform this operation over a tray to catch the ball
bearings that will be displaced.
Collect the spacer(s) from the centre shaft.
Hold both ratchet pawls in position and remove the
wire circlip from around the middle of the freehub centre,
being careful not to over bend the spring.
Again, perform this operation over a tray to catch the
pawls that will be released.
The circlip both retains the pawls and acts as the operating spring.
Remove the o-ring seal from the base of the freehub centre,
noting it's orientation.
Clean and inspect the freehub components.
Water may have entered the freehub leading to corrosion;
in this case replace the ball bearings with new and
polish the bearing races with a metal polish,
e.g. Solvol Autosol, ensuring that all traces of
metal polish are cleaned off before reassembly.
Grease and refit the o-ring seal to the base of the
The taper faces outwards.
Apply light grease, e.g. wheel bearing grease,
to the ratchet pawls and hold in position on the
freehub centre while fitting the wire circlip.
The locating tang (bent over end) of the circlip
should be positioned in the large cut-away on the
opposite side from the pawls.
Ensure that the spring sits in the groove in the pawls
and freehub centre and check the pawls operatate freely.
Grease and fit the spacer(s) to the freehub centre.
Lightly smear grease all over outside of freehub centre
and inside splined outer body.
Do not over grease; too much will make the freehub 'sticky'.
Apply light grease to inner bearing race on freehub
centre, press ball bearings into grease and insert
centre into splined outer drum.
Repeat for outer bearing race and replace lockring.
The lockring has a left hand thread.
Tighten lockring until bearing play is taken up but the
freehub still turns freely.
There are two bearing races, the inner race between the
freehub centre and splined outer and the outer race
between the splined outer tube and lockring.
There are 25 x 1/8" (3mm) balls to each race.
Finally, if the freehub is too far gone, you can upgrade
to the FTS-L hub; ask your dealer.
But it's not cheap and you may find it more cost effective
to buy a new wheel.