Re-greasing freehub

dinyull

On my last few rides I've noticed a grinding noise when I'm free-wheeling at 30+mph, the noise disappears when I start pedalling again.

Putting 2+2 together I'm assuming the freehub needs re-greasing - does this sound right?

The wheels are Mavic Cosmic Elite, 12 months old and have covered about 4k miles in all weather.

How easy a job is it and what grease is required? I'm fairly competent with a spanner so more than willing to give it a go, just want to make sure I've got the right bits before I open things up.

Having said that the wheel does require truing, so would I be better getting LBS to sort whilst they're doing that?

imposter2.0

Probably the freehub bearing rather than the freehub itself, ie the ratchet system (which typically should not be greased as such). Replacing the bearing would be the best thing to do..

ugo.santalucia

You can do it yourself. Depending on the model you will need two Allen Keys to fit in the slots or one and a cone spanner or one and a Mavic pins tool to undo the nut. Once the drive side cap is off, the freehub body slides out. In Mavic hubs, the two pawls sit on the axle and are loaded with springs... make sure they don't pop and if they do, make sure you don't lose them. Clean and lightly grease as appropriate and reassemble making sure the springs sit correctly behind the pawls. I'd say with Mavic the trick is to wrap the freehub in a sandwich bag before pulling it, to avoid bits flying around

dinyull

Sorry Imposter, is there anyway you can show me what you mean by the freehub bearing - pic or diagram? That went straight over my head. I'm a complete novice when it comes to wheel mechanics.

Ugo, any suggestions on grease? I've seen a lot suggesting mineral oil?

ugo.santalucia

Mineral oil is fine in summer... use any grease, the demands of a freehub are pretty ludicrous compared to the performance offer by budget grease

imposter2.0

Dinyull wrote:

Sorry Imposter, is there anyway you can show me what you mean by the freehub bearing - pic or diagram? That went straight over my head. I'm a complete novice when it comes to wheel mechanics.

Ugo, any suggestions on grease? I've seen a lot suggesting mineral oil?

There's two seperate components here. The freehub itself will spin on a bearing - the ratchet mechanism is only there to engage or spin the cassette when you pedal or freewheel.

I could be wrong, but the grinding noise is probably coming from the bearing, rather than the ratchet - but you can service both when the freehub is off. Sorry I don't know where there are any diagrams, although there might be something on the Park Tools site.

Light oil is all you need on the ratchet.

arlowood

This thread might be of use - particularly the link to the Mavic Dealer Manual.

Drilling down into the detail you will find exploded diagrams of the rear hub set up and if you click on specific parts it gives you help with servicing tips.

viewtopic.php?t=12951135&p=18647629

dinyull

Cheers all.

Having done a bit more on-line research and coming across 'Mavic Death Squeal' it would appear this is a common problem. Shame too as I've read many times about Mavic wheels being bombproof. Seems an easy fix, although a bit of a pita.

Going to try cleaning and oiling before replacing the bearing/freehub.

dinyull

Sorry Ugo, another question on grease...

Would wet lube be ok? I've read that some have used this, but wanted to make sure. From what I've read, a very thin oil is needed, not grease. Just made a lunch trip to LBS and they were out of mineral oil.

ugo.santalucia

Use oil then. It's just a pawl on a spring, there is nothing magic... any lubricant will do

desweller

If you use a heavy grease the pawls will stick. Been there, done that. Oil is fine.

DKay

DesWeller wrote:

If you use a heavy grease the pawls will stick. Been there, done that. Oil is fine.

Me too. Used too much grease and ended up with a two way freehub 20miles from home and you don't tend to take a chain whip, cassette removal tool and big spanner with you out on rides.

Had to take remove all of the grease with WD40 and then just added back a small amount to keep things lubricated. The end result being that I ended up stranded out on a ride again, but only half a mile away from home this time.

I now don't use any grease at all and use a thick motor oil I have left lying around instead. I've heard people using chainsaw oil to good effect too.

bernithebiker

DKay wrote:

DesWeller wrote:

If you use a heavy grease the pawls will stick. Been there, done that. Oil is fine.

Me too. Used too much grease and ended up with a two way freehub 20miles from home and you don't tend to take a chain whip, cassette removal tool and big spanner with you out on rides.

Had to take remove all of the grease with WD40 and then just added back a small amount to keep things lubricated. The end result being that I ended up stranded out on a ride again, but only half a mile away from home this time.

I now don't use any grease at all and use a thick motor oil I have left lying around instead. I've heard people using chainsaw oil to good effect too.

Chainsaw oil is basically low grade engine oil with an anti-fling, 'sticky' additive in it. I get through about 5 litres a month. I wouldn't put it anywhere near my bike......!

dinyull

Ok, so an update.

I took apart the freehub, gave it a good clean and oiled it. I thought this had cured my problem until halfway through my ride on sat when the noise returned.

So, I'm looking to replace the freehub body. Can anyone confirm if this is the correct part for a 2013 Cosmic Elite: http://www.chainreactioncycles.com/mavic-freehub-body-ftsl-m11/rp-prod33442

Cheers

pippi_langsamer-2

Ask yer mothers/ grannies for some of their sewing machine oil. Paper shredder service oil or hair clipper oil is similar. Very low viscosity which is what Mavic seem to recommend to prevent unwanted drag if oil/ grease with too high s viscosity is used.

dinyull

Update for anyone searching in future.

I replaced the freehub with the one linked above on Sat and problem solved. Cheers for all your input.