In this How-To we will be looking at how to service/overhaul a Freehub. There are many types of freehub, in this How-To we will be looking at a Mavic one, this guild can be followed for most hubs with sealed bearings. For those of you who don’t know what a freehub is, a freehub is basically a mechanism on the bicycle's rear wheel that allows the wheel the spin freely when you stop pedalling. A fixed wheel or fixie bicycle does not have this feature when you stop pedalling. On a fix wheel bicycle your rear wheel stops and causes a jerking sensation to your feet at the same time you will be skidding and sliding on the road.
How to know when to service your Freehub?
This all depends on how much you ride your bike and if you spend a lot of time riding in the wet. If you spend most of the time cycling in the rain or cycling over river crossings (mountain biking), chances are water would have made it’s way into your freehub and washed away the grease inside of the hub.
If you ride mostly in the dry but can feel a slight drag when you coast (stop pedalling) then it's time to service your freehub. Another method to check is to lift your bike up so that the rear wheel is not in contact with the ground and spin the wheel forward, if you can hear tick-tick-tick and your pedals stay put then your freehub is ok but if you hear tick…...tick…….tick and your pedals sort of spin with your wheel then you have some friction in your freehub which sends drive back via the chain and into your pedals.
How hard is it to service a freehub?
Not very hard if you already know how to remove your rear wheel and cassette. If you don’t know how to remove your cassette then don’t worry, I have a guild for that here.
Servicing your freehub should take about 15 minutes including the removal of your rear wheel and cassette. It took me about 20 minutes to do this while trying to photograph everything so you should be able to do this fairly quickly
Tools and parts you will need
Adjustable spanner/wrench, you will need two
Cassette lockring remover
Step 1: Start off by removing the rear wheel from your bike then remove the cassette, if you don’t know how to remove the cassette, follow the guild here.
Step 2: Most freehubs will have two fixing nuts. The side opposite to the freehub will be fixed with two nuts, this side is NOT to be loosened. Place an adjustable spanner on each side of the fixing nut, turn the spanner on the freehub side counter clockwise to loosen the fixing nut. Once loosened continue with your fingers until the nut is removed from the hub.
Step 3: If you are at this step then you are nearly done. Once the lock nut is removed, all you need to do is pull off the freehub with your hands, it is tight but not so tight that you need Thor’s arms to pull it off, Chirs Froome’s arm size would have enough power to get this off. Do take care when pulling off the freehub as precious little paws and springs can go flying off never to be found again.
Step 4: The paws can be removed from the hub, all you need to do is lift it off slowly and try not to lose the springs. Inspect the paws and freehub teeth for damage and wear. The teeth on the inside of the freehub body should be fairly sharp edged ramps and paws should be in one piece (as shown in the image below).
Inspect the edges of the paws to see if it is showing signs of roundening off or if there are signs of rust or worst case, springs came off inside and are completely disintegrated. If parts are worn, damaged or missing then you will need to check the exact make and model of your freehub and look online for parts. If all is OK then clean out all the parts with degreaser or WD40 then wash off the degreaser and wipe off with a rag.
Image below is the paws removed from the hub body, springs can be detatched from the paws for further cleaning.
Step 5: Reinstall the paws to the hub. It is easier to install the springs on the paws before you put the paws back on the hub. Apply grease to the springs, paws and the inside of the freehub.
Image below shows some grease on the paws and springs, this will help hold them on the hub to assist you with the next step.
Step 6: This step requires a little patience. Carefully and gently slide the freehub back on the hub without knocking the paws and springs off. As you can see in the image blow, the paws will prevent you from sliding the freehub all the way down.
To push the freehub all the way down you will need to compress the paws inwards. Using your fingers, grab the paws and push them in while pushing the freehub down with the palm of your hands. This is to be done simultaneously, if done correctly the freehub will slide back on and click in place. If you can’t get the freehub back in or while you are pushing the paws or springs came off then try again but add a little more grease to help hold the small parts in place while you try to push everything back in.
Step 7: Lastly, place the adjustable spanner back on the fixing nuts and tighten the lock nut back, make sure this is tight but not so tight that you damage the lock nut. Reinstall your rear wheel, give it a spin and listen to that tick, click sound and continues to spin for while before coming to a stop.