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How To Owerhaul Your Shimano Freehub


Follow our step-by-step guide to freshen up your cup-and-cone bearing rear hub


TIME One hour
COST 22-30$ for cone spanners, 30-45$ for freehub body (if needed)

Tools for the job

1 Torx T25 key (only needed if your rear wheel has a six-bolt rotor – Centerlock discs require a cassette lockring tool or external bottom bracket spanner)
2 Correct size cone spanners for your hub (in this case 15mm and 17mm)
3 Cassette lockring tool (if yours doesn’t have a handle you’ll also need an adjustable spanner)
4 Grease
5 Magnetic dish or plastic tub
6 Magnetic-tipped screwdriver
7 Chain whip
8 11mm (QR hub) or 15mm (throughaxle hub) Allen key
9 Pick
Not pictured 
Clean rag
Pen or other non-magnetic object
Degreaser



01 Remove the rear wheel. Clean it thoroughly, especially around the hub. Remove the axle. Wrap your chain whip around a large sprocket on the cassette to stop it spinning. Insert your cassette tool and turn it anticlockwise (ours has a handle – if yours doesn’t, use an adjustable spanner), bracing against the chain whip, to remove the lockring.

02 Slide the cassette off the freehub body, noting the order and orientation of the sprockets and spacers. Clean the freehub body and cassette. Remove the brake rotor, turning the bolts anticlockwise with a T25 Torx key (six-bolt rotor) or the lockring anticlockwise with a cassette tool or external BB spanner (Centerlock rotor).

03 If your hub has a rubber axle cover on the non-drive side, remove it now. Starting on the non-drive side and using the correct size cone spanners for your hub, sit one spanner on the exposed inner cone and one on the outer locknut. Hold the spanner on the inner cone still and turn the other spanner anticlockwise to remove the locknut. Put it safely to one side.



04 Remove any spacers on the axle and place them next to the locknut in the order they were removed – this will make reassembly easier later on. Now loosen and remove the cone and sit it in order with the locknut and spacers. Finally, pull the axle out of the hub from the drive side.

05 Use the magnetic end of a screwdriver to remove the hub’s axle bearings and sit them in a magnetic dish or plastic tub. Be careful not to lose or misplace any, and make sure you count how many bearing are in each side of the hub (this will vary depending on the hub). Douse the bearings in degreaser and leave them to soak it in.

06 Insert an 11mm (QR hub) or 15mm (through-axle hub) Allen key through the freehub and into the bolt holding it to the hub. Turn the Allen key anticlockwise (if the bolt’s really tight, tap it with a hammer first) to remove the freehub body. Take note of any spacers attached to the freehub body or hub. If there is a spacer, remove it and put it safely to one side.



07 Give the freehub body a spin. Do the bearings feel rough or look damaged and worn? Wiggle the threaded end of the freehub back and forth to feel for play. Inspect the cassette splines for damage too. If you think you may need a new freehub, get some advice from your local bike shop.

08 If the freehub doesn’t need replacing, give it a thorough clean with degreaser and a clean rag. Next, clean the rest of the hub’s internals – the axle, cones, spacers, etc. Clean everything in order, one part at a time, making sure they go back in the right place ready for reassembly. Apply fresh grease to all the parts you’ve just cleaned.

09 Use degreaser and a rag to clean the inside of the hub shell, paying particular attention to the bearing races. Once clean, inspect the bearing races for any damage or pitting, which will affect how smoothly the bearings spin. Also inspect the hub’s cones for any damage. If they don’t look good, pop to your local bike shop and get some replacements.



10 Finally, take the bearings, which have been soaking in degreaser, and, one at a time, clean off any grease, dirt and grime. Then transfer them to a piece of clean rag, making sure not to lose any. Assuming everything is in tiptop condition, it’s time to start rebuilding the hub.

11 Give the freehub internals another lube and then seat the rubber seal back in place, making sure it’s the right way up. Grease the threads in the hub and put the spacer (if you removed one) back on the axle. Sit the freehub body in place on the hub, ensuring it’s located properly, and use your 11 or 15mm Allen key to tighten it to 40Nm.

12 Fill the hub’s bearing races with grease, then sit the bearings in place with your magnetic screwdriver, ensuring that the correct number are sat on each side. If a bearing drops into the hub shell, use the screwdriver to retrieve it. Use a non-magnetic object (such as a pen) to push all the bearings into a neat circle around the bearing race.



13 With all the bearings sat in place, check that the locknut is tight against the cone on the drive side of the axle. Sit one cone spanner on the locknut and the other on the cone, then turn the spanner on the locknut clockwise until it’s super-tight against the cone. Slide the axle through the hub from the drive side and carefully wipe away any excess grease.

14 Fit the cone to the axle, turning it clockwise until it sits loosely against the bearings. Slide on any spacers and screw on the locknut. Lightly tighten the locknut down onto the cone and spacer. The axle should spin smoothly with next to no play. Hold the spanner on the inner cone still while turning the spanner on the locknut clockwise to lock the cone in place.

15 Now feel the axle again. Chances are there’ll be a small amount of play in the system. If the axle is tight and doesn’t spin freely, loosen the locknut and cone and repeat step 14. If there’s play in the system, fit spanners to the locknuts on both sides of the hub and tighten them against each other, a tiny amount at a time. Then check the axle for play again.

16 You may need to repeat steps 14 and 15 a couple of times to make sure everything is perfect. Once the axle is free of play and spins smoothly, refit the cassette, brake rotor and axle, and reinstall the wheel in the bike. Check that the cassette spins freely and the freehub works as it should, as well as that the hub bearings spin freely.



WORKSHOP WISDOM

Working with loose ball bearings can be a bit of a nightmare if you’re not fully prepared. Make sure that you’ve got a clean work surface with no places for bearings to hide in and that you lay everything out in order, because it’s really easy for one small but crucial part to go missing.

If you don’t have a magnetic-tipped screwdriver, you can easily magnetise one yourself by rubbing a magnet down its length in the same direction several times.

It takes a while to get hub bearing tension perfect, so don’t be afraid to spend a lot of time on the last few steps just to get everything perfect and as it should be.

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