May 17, 2012

Profile 3/8 Mini Cassette Hub Overhaul

The instructions on this page are applicable for the 3/8 Profile Mini, Totem, and Madera V2 Cassette hubs.

It’s preferred that you use an arbor press or a bearing press to install new bearings in your hubs, but since we recognize that not everyone has access to those, we provide these instructions to make things easier for you. We are happy to overhaul your hubs here at Profile for a small fee. Please contact us for details.

Overhauling your hubs is not something that needs to be done more than once or twice a year, unless you ride 3 or 4 hours a day, everyday. Then you might need to do it 3 or 4 times a year, but the point is that you shouldn’t take your hubs apart just for the sake of taking your hub apart.

You will need new bearings, two 8mm allen keys for the 3/8″/10mm axle, your bike’s axle slots, and a rag. You should inspect all of the hub’s part before you begin to reassemble it, to ensure that the hub will perform as close to new as possible when you’re done. Inspect the hub flanges for cracks, and make sure that the aluminum center axle doesn’t appear bent, bashed, worn, stripped, or cracked. You should also inspect the ratchet ring for wear. A good rule of thumb is that if your hub isn’t skipping constantly, then your ratchet ring is fine. Also make certain that your cone spacers aren’t crushed or otherwise deformed. If they are difficult to remove from the axle or hub, that’s a pretty good indication that they are damaged. you can purchase Profile Mini Hub Small Parts in our online store, or your local bike shop can order the parts for you.

Overhauling our drivers is covered on this page (coming soon!).

click to enlarge

Mini Rear 3/8″ 10mm Axle Hub parts:

  • a. 3/8″(10mm) axle bolts (2)
  • b. Non- Drive Cone Spacer (1)
  • c. Hub Bearings (mfg #6903) (2)
  • d. Aluminum Center Axle (1)
  • e. Hub Shell (1)
  • f. driver spacer
  • g. driver
  • h. drive-side cone spacer


1. Remove the wheel from the bike with the allen wrenches and then loosen the drive side (DS)axle bolt about half way out. Then take a mallet or hammer and strike the back of the bolt. This should pop the non-drive side (NDS) bearing out after a couple of good whacks. You don’t need to hit it as hard as you can.


2. This is the result of step one. Remove the DS axle bolt, and slide the conespacer, driver, and driver spacer off the aluminum center axle. The axle in these photos is pretty old, don’t worry if yours looks different. Remove the NDS axle bolt, cone space, and bearing from the center axle.

3. Thread an axle bolt about halfway into one end of the center axle- it doesn’t matter which end at this point. Place the center axle back in the hubshell through the DS hub body bearing (the end without the bolt on it). Again use the hammer to hit the bolt to remove the DS bearing.

4. Use a rag to clean all the parts you’re re-using. Inspect all of the parts for signs of damage or wear. This particular wheel is off the shop’s errand bike, and it’s been around for a long time. This is probably one of the first Mini hubs we ever built, so it dates from around the year 2000 or so. That ratchet ring still looks new. It is possible to wear them out, but you need to ride an awful lot to do it.

5. Once you have the hub completely apart, clean the bearing seats, axle, bearings (externally only, if you’re keeping the old ones,) and inspect all components for damage. If you see any cracks, crushing, distortion, or deformation then you should replace that part. Inspect your bearings for side to side play.

Then, slide your bearing (c)onto the axle (d). If you are installing shims, they should go on the axle, followed by the bearings. After the bearing, slide on a cone spacer (b), and tighten the axle bolt (a) all the way down, finger tight is fine.

6. Insert the axle assembly through the NDS of the hubshell.


7. for re-assembly, I recommend actually doing a bit of dis-assembly first. Since we’re using the driver to help us press the bearings back in, it’s easier if the pawls and springs are out of the way. To do this, lay a light coloured rag down flat on a table, and set the driver down in the middle of it, pawls and springs side up. We’re doing this to minimize the chances of losing one of these tiny but crucial (and expensive) parts of your hub. Note the direction the pawls are facing. Slide them straight up to remove them, and the spring will more or less fall out.

8. Back on the DS, insert the shim (if needed), the bearing, the driver spacer, the driver, and the cone spacer, and use the axle bolt to hold it all together.

9. The bearings should not slide into the hubshell at this point- if they do, or if you can slide them in and out of the hubshell with your bare hands, there is an issue with your hubshell. Call us and discuss it. 727.391.7370

10. You will ideally have 2 8mm allen wrenches for this step. Use the bolt on the far side to hold the axle steady. Make sure that the bearings and conespacers are lined up square to the hub. As you tighten the bolts the bearings should be drawn into the hub. It shouldn’t take a great deal of force or pressure.

11. You will feel a definite stop when the bearings are completely inserted. The edges of the conespacers should also be more or less flush with the curve of the hubshell as well. Loosen the drive side axle bolt.

12. Slide the drive side axle bolt into the dropout of your frame. Tighten the bolt down again. This should seat the bearings completely. Loosen the bolt, remove the wheel from the frame, and then remove the axle bolt and driver from the hub. Make sure that the drive side hub body bearing is flush with the hubshell. If it’s not, find a deep socket which is as close as possible in size to the bearing itself , and CAREFULLY strike the socket with a hammer so that the bearing is flush in the hub body. The socket should be about a 21mm or 7/8″, the outside diameter of the bearing should be as close as possible to the outside diameter of the socket.

13. Re-Install the pawls and springs into the driver. If you have questions on how to do that, click here. Slide the driver back onto the axle, making sure that the driver spacer is still located next to the driveside hub body bearing. Slowly rotate the driver backwards while pressing the cassette driver towards the center of the hub. If the pawls prove difficult to slip into the ratchet ring, you can use a slim flat-bladed screwdriver to press the pawls down towards the axle. This should allow the driver to be fully inserted into the hub. It should have a definite “click” when you spin the driver backwards, and it should not spin freely when you spin it forwards. If it does not do these things, the pawls are installed backwards.

14. Replace the drive side cone spacer, and put the wheel back on your bike. Tighten the bolts as you normally would, and check the wheel for side to side play and smoothness. If you have side to side play, then you should start over, paying special attention to the inspection stage. If you still can’t get rid of the side play, contact us, and we’ll get it fixed.

If you feel roughness, but no side to side play, remove the wheel from the bike, and snug both bolts to the hub. They should be maybe a half a turn past finger tight. Hit one of the bolts with your mallet sharply, but not like you’re trying to ring the bell at the county fair. One or two taps should completley seat the bearings if they weren’t seated before. Anything more than that, start the process over.

If you are unable to resolve an issue with your hub, we do perform repairs here for a nominal fee. Please don’t hesitate to contact us if you run into difficulties. Riding a poorly performing hub is never a good idea.

The principals of overhauling all Profile Hubs are basically the same, with axle dimension and cone spacers being the primary difference.

(click for 14mm Mini rear cassette hub page)

DISCLAIMER: These instructions are provided as a service. The best way to install sealed bearings is always a bearing or arbor press. The methods discussed here are alternatives for the home bike mechanics with typical home bicycle tools. If you are not careful, you will damage your hubs and bearings. Profile cannot be held responsible for any damage caused by attempts at repair attempted by anyone other than employees of Profile Racing.

If you are unsure of your abilities, take your bike to your local bike shop, or contact us at Profile. We are happy to overhaul your hubs for you here. Contact Shane at Profile at 727.391.7370 for details.

May 17, 2012


We are taking precautions to protect our employees and follow CDC and state guidelines. In the meantime, our machine shop is still running, we're here to assist you and we'll be shipping product to help support bike shops during this difficult time.