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Onyx rear hub service

29K views 58 replies 18 participants last post by  happyriding 
#1 ·
1) How often?

2) What needs to be done?

I've looked at the Onyx service videos, but they don't show the steps necessary to get at the sprague clutch. It looks like you have to take the bearings out.

Has anyone done a rear hub service? How did you get the bearings out?

I've got some persistent creaking in my drivetrain, and the only thing I haven't taken apart and cleaned is my rear hub.

Thanks.
 
Discussion starter · #4 ·
Sparticus,

Did you buy the grease on amazon for $49? I can't believe it's that expensive. Shouldn't it be cheaper than normal grease because it doesn't contain additives??

farfromovin,

I looked at all the Onyx mtb hub videos but they don't show how they remove the bearings--they just show the necessary tools. I have one of those blind hole bearing pullers with a slide hammer and a bearing press, but I would like to see how Onyx actually does the procedure. I like to keep my hubs well serviced by servicing them at least every 6 months, and I'm about due, so even if the creaking isn't coming from the hub, I would still like to service my hub.
 
Discussion starter · #7 ·
Does anyone know what size bearing is used in the Onyx Boost rear hub? I just received some of the magic grease, and I've got a blind hole bearing puller with a slide hammer, and a bearing press with various sized drifts, but I wanted to check if I have a the correct drift for the bearing in my hub before I get started.

And, if anyone else is considering servicing their hub, according to this

The Drive mechanism is greased for life. It is important if you take apart you hub not to contaminate the internals. The sprag comes greased with a Long-Term ISOFLEX LDS 18 Special A grease and typically will not need to be replaced.
Full text:

Onyx Maintanence

Keeping your Onyx Hub clean and free of dirt and debris is key in maintaining its high performance capabilities.

1. Use a brush (paint brush or similar) to clean off outer components of hubs.
2. If needed you can use compressed air to blow out tough to reach crevices, being careful not to send a direct blast into bearings.
3. Wipe down the shell with damp rag.

The Drive mechanism is greased for life. It is important if you take apart you hub not to contaminate the internals. The sprag comes greased with a Long-Term ISOFLEX LDS 18 Special A grease and typically will not need to be replaced. Lubricants with additives that decrease the coefficient of friction, i.e. MoS2 or graphite are NOT possible.

With grease lubrication please take care that the clutch is not filled completely with grease: "Less is more" in this case. The clutch should be "greasy" - that's enough.
And generally: It is not allowed to use any lubricant with additives (for example MoS2 or graphite), which decreases the friction coefficient.

If you find it absolutely necessary to re-grease your sprag, please make sure you have everything available before doing so. Once you have your materials, disassemble the hub and remove the sprag. Be careful not to remove the spring around the sprag cage as this will cause the individual sprags to fall out. Clean the sprag using WD-40 and blow out with LOW pressure compressed air. After it is dry, fill the empty space with in sprag with the LDS 18 Special A grease. You want to achieve a 60% fill ratio. Here are the steps!

1. Clean outside of hub and driver before proceeding, this is to keep any debris out of hub during the next steps.

2. Remove Driver side Bolt and widget.
3. Pull and rotate CCW the Driver and remove from shell.
4. Using an ID bearing puller, remove the outer support bearing. You may need to LIGHTLY apply LocTite or similar to the outer portion of the bearing during reassembly.
5. Using a small flat screwdriver, remove the snap-ring from the sprag sleeve.
6. Remove sprag from hub, noting direct of the tails (should be pointing to the left). If you put in backwards you will have a Left hand drive hub!
7. Do NOT remove the spring that is located around the sprag.
8. Place sprag in a container of Mineral Spirits and gently aggitate. Once clean, use WD-40 to rinse it off.
9. Use LOW pressure compressed air to finish off the cleaning, being careful not to blow the sprays out of the cage.
10. Clean inside the hub as best as you can with a lint free towel.
11. Regrease the Sprag using LDS 18 Special A grease only, filling the empty spaces with about 60% grease.
12. Put snap ring back into sleeve, making sure it's fully seated into groove.
13. Install outer bearing, if loose, use a small amount of bearing compound or Loctite.
14. Clean off driver and wipe down with lint free cloth.
15. Insert driver and rotate CCW while pushing in.
16. Install driver side widget and bolt.

Making sure to keep everything clean, reassemble the hub.
 
Discussion starter · #52 ·
Just come across this post.
I don't know why Onyx say only they or a machine shop can replace the centre bearings, i've done several myself no problem. I have a park tool bearing spacer / bushing set and some other bits and pieces to use as spacers etc. It is not as simple as a conventional hub with 1 bearing either side that I agree, the only issue is that the NDS bearing and the centre bearing are the same size, so once the outer bearing and its locating circlip are removed, you remove the inner bearings circlip and use the puller to pull the bearing out and with a rejig of spacers etc to then pull it out through the outer bearings bore and a reverse to pull the new inner bearing through the outer bearing bore then pull into its central location. Its a bit of messing about to set it up right but perfectly doable.
Can you get the inner bearing out with a slide hammer? What size drifts do you need to press in the various bearings?
 
Discussion starter · #56 · (Edited)
I've got a Classic Boost rear hub:


and according to the parts listed for that hub, the required bearings are:

6804
6805
6902

I looked at the Tech figures of the hubs here:


and it looks like the rear hub may require 4, 5, or 6 bearings. The video on that page shows 4 bearings. Does anyone know how many bearings are in the rear hub, and how many of each I need? Thanks.
 
Discussion starter · #58 · (Edited)
I finally l located an email address for Onyx:

sales@onyxrp.com

I asked them which bearings are in my 2018 Classic Boost 6 bolt rear hub with a Shimano freehub (i.e. I use Shimano cassettes). Here was their response:

Maintenance on the hub can vary depending on usage.
At this time frame (2/2023 with no service ever), we would suggest cleaning and regreasing the clutch mechanism. This uses a specific grease and should be done every few years as it will absorb condensation.

On the classic hubs from ~2018. The brake side bearing is a 6804. The drive side bearing is a 6902. These are the two most common bearings to wear out.
The clutch area has a support bearing on each side. 6804 and 6805 size.

All the stock bearings in the hub are ceramic hybrids. They can typically be cleaned and greased rather than replacement. We have video walk throughs on our youtube channel for reference on the process.
On the classic pre MFU, the shimano freehub has a single 6902.
On the current classic with MFU, the shimano freehub uses a 6802 and 6902 stacked over a spacer.
So, if you want to have replacements on hand for all the bearings in an Onyx Classic 6-bolt Boost hub with a Shimano freehub, and the hub was made before the current MFU design, you need the following bearings:

2x 6804
1x 6805
2x 6902
 
Discussion starter · #59 · (Edited)
I pulled apart my Onyx Classic 6-bolt rear hub to service it. There was no grease under the end caps, and there was dirt on both outer faces of the bearings, which I cleaned off.

I pushed the axle out, then I pulled the freehub out of the hub body just like in the service videos. The extension protruding inward from the freehub had a lot of grease on it, and the grease was wet, clean, and tinged dark brown (Kuber Isoflex?). The service videos don't show any grease on there.

None of the collets for my slide hammer would fit the drive side bearing--one was about half a millimeter too big, and the next smaller collet was way too small, so I used an expanding type bearing puller, which only grips the inside of the bearing, and you tap it out from the other side of the hub. I purchased the tool from bearingprotools.com. Confoundingly, the drive side bearing was a 6805 bearing--not the 6902 claimed by Onyx.
Wheel Bicycle tire Bicycle wheel rim Automotive tire Bicycle hub


Automotive lighting Gas Nickel Jewellery Auto part

(6805 bearing puller on the left, press on the right)

The DS bearing has an orange seal that faces outwards, which says:
Verinent


6805 RH
And on the edge of the inner race facing outwards it says:

Onyx Racing Ceramic Balls
On the inside face of the bearing, there is a black seal, which says:
Verinent

6805 RS
I removed the orange seal with a pick to service the ball bearings, but the grease was wet, clean, and plentiful; so I put the seal back on without doing anything.

After tapping out the DS bearing, I removed the cir-clip, which allowed the spragues to slide out. Both of them were wet with clean grease, and they didn't need servicing. I serviced them anyway. I didn't want to use the toxic mineral spirits shown in the service video, then have to take the used portion to a hazardous waste dump, so I soaked the spragues in isopropyl alcohol, and I used an old toothbrush to clean them. I ordered the special Kuber Isoflex grease about 6 months after buying my hubs, and now 4-5 years later, I noticed it's not the right kind. I don't know if I ordered the wrong item, or the vendor shipped the wrong item, but I've got Kuber Isoflex NBU 15, so I went online and I ordered the correct Kuber Isoflex LDS 18 Special A. Expensive mistake.
Household hardware Font Rectangle Cylinder Auto part


Automotive tire Wheel Rim Bicycle part Automotive wheel system

On the NDS, the bearing has an orange seal facing outwards, which says:
Verinent

6804 RH
The bearing in the middle of the hub has a snap ring holding it in place, which you access from the NDS. On the black bearing seal, it says:
Verinent

6804 RS
The black seal faces the DS, and there is an orange seal that faces the NDS. If you were to remove the snap ring, I don't see any reason way you couldn't pull that bearing out the DS.
Bicycle wheel rim Bicycle hub Bicycle tire Automotive tire Bicycle

The Shimano compatible freehub has a bearing with an orange seal facing outwards, which says:
Verinent

6902 RH
I stuck my finger through the middle of each bearing, and they all felt smooth when I rotated my finger.

Once the special Kuber Isoflex grease arrived, I put some on the spragues. I tried putting a glob of the Kuber Isoflex on top of the inner bearing, but it was hard to apply anything but a thin layer of grease. Then I reinstalled the spragues (teeth facing counter-clockwise), but I had a little trouble getting the cir-clip back in--eventually I got it to seat in its shallow groove above the spragues.

Then I pressed the DS bearing back in. I didn't have anything to brace against the opposite side of the hub. Everything I had was too small in diameter, and therefore I would have been bracing against the inner race of the bearing or the ball bearings themselves. I finally managed to jam a female cup for a bearing extractor into the opening on the NDS, so that I was bracing against the outer race of the bearing, and after pressing in the bearing on the DS, I had a hard time getting the cup back out. I will have to order a 6804 bearing extractor and press.

Unlike in the service video, I waited until after I inserted the axle through the hub body to apply loctite to the threads at the end of the axle. Then I carefully applied some sticky marine grease under both end caps, and I reinstalled the end caps. The axle felt a little tight when I spun it with my fingers, which I expected might be the case after reinstalling the bearing, so I set about to adjust the bearing preload.

I removed the NDS end cap, and I loosened the screw on the preload collar, but the sticky marine grease seemed to prevent me from setting the preload correctly and getting the axle to spin easily. So I removed both end caps, and I removed the axle, and I cleaned off all the sticky marine grease I had applied. Then I reinstalled the axle, and I applied loctite to the threads at the end of the axle. I think I could have gone ahead and installed the end caps without any grease under them--they don't say to apply grease in the service video--but I decided to apply some Slick Honey, a much lighter, thinner grease than the sticky marine grease I used previously. That seemed to work well, and I eventually got the preload collar adjusted: I tightened the preload collar by hand, and as soon as it met any resistance, I found I had to back off the preload collar about 1/4-1/3 of a turn to get the axle to spin smoothly--more than they show in the service video.
 
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