crap bearings

Alejandrosdog

So here we are 1400 mostly dry miles since my last bearing change in a DTswiss 240 hub.

and the creaking and groaning is horrific, disassembly and all feels smooth without lateral play when in situ . Remove bearings from the free hub AND the hub shell and they just spin roughly round, completely crackered

Enduro bearings I'm beginning to believe are more than a little pants though 6802 is a pretty pathetic size to use in that application anyway.

Does anyone have better luck with other brands?

Nick Payne

I have DT Swiss hubs that have been ridden much further than that and the original bearings are still fine. Some are wheels I built myself using 240 hubs, others are factory-built DT Swiss wheels with 240 level hubs. BTW, I think the 240s takes 6902, not 6802. If you're getting replacement bearings, LLU bearings with a full contact seal should last longer than LLB bearings with a semi-contact seal.

SKF now make what they call "solid oil bearings", with claims of increased bearing life compared to bearings using seals and grease. I haven't used them and can't comment on the claims, but the SKF description of them is at https://www.skf.com/au/products/bearings-units-housings/engineered-products/bearings-with-solid-oil/index.html, and one of the available sizes is 6902 - e.g. https://www.bike24.com/1.php?content=8;product=283455.

Alejandrosdog

Hi Nick,

I hope I’m right about the size these are the 240 style hubs in a dt clincher wheel. The drive side hub bearing is bigger and seems to have survived but since ive removed it ill replace it as well.

The drive side bearing is 15x26x7 the other three are 15x24x5 which is 6802

I stand ready to make a return trip for more bearings...

Ill have a look at those SKF bearings thank you for the link.

Nick Payne

Bike24 have a table of bearing sizes for different DT Swiss hubs: https://www.bike24.com/p2124210.html. Mine are thru axle disc hubs, which might explain the different size bearings.

crankycrank

Good info here from Mr. Hambini. https://www.youtube.com/watch?v=E-FqWpi ... dex=7&t=0s

Alejandrosdog

thanks All

Ben6899

Are you sure it's not a misalignment that's causing the wear? Enduro bearings are fine.

jermas

It's nearly impossible to have a bearing misaligned if it's fully pressed home. If it was just wear the bearings wouldn't be very rough- just sloppy. It's most likely rust/pitting on the balls and races making them feel rough and causing rapid wear.

Ben6899

jermas wrote:

It's nearly impossible to have a bearing misaligned if it's fully pressed home.

This isn't true. Even with fully pressed home bearings, there could be parallel or angular misalignment. Owing, for example in BB bearings, to poor frame manufacturing tolerances.

It's a rarity, but not an impossibility.

jermas

Yes, but not in a hub/freehub.

Ben6899

It's not impossible.

Not wanting to be argumentative, but there must be an underlying reason for the poor bearing life that Alejandro/Vino is seeing.

jermas

It's often the type of grease used (inside the bearing) that's determines the bearings resistance to water and therefore rust. Calcium and better still calcium sulfonate greases have the best resistance to water including salt water.

Alejandrosdog

the bearings didn't feel rough just sloppy and they would whizz round almost loose when on the end of my finger. Crackered. Almost like there was no grease in there at all. (in fact I think ill fish them out of the bin and have a look

I pressed them in with a proper bearing press, Im pretty sure they were not misaligned. there's no scoring or marking on the axle either. I use one of the proper wheels bearing press kits too not a threaded bar and some washers.

Alejandrosdog

https://postimg.cc/gallery/276ccuabm/

The bearings from inside the hub body feel smooth and solid. these are the bearings with a red seal on one side and black on the other. They are the original hub bearings and for ease of id have been shown in the picture red side up

The bearings with the black seal are enduro bearings and were in the free hub body

Ive removed them all to ensure I get the horrific noise the hubs are making sorted. on reflection I should maybe have done the free hub and see if it made a difference before doing the hub body. However.

The free hub bearings were changed some time in June I think.

The second picture shows one loose whizzing enduro bearing with a seal removed and one original DT bearing with a seal removed. It is clear from the picture that there is NO grease in the knackered enduro bearing, it is all gone or was never there in the first place.

The dt bearing which doesn't feel knackered has plenty of grease still.

I removed the seal on the other bearing which didn't feel quite as bad and there was a "hint" of grease still visible.


I don't jet wash my bike, and I don't use degreaser to clean the cassette on the wheel (when its time to do that I remove the cassette from the wheel to make sure I can get in the nooks and crannies) i.e. the hub shouldn't see any degreaser and is washed with a sponge and warm soapy water.

Ive had similarly rapid bearing failure in zipp808 free hubs.

I think its just crap bearings.

jermas

Are they C3 bearings? These are made with a larger radial clearance and are almost sloppy when new. I've seen C3 bearings used in cycle hubs before. Normally they're used for high speed applications, so no idea why they use them apart from possibly less drag.

Alejandrosdog

jermas wrote:

Are they C3 bearings? These are made with a larger radial clearance and are almost sloppy when new. I've seen C3 bearings used in cycle hubs before. Normally they're used for high speed applications, so no idea why they use them apart from possibly less drag.

I've no idea, I haven't got the original packaging which was the little enduro boxes and they came from a LBS so I doubt it. Theres nothing marked on the seal except 6802rs and Japan.

jermas

Mmm, just looked at the Enduro website- it looks like they do use C3 bearings. This might explain the wobble/ rapid wear.

Alejandrosdog

jermas wrote:

Mmm, just looked at the Enduro website- it looks like they do use C3 bearings. This might explain the wobble/ rapid wear.

I need to research this, my brief look at their sight indicates they use C3 clearance for longevity.....

cycleclinic

Endure bearings are not fine. My shop experience is they dont last.

Skf, ina, or ntn are the best brands to go for. In dt swiss wheel the 240 hubs are not always the same as the hubs we buy as hubs alone. 6802 is too small and never lasts long. You may get more life with a good bearing but the issue is mostly the size.

Dt swiss to my knowledge dont use clearance bearings. Miche use c3 bearings but they also have bearing preloaded adjustment to remove play. Dt hubs dont have this so should not use clearance bearings.

Alejandrosdog

thecycleclinic wrote:

Endure bearings are not fine. My shop experience is they dont last.

Skf, ina, or non are the best brands to go for. In dt swiss wheel the 240 hubs are not always the same as the hubs BMW buy as hubs alone. 6802 is too small and never lasts long. You may get more life with a good bearing but the issue is mostly the size.

Dt swiss to my knowledge dont use clearance bearings. Miche use c3 bearings but they also have bearing preloaded adjustment to remove play. Dt hubs dont have this so should not use clearance bearings.

This pretty much matches my experience and thoughts. I guess i need to try different brands and also accept that 6802 isnt man enough for the job anyway.

cycleclinic

I actually typed "we buy" and that became BMW buy. FFS. I hate modern technology. I cant pick up these errors when I read back.
non is meant to be NTN. How the hell do I turn off predictive text on my phone. I dont want it and never asked for it. I dont need my phone compounding my typing an spelling errors by creating words I never tried typing.