crap bearings

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Alejandrosdog
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crap bearings

Postby Alejandrosdog » Wed Oct 09, 2019 06:49 am

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
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Re: crap bearings

Postby Nick Payne » Wed Oct 09, 2019 07:21 am

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.

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Alejandrosdog
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Re: crap bearings

Postby Alejandrosdog » Wed Oct 09, 2019 09:13 am

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
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Re: crap bearings

Postby Nick Payne » Wed Oct 09, 2019 22:57 pm

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
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Re: crap bearings

Postby crankycrank » Thu Oct 10, 2019 01:14 am


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Alejandrosdog
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Re: crap bearings

Postby Alejandrosdog » Fri Oct 11, 2019 08:13 am

thanks All

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Ben6899
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Re: crap bearings

Postby Ben6899 » Fri Oct 11, 2019 12:54 pm

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

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jermas
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Re: crap bearings

Postby jermas » Fri Oct 11, 2019 14:03 pm

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.

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Ben6899
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Re: crap bearings

Postby Ben6899 » Fri Oct 11, 2019 14:22 pm

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.
Last edited by Ben6899 on Fri Oct 11, 2019 15:11 pm, edited 1 time in total.
Ben

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jermas
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Re: crap bearings

Postby jermas » Fri Oct 11, 2019 15:05 pm

Yes, but not in a hub/freehub.

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Ben6899
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Re: crap bearings

Postby Ben6899 » Fri Oct 11, 2019 15:07 pm

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. :)
Ben

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jermas
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Re: crap bearings

Postby jermas » Fri Oct 11, 2019 15:17 pm

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.

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Alejandrosdog
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Re: crap bearings

Postby Alejandrosdog » Fri Oct 11, 2019 16:24 pm

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.

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Alejandrosdog
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Re: crap bearings

Postby Alejandrosdog » Fri Oct 11, 2019 16:50 pm

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.

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jermas
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Re: crap bearings

Postby jermas » Fri Oct 11, 2019 17:00 pm

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.

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Alejandrosdog
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Re: crap bearings

Postby Alejandrosdog » Fri Oct 11, 2019 17:14 pm

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.

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jermas
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Re: crap bearings

Postby jermas » Fri Oct 11, 2019 17:16 pm

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

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Alejandrosdog
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Re: crap bearings

Postby Alejandrosdog » Fri Oct 11, 2019 17:21 pm

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.....

thecycleclinic
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Re: crap bearings

Postby thecycleclinic » Fri Oct 11, 2019 21:41 pm

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.
Last edited by thecycleclinic on Sat Oct 12, 2019 10:03 am, edited 2 times in total.
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Alejandrosdog
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Re: crap bearings

Postby Alejandrosdog » Sat Oct 12, 2019 03:08 am

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.


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