Sram DUB BB bearing replacement

willawry'd · Jul 5, 2023

lefthanded said:
Do you know what the original bearing was? It that 30 mm inner diameter? It it a standard 6806?

The original SRAM DUB bearing measures 30x40x6 by my calipers, so not a standard 6806 (30x42x7). The reference seal ID shows: 6806W6LHV HUX-SRAM
Wheels DUB isn't either... 6806/29 (29x42x7).
SRAM is on the left of each pic; Wheels on the right.

lefthanded · Jul 8, 2023

willawry'd said:
The original SRAM DUB bearing measures 30x40x6 by my calipers, so not a standard 6806 (30x42x7). The reference seal ID shows: 6806W6LHV HUX-SRAM
Wheels DUB isn't either... 6806/29 (29x42x7).

Thanks a lot, that's great info!

It seems like this is a unique custom size Sram came up with and has it made by a low quality manufactorer. So Sram's "durable" bottom-bracket is nothing but a lie and it is exactly not made to be durable but made for frequent replacement with cheap bearings only Sram sells. I'm sure (respectively, I hope and expect) Sram Germany's engineers know bearings very well, yet they made their choices. Yes, Sram is a great company with great morals.

BB bearings wearing out, I feel like I'm back in the 80's with cup'n'cone BBs. What a bad product.

Bearing Technical Information - Hambini Engineering

This guide has been written to provide information and assistance to allow you to replace bearings. The guide is predominantly based around the replacement of

www.hambini.com

Slowandfat · Jul 9, 2023

Maybe I'm wrong, but I don't think SRAM DUB BB's are really intended to be serviced with bearing replacements. You simply clean and regrease (no need to pry off bearing seals, just wipe the unit clean and regrease threads/contact points). When it dies, you replace with a new BB. They are inexpensive, and easy to replace. For this application, I think they work well enough, and are reasonably durable. At least that has been my experience. If you want a BB that you can replace bearings, you're going to have to pay more (Hope, Wheels Mfg., etc.).

GoldenKnightMTB · Jul 9, 2023

Pull apart, clean, re-grease. This is also a $30 bottom bracket.

J.B. Weld · Jul 9, 2023

Slowandfat said:
Maybe I'm wrong, but I don't think SRAM DUB BB's are really intended to be serviced with bearing replacements. You simply clean and regrease (no need to pry off bearing seals, just wipe the unit clean and regrease threads/contact points). When it dies, you replace with a new BB. They are inexpensive, and easy to replace. For this application, I think they work well enough, and are reasonably durable. At least that has been my experience. If you want a BB that you can replace bearings, you're going to have to pay more (Hope, Wheels Mfg., etc.).

You are not wrong.

cmg · Jul 9, 2023

GoldenKnightMTB said:
Pull apart, clean, re-grease. This is also a $30 bottom bracket.

l dont know every riders financial position, but BBs are pretty cheap, and actually last a good time (normally), so l see no point in "servicing" them....

just dispose of them correctly when you replace them

lefthanded · Jul 9, 2023

Slowandfat said:
Maybe I'm wrong, but I don't think SRAM DUB BB's are really intended to be serviced with bearing replacements.

They are obviously not meant to be replaced.
Which is wasteful in two ways. Firstly, they use low quality bearings of a low-budget manufacturer that naturally fail more often than bearings from renowned brands.
Secondly, disposing otherwise perfectly fine aluminum cups makes no ecological sense. It's just wasteful of resources and doesn't fit into this day and age IMO.

Slowandfat said:
You simply clean and regrease (no need to pry off bearing seals, just wipe the unit clean and regrease threads/contact points).

That's not servicing the bearings, so I don't know what this is good for in this context 🙃 . (As disussed earlier, this kind of bearings is not meant the be greased, and I wouldn't do that.)

Slowandfat said:
When it dies, you replace with a new BB. They are inexpensive, and easy to replace. For this application, I think they work well enough, and are reasonably durable. At least that has been my experience. If you want a BB that you can replace bearings, you're going to have to pay more (Hope, Wheels Mfg., etc.).

I'm surprised by the acceptance of BB bearing failures here. As written before, since I replaced my last cup'n'cone BB in the early 90's. BBs have been lasting "forever" in my bikes, even the mid-tier ones.
I'm just not willing to accept that bearings in a 2022 Sram GX level BB need to be replaced "routinely" and don't last for many many years, and many many miles, that would usually constitute a large portion, if not all, of the typical service life of the whole bike until it is somewhat retired. That's been at least my experience with all my personal bikes in 30 years. If consumers are now accepting of frequent BB replacements, that's a huge step back into the 80's.

As far as I know Sram DUB BBs are only made in one quality version (not counting silly ceramic bearings) and they do not offer a more expensive option with higher qualitiy and more durable bearings. If Sram wanted to make a quality BB, they would at least have not made the bearings cheaply but by a quality manufacturer. Sram's cheap DUB BBs are only good for Sram and those who make money off their failures IMO.

I'm not sure what JB, a professional bike mechanic, as far as I understand, "likes" in your comment.

lefthanded · Jul 9, 2023

GoldenKnightMTB said:
Pull apart, clean, re-grease. This is also a $30 bottom bracket.

I don't want to have to service a BB. I didn't need to in decades. Servicing BBs is as 80's as it gets.

Psychoholic Racing · Jul 9, 2023

lefthanded said:
Yes exactly. They are lifetime greased.

Those videos where people "service" (and advise to do so) - what the bike people call - "cartridge bearings"... I always find them a little funny.

Firstly, as you write, those are not meant to be serviced. Secondly, chances are the seals get damaged and perhaps even debris makes it inside during the operation. Thirdly "cartridge bearings" were introduced to bikes to not need to service bearings yearly or on whatever basis but promised to run for many years. That's what my practice has been. And this worked has been working well - apart from two bearings in Sram products. Fourthly, probably most people put too much grease in the bearings.

be careful. I said the same thing about these bearing not being made to service and sealed/ lubed for life and all the “Know it all” experts bashed me. I’ve only sold bearings for over 25 years and been to factory training so what would I know.

lefthanded · Jul 9, 2023

Psychoholic Racing said:
be careful. I said the same thing about these bearing not being made to service and sealed/ lubed for life and all the “Know it all” experts bashed me.

I get bashed a lot by Sram fans 🤷‍♀️. Okay if they keep it at a technical level.

J.B. Weld · Jul 9, 2023

Let's all cancel DUB.

lefthanded · Jul 9, 2023

The only advantage of DUB is that Sram can make a single crank and bearing design for all frames. That's a reasonable motive, and I don't have anything against that. The implementation though seems crap and malicious. BB servicing was a thing of the past. I as a consumer appear to not benefit from DUB but instead suffer from crappy proprietary bearings. @J.B. Weld, let us know what I benefit I miss.
The only ones DUB seems good for is Sram, dealers and repair shops as far as I can see.

A BB must operate flawlessly under typical riding conditions for years and years without any service. That's my expectation and standard. It's also backed up by experience with bike BBs.
Imagine routine need for service on car bearings. Needing to service and or replace bearings multiple times during the lifetime of a bike is ridicluous.

john_bikeguy · Jul 9, 2023

lefthanded said:
The only advantage of DUB is that Sram can make a single crank and bearing design for all frames. That's a reasonable motive, and I don't have anything against that. The implementation though seems crap and malicious. BB servicing was a thing of the past. I as a consumer appear to not benefit from DUB but instead suffer from crappy proprietary bearings. @J.B. Weld, let us know what I benefit I miss.
The only ones DUB seems good for is Sram, dealers and repair shops as far as I can see.

A BB must operate flawlessly under typical riding conditions for years and years without any service. That's my expectation and standard. It's also backed up by experience with bike BBs.
Imagine routine need for service on car bearings. Needing to service and or replace bearings multiple times during the lifetime of a bike is ridicluous.

Agree. SRAM dub bottom brackets seem to be designed to be a throw away item. I had them in 2 new factory built high end xc bikes. Replaced them every 6 months or less due to contamination issues. They are not designed to be serviced. The seals are very poor on these. Eventually replaced with enduro bearings and good seals. I have had no problems since. One of the best upgrades for ocd bike enthusiasts like me that can’t stand grit sound/feelings. If SRAM would spend a few dollars on better seals then these bottom brackets might last a lot longer for people with modest trail conditions.

J.B. Weld · Jul 9, 2023

@lefthanded- DUB isn't perfect but the whole system (crank & bb) is better imo. Simpler, easier to service, lighter, stiffer, etc. Cartridge bearing bb's and 3 piece cranksets were (are) good but not infallible or as enduring as you seem to suggest. I've been working on bikes for several decades and there has never been a time when we weren't busy servicing & replacing bb's. Never. For sure DUB isn't a forever bb but for the money it seems plenty serviceable to me. As mentioned I routinely service bikes with many thousand miles and find their DUB bb's to be spinning just fine. I have run a DUB bb on one of my own bikes for over 10k. Conversely I have seen them crap out with less than a few thousand miles when ridden in adverse conditions or when there are tolerance issues. So maybe not perfect but certainly not total junk as you suggest.

Everyone is free to choose, there are still cartridge bb's and 3 piece cranksets available so no one is twisting anyone's arm to buy DUB only. If you don't like it don't buy it.

MTB Engineer · Jul 9, 2023

DUB aside, all bike designs with proprietary bearings are only made to make a buck selling proprietary spares at ridiculous prices.

While I don’t think the 29mm spindle in DUB is necessary and 24mm or heck, 25mm with STANDARD BEARINGS would be great, DUB is still heaps better than GXP ever was.

Slowandfat · Jul 9, 2023

dan l · Jul 9, 2023

I see lefthanded is at it again with his regurally scheduled SRAM hate threads. Wonder what SRAM part he will feature next week? Wonder what dubious claims he will make. Tune in, same time, same site, it’s sure to entertain the whole family!

Slowandfat · Jul 9, 2023

[QUOTE="lefthanded, post: 15992786, member: 911718"
That's not servicing the bearings, so I don't know what this is good for in this context 🙃 . (As disussed earlier, this kind of bearings is not meant the be greased, and I wouldn't do that.)
[/QUOTE]

I am not suggesting servicing the bearings in a $35 bottom bracket! In your original post, you mentioned that your BB was starting to make noise. I am merely offering some advice that may remedy that. If it works, great. If not, you know it is the bearings, and then it's time for a new BB. Hopefully this will be "good for this context".

Slowandfat · Jul 9, 2023

(deleted post)

lefthanded · Jul 9, 2023

dan l said:
rufurslly

Is this a word?

dan l said:
Wonder what SRAM part [lefthanded] will feature next week?

Anything that breaks next week. I hope nothing. But please advise if you know what failure I should prepare for.
Rest assured I'm not biased particularly against Sram and that I would disclose my experience and opinions exactly the same way for any other brand. It just happens to be that only Sram parts fail on my bikes. You see the pattern?

Sram DUB BB bearing replacement

willawry'd

lefthanded

Bearing Technical Information - Hambini Engineering

Slowandfat

GoldenKnightMTB

J.B. Weld

cmg

lefthanded

lefthanded

Psychoholic Racing

lefthanded

J.B. Weld

lefthanded

john_bikeguy

J.B. Weld

MTB Engineer

Slowandfat

dan l

Slowandfat

Slowandfat

lefthanded

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