Omnium replacement BB recommendations

General Help
1

Hi All, long time reader first time poster!

I’ve recently made the trasition from carbon 20 speed to Cro-mo fixed (All City Big Block) for my commuter and as a part of my build, I installed a sweet set of Sram Omniums (yes, 165 x 48t). I did a lot of reading before commiting and the general concensus was that the BB on these were pretty rubbish.

Turns out they are incredibly rubbish… 6 weeks and 1300ish kms later and it’s well on its way to being fried.

I had planned on changing it out anyway given the spectacular reviews, but I hoped it would be a fair bit later down the track so I hadn’t given replacement options much though.

So enter the collective destructive experience of FOA; What are some bulletproof (68mm) options for me?

Cheers

2

Bulletproof 68mm?

Square taper sealed cartridge bottom bracket, preferably SKF, or a Shimano UN9x if you can find one.

Matched to any quality forged Japanese cranks. Sugino / Shimano / SunTour.

Failing that, perhaps a new gutter seal Sram GXP BB, or a SRAM compatible King

3

shit man whats wrong with you? i normally get 5-10000km out of them, and thats only because they get a bit creaky and annoying.

but yes, they are quite shit, but for 30bucks delivered, what do you expect??

couple things of note though. i dont bother putting gease behind the dustcaps anymore as this just seems to attrack grit and makes them noisy. also try and make sure u get the newer style ones, think from 2010 onwards the design was a little better, looked nicer, and had less drag.
these ones:

BUT… im also interested in a good possible replacements, one was suggested to me ages ago, but i cant remember :frowning:

4

I was about to say the same thing, I have well over 5000km on my current gxp bb and it is still going strong. That includes winter commuting/all conditions not just fair weather riding.

You could trying using one of the Truvativ gxp bb from the mountain bike range rather than a standard road/track gxp bb. Apparently the seals on the mtb ones are much better at keeping the elements out.

5

Yeah, I’ve already commited to the external dicipline and aside from the BB I’m pretty happy with them, nice straight chainline, super stiff etc.

Do you think a million dollar Chris King would last proportionally to the cost? I’d hate to install one and then have it chop out in the same time frame…

Hey Red, do you manage to quieten them down by doing that? Mine have a distinct ‘click’ at the same point in the non-drive side revolution, and what feels like a slight grind (although this may be made mentally worse by the noise)

Its already had a fair bit of wet weather work, but probably not much more than anyone else around here…

6

over torquing your omniums is also a great way to accelerate the wear and tear on the bottom bracket

7

Would the omnium fit straight in? Does yours still run nice any quiet?

What am I doing wrong here?!

8

Hmm, i just use an allen key and make sure there’s no play left. Highly scientific.

9

well if it clicks, and doesn’t spin smooth - it’s either not installed correctly or it’s way too tight… highly scientific

10

^^ ive never worn them out enought that they “grind”… maybe it is all in your head :slight_smile:

but yeah, pull them out, use a rag with a bit of petrol to clean the grease out then put the caps back on. i suspect you will find road grime and shit in there that will need to be removed. and moving forward, i clean mine out about every 2 weeks. more frequent if im riding in alot of rain or shit surfaces, and also clean the threads of both the frame and bb incase and grit has worked its way in there.

seems to work well for me

11

might give a CK one a go… am already on my second sram gxp. was considering the ceramic sram gxp…

12

dont overcomplicate things dickhead.

its srsly pretty hard to overtighten omniums that much.

13

The bonus of the CK is that you buy the grease injection tool and regularly flush the contaminated grease out of it.

Like the old WTB Grease Guard components.

14

Thats what i’d heard, but my guns are pretty huge…:slight_smile:

I might give them a thorough clean out tonight, just seems a little counter intuitive to be wiping grease out rather than cramming it in. But I agree entirely with grease being a grot magnet.

Is the CK service kind of like the speedplay service? As in you can do it without removing stuff from the bike? Not that Omnums are the most difficult thing to remove going around…

15

Mine does still runs nice and quiet. That said my sram PF30 BB on my other bike is already making some clicking noise (maybe it’s just the pedals).

As far as I understand the Omniums should fit straight in to a Truvativ mtb bb.

EDIT:

Agreed, I think the torque specs are 47-54nm… Unless you are using a long hex key that has lots of leverage I doubt they’d be overtightened.

16

yeah do that. and realy the grease behind the dustcaps isnt that essential imo, it has nothing to do with the bearings themselves, and the way they are fasioned(at least the newer ones) there isnt really enough contact between surfaces to really need greese(not sure that makes sense, just have a look when u pull the out). it seams to be more of a “just incase” kinda thing to me. but anyways, plenty of k’s on mine no worries.

EDIT: and let us know how any others go that u try. i dont mind blowing through 30bucks worth of bb, but if i bought a nice ck or token or somthing that blew up just a quick, i would be pissed… be my guiny pig :slight_smile:

17

Deal! We’ll just go halvies on the CK and I’ll send it over once i’ve clocked up 50% of the recommended Km’s! Gags…

18

Fucken proprietary BB “standards”, how do they work?

19

yeah its lame there are 3 (?) different BB’s for the same axle diameter (24mm).

20

Was going to say the same thing. My Omnoms are three years old now with the original BB on my track bike which is never ridden gently. I used to commute on it too so it’s seen some dirt/water.
Despite this problem of BB’s, I would still use them over many available track cranks. Let me know how you go, I may have to replace mine eventually?