SRAM Omnium crankset

hmm pretty damning reviews of the on one sram copies. shame as i think they look nicer than the sram. anyone have a good experience with them?

hey there, i just came across this thread. for what it's worth here are my thoughts.

i installed omniums a quite few months back and i did feel a bit of a difference compared to not the bad at all but heavy andel (blb) set. they feel more rigit when accelerating at high speeds for example, or slowing down. i quite like the modern, blocky look, too.

the gxp bottombracket options are a bit of a mission to find out about as the gxp system is slightly different from the shimano one, in axle dimensions and design, eliminating bearing sideload. what makes finding bb alternatives a bit challenging for me, is the fact that i need italian threadded bb cups and most 3rd parties give a fnarc about those. (yes the king does and so does my personal fave hope but not IT threadded)

my observations are, the cranks and spider arms are close to the frame, phat stays might get scraped.
Stincking with the original BBs, the sram standard design team bb until 2010 has quite a bit of drag due to the way the seals work. it seals well but is rather draggy and should be greased or at least oiled (chainoil) in month intervalls for best sealing results through the shit weather period.

i ran my first bearings to the ground and upgraded to better spec stainless steel bearings from Enduro Bearings (through bedt, they have refitting service when u send your cups in).

Thing is, these are not the same dimension as the sram bearings (sram has a proprietary size), but 1 mil slimmer. to compensate the loss of 2mil overall on width at the axle, Enduro delivers a set of higher spec silicone, better fit and thus lower drag seal washers with it in the right thickness, ftw.

all in all a good upgrade imho and i already clogged down more miles on the new bearings than on the standard ones. i think worth the money over just a new set of bb cups.

now here it comes, the new bb cups, the 2011 version has a different design, outside as well as inside. through a new seal design and material, the drag is reduced to the level of the silicone Enduro ones. sadly they also changed the drive side bearing's ID size slightly so that the enduro replacement as it is doesn't fit. the'll have to come up with a new offer or one has to tinker the bearing in place and use an extra 1mil washer drive side.

and to round my post up i'd like to point you to my sale thread of sets of english threadded BB cups, both the team and the new 2011 ceramic blackbox gxp cups in racing fast red for 40!!! quid less than anywhere online, if i may.

is there some kind of seal to cover the hole at the centre of the cranks and goes into the hollow of the axle?

No.

?

^ha i havent riden them yet, but the hole goes straight through the hollow of the spindle and out the other side of the BB, surely all kinds of gunk will get in there? please tell me if i am being retarded...

^ha i havent riden them yet, but the hole goes straight through the hollow of the spindle and out the other side of the BB, surely all kinds of gunk will get in there? please tell me if i am being retarded...

There is nothing in the hole to be harmed by said gunk. Loads of cranksets have this.

There is nothing in the hole to be harmed by said gunk. Loads of cranksets have this.

thanks hmm i still think its dumb, a plastic cover would weigh nothing and eliminate any gunk. i will try an array of circular plastic things until something fits....

Hey come with a plastic spacer with rubber seals between the cups, so anything Tha does go in there will probably go straight out the other side or sit there doing nothing.

I have no issues with the bb on mine yet and have used it for a year, looking back through this thread does make me want a Chris king bb still though...

Hi, can any one give me a little advice? I want to fit Sram omnium track cranks on my Dolan pre cursa. I'm also fitting Goldtec track hubs as part of this new build. I'm just wandering will the crank need spacing on the drive side, to get a perfect chain line with out any fouling?

Cheers! : )

it won't need spacing but the spider will be very close to the chain stay. Not sure about the chain line with Goldtech's though.

As far as I know, Omnium's have a 45mm chaniline the same as Goldtec, so you should be alright. Probably worth checking the transmission database though.

nope, IIRC omniums are possibly 42mm, goldtecs are 45

whatever the exact specs they are different - i know because i have them both and it is noisy.

am probably going to move to using a 3/32 sprocket to allow a little more play at the rear end. long term i plan to buy new hubs.

omniums are possibly 42mm, goldtecs are 45

↑This (ish)
Avoid unless you fancy customising the spacer/end caps on the Goldtec axle to make a dished single sided hub.

Couldnt you squeeze a spacer inbetween bb cup and frame to space the chairing out a little?

Older goldtecs were made with a 45mm chainline, but the ones they are producing currently (since they started doing them with the raw silver finish) are 42.5mm, so should work with your omniums without any issues.

http://www.mountainbikecomponents.co.uk/items.asp?CategoryID=15&Name=Goldtec+Track+Hubs

Couldnt you squeeze a spacer inbetween bb cup and frame to space the chairing out a little?

I had thought about this but am but am concerned there may be problems pulling the cranks too tight against the external bb

I have done it with a shimano road external bb with no issue. (To use road ultegra cranks on a track bike)

The 'tightness' is dictated by the plastic bolt that goes into the axle on the non drive side and although there is an indent in the axle that the metal pin on the plastic spacer on the nds crank pinchbolts must locate into, there is a small amount of adjustment available.

I have a 1mm spacer knocking about indoors if you need it James. It works fine and without issue.

Why were Goldtec making a 45mm hub anyway?

On the Srams, there is no plastic tightener, so you are just using one bolt to tighten the cranks up against the bb cups.

Just seen Mr Bear's post, I may have to give it a try, just don't want to knacker the BB.

Older goldtecs were made with a 45mm chainline, but the ones they are producing currently (since they started doing them with the raw silver finish) are 42.5mm, so should work with your omniums without any issues.

Goldtec have been calling it 42.5mm for some time and were notorious for catching people out - it's mentioned on threads here more than once. My older ones are definitely 45mm.

Do you have any new ones yourself, or are you going by the web site alone?

I suspect goldtec are measuring to the mounting face, not the actual chain centre line. That would explain why they are now offering 40mm, which would be impossibly narrow if it were actually the chain centre line.