Replacement BB for Giant other than Shimano Press fit

Stuartyboy
Stuartyboy Posts: 22
edited March 2011 in Workshop
Morning all,

Im having a bit of a mare at the moment with my Giant Rapid Advanced 2010. The BB is described as a Shimano Press fit SM FC7800 HD. For a long time I have suspected the BB is causing a lot of drag and for a long time its been all push and no go! It runs a R600 compact crankset 34/50

Having stripped out the cranks I noticed that the drive side cup rotates quite freely and the non drive side is very stiff. When the cranks are in place they rotate for 2 rotations and nowhere near as free as I have seen on other bikes.

I have decided to replace the bearing set and while I wait on the appropriate tools to do the job (its a carbon frame so Im not prepared to cowboy the BB cups out with any ole drift!).

The problem is is that I seem very limited to what replacements I can purchase. For around 30 quid I can have the same Shimano 7800 cups from Wiggle:

http://www.wiggle.co.uk/shimano-dura-ace-7800-bottom-bracket-cup-set-press-fit/

Due to the performance of the factory fitted set I'm not to keen in installing another Shimano bearing and judging by the cheap price I gather that they arent the highest of quality so I am looking for a replacement by another manufacturer. Ive contacted Hope and they informed me that they do not manufacture press fit bearing so thats them ruled out. Have looked around various sites but it seems like the only option is the Shimano bearing :evil:

Any ideas from a fellow rider?

Many thanks
Giant Propel Advanced 3
Giant Defy 0
Giant Rapid Advanced 0 Road
Scott CR1 SL

Comments

  • ride_whenever
    ride_whenever Posts: 13,279
    You may be able to put better bearings in (if you pull the old ones out of the cups) but it's almost certainly that you're over pre-loading the bearings hence them being a bit tight.

    The other thing would be the bearing cups not being quite square in the frame, go to a very well equipped high end bike shop and ask them to check the ream on the bb shell that it is spot on and straight, if it wasn't quite right then that would give a lot more resistance.
    Neeermad
    Carbon 456
    456 lefty
    Pompino
    White Inbred
  • Stuartyboy
    Stuartyboy Posts: 22
    Ridewhenever,

    Many thanks for your quick reply!

    I was hoping to replace them with better quality ceramic bearings and unaware that the actual bearings where removable from the cups. Would these SRAMS be a good match?

    http://www.wiggle.co.uk/sram-bb30-ceram ... -assembly/

    the tightness of the bearing has been the fault of the dealer when assembling the bike and when i reinstall the bearing I will keep an eye on the pre loading of the bearings etc. Im hoping that the BB shell is not the problem and is true and straight. As it stands the BB shell is as clean as a whistle and the bearings dont appear to have failed due to water ingress through the BB Shell.

    Im hoping to get the right tools for the job tomorrow. I'll post the outcome of my findings! Hopefully after that Ill get back on the saddle and feel as though Im getting somewhere!

    Thanks again!

    Stu
    Giant Propel Advanced 3
    Giant Defy 0
    Giant Rapid Advanced 0 Road
    Scott CR1 SL
  • markshaw77
    markshaw77 Posts: 437
    I have the same press-fit bearings on my Scott CR1 and while I haven't had the issues that you have had, the after-market replacement choice (beyond the Dura Ace ones that you linked to) is almost nil.

    The only ones I found (offering S Steel and Ceramic) were here:

    http://www.enduroforkseals.com/id258.html

    But i have no idea on their quality!!

    As well as checking the pre-load level which is easy to over-do, the other thing that you might be able to do to reduce the 'drag' is to remove the dust seals from the press-fit units - it is quite tricky, but if you google around, there are some examples of how to do it. Obniously, it leaves the bearings more open to the elements, but if you are after performance, that may be somewhere to start.

    HTH
  • maddog 2
    maddog 2 Posts: 8,114
    I run the Enduro ceramic bearings in my Giant (TCR). Excellent. Free spinning, well made.
    Facts are meaningless, you can use facts to prove anything that's remotely true! - Homer
  • Stuartyboy
    Stuartyboy Posts: 22
    maddog2

    Cheers for your reply and Im now looking at the Enduros. As a matter of interest where did you purchase them?

    Im having a right task of getting my head around the whole BB30, BB86 thing.

    Ive worked out that my Rapid uses the BB86 standard- utilising 24mm spindle diameter on the crank axle, 86mm wide BB Shell and 41mm in Diameter.

    There seems to be a lot more options for BB30 than BB86 and I was wondering whether I could convert the Rapid to a BB30 standard giving all the benefits that comes with it??

    Anyone have any experience of this? Performance wise is the BB30 better than a BB86 setup. Its a bit confusing and As ive experienced hard to acquire new BB for the 86 set up.

    Stu
    Giant Propel Advanced 3
    Giant Defy 0
    Giant Rapid Advanced 0 Road
    Scott CR1 SL
  • Monty Dog
    Monty Dog Posts: 20,614
    BB86 and BB30 are not interchangeable - your cranks are BB86. BB30 uses a 30mm diameter crank spindle whereas BB86 uses 24mm e.g. standard HT2 / FSA MegaExo. The likes of Shimano are looking to make BB86 the industry 'open standard' because it's actually a simpler design and your don't need to pay a licence fee for it's use. For an alternative, look at the KCNC BB86 bearings:
    https://clee-cycles.co.uk/cc/catalog/pr ... tfnp0k0i72
    Make mine an Italian, with Campagnolo on the side..
  • maddog 2
    maddog 2 Posts: 8,114
    I ordered the Enduros directly from their website. My order was a bit different as I run a Sram c/set which has different cups to Shimano.

    BB30 is different - the c/sets are different (narrower axle). BB86 is basically a normal hollowtech2/GXP chainset but uses press-fit BB cups rather than screw-in external cups. There may well be more BB30 options in terms of BB cups but not chainsets.

    The BB86 is a little unusual it is true but the reality is that it's a doddle to set up. Just press-fit the BB cups (with a headset press) and fit a std chainset. Job done.

    Shimano do basic BB cups. Enduro do fancier ones. There may well be others too.
    Facts are meaningless, you can use facts to prove anything that's remotely true! - Homer
  • Stuartyboy
    Stuartyboy Posts: 22
    Many thanks for all the replies gents.
    I eventually ordered a new set of Endura cups and bearings from the States. I couldnt find them anywhere in the UK.

    Tried getting the actual bearings out of the Shimano cups while Im waiting on the new sets to arrive. Not surprising that they arent meant to be user serviceable and incurred a bit of damage. What do you expect for 30 quid a set though.

    Heres hoping the bike is back on the road within the week.

    Thanks again!

    Regards

    Stu
    Giant Propel Advanced 3
    Giant Defy 0
    Giant Rapid Advanced 0 Road
    Scott CR1 SL

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