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Any intricacies to removing a Dura Ace 9100 crankset - can I convert from pushfit BB?

daniel_bdaniel_b Posts: 10,714
edited September 2018 in Workshop
Afternoon all,

being paranoid here, but I have a new bike with a 9100 53\39 crankset, and going against Shimano's recommendations, I am going to replace the 39 with a 36, thus giving a 17T differential, instead of the recommended 16T.
However, I want to give it a try, and if it does not work smoothly enough, and spoils my enjoyment of the bike, I will buy a 52, or swap out the whole crankset for a 52\36.
Also not sure if this will require the lowering of the front derailleur.

I have built bikes before, using 105 and Ultegra, but never touched dura ace and am concerned I might end up wrecking a hugely expensive part, so just wanted to check it is BAU when it comes to extracting the crank with a crank puller, same as any other hollowtech unit?

I am also replacing the 11-30 cassette with an 11-28, and changing the chain, so not sure if I might need to shorten the chain (or rather make the new chain shorter than the outgoing one) or not.
It's been a while since I have fitted a chain to a new bike, but iirc, the method that seemed to work ok, was to ignore the derailleur, put the chain around big\big and add 2 links, or have I made that up?

If that is the case, then going from a 30 to a 28 will likely make marginal difference.

Additionally, it has occurred to me, as I will have the crankset out, I have the option of getting shot of the push fit BB.
Now I have to hold my hands up here, and say I am not overly au fait with the varying sizes and compatibility issues, so am hoping someone can shed some light.
The stock BB on my bike is a Shimano SM-BB92-41B
Would it be advisable to replace it, and if so, what would people recommend, that would still allow me to defit the Dura ace crank.

Not too worried about cost - south of £100 would be preferable.
Felt F70 05 (Turbo)
Marin Palisades Trail 91 and 06
Scott CR1 SL 12
Cannondale Synapse Adventure 15 & 16 Di2
Scott Foil 18

Posts

  • imposter2.0imposter2.0 Posts: 11,969
    If you have a Shimano pressfit BB and you want to retain the DA chainset, then the width of the BB shell dictates that the only option is to keep the pressfit BB. You can also go 50/34 or 52/36 on the existing crank arms - no need to change the chainset. Won't be cheap though..
  • Daniel B wrote:
    Afternoon all,

    being paranoid here, but I have a new bike with a 9100 53\39 crankset, and going against Shimano's recommendations, I am going to replace the 39 with a 36, thus giving a 17T differential, instead of the recommended 16T.
    However, I want to give it a try, and if it does not work smoothly enough, and spoils my enjoyment of the bike, I will buy a 52, or swap out the whole crankset for a 52\36.
    Also not sure if this will require the lowering of the front derailleur.

    I have built bikes before, using 105 and Ultegra, but never touched dura ace and am concerned I might end up wrecking a hugely expensive part, so just wanted to check it is BAU when it comes to extracting the crank with a crank puller, same as any other hollowtech unit?

    I am also replacing the 11-30 cassette with an 11-28, and changing the chain, so not sure if I might need to shorten the chain (or rather make the new chain shorter than the outgoing one) or not.
    It's been a while since I have fitted a chain to a new bike, but iirc, the method that seemed to work ok, was to ignore the derailleur, put the chain around big\big and add 2 links, or have I made that up?

    If that is the case, then going from a 30 to a 28 will likely make marginal difference.

    Additionally, it has occurred to me, as I will have the crankset out, I have the option of getting shot of the push fit BB.
    Now I have to hold my hands up here, and say I am not overly au fait with the varying sizes and compatibility issues, so am hoping someone can shed some light.
    The stock BB on my bike is a Shimano SM-BB92-41B
    Would it be advisable to replace it, and if so, what would people recommend, that would still allow me to defit the Dura ace crank.

    Not too worried about cost - south of £100 would be preferable.

    https://wheelsmfg.com/bb86-92-outboard- ... black.html

    This was a solution to creaky, unbraced BB92 bottom bracket bearings. It was basically 2 pressfit bearings braced with a 2 part screw together shell, which maintained the shell length and spindle diameter. But I don’t think they’re available anymore.
  • are you sure you need to get a smaller inner ring if your cassette has gone up to a 30? be some expensive changes.

    Also ignore anything bottom briquettes has to say; his grasp on reality is tenuous.
  • daniel_bdaniel_b Posts: 10,714
    Thanks all,

    I have a replacement BB, that I bought off a forum member who had used it in his CR1 - I have it in stock, for when the stock one needs replacing.
    As the CR1 is a BB91, I am assuming that it would not be an option to fit it on this bike?

    Disappointed to hear that I can't change it anyway, I know you could on the CR1, but assume that is because it is a 91 and not a 92?
    Looks like pressfit it is then.

    Appreciate I could simply change the chainrings (Both) but if I find I have to do that, I suspect it will be more cost efficient to sell the 53\39 and buy a new 52\36, hence me wanting to try the 53\36 as a comparatively cost effective option.

    The 11-30 rear cassette is a Dura ace one, and I am going to remove this brand new to sell, together with the unused dura ace chain. The funds from these will more than cover the cost of the 36 inner ring, and the far more reasonably priced 11-28 Ultegra R8000 cassette. I'm not a fan of a gappy rear cassette, dislike the 11-32 a lot on my winter bike, but appreciate it has it's place at the moment, and so in an ideal world an 11-28 is as wide as I want to go.

    Looks like this may well be a fruitless path, so probably just stick with the factory item, and hope that when it needs replacing something superior may be on the market.
    Felt F70 05 (Turbo)
    Marin Palisades Trail 91 and 06
    Scott CR1 SL 12
    Cannondale Synapse Adventure 15 & 16 Di2
    Scott Foil 18
  • daniel_bdaniel_b Posts: 10,714
    Although this Hope is still pressfit, do you think it would be much of an improvement over the stock one?

    http://www.chainreactioncycles.com/hope-pf41-press-fit-stainless-bottom-bracket/rp-prod118519
    Felt F70 05 (Turbo)
    Marin Palisades Trail 91 and 06
    Scott CR1 SL 12
    Cannondale Synapse Adventure 15 & 16 Di2
    Scott Foil 18
  • imposter2.0imposter2.0 Posts: 11,969
    Daniel B wrote:
    Although this Hope is still pressfit, do you think it would be much of an improvement over the stock one?

    http://www.chainreactioncycles.com/hope-pf41-press-fit-stainless-bottom-bracket/rp-prod118519

    Is there anything actually wrong with the standard BB..? Shimano pressfit is generally pretty reliable, one of the better pressfit standards out there...
  • daniel_bdaniel_b Posts: 10,714
    Imposter wrote:
    Daniel B wrote:
    Although this Hope is still pressfit, do you think it would be much of an improvement over the stock one?

    http://www.chainreactioncycles.com/hope-pf41-press-fit-stainless-bottom-bracket/rp-prod118519

    Is there anything actually wrong with the standard BB..? Shimano pressfit is generally pretty reliable, one of the better pressfit standards out there...

    I had heard of instances of them creaking.

    Just whilst I have it all apart, I like to see if there are any tweeks or improvements that can be made.
    Felt F70 05 (Turbo)
    Marin Palisades Trail 91 and 06
    Scott CR1 SL 12
    Cannondale Synapse Adventure 15 & 16 Di2
    Scott Foil 18
  • imposter2.0imposter2.0 Posts: 11,969
    You might be confusing Shimano press fit with BB30? If it's working fine, I'd just leave as is. I have two bikes here with Shimano press fit - one has two years on the BB and the other has one year on the BB - both are still working perfectly with no movement and no noise.
  • daniel_bdaniel_b Posts: 10,714
    Imposter wrote:
    You might be confusing Shimano press fit with BB30? If it's working fine, I'd just leave as is. I have two bikes here with Shimano press fit - one has two years on the BB and the other has one year on the BB - both are still working perfectly with no movement and no noise.

    Aha, I think you may well have hit the nail on the head there sir :oops:

    Thankyou kindly, I will leave well alone!
    Felt F70 05 (Turbo)
    Marin Palisades Trail 91 and 06
    Scott CR1 SL 12
    Cannondale Synapse Adventure 15 & 16 Di2
    Scott Foil 18
  • ryan_w-2ryan_w-2 Posts: 1,162
    Let me get this right... You want to change from 39/53 with paired with a 11/30 to a 36/53 with 11/28?

    39/30 gives you a 1.30 gear ratio.

    36/28 gives you a 1.29 gear ratio.

    You have lost the plot mate...

    PS: 53/36 works 100% fine.
    Specialized Allez Sprint Disc --- Specialized S-Works SL7

    IG: RhinosWorkshop
  • daniel_bdaniel_b Posts: 10,714
    Ryan_W wrote:
    Let me get this right... You want to change from 39/53 with paired with a 11/30 to a 36/53 with 11/28?

    39/30 gives you a 1.30 gear ratio.

    36/28 gives you a 1.29 gear ratio.

    You have lost the plot mate...

    PS: 53/36 works 100% fine.

    lol, pleased to hear 53\36 will work fine.

    Nope not lost the plot at all, I've said that I don't like a gappy cassette, and also the fact that selling the unused dura ace one not only pays for a closer ratio Ultegra one, but also pays for the 36 inner ring.
    The other benefit is then if I do head into the alps, and want to\had to go for an 11-32, I have an even lower gear than the 39 with the same cassette would have permitted.

    So in summary:
    I'm no worse off financially
    I have a closer set of ratios
    I have better capacity for lower gears should I ever need them


    And as long as it does actually work, I see only upsides :D
    Felt F70 05 (Turbo)
    Marin Palisades Trail 91 and 06
    Scott CR1 SL 12
    Cannondale Synapse Adventure 15 & 16 Di2
    Scott Foil 18
  • ryan_w-2ryan_w-2 Posts: 1,162
    I see heavier weight and downgrades...

    All summer I've used 11/25 with 52/36. Just put a DA 11/30 on since going to Spain in 2 weeks, took me about 5 minutes to adapt, and would be extremely content using the 11/30 all year round if I had to.

    I'd spend a few quid on the 36T chainring yet 100% keep the cassette. But that's just me.
    Specialized Allez Sprint Disc --- Specialized S-Works SL7

    IG: RhinosWorkshop
  • daniel_bdaniel_b Posts: 10,714
    True, everything is relative though.

    I've just spotted a DA 12-28 cassette. Now that genuinely appeals.
    Felt F70 05 (Turbo)
    Marin Palisades Trail 91 and 06
    Scott CR1 SL 12
    Cannondale Synapse Adventure 15 & 16 Di2
    Scott Foil 18
  • svettysvetty Posts: 1,904
    Daniel B wrote:
    True, everything is relative though.

    I've just spotted a DA 12-28 cassette. Now that genuinely appeals.
    But costs way more than the Ultegra 11-28.....
    FFS! Harden up and grow a pair :D
  • daniel_bdaniel_b Posts: 10,714
    Svetty wrote:
    Daniel B wrote:
    True, everything is relative though.

    I've just spotted a DA 12-28 cassette. Now that genuinely appeals.
    But costs way more than the Ultegra 11-28.....

    Oh yes I know, £145ish, versus £45!

    That was another reason to move away from a comparitive consumable of the rear cassette across to the Ultegra version.
    Only 60g or less weight penalty too.
    Downside is, the buggers don't make the Ultegra one in any of the really useful combinations, I wonder why :roll:
    Felt F70 05 (Turbo)
    Marin Palisades Trail 91 and 06
    Scott CR1 SL 12
    Cannondale Synapse Adventure 15 & 16 Di2
    Scott Foil 18
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