• hi, new to the forum although been riding a long time. I have been riding this Langster since Feb this year and it's time to replace the BB.

    I'm struggling to remove it at the moment but using a tape measure it appears to be 68/103

    Can anyone confirm if this is correct and if so any recommended BB?

    Also if anyone knows which year model the Langster is that would be good too.

    https://www.instagram.com/p/BxWxj7ZhxOs/

  • No one? I applied a bit of GT85 yesterday (run out of WD40) and left it overnight. That and my good friend Mr Leverage who helped thanks to using a socket wrench extender and it's out.

    BB is an RPM BB-7420 model. It's too rusty to see the size marked on it but my tape measure confirms BB shell is 68mm and axle width is 103 mm

  • I need advice.

    I have a 54cm Pre-Cursa, 170mm Andel fluted cranks, Un55 105mm BB and rear Quando hub (Varno build).

    Will it give me a useable chainline (OR, how do I find out how to calculate it before fitting it all and hoping for the best)?

    First bike build for 10 years so I have forgotten everything.

  • Are the cranks these ones? If so, it looks like you need a 110mm BB to get a chainline of 42mm (105mm will be 2.5mm out).

  • Balls. They are, yes.

    Is chainline being out by 2.5mm gonna be a big problem?

  • Probably fine, but a un55 in 110mm isn't going to set you back much so personally I'd get it right and not have to worry about bursting in to flames or being beset by a plague of skidding locusts (or whatever happens when chainline is out by too much).

  • Just double checked, it’s 107mm. At 1.5mm I’m gonna risk it! 😮
    Cheers for your help!

  • Hmm. Might not be the right place to post, but anyway. Chorus chainset (drive-side only) keeps working loose and I have to re-tighten the bolt after a couple of long-ish rides. Any ideas about where the problem might be? Have been riding this for over 18 months and has been fine, trouble started (I think) when I replace the outer ring as it was pretty worn out. Pics for context of the set up. Thanks in advance...


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  • I had the same problem ages ago, what I did was-
    Got 18" breaking bar with a 8mm hex driver in and tightened it up as tight as possible by hand, then put the pedal at 9 and the bar at 3 and then stood on both. I never had any reason to remove them before I sold the bike and they didn't come undone in the year after I did this.

  • Ah, right, cheers. Have a breaker and a big 1/2" drive socket with that hex. Was a bit nervous about overdoing things as I'm a right lump, but I'll give this a go.
    Might be over to the 'Uve bin Indra'd' thread later.

  • So I can't get a decent chainline for love not money on my track bike. In comparison to other cranksets I've got it seems this one (Sugino messenger I believe) is quite offset? Is it just me?


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  • Don’t worry Indra is live and well

  • What axle length should I look for in a bottom bracket meant to accomodate a crankset with two chain rings? It's a Campag Veloce or Chorus (don't remember which and the branding has worn off) crankset if that helps...

  • Wondering if anyone can help me with a BB query. I’m currently running a praxis t47 bb and m30 cranks installed. If I were to remove these cranks and install a regular bsa bottom bracket for some shimano cranks would the bb shell threading accept the new bb? Or is it a unique t47 thread?

    I’m aware of shims you can get for the t47 to accept a 24mm shimano crank, but I want the t47 and 30m cranks together on another bike.

    Thanks in advance

  • Hi can any one help me what type of BB tool I'll need to get this BB out so I can give it a service. Thanks


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  • Anyone know what the chainline measurements are for either side of the middle/outer spider on a hollowtech 2 mtb crankset are?

  • Can anyone tell me if an mtb direct mount chainring would work on a set of direct mount road cranks?
    I currently have a 36t Absolute black chainring on my Sram X1 cranks, Im building up a cx bike and was going to use a sram force chainset, will I be able to use the AB chainring on the force cranks?

  • Posted in main forum...

  • I bought a set of Dura Ace 7700 cranks off eBay and they came with a DA Octalink BB which doesn't fit my frame as ITA vs BSA. Anyway the BSA BB is 109.5mm and the only ITA verison I can find in the same length is £97.

    SJS Cycles has a 113mm for £7.99. Should be fine right?

    Running DA 7800 mechs and DA7900 DT Shifters.

  • I'm trying to run a new veloce 10 speed front mech with oldish 10 speed Chorus setup, but can't get the front mech to shift up to the big ring. The chainrings are TA (vento) I think -I'm trying top run a 39/50 combo. Any ideas what the problem might be, or if there is a compatibility issue anyone?

  • It should work, there isn’t a significant change in derailleur geometry. Is there enough cable tension and are the limit screws set correctly?

  • Anyone know what tool I need to get this off? I’ve already managed to remove the outer ring using my lock ring tool, but this thing needs a specific tool.

    Also, any idea which way it will need to turn to get it out? The outer ring came off anti-clockwise.

    Cheers!

  • Sorted it. Hammer and screw driver :)

  • I need to change the otp crankset that came with a pompino to a chainring with 26t.

    1. Where do I get this smol chainring from? @citygent kindly advised nicking the little ring off a deore or I see wiggle has something 26t for a tenner
    2. Can someone advise on appropriate cranks, if separate? Cheap as chips, if possible
  • Could I get an Id on what type of bottom bracket Ill need for this frame please?


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Transmission database - for all your crank / bb / bottom bracket questions

Posted by Avatar for kowalski @kowalski

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