CriminalTrials.co.uk Posted February 11, 2012 Report Share Posted February 11, 2012 Hoping someone can help me fathom somthing out here. How do the new external BB's work? Such as these ones? LINKAGE Im confused as their doesnt seem to be any way of fixing the axel to the BB? Do i need special cranks to go with the new BB's? Thanks in advance Danny Quote Link to comment Share on other sites More sharing options...
AndrewEH1 Posted February 11, 2012 Report Share Posted February 11, 2012 (edited) That's because the axle is attached to the cranks! I don't completely understand them myself but they seem to work great! You'll need new cranks if you want to use this type of bottom bracket go with some Shimano or Truvativ ones. Edited February 11, 2012 by AndrewEH1 Quote Link to comment Share on other sites More sharing options...
Revolver Posted February 11, 2012 Report Share Posted February 11, 2012 The axle's on the cranks. There's a bolt that pulls the cranks towards each other, onto the axle. There's a hat-shaped washer that's usually on there to make sure the cranks push together right - without it the cranks crush the bearings when tightened. It's called hollowtech II I think, so you need some hollowtech II cranks to go with it, or a new BB and matching cranks. Quote Link to comment Share on other sites More sharing options...
CriminalTrials.co.uk Posted February 11, 2012 Author Report Share Posted February 11, 2012 That's because the axle is attached to the cranks! I don't completely understand them myself but they seem to work great! You'll need new cranks if you want to use this type of bottom bracket go with some Shimano or Truvativ ones. Thanks for the info guys. So the cranks are simply push fit still but no bolts? how do they stay tight? Quote Link to comment Share on other sites More sharing options...
Revolver Posted February 11, 2012 Report Share Posted February 11, 2012 Nope. There's a bolt on one end of the axle in a two-piece system, or either end in a three-piece system. This bolt stops the cranks flopping off the axle. There's a pinch bolt on one or either crank (depends on the system) that holds the crank onto the interface. Quote Link to comment Share on other sites More sharing options...
bike_dummie Posted February 11, 2012 Report Share Posted February 11, 2012 (edited) They work in the same way as 2pc bmx cranks but instead the bearings screw in like a standard bb all you need to do is slide the axle through the bb and then put the other crank on and tighten, at least i think thats how it works. link not sure if this will help? Edited February 11, 2012 by bike_dummie 1 Quote Link to comment Share on other sites More sharing options...
CriminalTrials.co.uk Posted February 11, 2012 Author Report Share Posted February 11, 2012 ahhh i get it now. Sounds pretty good actually, guess thats the way things are moving, at least in the XC world anyway. Thanks for your help lads. Much appreciated as always Quote Link to comment Share on other sites More sharing options...
Robwalker Posted February 12, 2012 Report Share Posted February 12, 2012 i do believe that echo also offered an external bb system, supplied with an isis axle, allowing you to run external cups with normal isis cranks. The advantage of external cups is that the load is spread more evenly, and the pressure from the crank turn is closer to the bearings, so the effect of leverage is reduced. Quote Link to comment Share on other sites More sharing options...
krazykid009 Posted February 12, 2012 Report Share Posted February 12, 2012 I run the Shimano Hollowtech external BB system for trials, and I don't think I will ever go back to ISIS or square taper, it's quite simply great! James Quote Link to comment Share on other sites More sharing options...
Endohopper Posted February 12, 2012 Report Share Posted February 12, 2012 I run the Shimano Hollowtech external BB system for trials, and I don't think I will ever go back ... Damned right ! Running a cheapo Deore crankset and X type BB on my street bike ,superbly stiff and a doddle to install. Kinda tempted by the Saint cranks though. Quote Link to comment Share on other sites More sharing options...
CriminalTrials.co.uk Posted February 13, 2012 Author Report Share Posted February 13, 2012 Hmm all sounds gurrd. Would like to see a pic of an echo external setup! Thanks guys Quote Link to comment Share on other sites More sharing options...
ghostrider88 Posted February 13, 2012 Report Share Posted February 13, 2012 Hmm all sounds gurrd. Would like to see a pic of an echo external setup! Thanks guys Google? Quote Link to comment Share on other sites More sharing options...
monkeyseemonkeydo Posted February 13, 2012 Report Share Posted February 13, 2012 Quote Link to comment Share on other sites More sharing options...
Revolver Posted February 13, 2012 Report Share Posted February 13, 2012 I'm sure there is a way of making a square taper or ISIS axle to fit into a hollowtech BB. If I had a CNC machine I might try making one myself. Quote Link to comment Share on other sites More sharing options...
Philly_Biker Posted February 14, 2012 Report Share Posted February 14, 2012 (edited) External bottom brakets are the way to go these days on new Mtb and Road bikes. Road bikes have already superceded the external bottem braket and some companies now run large size internal bearings with a propritary crank. Never thought about using them for trials. You could make it work you would just have to find a crank that runs an axle meant to run with external bearings. Axle just needs to be the correct length and diameter so that it works with the BB. Might take some jimmy rigging and some trial and error. Ceramic BBs have very little friction. A ceramic bearing BB crank will spin effortlessly compared to a regular shimano non ceramic BB. That echo setup looks pretty good. I had bad luck with echo brakes though. Happy Valentines Day! Edited February 14, 2012 by Philly_Biker Quote Link to comment Share on other sites More sharing options...
ghostrider88 Posted February 14, 2012 Report Share Posted February 14, 2012 I'm sure there is a way of making a square taper or ISIS axle to fit into a hollowtech BB. If I had a CNC machine I might try making one myself. I think the problem would be how to preload bearing with this system.Other than that it wouldn´t be a problem of course. Quote Link to comment Share on other sites More sharing options...
Revolver Posted February 14, 2012 Report Share Posted February 14, 2012 Screw thread with a lockring, or some kind of washer that tightening the crank would push into the bearings. That second one would work better with ISIS I think. Quote Link to comment Share on other sites More sharing options...
ghostrider88 Posted February 14, 2012 Report Share Posted February 14, 2012 Screw thread with a lockring, or some kind of washer that tightening the crank would push into the bearings. That second one would work better with ISIS I think. Hm,it might work,but ot would be a lot of work for what it is and tolerances would have to be very tight(or spacers really thin,like 0,2mm I guess?). Quote Link to comment Share on other sites More sharing options...
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