Shenlong
Dirt Disciple
Are you sure about that?
What's wrong with Isis bottom brackets?
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External bearing push the cranks further apart.. Pretty sure you need to use the 128mm (downhill) axle, as 118/113 are mtb standard and road is even shorter.
Anything else isn't ISIS.
So pointless as a replacement unless the cranks are designed for them.
Later Truvativ moved the bearings outside with the Howitzer standard, you know the creator along with RaceFace and Chris...
Of course in itself creating a unique standard outside it universal for all standard...
But ISIS also then came up with the true fix, the ISIS Overdrive, enlarging the shell and sticking proper bearings in them.
I think HT2 worked too well so this didn't really take off and most followed that style with yet again other standards.
ISIS was a great idea restricted by Shimano. A nice infill for a while.
SRAM (Truvativ) seem to have more clout in creating and getting others to use new standards.
Anything else isn't ISIS.
So pointless as a replacement unless the cranks are designed for them.
Later Truvativ moved the bearings outside with the Howitzer standard, you know the creator along with RaceFace and Chris...
Of course in itself creating a unique standard outside it universal for all standard...
But ISIS also then came up with the true fix, the ISIS Overdrive, enlarging the shell and sticking proper bearings in them.
I think HT2 worked too well so this didn't really take off and most followed that style with yet again other standards.
ISIS was a great idea restricted by Shimano. A nice infill for a while.
SRAM (Truvativ) seem to have more clout in creating and getting others to use new standards.
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A quick look at Trialtech and they have one standard ISIS BB but that's too long for these MTB cranks, all Trials seem to be at the Downhill length.
The other is specialist and the axle length breaks the ISIS spec, it seems the 'Spanish' all break the spec in length (I see 124 as another option, not part of the spec). So not technically ISIS spec.
It may borrow the spine.
Honestly that's all irrelevant for someone needing a 113 or the longer 118 length.
Trialtech | Bottom Brackets
Performance Trials Bike products made from high quality materials to cater for serious and professional trials bike riders.
www.trialtech.co.uk
It may borrow the spine.
Honestly that's all irrelevant for someone needing a 113 or the longer 118 length.
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Also can we have this moved to 1998+ because none of this is true retro ;-)
They didn't start talking about it till 1998...
*Flagged for a move niw
They didn't start talking about it till 1998...
*Flagged for a move niw
Shenlong
Dirt Disciple
Not necessarily a bad thing. Some riders prefer a slightly wider stance. Chainstay clearance is also increased. The Echo External bottom bracket from 2006 is the only ISIS bottom bracket with external cups to this day - axle width is 128mm. Nothing crazy wide.
From previous experience, Middleburn RS7 ISIS cranks were relatively narrow cranks so even when fitted to a 128mm Trialtech Sport Lite ISIS BB, they're similar feeling in attack position compared with 68/73mm Shimano HT2 MTB cranksets. YMMV.
If 128mm pushes the chainline out further than ideal for a particular setup, there's always the option to dial it in with shims on a 104/64 BCD spider.
For Middleburns, you also have the added flexibility of having a competent machinist make you a specific offset Direct Mount ring or an offset spider.
Let's not forget that 122mm and 127.5mm square taper BBs also exist. For both 68mm and 73mm BBs. For non-DH bikes and non-Trials bikes.
A bonus of having an external cup ISIS BB is that since ISIS axles are 22mm in diameter, you have more space for larger bearings than the ones in 24mm HT2 BBs.
On the ISIS Drive official page: https://www.isisdrive.com/menu-3 - there is no mention of how wide or narrow the axle must be to qualify as ISIS.
If there is an official rule about needing specific width axles (e.g. 113mm, 118mm, 128mm) to qualify as ISIS then I'd be interested to know where you got this information from! If you can provide credible primary sources or official documentation - even better.
Always good to learn new things every day. 
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You cannot compare square to isis.
ISIS standard has 4 fixed lengths so you know your crank will just fit and work. The crank is then designed around that length.
122/127 square taper are for cranks that are designed around them but still hit a 47.5 chainline or less depending on 6 or 7 speed.
Super low profile cranks starting in the XTR 8soeed era using 107 still hit the same chainline but stick these crank on a 127 cranks and your shifting is out even if you like a widestance/Q-factor and the front mech tend not to like that.
That 10mm chainline shift, or at least two cogs at the back.
That's not how BBs alignment works.
And bodging shims here and there just to use an ISIS is pointless when you can just get a different crank for probably what the load of shims or new profiled spider.
And you cannot do that with turbines.
It's a bodge at best or OK for commuting or single speed.
Feel free to use them, but no need to recommend a bodge to others just to use some old cranks.
And yes I do run ISIS BB and cranks, currently on my main rider.
If you need a 113 ISIS the get a 113 ISIS, like skf mentioned or otherwise.
As for lengths.
Grab the spec documents, it's a pdf under documents.
The Overdrive spec pages don't seem to work for me but you can get at them.
I might need to try a different browser.
I'm surprised the BMX/Trials users didn't go for that, but that Spanish spec looks reasonable.
Here's the table snippet.
ISIS standard has 4 fixed lengths so you know your crank will just fit and work. The crank is then designed around that length.
122/127 square taper are for cranks that are designed around them but still hit a 47.5 chainline or less depending on 6 or 7 speed.
Super low profile cranks starting in the XTR 8soeed era using 107 still hit the same chainline but stick these crank on a 127 cranks and your shifting is out even if you like a widestance/Q-factor and the front mech tend not to like that.
That 10mm chainline shift, or at least two cogs at the back.
That's not how BBs alignment works.
And bodging shims here and there just to use an ISIS is pointless when you can just get a different crank for probably what the load of shims or new profiled spider.
And you cannot do that with turbines.
It's a bodge at best or OK for commuting or single speed.
Feel free to use them, but no need to recommend a bodge to others just to use some old cranks.
And yes I do run ISIS BB and cranks, currently on my main rider.
If you need a 113 ISIS the get a 113 ISIS, like skf mentioned or otherwise.
As for lengths.
Grab the spec documents, it's a pdf under documents.
The Overdrive spec pages don't seem to work for me but you can get at them.
I might need to try a different browser.
I'm surprised the BMX/Trials users didn't go for that, but that Spanish spec looks reasonable.
Here's the table snippet.
Shenlong
Dirt Disciple
It depends. What chainline is the OP/someone aiming for. Does OP/someone plan to use his ISIS Middleburns for a Singlespeed or Geared setup. How far is OP/someone willing to go to keep using his ISIS Middleburns. Many variables to work with.
If the OP/someone has to use a 113/118mm ISIS BB for their specific drivetrain setup then obviously the Trialtech Sport Lite, the Echo External, and a custom Hambini External Cup ISIS BB won't be of much use to them. Still, it's good to know these options exist.
Hence why I also suggested the SKF ISIS bottom bracket in my first post in this thread. The SKF ISIS BBs come with a 10 year warranty including the bearings. They are available from Rene Herse in 113mm or 118mm for BSA frames: https://www.renehersecycles.com/product-category/components/bottom-brackets/
It is still better to be aware that there do exist specific ISIS BBs such as the SKF, Trialtech Sport Lite, and Echo External that have greater bearing longevity than catalogue cloned ISIS BBs. Out of these three specific options you have 113mm, 118mm and 128mm to choose from.
There is also the option of asking Hambini to make you either a copy or an improved version of the Trialtech Sport Lite's design, with a 113/118mm axle. Have top quality bearings such as SKFs or NTNs fitted. Or perhaps improve upon the current SKF ISIS bottom bracket design.
Instead of focusing on the negative aspects of average ISIS bottom brackets, I prefer to provide alternative solutions for anyone who has ISIS cranks that they want to keep using. At the same time, I'm also open to suggestions if anyone knows of any other niche unique design ISIS BSA threaded BBs out there. The more you know the better.
Let's not get hung up on axle widths. Axle width is besides the point. Why I brought up specifically the SKF, the Trialtech Sport Lite, and the Echo External is to show that not all BSA threaded ISIS bottom brackets are terrible.
ISIS Overdrive is a good solution. However, unless the OP/someone has a frame with a BB shell large enough to fit Overdrive, it's irrelevant to their needs. It is still good to know that ISIS Overdrive exists though.
Fluffychicken I truly admire you for the amount of time you are spending on this guy,theres an old saying
”If one person says you are wrong it’s a difference of opinion,if two people tell you you’re wrong it’s a coincidence,but if three people tell you you’re wrong it’s because you’re Wrong”
”If one person says you are wrong it’s a difference of opinion,if two people tell you you’re wrong it’s a coincidence,but if three people tell you you’re wrong it’s because you’re Wrong”
Shenlong
Dirt Disciple
Note that the only Trialtech model I've suggested in this thread is the Sport Lite threaded BSA BB.
I purposefully have not mentioned Trialtech's Spanish ISIS BBs until now since you've brought them up - because they are not BSA threaded ISIS bottom brackets.
Overdrive BB frames and Spanish BB frames are nice. Though largely irrevelant to most people since they most likely have BSA threaded frames. The focus of this discussion is centred around the BSA threaded ISIS bottom bracket standard.
Whilst 124mm isn't part of the officialdom ISIS spec. It is still an ISIS spline at each end, which in the real world, ISIS cranks do fit.
Fixating on the axle width is completely beside the point.
It's unwise to tar all ISIS bottom brackets with the same brush, especially without any actual real-life personal experience testing some of the better ones.
Hence why I've suggested contacting Hambini if a 128mm axle isn't ideal for someone's particular setup. Ask him to make a 113mm or 118mm wide version of the Trialtech Sport Lite design, the SKF design, or the Echo External design. Perhaps he can come up with an original design that is even more reliable, within the constraints of the BSA threaded standard.
If 128mm Trialtech Sport Lite, Echo External, and the Hambini custom route aren't up your street, then you still have the SKF 113mm and 118mm ISIS bottom brackets as options.
On page 2, suburbanreuben has shared his experience with using an SKF ISIS BB: "I have an old SKF that has been fitted to my SS for at least ten years, and has seen thousands of miles of use. I no longer use it. The bb Is absolutely fine but the ti pedals have seized in the cranks and the bearings are phut..."
