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So I happily ordered a Shimano MT 800 bb marvelling at the good price and went ahead to install it with my Park Tool BBT-9 only to find that they have shrunk the cups. Eventually I have discovered that I need a TL-FC25 Installation Tool Adapter, that is now ordered. So the old BB is going back in whilst I wait delivery or its going to have to be the crossbike....
So what happened
Any thoughts welcome, I am off to have a beer as its too dark to put it all back together
Yeah, annoying isn't it? That's why I've stuck with Deore BBs.
Shimano made this change a while back, probably four years ago… old after market stock must have sold through now. Used to come with a plastic adapter to use with the older bigger tool. Might not any more.
Local shops (if you have one) probably have a load of the plastic adapters lying around.
Cheers everyone so far, hopefully it will work with the Park Tool which is a great bit of kit.
Is this smaller size the standard or will they go back up again?
Are they all the same width, just a smaller diameter?
Looks like it, I did think about getting the molegrips out, but thought better of it.
Yep smaller size but helpfully when I bought my Pace build a couple of years ago they put the new smaller shimano BB tool in with the docs. I presume all higher group sets will have this size for a while until they change the standard again
I too was baffled by this once. Then, being an idiot, I managed to buy an adaptor which was the wrong size 🤦 I think the lbs gave me a spare in the end. On the plus side they look better than the bigger silver ones, especially on a metal BB shell.
Even more frustratingly, the Dura Ace and Ultegra versions are both smaller, but not the same amount of smaller. Shimano's Incompatibility Department was working overtime when they designed those.
Agree they're annoying. I got a few in a sale a few years back, but wouldn't buy them again when there's so many other BBs that don't need a stupid plastic tool. Presumably the bearings are smaller too, i.e. wear more quickly.
The ones I got all came with the tool (more unnecessary waste) - think I gave them all away on here, but I'll have a look.
Shimano’s Incompatibility Department was working overtime when they designed those.
I heard they recruited an Engineer from SRAM for the job, due to previous experience and expertise.
I always got an adapter in the BB. guess they don't come with those now?
I bought a cheap steel tool (Icetoolz? BBB?) rather than stripping out yet more plastic adapters. Works great with a ratchet handle, and the MT800 BBs last very well (both mine currently have >3 years on them).
There are 3 sizes of Shimano (have been for many, many years now)
39mm Dura Ace / XTR
41mm Ultegra / XT
44mm Tiagra / Deore
The new smaller bb tool, is also the same tool for removing their chainrings on 12 speed cranks.
The new smaller bb tool, is also the same tool for removing their chainrings on 12 speed cranks.
but you’ll still need the old big size for shimano centre lock discs (guess how I just found that out!)
They changed over 7 yrs ago.
Think I have a plastic adaptor you can have if your local to Chorley, lancs.
The fact that there's two versions of the plastic adapter just adds to the cluster ***k of standards, I mean why, just why do they do it, the fact they didn't make their DM chainrings compatible with the plastic adapter or make their centre lock rings fit the old BB tool nicer is a mystery, the fit is so bad for their hub lockring I thought I needed yet another tool.
Mine was the same size as my Shimano direct mount chainring tool. Not sure if that helps??
but you’ll still need the old big size for shimano centre lock discs (guess how I just found that out!)
If you buy the 'right' stock bike you need one undersized BB tool, one normal sized and a long-reach old school BB tool.
Marin, I am looking at you.
Everyone complaining about SRAM and their standards, yet on that diagram, SRAM is there twice (44 & 46), which is just an old and new standard.
Shimano are actively selling 3 standards for their current offerings.
But yes, SRAM is the problem in standards.
I seem to remember that new XT being the same size as XTR from the late 2000s? I randomly had a plastic tool adaptor hanging around when I had the same situation as the OP, and was pretty sure it came with the XTR BB many years ago...
Everyone complaining about SRAM and their standards, yet on that diagram, SRAM is there twice (44 & 46), which is just an old and new standard.
Shimano are actively selling 3 standards for their current offerings.
Sram do T47 DUB as well which is 52.2mm
I've bought a couple and they came with adaptors- I thought they all did, is this an OE vs retail thing, or is it just that they did it initially and stopped, or something?
OP, did you sort an adapter out ok?
If not I might have one buried in the mancave, somewhere.....
Sram do T47 DUB as well which is 52.2mm
But they did not create the standard. Supporting it to make their product available is quite different from proliferating standards.
Been like this on road bikes for a while. It can only be to save - very small amount of - weight. Shimano are buggers for this, but then we as consumers always want lighter and lighter components.
Its the reason for:
- Aluminium granny rings
- Aluminium chainring bolts
- Bonded crank arms
- ISIS bottom brackets
All lighter than their predecessors but also worse.
matt_outandabout
I heard they recruited an Engineer from SRAM for the job, due to previous experience and expertise.
SRAM probably deserve more praise than criticism for how they manage compatibility. Look at the mess that is I-spec compared to mounting a Sram shifter, for one
honourablegeorge
Full MemberSRAM probably deserve more praise than criticism for how they manage compatibility.
The problem isn't really how they manage compatability, it's that they do it very well, but in ways that disadvantage customers. The BBs are the best example of this, they're carefully engineered to be, well, incompatible with almost everything else and shit, so pretty much nobody chooses them off the shelf, and then they're sold in huge volumes to bike manufacturers. So you, the customer, get a bike with nice cranks and an absolutely gash bottom bracket which, when it breaks, you have very limited choice for replacements, and you end up buying another one the same from SRAM. Or you replace the whole crankset for lots more money. It's smart and it's rubbish.
AFAIC the only reason they changed from GXP to Dub is because there was too much aftermarket for GXP.
I have just stripped my Bird Aether for sale and to my suprise, the plastic adapter worked perfectly well to remove the BB. I used a socket type of tool with it fitted inside it, not sure how easily it will come out so fingers crossed.
And after two years of riding, its still smooth. Admittedly, I do ride other bikes in winter.