benmh

Better brake adapters (after catastrophic failure of shimano adapter & caliper)

28 posts in this topic

Hi all,

After less than 2 months of use, my Shimano XT caliper and adapter (+20mm for a 180mm rotor) absolutely exploded - adapter and caliper both into three pieces each. I'm lucky this happened on a 2ft up to rear and not the drop-gap I was doing 10 minutes earlier, but I was still sent to my back incredibly hard on the corner of a ledge so I'm keen for this to never, ever happen again.. if I landed a few inches further on the corner of the ledge I'd probably be writing this from a spinal injury unit.

I had no previous issues with the XT other than bad pad knock, but some threads on here say that newer shimano calipers are indeed snap-happy, so I'm going to move to an MT5. I've got my XT lever here waiting for a shigura swap if I'm not feeling the carbotecture lever body.. not too worried on the this front.

I'm a bit more confused on the adapter fron and hoping for any / all advice. I want to have the confidence in brake setup that I had prior to this, especially for bigger moves. With this in mind I want to replace it with the most heavy duty brake adapter I can find. I've read good things about hopes, but they look pretty thin as well with the CNC cutouts throughout? Magura adapters look pretty much the same as shimanos - any thoughts on them? Any other recommendations welcome, but I am over in Australia so some things aren't quite as easily available.

Cheers!

IMG_4524.jpeg

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Oi! That's hardcore! I'd recommend only using Magura or Hope adapters. I've only broken one Magura adapter in 11 years and no Hopes so far (but using Hopes far less). Glad you came out of that one OK!

I'd warranty that caliper too. XT has a 2 year warranty.

Edited by Swoofty

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I actually just snapped a Magura adapter QM41 (IS rear 180) on my 26" czar and didn't even notice it before the brake started rubbing slightly. Technically the caliper remained attached by the rear bolts only without snapping completely off, which is crazy considering I even managed to gap few times without noticing anything too weird.

I don't think the QM41 has enough material around the front bolt hole (snapped right there), and the design adds too much leverage after the bolt, so I don't recommend using these at least.

But personally I would stick to Hope, they just look more solid design and material wise.

 

Edit: I mean would you trust this:
 

qm41fail.jpg

Edited by Jere_h

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A lot of people have had this problem over the years, it tends to be the over tightening of the caliper on top which can weaken the holes where bolts go through or there is a lot of shock going through the setup when running a 203mm rotor. But as your running a 180mm rotor it’s hard to tell if it’s just weak about the holes on this particular caliper or you just had bad luck this time round.  I went down the root of running one of these adapters.  Yes it’s a 185mm, but you can either file it down yourself or take it to an engineer to put it to 160mm/180mm. Plus there cheap on eBay, I’ve not had any problems since. I run a shimano 203mm icetech rotors with shimano Zee brakes F+R. I also put one fat washers with green cab bolt on top of the calipers to give them a bit more stiffness.

https://www.ebay.co.uk/itm/Avid-Post-to-IS-Disc-Brake-Mount-Bracket-Adapter-REAR-for-185mm-Rotor/352149302576?pageci=22d30051-18d2-4329-b7f4-d3d33d11e7b8&epid=1305524222

 

5EE9D801-2353-49F3-A080-07CC6D70CCD1.jpeg

Edited by John Shrewsbury

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Big vote for hope adapters here. I’ve had the same two on front and rear for a couple of years with zero issues. 

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Please contact Shimano.

My rear brake (Zee) failed the same way some months ago and they told me nobody reported such a failure.

It is not the first time I read on this forum this issue, maybe it is a safety issue so it would be nice if other people reply here and contact shimano with similar cases!

 

EDIT: found this thread:

 

Edited by La Bourde

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If you buy a chunky adaptor and use proper washers and bolts you'll never have a problem. I'm heavy, I used 203 Saints for years, never broken a caliper.

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m9.thumb.jpg.588b9baa279bb9856db80d09597d25ae.jpg

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Isn't that the old Saint that wasn't prone to failures? But yeah looking at that chunk of aluminium and comparing it to the basic "xc" adapters (magura, shimano), no wonder they have caused issues. That looks like moto stuff, put those and the beefy MT5 calipers and you'll be looking at the frame mounts again if something breaks haha.

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13 hours ago, LEON said:

If you buy a chunky adaptor and use proper washers and bolts you'll never have a problem. I'm heavy, I used 203 Saints for years, never broken a caliper.

This.

When calipers break it is almost invariably one or more of the following:

- Random bolts / washers setup

- Bolts not kept tight

- Adaptor breaks first and takes the caliper out too

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4 hours ago, Jere_h said:

Isn't that the old Saint that wasn't prone to failures? But yeah looking at that chunk of aluminium and comparing it to the basic "xc" adapters (magura, shimano), no wonder they have caused issues. That looks like moto stuff, put those and the beefy MT5 calipers and you'll be looking at the frame mounts again if something breaks haha.

They are, the newer M820 do seem to be weaker, but people broke the M810 too. Calipers will last, it's up to you to support it, that whole area is only as strong as the weakest link.

Edited by LEON

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On 11/18/2020 at 3:12 AM, Jere_h said:

I don't think the QM41 has enough material around the front bolt hole (snapped right there), and the design adds too much leverage after the bolt, so I don't recommend using these at least.

QM41 is the one I broke too, same place. The Hope equivalent definitely has more meat around that area.

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I had this happen to me yesterday on an XT calliper and came here looking for the same thing haha 

 

 

240862FE-CC9C-41B1-AFC3-8EB7337E42FD.jpeg

0C34DE39-F313-4283-84DF-B11A745EF2AE.jpeg

Edited by Fergus
Photos didn't upload

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On 19/11/2020 at 0:01 PM, LEON said:

m9.thumb.jpg.588b9baa279bb9856db80d09597d25ae.jpg

What adapter is it mate?! 
 

Thanks to everyone for the advice. I’ve ordered a Hope and will see how it goes for the moment.. If I can find one like the above I’ll move to it for sure though!

Edited by benmh

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4 minutes ago, Fergus said:

I had this happen to me yesterday on an XT calliper and came here looking for the same thing haha 

 

 

240862FE-CC9C-41B1-AFC3-8EB7337E42FD.jpeg

0C34DE39-F313-4283-84DF-B11A745EF2AE.jpeg

This is very, very interesting indeed! That is almost millimetre identical to mine. 

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16 minutes ago, benmh said:

What adapter is it mate?! 
 

Thanks to everyone for the advice. I’ve ordered a Hope and will see how it goes for the moment.. If I can find one like the above I’ll move to it for sure though!

Search Hayes or avid Fat adapter. 
It might be difficult to get one in 180mm. I only managed to find a 185mm here and filed it down https://www.ebay.co.uk/itm/Avid-Post-to-IS-Disc-Brake-Mount-Bracket-Adapter-REAR-for-185mm-Rotor/352149302576?pageci=22d30051-18d2-4329-b7f4-d3d33d11e7b8&epid=1305524222

Edited by John Shrewsbury

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1 hour ago, benmh said:

This is very, very interesting indeed! That is almost millimetre identical to mine. 

That's a pretty feeble looking adapter. 

 

1 hour ago, benmh said:

What adapter is it mate?! 
 

Thanks to everyone for the advice. I’ve ordered a Hope and will see how it goes for the moment.. If I can find one like the above I’ll move to it for sure though!

Can't remember, just a generic no name one that's huge, Hope are good too. But I think a fat solid block is the safest bet.

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I think that adaptor you have Leon is one that comes with BB7 brakes.

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There are 2 kinds of adapter...

20201120_205342.jpg

If you knowingly use anything like the bottom row you deserve to get injured.

Edited by LEON
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2 hours ago, Adam@TartyBikes said:

I think that adaptor you have Leon is one that comes with BB7 brakes.

I've definitely used Avid before, it's got a disinctive slit type thing on the side where the light is reflecting off.

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15 hours ago, LEON said:

There are 2 kinds of adapter...

If you knowingly use anything like the bottom row you deserve to get injured.

Looks like me and OP have learned this lesson the hard way, what is fine for a mountain bike is not always okay for trials! Got some Hope adaptors on the way... 

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Funnily enough, Spode just did this, manly Hope adapter, not so manly caliper.

 

 

IMG-20201122-WA0004.jpg

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Looks like if it isn't a Saint, Shimano < trials.

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Pretty much. But an OLD Saint, new ones seem more fragile. Just find out all the brakes that are powerful enough, then pick the best built caliper, trials is too much for a lightweight/xc caliper. 

Never seen a Hope Trial caliper break...

Edited by LEON

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In defence of shimano I have only had the modern ones break with a poor adapter - I’m 13 stone and have been using an xt and deore on separate bikes over the last 2 years and been fine. 

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