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I bought an Abus bike lock which came with a tube mount called the Abus EaZy KF.

Abus EaZy KF

The issue is that this mount only supports up to 36 mm diameter tube but the smallest tube on my bicycle is 38 mm. I tried to make it work regardless but the screws hit the tube.

oversized tube

Is there a general way to adapt this kind of clamped accessory meant for a smaller tube?

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    There is not a very easy way to adapt or change out such a specialty clamp. By "specialty" I'm referring to the shape and design of the part of the clamp other than the ring that goes around the tube. A sufficiently large clamp band would not have the correct interfacing design to mount the lock. Best bet would be to check with Abus via their customer service to see if they would have proper sized clamp for your bike that fits also your lock.
    – Jeff
    Aug 24, 2023 at 8:49
  • Thanks @Jeff, yeah that's what I feared but wasn't certain. I've reached out to Abus and they only have one other similar product but it only supports an even smaller diameter lol. I think the best thing I can do is get some velcro straps and strap the lock directly to the frame.
    – Daniel
    Aug 24, 2023 at 11:19
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    Seems odd to me that the manufacturer makes only one, too small, of size clamp. Making a 34.9 diameter clamp and providing shims for smaller tubes makes more sense despite the additional production costs.
    – Jeff
    Aug 25, 2023 at 20:23
  • Common problem. Bike frames these days can diameters from less than 20mm (old school steel) to 50mm or more (carbon and alloy MTB), and weird shapes to boot. There is no easy answer except a range of parts or use standard fitments. Only though - does it fit on the seat post?
    – mattnz
    Aug 29, 2023 at 4:09

1 Answer 1

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Your options boil down to BUY something, MAKE/ADAPT something, or find a WORKAROUND.

Buying an item for this purpose is easiest, as long as you can identify a part that will do the job as required. Abus might not even have an item that can help you here.


Making or adapting something is a valid solution if you're handy, and prepared to put in some time.

I see a philips-head bolt in the recess that holds the lock. If you unscrew that then you'll have the lock-holding part that can secure to a fresh clamp.

Here's a quick model I whipped up for 3d printing. Yellow is intended to use a pinch bolt to hold onto the 38mm seat tube. If the output isn't strong enough to hold the weight of the lock over bumps, then the Orange one is to be used with a stainless steel jubilee/radiator hose clamp of suitable size.

enter image description here

https://www.tinkercad.com/things/fDdn3fp4C8m-38mm-seatpost-clamps-for-abus-lock

In the Orange one, the idea was for the bolt to pass through the jubilee clip at some point. That puts all the 3D printed parts in compression and nothing in tension.

The Yellow one might not have sufficient flex to get around your frame member as designed.


Finally, Workaround might be putting the lock in your bag, or tucked into a waistband, or resting in a drink bottle cage.


Update from OP: thanks for pointing me in the right direction. I ended up modelling something and printing it out, it worked quite well:

enter image description here

It is parametric so you can input any tube diameter you want!

Parametric example of the adapter

I posted the source file to thingiverse here: https://www.thingiverse.com/thing:6201957

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    for the interface between the mount and the lock receiver, a model to look at may be this one: thingiverse.com/thing:2337048
    – Rеnаud
    Aug 29, 2023 at 6:55
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    @Renaud My thought was to swipe that piece from the existing clamp. But yes if OP needs to store lock on multiple bikes, then its easier to have a mount on each and just move the lock. That's what I do with my fancy front light.
    – Criggie
    Aug 29, 2023 at 7:51
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    that's what I understood indeed (the design I linked to is not the full support, just the part that receives the proprietary receiver). My suggestion was just that instead of the rectangular part your design, using a circular one with the holes would have allowed a better interface between the receiver and the mount (the relevant picture is the second one, not the first one)
    – Rеnаud
    Aug 29, 2023 at 9:05
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    Thank you so much for the info and the model! You all directed and inspired me to make my own model which I'll be printing out and testing. If it works I'll post it to thingiverse 👍
    – Daniel
    Aug 31, 2023 at 1:25

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