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Abus Amparo 4850 Frame Lock

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JimK:
The frame lock showed up in today's mail, the lock that I bought for our teenager's bike, the bike that we're planning for him to ride on the Erie Canal ride in July and then on campus when he goes to college in the fall. When we visited campus a couple weeks ago, I saw a lot of half-decent bikes locked up everywhere with cheap cable locks. I asked one of the students who gave a presentation at the Engineering Open House about bike thefts and he said it wasn't a big problem. We shall see! But a lock that you can't really lose, I figure that might help!

Here's the lock, on 1/5 inch graph paper:



This is Version: NKR with mount CL. It gets mounted with a couple stiff plastic straps:



These straps have ridges along the inside but it's a threaded plug that catches them. There's a screwdriver slot in the plug so you can tighten or loosen the straps easily. The plug is relatively soft plastic though - not sure how many cycles of screwdriver application the thing will endure, but I expect they won't be going anywhere.

Here's the lock mounted:



That's a Jamis Trail X1 bike from maybe two years ago. I just put on the Planet Bike Hardcore 60 mm fenders. The tires are Schwalbe Marathon Dureme 50-559.

I was trying to imagine this lock down at the chainstays, Dan: I think the big trouble will be the clearance between the chainrings and the wheel. Anyway, with the graph paper picture, you could probably make a cardboard cut-out and test the clearances!
 

Danneaux:
Jim,

Wow! You've done an outstanding job photographing the new lock, and placing it on graph paper was inspired. Are those 1/4" squares? Even better than measuring, I can copy the photo to one of my graphics applications and scale it to full-size in printing, cut out the picture, and hold it in place to check clearances. Next-best to having the lock on-hand, but not as secure.  ;)

After all this, may I impose with another measuring question? Please, could you tell me:
a) How thick is the lock itself?
b) How thick is the lock (when mounted) from the surface of the seatstay?
c) Where does the key go? Is it located on the right side as we view the lock on the graph paper? If so, that might be problematic in clearing the chainrings as well.

What I am trying to do is check clearances between the top of my chainstay and the bottom of my front derailleur so I can see if it is possible to mount the lock there (the conventional seatstay location is out for me, thanks to interference with the Zefal HPX pump, and I think there I may be just shy of the clearance needed to mount it to the v-brake bosses on a separate bracket...I don't think it would clear my forward rack mounting tangs).

Best, and all thanks for the great job you've already done!

Dan.

JimK:
Here are some more shots that should address your questions, Dan.

Looking at the lock width-wise:



Here is the key in the lock



and here is the key almost all the way out of the lock:

Danneaux:
Jim,

This is just terrific; I've been sprawled on the livingroom floor the last half-hour with a to-scale cutout of the lock, trying it in various places. I surely appreciate your efforts, and this latest is icing on the cake!

In your photos, could the lock have been moved down, nearer the tire? I'm guessing the inside edges have caught on the edges of the fender and that is what is limiting movement.  Also, it appears you did indeed get the model with the removable key, which I would also need if the lock is to clear the chainrings in use.

Man, it's going to be tight. If it makes it, it'll just...oh, drat. I was measuring with the derailleur on the outer chainring. I just realized that and moved it to the inside ring and there went my clearance 'cos the derailleur not only moves in, but down as well. Oh...man. Well, I haven't given up yet; I'll have to approach this from a different angle.

On a side note...Jim? The plastic mounting blocks look about a gnat's eyelash away from the tire sidewall. Are they really that close, or is it the camera angle? I suspect it's the angle, 'cos I don't see how they would extend in any further than the metal bracket part of the lock.

I sure appreciate your patience and the terrific photos and measurements, Jim; thanks!

Best,

Dan.

JimK:

--- Quote from: Danneaux on April 12, 2012, 02:58:23 am ---could the lock have been moved down, nearer the tire? I'm guessing the inside edges have caught on the edges of the fender and that is what is limiting movement. 

--- End quote ---

I think I could have moved the lock down - I don't think I was hitting any constraint in that dimension. I will take another look and report back - probably tomorrow.


--- Quote from: Danneaux on April 12, 2012, 02:58:23 am ---Also, it appears you did indeed get the model with the removable key, which I would also need if the lock is to clear the chainrings in use.

--- End quote ---

Seems this CL mount only comes with the removable key.


--- Quote from: Danneaux on April 12, 2012, 02:58:23 am --- the derailleur not only moves in, but down as well.

--- End quote ---

Yeah, that is a tight spot. But it sure would be cool if the lock could actually fit there!


--- Quote from: Danneaux on April 12, 2012, 02:58:23 am ---On a side note...Jim? The plastic mounting blocks look about a gnat's eyelash away from the tire sidewall. Are they really that close, or is it the camera angle? I suspect it's the angle, 'cos I don't see how they would extend in any further than the metal bracket part of the lock.

--- End quote ---

The camera angle does make it look bad. But the mounting blocks are a bit tighter than the lock proper.... at least the way I have it mounted, but I don't see any other way. The strap goes around the seat stay. The end that comes around the outside of the seat stay, that end passes through the slot in the lock and then through the mounting block that's connected to the other end of the strap. That end of the strap had come around the inside of the seat stay, and between the inner edge of the lock and the tire.

As I recall, the inner edges of those mounting blocks are about a finger's width away from the tire. I can try to get a measurement on that tomorrow.

The straps and blocks are only going to narrow the gap by a mm or two on either side. You can see that the lock itself is not at its narrowest at the level of the slots that the straps go through. So it seems the straps/blocks will not add any significant further restriction to the width of the tire that the lock can handle.

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