An Abus Bordo Granit X-Plus 6500 is the top of the line of Abus folding locks. It can secure the frame and rear wheel of an ST2 to a bike rack, but not both wheels unless you buy a second one. They are sold in black, red and white versions. To mount the Abus lock holster to the water bottle bosses, I used two metric stainless steel button head cap screws, size M5-0.80 x 20. I also added nylon washers as spacers between the down tube and the Abus lock holster because the holster has curved ridges designed to mount to a round frame, and as you know the Stromer down tube is relatively flat. The right metric threading for the water bottle mount screws is critical or you risk stripping the threads, so be careful to buy the right ones. Also, since the screws are going into the frame close to the battery compartment, they can't be too long. The M5-0.80 x 20 size takes into account the nylon washers I used. The original button head cap screws on your Stromer are fine for water bottle cages, but way too short for mounting the 6500 holster. I was assured by Stromer that the weight of the lock wouldn't be a problem, with further assurances coming via internet photos of ST2s from European owners. They appear to be a favorite lock for Stromers on the continent. Attached is a photo of my white ST2 with a white Granit X-Plus 6500.
No lock is theft proof. Battery powered angle grinders have seen to that. So you never want to park your expensive bike outside overnight (Abus or no Abus), and otherwise you need to use your discretion where you park your bike during the day and for how long. Of course, using the lock mode on the ST2 is also a good idea, but it doesn't offer complete backup protection if someone cuts through your lock. By the way, to prevent myself from inadvertently tripping the theft mode, when I park my ST2 I wrap a yellow spiral plastic wristband (the kind designed for key rings) around the left brake lever and the bar grip to remind me not to move the bike while it is in lock mode. It has prevented me from making this mistake on more than one occasion when I'm distracted by other things.
Congrats on your new ST2, and I hope your battery issue is in the past.
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