How to mount central (two-legged) kickstand on normal bike frame I bought this kickstand, but it has grooves in the top that the instructions said should slot into the "stand plate" on the frame.



My frame looks like this: doesn't seem to have a plate of any kind, and the chainstays don’t fit into the grooves on the kickstand.



So is this kickstand a weird one that needs some kind of plate, or are all centre kickstands like this?   If so, how do I fit one to my frame - can I buy a separate base plate?  This was the only thing I could find like that..
The groves are for any cables that are routed under the stays.
Your kickstand should have come with a counter plate - B in the picture below
Your kickstand is slightly different but the mounting instructions will be the same as the kickstand below
ergotec Double-leg kickstand Double Flex 3 manual

Bicycles without a stand plate

Check if the distance between the housing of the bottom bracket bearings
on the frame and the tyre of the rear wheel is sufficient for the assembly
operation.
Now you attach supporting surface C from below to the chain stay on the
frame. If there are cables here you press these into the notches D provided
for this purpose.
Adjust the double-leg kickstand in such a way that when folded into place
there is space of at least 15 mm between the kickstand and the tyre of the
rear wheel.
Now you place counter plate B on the chain stay from above and fasten it with clamping screw A.
Tighten clamping screw A to a tightening value of 21- 23 Nm.
Finally you check that the chain can move freely. For this purpose you should
engage all the gears once.