I have seen there are some quick fastener backracks to clamp to the saddle tube and quickly got told that they are not very stable. i am looking for a back rack which can be added occasionally on a quick desicion without a big montage just when i feel i need to add a little weight but nothing heavy duty, so does anyone have some experience with something similar to that and knows some good products matching for pretty much any 20" foldable - not extending too much for example? I have read that the original backrack usually carries around 25 kg max, and has to be screwed onto the frame. i guess i'll never have that much cargo with me anyhow, i am thinking about adding 10 kg at the very most. e.g. small bag with jacket, food, and other accessories. anyone is experienced and happy with these kinds of back racks? i guess the quickrelease won't be able to support much or with more weight will bent downwards.

Xootr crossrack or Klick Fix both work well.

Whoever told you that is wrong. I have the Tern seatpost rack that ThorUSA.com sells and it works great for the kind of load you're describing.

Oh,...I need to upgrade to this. I get hit in the inner thigh with my current one. Sux,...this solves the problem.

thanks for the replies, yeah, the other local forum consists of only about like 5-10 people who are left as "active users" who are all kinda moderators or users with 2000+ posts - i assume their advisory is pretty much nailed into stone, what they don't have or like is bad by default? the rack on thorusa.com is supposed to carry 10 kg... need to weight what a small rack of beer weights :O here in my country we have a handy box of beer with 11 x 0,5 liter bottles which seems to fit perfectly on a back rack ... other than this, i'll take a look if that seatpost rack is available here too.

10 kg works out to about 22 pounds where I live, which should handle a 12-pack of beer. The weight limit seems arbitrary to me anyway; they're trying to determine a limit at which the beam will stress at the joint, or the rack will bend the seatpost.

I say wrap the post with some cloth handlebar tape, clamp the rack on there tight at the bottom of the post and plop your beer on it. If you start hearing some aluminum creaking noises, stop and drink a couple!

I am not drinking beer. That was just an example. So anything below 10 kg should be fine.

Ok, don't drink the beer.