yangmusa

Many folding bikes have large diameter seatposts, including my R&M Birdy.

Do any of you know of a seatpost mounted rack that fits such a large seatpost? I've been looking around, but all the racks I've seen so far only go up to a 32mm seatpost.

(And yes, I do know there is a R&M rack made for the Birdy. But it costs $150, which I think is frankly ridiculous!)

timo888 

There's one from Delta that Xootr has modified with longer bolts. And there's the Crossrack.

And ThorUSA offers the KLICKfix and the Pletscher Orion

Regards
T

FlickaSailor

Depending on what you want to carry, you might want to check out the Topeak DynaPack or DynaPack DX. They come with 3 sets of clamp inserts to choose from to be able to handle 25.4mm to 34.9mm diameter seat posts.

I have one on the center section of my Mobiky's seat post which is 33.3mm in diameter. You can see the mount part that stays on the seat post in the pictures below. I really like this system. The DX model that I have includes 3 side-to-side divider panels and there is a large center-meshed divider that splits the entire bag into a bottom and top compartment. This divider is designed to fold easily in the middle so you can lift one end or the other to get to contents carried in the bottom of the bag. The mesh allows you to see into the bottom of the bag without having to lift the divider out of the way. The DX (larger model) also has a zippered expandable section to make the entire bag larger in case you come home with more than you left with or if you are parked, you can put your bike helmet in it...





Cyqlist got these measurements for me from his Mobiky right before I ordered mine in case anyone else could use this info.

Handlebar stem: 15/16" or 23.9mm

Seat post upper: 1 1/16 or 27.1mm
Seat post middle: 1 5/16 or 33.3mm
Seat post lower: 1 21/32 or 42.0mm

-Eric

yangmusa

I actually already have a Klick-fix extender with a huge (12 liter?) bar bag attached to the seatpost. I also have the Birdy front rack, which takes two lowrider panniers and can carry up to 10 kg/22lb.

I wasn't aware of the Delta and Pletcher racks, so thanks for the heads up. I'm primarily looking for a rack that extends downwards so that it can carry panniers for touring. It looks like Delta do another seatpost rack that could probably be modified with longer bolts just like Xootr did...

yangmusa

Bump. Just an update to note that the Klickfix extender took up so much room on the seatpost that the bike toppled over when folded. So the bar bag is back on the handlebars, which is more convenient for map reading anyway - even if it does block my front light

yangmusa

Bump #2.

Just a note to say I finally bought a seatpost rack!

I had almost decided to get the Pletscher Orion, but while I was thinking it over the price increased by 50%! (That may be reasonable given the exchange rates, I don't know).

So, I ended up getting creative and modifying a Performance Bike Transit rack to fit. I only paid $25, I wonder if they charged me for the bolt on rack by mistake? Anyway, a short trip to the local hardware store to buy a length of threaded rod and a donated quick release later - the rack fits!

The rod touches the seatpost on the front side - so I've wrapped a length of old innertube on it to prevent scratching the seatpost.

The rack goes on very quickly and appears to be very securely mounted. Time will tell... watch this space (most likely I won't update unless it fails!)

makeinu

Although the saddle looks normal length, it's really much shorter because it's noseless (the back portion is just there for UCI compliance).

jur

Just don't load it too much.

yangmusa

Yes, the packaging said 25 lb capacity. And the Birdy front rack is rated at 10 kg. I certainly hope I can pack for a day or two in less than 50 lbs!