knotty

Wondering about those seatpost attaching racks, are there any disadvantages? will it damage a carbon seatpost? and how much weight will they take?

Been wanting to fit my underseat wedge contents (tire patch kit, tube, multi-tool) a camera, and little food into a single pack. Not very much weight at all for just longer day trips.

Thanks..knotty

cooker

The one I had rode too high under the seat, which forced me to load any bulky stuff well back, and the rack eventually snapped at the junction with the seat post clamp. If you have a compact frame/slanting top tube it will fit better, because it can mount farther down below the seat. And they may not be a good idea for a carbon post because they might crush it. I assume you would have to be carefull of overtightening it, just like with the components on a carbon frame.

swc7916

You might take a look at these bags: https://detours.us/index.php?cPath=33

I have the Bobtail on a carbon seatpost and it is big enough for my purposes. I don't think that I would use a larger bag than this one. It does bounce on rough roads however, and I lost a taillight that was just clipped on the provided strap.

supcom

I think you will find that seatpost makers generally do not recommend clamping their racks to a carbon fiber seatpost. That's not to say that it isn't done, but there is a risk. Of course, you can swap out the seatpost to be safe.

Other than that, they work fine, though they are all fairly limited in max weight. Topeak's racks are very nice because their companion trunks slide on and off the rack in an instant without fiddling with velcro straps.

while the detours bags look nice, even the largest of them is limited to 5 lbs weight, according to the maker. 5 lbs?! Most seatpost racks will handle 20 lbs.

wahoonc

Don't work for me...I have broken a couple of them, but then again I have a tendency to overload things

Take a look at a Bagman rack too. It would attach to the saddle rails and you wouldn't have to worry about your plastic seat post being crushed or cracked.

Aaron

CastIron

Any one have/used/seen used in person the Moots Tailgator?

Chris L

Nope. Save your money.

I've been down that path. If you put any weight at all on it, you can expect a long walk home from the middle of nowhere -- either that, or trying to rig up your saddle after breaking the seat post. If you're carrying anything substantial, you need to get a rack that mounts to your frame. If you're carrying anything light enough to be supported by a seat-post rack, it will probably fit in your saddle bag and jersey pockets.

lechat

i have a cheap nashbar ascent rack and nashbar basic trunk bag <$30.00. and it's fine for running to the store and such. the rack has a QR and rubber collar for my 27.2 post. it's fairly light and is rated for 25 lbs. wouldn't use it for touring or anything like that but it beats a backpack.

knotty

Thanks for the replies all, yes Chris L, my main concern about the seatpost racks was the unsupported weight (the trunk bag) on the end of a rod essentially clamped to the seatpost, just bobbing there with every vibration of the bike. Something like a torsion bar.

Now, if there was a support truss going to the bike frame, seems it would take a lot of the load off the seatpost but then you would have a regular rack.

Oh well, back to the original idea, the frame bolted rack.

Thanks!..knotty

supcom

My Topeak rack is very stiff and with a normal load (less than 20 lbs) is does not have any noticeable bob to it. It's really a non-issue on regular roads.

For really rough roads or trail use, I would go with a conventional rack or a large saddlebag.

bifo

I have a seatpost rack purchased from Performance. The max load is 25lbs. You'll need to torque the mounting bolts pretty tight to get a solid non-squeaking fit, so I wouldn't recommend it for a carbon post. Coupled with a cargo net, it's great for running to the store or to carry a sweater & lock.

Here's a pic
https://i218.photobucket.com/albums/c...SC00003c-1.jpg

swc7916

The original poster wrote:

I interpret that to mean that they wanted something larger than an underseat wedge, but not much larger. AND they wanted to use it on a carbon seatpost. Would you advise hanging 20 lbs on a carbon seatpost? I wouldn't. To me, the Detours Bobtail fits the bill, since it is not too big and the lower weight capacity will help ensure that it will not damage the seatpost.

Boudicca

I have a slightly smaller version of this https://www.bikemania.biz/Vaude_H2O_W...ude_722190.htm which is very neat -- it clicks on and off the seat post really easily and fits a jacket, some snacks and a few other things -- just enough for a day ride when you're not sure of the weather. It's been stable so far. Right now I am looking for a second clamp so I can move the bag from one bike to another without taking the whole seatpost out.

I'm not sure I would use it with a carbon seatpost though.

Boudicca

Actually this is a better picture (and the actual bag).

https://shopping.canoe.ca/shop/produc...d_2857341.html

Pepper Grinder

Post #2: https://www.bikeforums.net/commuting/191491-no-eyelets.html