Touring - Lightweight seatpost rack? On carbon seatpost?

This is kind of off-topic, but I figure the folks around here know a lot about stuff like this. I'm currently building up a Specialized Allez frame to be my "fast" bike - for weekend rides and centuries. My other road bike is a Surly LHT with racks, fenders, and a double-stem setup. I've been using it on my weekend rides. With all that stuff on it, I can carry a sandwich, a book, an extra shirt for cold weather, tools, etc. But, as you can probably surmise, it's HEAVY!

My goal in building up the Allez is to have a much lighter ride. So I'm trying to resist the urge to load it up with all sorts of crap, like I tend to do. However, I still want to be able to carry a few things, like a book and a sandwich. One of my favorite rides involves a stop halfway through at a nice, quiet park. I eat my sandwich and read my book for an hour, and thoroughly enjoy the moments of peace and lack of stress.

Is there a seatpost rack that is lighter than most? Can you put a seatpost rack on a carbon fiber seatpost?

My other option is an old Blackburn Expedition rack I have. It's pretty light. I also have a collection of rack trunks, some of which are light.

What would you do?

I've got a seatpost rack, and it sucks. It sits so high up that it throws off your weight distribution, and it also tends to slip. I would recommend a large seatbag, such as the Carradice Barley or similar bag sold by Acorn. The Barley will hold as much gear at the typical rack-top bag, but the weight is much better distributed. You hardly know its there. It works better with a bag rack such as the Carradice Bagman or similar racks sold by Rivendell and Velo-orange.

Is there a seatpost rack that is lighter than most? Can you put a seatpost rack on a carbon fiber seatpost?

What would you do?

Personally I wouldn't run a post rack on a CF post. They clamp on and I'd be worried about fatigue. I'd run a rear rack if you have the connections on the dropouts, and there are brackets that go on the seatpost to mount the front brackets to if you don't have the provision on the seatstays. That way the seatpost ony serves to steady the rack instead of being weight bearing.

-R

Some people like the seat post racks but they don't install them on a carbon seat post. I've read of broken carbon seat posts, plus the load is more easily shifted or twists the seat post.

I use a lightweight rear rack and trunk on my old steel road bike. The bike is only a little heavier than my lightweight road bike. It's very comfortable and easy to carry extra clothes, rain coat, food, water etc. It's also faster and easier on a long ride compared to my heavier touring bike. I would try to make do with the rack you have. Good luck.

Thanks. I think you're confirming what I was thinking.

I've got a seatpost rack, and it sucks. It sits so high up that it throws off your weight distribution, and it also tends to slip. I would recommend a large seatbag, such as the Carradice Barley or similar bag sold by Acorn. The Barley will hold as much gear at the typical rack-top bag, but the weight is much better distributed. You hardly know its there. It works better with a bag rack such as the Carradice Bagman or similar racks sold by Rivendell and Velo-orange.

+1

Bagman + Carradice seat bag.

Right now they are pretty reasonable is you just buy direct from the Carradice site in the UK.

I wouldn't use a carbon seat post under any circumstances. A Thomson seat post weighs about the same, costs less and doesn't break if you tighten the clamp a quarter turn to much.
That said, I think I would just get a small backpack or Camelbak before I would resort to a seatpost rack. I can get a sandwich and paperback in the pockets of my jersey.

I enjoy a rack for the same reasons you mentioned. I just mounted a seatpost rack yesterday on my new Specialized Roubaix. After reading of crushed CF seatposts searching BF, I replaced the carbon fiber seatpost with a Ritchey Comp aluminum post. Couldn't really feel any difference in weight just hefting them. Seatpost racks sit too high for aesthetics, but my bag is low enough to keep the whole thing level with the seat. Much prefer a rack with "legs", but the Roubaix has no eyelets, and I'm not clamping any adapters to the CF chainstays. All in all, it works like I want it to, even if it isn't a classic look. Much cheaper than the large bags, and instantly available for the instant gratification crowd. :) Years ago, everyone made a nice nylon or Cordura under-the-seat bag that was maybe 10" wide or so. Seems like one could be made and marketed for $45-50 easily by Eclipse, or such companies. Hard to believe the demand isn't there. But I guess it's not. Ricky Racer is happy with his wedge, and there's not enough of the rest of us, it seems.

My thinking in getting the carbon seatpost was that it might dampen some of the vibrations I've heard come with an aluminum frame. Was I foolish? I've only had steel frames before, except for my mountain bike which has fat tires and suspension forks. I'm sure I'll know a lot more after I've finished assembling it and have ridden it a few dozen times. I'll probably look back at some of the questions and concerns I've had and laugh. But this is now and that will be then.

Going with wider tires will dampen the vibration much more than a carbon seat post. I am not even sure there is any truth to the theory that a carbon seat post dampens vibration any more than Buzzkill bar ends or Zertz inserts. It is all about marketing.

There's no performance benefit to using a CF seatpost. I can't say for sure about comfort, but I expect you'll do better with the right saddle than with a CF seatpost.

One thing to keep in mind is that aerodynamics will slow you down more than weight. As far as I can tell, a Topeak DynaBag is probably the best compromise between storage capacity and aerodynamic profile.

Other things you can do to increase comfort include using Fizik bar-gel, and getting a CF fork.

Get this http://www.axiomgear.com/product/racks/rear_low_profile_aero_racks/product.php?id=140

I agree that a seat post rack on a carbon seat post is risky. I have used the Caradice Pendle with a Bagman Rack (the rack mounts on the seat so it's okay) but agree that it throws the balance of a light bike off (although you get used to it). Now-a-days I have removed the Pendle and reverted to a small fanny pack which seems to be the best compromise.