So there I was, riding along no handed up a slight hill in downtown Los Angeles when all of the sudden, I wasn't sitting upright, but rather falling backwards. I stuck my right hand out to break my fall, breaking my right thumb at the joint. I get up to find this:



The seat tube extension broke off at the top tube. Thankfully, Steve Lubanski, owner of my LBS (Open Road Bike Shop) and bicycle inventor came up with a solution:



It's an expander wedge, just like a quill stem. This cost me only $40 (with the little seat adapter thingy) versus quite a bit more to replace the steel tube (reynold 853). Thanks Steve!

EDIT: Does anyone want to buy a CF corima post? Think of it this way, it was STRONGER than reynolds 853 steel, so it's in MIGHTY fine structural condition.

call me traditional, but that looks like a bad idea.
but then again, your orginal seatpost screams bad idea already - 1cm past the max extension line on a seatpost that doesn't pass the top tube......
WTF DID YOU THINK WOULD HAPPEN?



from that last pic it looks like you only have about 3-4 cm on post/quill inserted. who want to take bets on when this is going to happen again?

yikes that is shallow. its only got about an inch in the tube. wow

Icky. Run the proper length seatpost, and stuff like that is much less likely to happen.

It's the little things, people. The little things.

I think the idea behind making the second one that short is so that the wedge (and the the "meat" of the seatpost) is at the seat tube/top tube junction, which is stronger than the paper-thin middle of just the seat tube. How much do you think it would cost to replace the tube? I'm guessing that's the only real solution.

I thought this was a great temporary solution, however.

ah.. you do notice that if the first seat post had been in further.. it would have been in past where it broke off.. thus, adding strength to the tube..instead, being out so far, it was basicall a tube snapping lever.. oops

is that the gt?

is this the reason youve been m.i.a. all summer?

That and because he's lame.


And a camp counselor...like me....but lame.

leave it up to the inventor of one of the dumbest pedal systems ever to come up with that kludge.

you're looking at megabucks to have that replaced. $100+ plus paint if it was lugged. Since it's TIG, then who knows.

how about this...
could you slot the end (the new top) of your seat tube and have a binder welded on?, you might not have to replace the whole tube, provided that that junction isn't at one of the butted bits.

then put in a proper sized seatpost.

Come on guys 'n girls. Do not pull out onto the highway when the 'oil' or 'brake' light are on in the dashboard.

that, right there, is the stupidest thing i've ever seen anyone do with a seatpost/seat tube. the max height line is there for a reason, and i don't think a seatpost that short is designed to be used in a frame where the seat tube extends 3 inches above the top tube.

i think i saw a 3Rensho once with about a foot of seat tube above the top tube. it was also a TT "funny" bike. and also very stupid.

you hardly ever have to worry about a seatpost breaking under normal riding circumstances. even *gasp* a carbon post. the tubing of the frame is much thinner than the tubing used for a seatpost. they're basically indestructable, as long as they're being used properly (not inserted too shallow, not cutting a carbon post, not clamping some dumb QR rack to a carbon post, not exceeding the weight recommendations for said rack-even on an alloy post this is dumb-, the list goes on and on).

Thanks. I think at the time I thought that was the maximum you should insert the seat post. It didn't really make sense that it said "max" but meant "minimum." I guess I wasn't considering that it meant "maximum you can pull it out" rather than "put it in."

EDIT: Also, the tube is REALLY REALLY thin at that junction, which is why I didn't just slot it and weld on a binder.

Must. resist. crude humor.

do you have any shots of the whole bike broken?

then you're a bit fux0r3d, eh?

yet you still think it's a good idea to wedge 2 cm worth of post in that exact same place?

It's a pursuit bike. Of course it's a good idea.

C'mon, lightning never strikes twice!

the max, means max height, as in, this is the maximum height that you should put your seatpost at. you could take it to mean that "this is the maximum amount you should insert the post," but then, that wouldn't make a whole lot of sense, given that most posts are between 250mm and 400mm long.

although, with that corima post, i suppose it could mean that...since the area where it's written is flat, and you wouldn't be able to clamp it. that still doesn't change what sloppy robot said about it being a giant seat tube breaking lever.

the expander wedge thing just looks dangerous as hell. frame: dead. it's gone. PASSED ON! that is an EX-bicycle frame.

"Max" lines are typically too near the end of the post anyhow. You need an inch and half, preferably two inches of post beyond the bottom of the toptube/seatube junction.

That or risk, ah, failure.

How long did that take to break? I mean, did you ride it with a post that short in an extended seat tube frame for long, or just a weekend?

-brad

I want to say 9 months, but it might have been a little bit less. This is daily riding, 40 miles or so a day, on average. Also, a lot of sitting up (thus putting pressure on the front of the tube).

I think I'm going to go with the "lightning doesn't strike twice" idea. I don't wear a helmet, and I do stupid sh1t in heavy traffic. Obviously, I don't care about my health, or my bike. Ride on!

wow...have fun...and would you mind if I take out a life insurance policy in your name?

I've already come to terms with the fact I will have to scrape my best friend's brains off the road one day. It gives me a nice warm fuzzy feeling at night.

When did he do that? Was it Sunday?

I don't even think this system even could be categorized as a 'pedal'. I almost thought it was some kind of joke, but there appears to be way too much content to be a hoax. Has anyone here actually tried this? I love it when people invent wierd stuff.

Well, it has independent lab tests (which is where he got the 3-4% increase in efficiency figure). They're not for sale yet (though he has a bunch of boxes at the shop). I've tried them out, and there's a noticable difference, I think, but it's hard to tell with such a limited testing period. If I started track racing, I would consider asking him for a pair, just for kicks. Anyway, a few people who have ridden them competitively think they're awesome, and I see no technical reason why they wouldn't be better.

This is like Shimano's dynadrive pedals. The downside there was you needed special cranks. That's pretty much why they didn't catch on. I think he might have a good idea, if the marketing goes right.