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Frame gets weaken from shortening chain stays

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Frame gets weaken from shortening chain stays

Old 08-25-15, 08:57 PM
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Frame gets weaken from shortening chain stays

I am considering getting my chain stays shortening from 43 cm to ~ 40.
Brazing drop outs again on this Columbus SL chainstays/seatstays will weaken them?
The reason I want to shortening them is I am so far forward on the bike that I need to use a zero setback seatpost. The seat tube angle is ~73 on a 58cm frame.

Last edited by avhed; 08-28-15 at 06:14 PM.
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Old 08-25-15, 09:34 PM
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Assuming this isn't a troll... You are confusing bike fit with handling geometry. Shorter or longer chain stays have nothing to do with seat set back.

Sure there will be some stay material change when doing what you ask about. But if done by a competent person the losses are very slight. However the disconnect in the original question makes me question the competence at play here. Andy.
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Old 08-25-15, 10:18 PM
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What type of dropouts do you have?

With horizontal dropouts, you can often move the wheel forward or back to some extent. Also, shorten the space in front of horizontal dropouts, and changing tires becomes a pain.

I agree with Andrew R Stewart, however. I'm not quite sure what you will gain.

As far as your question. Brazing the frame shouldn't significantly weaken it if done at the dropouts. Many chainstays are tapered, so cutting a few cm off could make your dropouts not fit quite right. You'll also have to decide what to do with the seat stays that will now be at the wrong angle.
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Old 08-25-15, 10:40 PM
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I suspect a sense of history is indicated here. Judging from the limited info given, I suspect that the 73° bike is of an era where a setback post was the norm, and I don't see the issue. Except maybe the use of a more modern non-setback post in a frame whose geometry was designed for one with setback.

Then there's the issue that moving the rear wheel forward won't do anything for the rider's position which isn't dependent on chainstay length in any way.

I think the OP has to go back to the drawing board and figure out what he's trying to achieve before considering the implications of an action that may not be warranted in the first place.
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Old 08-26-15, 09:29 AM
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just doing a 'bris' on the end of the tube , and bending the seat stay ,

brass melts at a pretty low temperature, But,

more heat seems required to melt the brass to pull stuff off than put it on, for some reason ..
Typical Repair, you will cut the dropout in half so as to only have to heat the individual joint with it and the frame tubes.
while Pulling with the pliers ..

the question remains Why does a 1/2 " matter so much?

Last edited by fietsbob; 08-26-15 at 09:33 AM.
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Old 08-26-15, 09:56 AM
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And then, unless you are sponsored it is quite possible most bikes are better with longer stays.
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Old 08-27-15, 07:02 PM
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Originally Posted by Andrew R Stewart
Shorter or longer chain stays have nothing to do with seat set back.

My bike fit is affecting handling geometry.The weight distribution is what I am trying change.
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Old 08-27-15, 07:13 PM
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Originally Posted by CliffordK
What type of dropouts do you have?

With horizontal dropouts, you can often move the wheel forward or back to some extent. Also, shorten the space in front of horizontal dropouts, and changing tires becomes a pain.

I agree with Andrew R Stewart, however. I'm not quite sure what you will gain.

As far as your question. Brazing the frame shouldn't significantly weaken it if done at the dropouts. Many chainstays are tapered, so cutting a few cm off could make your dropouts not fit quite right. You'll also have to decide what to do with the seat stays that will now be at the wrong angle.
Campagnolo 1010/B horizontal dropouts
If I shortening the space, I will be switching to vertical dropouts.
If cutting a few cm off will make the chain stay to dropout fit worse, I better leave it.
I thought the seat stays could be bent to the right angle. I read about some doing this successfully, so I am just gathering information.
Thanks for the replies.

Last edited by avhed; 08-27-15 at 07:18 PM.
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Old 08-27-15, 07:31 PM
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Well with horizontal slots the op have the ability to experiment and go through his own discovery. Remove the drop out/axle positioning screws and install the rear wheel all the way back. Ride the bike. the slide the wheel all the way forward. Ride again. What is the difference you feel? Report back.

As far as body fit effecting bike handling (and NOT the geometry, that's set in steel...) duh! Andy.
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Old 08-27-15, 11:05 PM
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The 1010b are the medium/short dropouts, right?

I was looking at a couple of my bikes. Clearance varied considerably from bike to bike.

My Colnago was made for 700c (equivalent) tubular tires. Clearance is pretty tight with the wheel moved all the way forward.

My Mercier has a LOT of clearance. I got it with 700c wheels, but I'm not sure if the originals were 27". The 700c seem to fit it well, but there is a LOT of clearance.

Both my Motobecanes have 27" wheels. Depending on the tire choice, the clearance is minimal. There is a bulge in the chainstays for the tires, and the chainstay spacer is pretty close to the tires. So, if one mounted small 700c tires, there may be some room for moving the tires forward, otherwise I'd leave them alone.

Nonetheless, go ahead and try adjusting the wheel position in them as suggested above. Also, find as steep of hill as you can find, with the wheel set as far forward as possible and the seat as far back as possible. Try climbing the hill seated just to see how the bike handles.

Some of the vertical dropouts are shorter than the corresponding horizontal dropouts, so that will naturally move the wheels forward slightly. I'd choose dropouts that are brazed in place rather than tig welded.
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Old 08-28-15, 05:15 AM
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Originally Posted by avhed
"... The reason I want to shortening them is I am so far forward on the bike that I need to use a setback seatpost. ..."
What's wrong with setback seat posts?
Don't 90 % of bikes use a setback seatpost of some kind ?

Last edited by Homebrew01; 08-28-15 at 08:18 AM.
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Old 08-28-15, 06:15 PM
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Originally Posted by Homebrew01
What's wrong with setback seat posts?
Don't 90 % of bikes use a setback seatpost of some kind ?
Sorry I left out the word zero in front of setback.
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