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PostPosted: Sat Oct 20, 2012 11:08 am 
Old School Hero
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Joined: Fri Aug 14, 2009 12:28 am
Posts: 200
Hello all,
My girlfriend and I have recently purchased a Mercian tandem(not yet finished the build, lots to change). We are really excited about going for long rides and possibly setting it up for touring at some point.

Image

Unfortunately the last owner had used a 26.6 seat pin in the rear seat tube and not 27.2. Due to the clamp being over tightened it has caused a crack into the frame around 1cm deep. While looking at the frame I noticed another around 5mm deep on the front seat tube also. We are reluctant to use it until we have sorted the problem, so that it doesn't get any worse.

Image

Question 1:
Some people have suggested drilling a 3mm hole below the crack and filing down the crack to meet the hole. Has anyone had any experience of this? It fills me with fear just thinking about it.

Question 2(three questions):
Maybe it would be best to take it to a frame builder? Anyone recommend a frame builder in London? How much would i be be expected to pay for this?

I would really appreciate your collective wealth of knowledge on this.

Thanks,
Luke


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PostPosted: Sat Oct 20, 2012 12:25 pm 
Retro Guru

Joined: Sun Aug 22, 2010 7:07 pm
Posts: 1324
Location: Cotswolds
From what I can see the rear crack is in the seat lug, with the correct seat pillar it should not matter. Are you sure it's 27.2, this would mean it's built with solo bike butted tubing, 23g at the top. I would have expected a thicker tube.


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PostPosted: Sat Oct 20, 2012 12:25 pm 
Retro Guru
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Joined: Wed Apr 25, 2012 2:08 pm
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Location: Shrewsbury
For what it is I'd go with drilling a small hole at the end of the crack, that will stop it moving any further. You could get it welded but that's going to cause all sorts of paint issues.


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PostPosted: Sat Oct 20, 2012 12:54 pm 
Old School Grand Master
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Joined: Fri Oct 14, 2011 8:41 pm
Posts: 8246
Location: Cumbria
The crack has nowhere to go as long as the seatpost is correct....... if worried I'd drill a small hole and run a junior hacksaw blade down to it and then protect against rust...

Lovely looking frame......doesn't look built for touring though :D

Shaun


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PostPosted: Sat Oct 20, 2012 1:13 pm 
Old School Hero
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Joined: Fri Aug 14, 2009 12:28 am
Posts: 200
Thanks for the advice.

@keithglos, This is the spec from the mercian website. Would seem to indicate a 27.2 seat-pin.
Image

@Robbied196 and midlife, thanks for the push. Looks like its time to bite the bullet........I will dill a hole and saw down to meet it. Wish me luck. Fingers crossed.......

I should have said, a light tourer......This is the bike in the guise it arrived. It's not a TT tandem either......for the most part, i want to use it for rides in the country, charity events and pootles about town with my girlfriend......but it could return to its racing past if i can convince my lady.
Image


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PostPosted: Sat Oct 20, 2012 5:17 pm 
Old School Hero
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Joined: Mon Oct 15, 2012 11:12 pm
Posts: 201
Location: Herts/Essex border
The crack is not that bad so I would go with the suggestion of removing the seat pin and drilling a small hole at the bottom of the crack to stop it spreading further down. Some frames are pre-built with this hole already there so it is a known problem. Then touchup the paint to stop rust.
If in doubt contact the people who built it Mercian Cycles, Derby :

http://www.merciancycles.co.uk/


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PostPosted: Tue Oct 23, 2012 2:18 pm 
Old School Hero
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Joined: Fri Aug 14, 2009 12:28 am
Posts: 200
Thank you for all your advice. I have started documenting the progress of the tandem build. if you are interested you can follow it on this link.
https://www.lfgss.com/thread95400.html


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