Drilling holes in CF frames to save weight

Discuss light weight issues concerning road bikes & parts.
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HanSolo
Posts: 467
Joined: Mon Jan 15, 2007 7:59 am
Location: Northern California, USA

by HanSolo

Hi,

I am interested in drilling holes through the seat tube of my Kestrel Evoke to save weight. It looks like a sturdy bike and I feel that the seat tube is not very structural....any thought? How about the top tube?
Everything can be drilled, except tires.

by Weenie


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Stolichnaya
Posts: 2614
Joined: Wed Oct 06, 2004 6:55 pm
Location: Vienna, AUT

by Stolichnaya

Are you serious? :roll:

Drill away and see what happens. You'll enjoy picking out a new frame when the current one unravels.

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$mokeyJoe
Posts: 694
Joined: Thu Mar 10, 2005 2:27 pm
Location: Belgium

by $mokeyJoe

You're kidding, right?
It'll look pretty cheap and not done!
*Light is beautiful*
BMC SLC01 5900g ... Litespeed Vortex 6300g ... Merida Carbon Lite 7000g ... Velocite Selene 8000g ... Argon18 E114 +/-8500g ... Trek 1500 9500g

Greg66
Posts: 242
Joined: Mon Sep 26, 2005 8:06 pm

by Greg66

No, no, I disagree with the previous posters. Go right ahead. Put as many holes in it as you can. Try some in the chainstays too. And the headtube. And the top tube, especially around the junctions. Be sure to report back with the results. I'm already excited at what will happen. :twisted:

CP
Posts: 565
Joined: Sun Oct 19, 2003 12:49 pm
Location: Arbaz, Switzerland

by CP

GO, GO, GO HanSolo,
then you will have to buy my C50

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ergott
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Location: Islip, NY
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by ergott

I think it will be fun to see what happens at someone else's expense. Be sure to post pics.

If you have carbon wheels you can reduce the weight by drilling out the sidewalls. Gotta reduce that rotating mass;-)

-Eric

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zebragonzo
Posts: 949
Joined: Thu Oct 18, 2007 7:35 am

by zebragonzo

Rotating mass is most important and tyres are far too heavy, try putting some holes in them too.
:roll:

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Mario Jr.
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Joined: Sat Jun 12, 2004 8:49 am
Location: Denmark
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by Mario Jr.

Don´t forget to drill the bottles.

GrahamB
Posts: 1343
Joined: Sat Oct 13, 2007 7:16 am
Location: Lyon, France

by GrahamB

It would depend if you drill them front-to back, or side-to-side. Both will save weight, but the lateral drilling will cause greater drag. Hence you will have an advantage only on grades above 12.6%, excepting the presence of a significant cross wind.

More advantageous would be to remove the seat-tube entirely with a hacksaw, cutting just above the BB and below the top-tube junction. This will also improve ride quality, but may make the bike ineligible for UCI-sanctioned events.

I've found surprisingly large weight benefits in drilling my bidon...
Graham

ParisCarbon
Posts: 816
Joined: Mon Feb 05, 2007 5:39 am
Location: Winnipeg Canada

by ParisCarbon

This is a joke.... I hope?? :roll:

Franziskaner
Posts: 165
Joined: Thu Nov 04, 2004 3:09 pm
Location: Trail somewhere in Germany

by Franziskaner

First off, big drill-bit budget drilling holes in epoxy...

Absolutely crazy... but good for a laugh on a Sunday aternoon
mountainbiking - the next best thing to sex

stumpytrunks
Posts: 1140
Joined: Tue Nov 30, 2004 4:25 am
Location: Tas, Aus

by stumpytrunks

I think the only amusing thing is the mockery that is being heaped upon someone who is thinking of doing what this forum used to be about. I'd wait for someone who knows what they're doing to comment before doing anything but I imagine that the chainstays would be a good option for small holes. Good luck with it.

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zebragonzo
Posts: 949
Joined: Thu Oct 18, 2007 7:35 am

by zebragonzo

Drilling holes in metal is a completely different matter. Metal has the same properties in all directions and so there are some areas that have lots of redundancies(/safety factor etc) built in. Carbon Fibre is a different beastie all together; layers are put together so that a minimal redundancy is present.

The only things that you can remove some material on it those things that bear no loading like headset spacers. NB. I've never understood why no one castleates spacers?

RollinOn27s
Posts: 1003
Joined: Thu Oct 06, 2005 4:17 am

by RollinOn27s

stumpytrunks wrote:I think the only amusing thing is the mockery that is being heaped upon someone who is thinking of doing what this forum used to be about. I'd wait for someone who knows what they're doing to comment before doing anything but I imagine that the chainstays would be a good option for small holes. Good luck with it.


Sorry, but no one here has ever drilled holes in carbon fiber frames to lose weight. No one. Never.

stumpytrunks
Posts: 1140
Joined: Tue Nov 30, 2004 4:25 am
Location: Tas, Aus

by stumpytrunks

Agreed, maybe not the best idea, but the idea is what used to make this site. In my thinking you would only be breaking the strands of carbon that you are drilling through, and with small holes you probably aren't going to stuff up too much, structurally speaking, if you are drilling out low stress areas.

Bad idea or not, if he/she is willing to do it and knows the possible consequences, what can be the problem. It's worth a try.

by Weenie


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