Drilling a steel classic road frame like swiss cheese...still safe to ride?
#52
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My point of contention was moreso your declaration that a drilled out frame would be safe for no-fat GC rider, but not for a Clyde. Without knowing the design and condition of the generic vintage frame that is to be used, the metallurgical and mechanical engineering aptitude of the one choosing what size holes in which quantity are going where, and the equipment being used to make said holes, I really have a hard time understanding how one can put that safety limit where you put it.
We both know that rider weight affects the factors that will distort or cause failure in a frame so why is it wrong to make the comparison. My intent had more to do with to what extent he could go to lighten the frame. More if the rider is light and less if the rider is heavy. Which is what you agree with me on in your next statement.
The risk is only to the OP. If they are competent enough to drill holes in the frame, they probably have enough intuition to tell if they've gone too far.
I was wrong about the OP wanting to do it for novelty. I re-read the post and they want to ride paved trails and commute. That is still a maybe it's okay and maybe it is not. My trails maybe. Your trails, maybe or maybe not. My commute, probably not. Your commute, I don't know.
Don't think me bad to argue with you. I actually have more respect for people that are willing to argue. In fact my closest friends are people I argue and nitpick about everything. I have had my opinions on things changed by supported argument.
#53
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That is a huge assumption. And 99.9% likely to be wrong. Once someone makes the decision to start drilling holes the size of half the tubing diameter in a bicycle frame, they've already gone too far.
#54
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It's okay for you to assume but I can't?
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The problem with these types of posts? If the question has to be asked, the OP probably doesn't have the knowledge required to actually do it safely. I generally err on the side of not encouraging people to do things that can seriously hurt them, if they don't have the skills to do it without asking very basic questions.
#58
Calamari Marionette Ph.D
Yes.
That is absurd. It's a recipe for disaster. Period. Any other notion is insanity or stupidity.
I'm not making any assumptions. I know what I read. A person that will drill multiple large holes in a standard steel bike frame is not competent to make a good decision on when to stop, because not starting is when to stop. That's neither an assumption nor an opinion, it's a fact.
Still it may not be an issue depending on how many.
It's okay for you to assume but I can't?
Last edited by SquidPuppet; 08-23-17 at 12:23 PM.
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Maybe an idea for Science Channel Mythbusters.
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Successful troll is successful.
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You should totally do it, if only for a cool looking frame. Please post pictures I want to see it!
If I were to do it, I think I'd do it only in the horizontal plane (as the picture above did.) I think drilling vertical would weaken the frame too much in the direction of the majority of the force.
If I were to do it, I think I'd do it only in the horizontal plane (as the picture above did.) I think drilling vertical would weaken the frame too much in the direction of the majority of the force.
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There is a lot of tubing analysis, crash analysis, and etc available. High quality tubing has been butted for years, as people realized mid-tube strength was less important than that at the ends of the tubes.
If I was to do it, I'd probably start a few inches back from the head tube (frequently bent), and bottom bracket (high stress area).
If I was to do it, I'd probably start a few inches back from the head tube (frequently bent), and bottom bracket (high stress area).
However the middle of the tube has to survive forces from both ends, with the length of the tube being a lever. The middle of the tube is allowed and expected to flex a little --- and drilling it would mean that that bend and flex would break the tube.
I'd say, everyone who wants to tell this guy it is safe and a good idea, should prove it on their own bikes. We can always find more posters.
(Russian Roulette? It's perfectly safe 80 percent of the time. Go for it.)
#64
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You should totally do it, if only for a cool looking frame. Please post pictures I want to see it!
If I were to do it, I think I'd do it only in the horizontal plane (as the picture above did.) I think drilling vertical would weaken the frame too much in the direction of the majority of the force.
If I were to do it, I think I'd do it only in the horizontal plane (as the picture above did.) I think drilling vertical would weaken the frame too much in the direction of the majority of the force.
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"I had a great ride this morning, except for that part about winding up at work."
Bikes so far: 2011 Felt Z85, 80's Raleigh Sovereign (USA), 91 Bianchi Peregrine, 91 Austro-Daimler Pathfinder, 90's Trek 730 Multitrack, STOLEN: 80 Schwinn Voyageur (Japan)
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Maybe the next time there is a $5 Free Spirit sitting at the thrift shop, I'll have to buy it...
#66
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+1, and besides we want to watch so be sure and mount your GoPro! Especially interested in the clips of "whistling like a banshee at speed".
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Why worry about precision drilling?
https://www.bikeforums.net/classic-vi...y-ads-583.html
https://www.bikeforums.net/classic-vi...y-ads-583.html
cannondale police bike - $100 (scottsboro/grant)
"well i have this old cannondale bike for sale that may or may not have a hidden story behind it? ....not that its a cannondale!..and not so much that its a police bike!!.....but the fact that it contains a bullet hole in the frame just in front of the seat......now why does it have a bullet hole? i have no idea!!!...is it tied to the fact that it was a police bike? was the rider of this bike being shot at? we may never know!!.... but one thing is for sure,it does have a super cool character mark....now the bike is a fixer upper needing the tires aired up (i have never checked to see if they even hold air) it will need oiling and adjusting!..this has a 18.5" frame...so whoever buys this bike is getting a cannondale police bike with a bullet hole that needs some tlc.....the price is $100.00 firm to some this may sound high to others this will be a bargain....but!! rest assured you will be the only one on the block with one LOL!!"
"well i have this old cannondale bike for sale that may or may not have a hidden story behind it? ....not that its a cannondale!..and not so much that its a police bike!!.....but the fact that it contains a bullet hole in the frame just in front of the seat......now why does it have a bullet hole? i have no idea!!!...is it tied to the fact that it was a police bike? was the rider of this bike being shot at? we may never know!!.... but one thing is for sure,it does have a super cool character mark....now the bike is a fixer upper needing the tires aired up (i have never checked to see if they even hold air) it will need oiling and adjusting!..this has a 18.5" frame...so whoever buys this bike is getting a cannondale police bike with a bullet hole that needs some tlc.....the price is $100.00 firm to some this may sound high to others this will be a bargain....but!! rest assured you will be the only one on the block with one LOL!!"
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So.... what is the answer if one finds a crack in their bike?
Drill a hole in it
I'm not convinced that many components that are frequently drilled out really cause a problem. Chainrings, for example, have been safely drilled for eons. I'm not into drilling cranks, but some people do it. Other components?
My guess is that the frame will be fine, if one is judicious with the drilling. not too big of holes, not too many, keep ends clear, etc. Nor do I expect it to suddenly collapse with no warning whatsoever.
Steel?
Drill a hole in it
I'm not convinced that many components that are frequently drilled out really cause a problem. Chainrings, for example, have been safely drilled for eons. I'm not into drilling cranks, but some people do it. Other components?
My guess is that the frame will be fine, if one is judicious with the drilling. not too big of holes, not too many, keep ends clear, etc. Nor do I expect it to suddenly collapse with no warning whatsoever.
Steel?
Last edited by CliffordK; 08-23-17 at 04:34 PM.
#72
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Okay thanks for the input everyone. My conclusions are:
- strategically drilling holes such that safety isn't impacted wouldn't reduce the weight enough for me to make a "poor man's" light bike
- steel bike tubing is not as thick as i thought, and while an excessively drilled frame might bounce around and be flexy while riding, a tube may overstress and kink at a certian point, which will yield a folded bike appearance.
- making a drillium frame would make for a nice conversation piece at home, but i don't have many guests over so its not worth the effort
- I'm 200lbs, i'd better play it safe for now and not buy or try to make any SL parts.
- my wrenching faculty is unhappy about these conclusions
- I will now resort to plan B which is to cut off the section of the drop bars that i don't use, since I only ride the hoods. I like when my fingers touch a bit of the drops so I'll probably cut around here...
- strategically drilling holes such that safety isn't impacted wouldn't reduce the weight enough for me to make a "poor man's" light bike
- steel bike tubing is not as thick as i thought, and while an excessively drilled frame might bounce around and be flexy while riding, a tube may overstress and kink at a certian point, which will yield a folded bike appearance.
- making a drillium frame would make for a nice conversation piece at home, but i don't have many guests over so its not worth the effort
- I'm 200lbs, i'd better play it safe for now and not buy or try to make any SL parts.
- my wrenching faculty is unhappy about these conclusions
- I will now resort to plan B which is to cut off the section of the drop bars that i don't use, since I only ride the hoods. I like when my fingers touch a bit of the drops so I'll probably cut around here...
#73
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I asked a bike shop if they could put two holes in my steel frame to permanently mount my water bottle. They were very clear that even just that will weaken the structural integrity to a dangerous point.
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You'll find basically 3 types of steel in vintage frames:
With a straight tube chromoly frame, then you likely have a fair amount of excess material mid tube that could potentially be removed. Sanding, lathe, or... DRILLING.
Butted Chromoly frames (or Reynolds 531, or various Columbus Tubes) already have awfully thin tubes, and any gains would be minimal.
- High Tensile Steel (generally straight tubing).
- Chromoly or similar alloy - Straight Tubing
- Chromoly or similar alloy - Butted Tubing
With a straight tube chromoly frame, then you likely have a fair amount of excess material mid tube that could potentially be removed. Sanding, lathe, or... DRILLING.
Butted Chromoly frames (or Reynolds 531, or various Columbus Tubes) already have awfully thin tubes, and any gains would be minimal.