1

i bought old Peugeot carbolite 103. With size 60cm which is very big for me, so I have an idea to cut it to 50cm. Do you think it's worth it and the risks?


Edit: Guys thanks for the fastest responding. I will search for another frame.

4
  • 20
    As someone who needs large frames - please don't take one out of circulation. Instead, sell it and buy one that suits your size.
    – Criggie
    Dec 21, 2021 at 21:14
  • Old bikes with good, usable frames but worn out, missing and broken components are common. If the components on this bike are good, use it as a donor bike onto another, with a smaller frame.
    – mattnz
    Dec 22, 2021 at 0:56
  • 12
    I think this is one of those “If you have to ask, the answer is no” type situations.
    – MaplePanda
    Dec 22, 2021 at 8:12
  • If it's a French bike made before 2000s, there's a good chance some components have French threads and you need another similar frame to reuse the components.
    – ojs
    Dec 22, 2021 at 11:31

1 Answer 1

22

It isn’t possible to resize a bike like this. You would be talking about removing each individual tube, cutting it down to size, and then rejoining them. We would be talking about all the tubes, not just one. You don’t know how much to remove. You don’t know how to rejoin the tubes. You would basically be destroying the bike to rebuild it even if you knew these factors. It would have been better to buy the correct size bike to being with, and if you have no idea what is the correct size you are better off buying new from a store or getting a knowledgeable friend to help.

One other factor to consider is how economical this action would be. Even if it were practical to re-construct the frame, you'd need to remove all the parts. You aren't likely to have the tools to do this, so this is already a bit of a pricey proposition. Given that these are steel tubes, you'd also need the equipment to cut and miter the tubes so that they can be joined. Then you'd need equipment for joining the tubes - I think the frame isn't lugged, but I can't tell if it's brazed or welded. Whatever the case, the framebuilding equipment is much more expensive than tools for bike servicing. Even if the process were possible and you had the skills to do it, this is unlikely to be practical unless you're already a framebuilder.

While not directly relevant to the question, one commenter referenced the concept of the Ship of Theseus. This is a thought experiment used in the metaphysics of identity. As applied to bicycles, the consensus is that if you upgrade the frame, it is essentially a totally different bicycle. That would seem to apply here.

6
  • 9
    Agreed. This would be tantamount to building a frame from scratch, which is a major, expensive undertaking (watch some youtube videos on hobbyist framebuilding to see what you'd be signing up for). If you do it wrong, the results would be at best unsatisfactory, at worst dangerous.
    – Adam Rice
    Dec 21, 2021 at 23:40
  • 7
    Indeed, such work would be so extensive it approaches Ship of Theseus levels of debating whether it's even the "same" bike at that point. Dec 22, 2021 at 1:07
  • 6
    Another point - if the frame tubes are butted, cutting them down could remove some or all of the thicker end of the tube, resulting in a tube and join of substandard strength.
    – John M
    Dec 22, 2021 at 10:39
  • 4
    I think building a frame from new tubes would be easier than cutting an existing frame and rebuilding it to smaller size.
    – ojs
    Dec 22, 2021 at 11:32
  • 9
    "you are better off buying new from a store or getting a knowledgeable friend to help" - Heck, you would even be better off building a new frame from raw materials than you would be trying to rebuild a frame by salvaging the materials from a used one.
    – J...
    Dec 22, 2021 at 13:06

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.