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folding bike repair


Phoenix_V

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We have a small Chinese folding bike on the boat. The frame folds in the middle with 2 hinges. One of the hinge pins has broken, I suspect related to it being rusted solid rather than over enthusiastic use. We have drilled it out and will replace with a bolt. I would like ths to be as strong as possible (obviously) should I use a stainless or a high tensile bolt?

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We have a small Chinese folding bike on the boat. The frame folds in the middle with 2 hinges. One of the hinge pins has broken, I suspect related to it being rusted solid rather than over enthusiastic use. We have drilled it out and will replace with a bolt. I would like ths to be as strong as possible (obviously) should I use a stainless or a high tensile bolt?

Long shank high tensile and keep it greased. Stainless steel has its uses but its not as tolerant under stress as mild or high tensile steel, It can suffer fatigue under certain uses.

Edited by bizzard
  • Greenie 1
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A prisoner has escaped from the metalworking shop of a local jail. When the warder opened the security door, the prisoner made a bolt for it.

 

 

I'll get me cycle clips.

Edited by Athy
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TThis is the way to go, my missus had a nasty accident when a 'repaired' bolt failed, leading to the bike folding up whilst going down hill.

Not quite sure what you think they are going to do that I can't?

Long shank high tensile and keep it greased. Stainless steel has its uses but its not as tolerant under stress as mild or high tensile steel, It can suffer fatigue under certain uses.

Thanks Bizzard

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Long shank high tensile and keep it greased. Stainless steel has its uses but its not as tolerant under stress as mild or high tensile steel, It can suffer fatigue under certain uses.

Sounds about right to me.

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I suspect that anything you fit will be better quality than the original one fitted to a cheap Chinese bike. Personally I would drive a new pin made of mild steel into the existing hole, but if you cannot find any steel of the correct diameter a standard shanked bolt secured with a locking nut. (Actually, I would probably make a new pin, but that is me!)

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Get a proper bike shop to look at it and be guided by them. I spent an hour in theatre with a plastic surgeon, 2 days in hospital, a week off work and have 8 hours that I can't account for when the carbon forks failed on my road bike in November. Any frame failure can have dangerous consequences, I was lucky, some cyclists have ended up paralysed or worse. If the bike shop says scrap it and get a new one then do it - it could save you a free ride in an ambulance.

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I found the best tool for my cheap Chinese folding bike was an angle grinder with a good cutting disc, chopped it up into parts and took them down the dump. From new had the following failure

Headset poor quality making for loose front forks, unreparable

Crankset fell out, very poor quality

Pedals ground

Front wheel rim split when tyre pumped up, rim quality was akin to that used in tin cans

Seat would not stay in place due to poor quality tube, poor quality quick release bolt, bolt hole flanges bent in rather than tighten up

Tyres were rubbish

When stripped down frame tube inner were rusted due to poor quality steel

General everything else was of poor quality and I believe dangerous

All this within the first 6 months

Never felt comfortable or safe on it as always expecting something else to fail

 

As I said above took great joy in chopping it into bits and removing it from the market altogther

 

 

I do hope that yours is not as bad as mine was

 

In the end bought a better quality bike second hand.

 

Edited to add

It did have a nice paint job though

Edited by reg
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I found the best tool for my cheap Chinese folding bike was an angle grinder with a good cutting disc, chopped it up into parts and took them down the dump. From new had the following failure

Headset poor quality making for loose front forks, unreparable

Crankset fell out, very poor quality

Pedals ground

Front wheel rim split when tyre pumped up, rim quality was akin to that used in tin cans

Seat would not stay in place due to poor quality tube, poor quality quick release bolt, bolt hole flanges bent in rather than tighten up

Tyres were rubbish

When stripped down frame tube inner were rusted due to poor quality steel

General everything else was of poor quality and I believe dangerous

All this within the first 6 months

Never felt comfortable or safe on it as always expecting something else to fail

 

As I said above took great joy in chopping it into bits and removing it from the market altogther

 

 

I do hope that yours is not as bad as mine was

 

In the end bought a better quality bike second hand.

 

Edited to add

It did have a nice paint job though

Had similar problems with an expensive Chinese Electric Bike

 

Found the same solution as you!

 

CT

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Had similar problems with an expensive Chinese Electric Bike

 

Found the same solution as you!

 

CT

Funnyly enough mine was an electric as well but only cost £400, bought it to test whether I wanted an electric bike or not, now a convert. At least I managed to strip the electrical components off including a Z £200 battery so not to far out of pocket.

 

I now only buy good second hand bikes with low usage, find they are often bought with good intentions are used once or twice, sit in the shed for a couple of years and then end up on Gumtree, suits me fine a good 3 or 4 year old bike cost about the same as a new rubbish bike

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My Chinese folder has been great, though it is aluminium and I have changed the rear wheel to a Nexus 4 speed hub gear, and given it a Brooks saddle .Folds v small and I do loads of miles on it, payed £20 for it second hand.

 

I could do with loosing a couple of inches though, or so the wife says ohmy.png

Edited by rasputin
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Chinese is a generic term that can be China or Taiwan and the quality of either countries products can be good or bad. I have had a Dahon for awhile and never had any issues with it. Hard to imagine a good bolt failing on the hinge so I am with the fix it crowd. Now something else may fail if the bicycle has been abused.

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I would also put myself in the " buy second hand but buy quality " camp .

I have a Dahon Espresso . Full size bike with 26 " wheels , folds up and goes in the engine room at the back of a 58 ft trad nicely .

Around £750 new . I paid £170 on ebay & it had sat in a spare room for 4 years when i bought it .

Though expensive i expect Bromptons are very high quality and second hand they still sell for several - as in £500 plus .

Im not well off - far from it but a Chinese cheapy is something i d never buy as I couldn't trust it knowing that every single moving part , each of which is important, has been produced for the lowest price possible and its quality & dependability are questionable

 

Second hand , but quality is the way forward i think

cheers

Edited by chubby
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Chinese is a generic term that can be China or Taiwan and the quality of either countries products can be good or bad. I have had a Dahon for awhile and never had any issues with it. Hard to imagine a good bolt failing on the hinge so I am with the fix it crowd. Now something else may fail if the bicycle has been abused.

I have to agree, although I appear in my previous post to be knocking all cheap Chinese goods as being poor quality that is far from the truth two examples come to mind of excellent low cost cost Chinese goods come to mind

1 I have 3 Cree tourches all excellent and low priced

2 My 3 Tracer MPPT controller would recommend them to anybody

 

The problem is that until you purchase the goods there is no way of knowing what you will be getting. It must be very frustrating for any manufacturer, Chinese or otherwise who makes an effort to then be undercut by highly polished pieces of, in some cases dangerous, goods.

 

The nice thing about bikes is that they are to some a bit of a fashion item so a good selection of good second hand bikes is generally available. Please don't tell anybody about that though

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I agree you get what you pay for and when this gets replaced it will be something better, but I am pretty sure the pin failed because it had rusted in place and snapped when we tried to fold the bike it certainly didnt fail in use so on that basis thought it worth replacing it.

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