Stupid mechanic errors you have made

[Deleted member 35268]

Yeah, why do a job once properly when you can do it in three goes. Thats my moto

 

[figbat]

Now oiling a motorbike chain with the bike on the stand in first gear on tickover could go very badly indeed !

Plenty of fingers have been shortened by this method.

 

[Peter Salt]

Replaced the front gear cable inner and outer.

Went out for a ride and had to re-tension right after - put it down to cable stretch and bumpy ride. Next two rides - same thing. Re-tensioned again and at this point was disappointed with the quality of the cable. Another week of riding and the same thing again - now I was really rather confused.

Decided to disassemble what I did. Turned out that where the cable from the shifter enters the frame (and carries on internally) the outer and inner have separated so that the outer cable compressed but looked normal whilst the inner went through the eyelet - effectively reducing the tension each time vibrations were introduced.

The worst of all was that the inner cable went in so deep that it was touching the (alloy) steerer tube. So every time I steered I was unknowingly, slowly sawing it in half...

Had to disassemble the whole bike, get rid of all metal shavings, buy new headset bearings (in case some shavings got in) as well as new fork/steerer tube. Still, felt like I dodged a bullet as this had the potential to end naaasty.

 

[MontyVeda]

forgetting to lock the QR skewer after putting the rear wheel back on, only to remember as I'm doing a 1mph faceplant outside my house.

 

[Profpointy]

forgetting to lock the QR skewer after putting the rear wheel back on, only to remember as I'm doing a 1mph faceplant outside my house.

Mmm, there was the hand-tight wheel nut incident on my car. I'd obviously planned to go round with a proper spanner after putting it down on the wheels once more but somehow got distracted. I realised summat was wrong on the way to work as driving felt a bit funny and realised what I'd (not) done. Annoyingly, I'd taken all my tools out, so was reduced to stopping after each mile driven and tightening them finger tight again. Just as I got to the works car park having pushed my luck a bit on the final leg, the wheel popped off but luckily only dropped the hub into the recess of the wheel rather than off altogether. The four nuts were in a row over a 20 yard distance. Borrowed a spanner at work and all was well. In retrospect that could have been a lot worse

I should perhaps add that this bit of muppetry was 40 years ago nearly

 

[Supersuperleeds]

A flat tyre developed overnight at home so I had to fix it in a hurry before doing my daily commute through quite busy west London traffic. As usual when I arrived at work, I carried it up the staircase. The front wheel fell off and bounced down to the landing. I hadn't tightened up the skewer.
It could have been interesting if I had attempted a wheelie.

I've done that. Only spotted it after ten miles, thank God for lawyers lips.

 

[Vantage]

I've just discovered why I'm having trouble rebuilding the rear wheel of the DeMayo. Whichever idiot originally built it, did so using the thicker spokes on the non drive side. What magnitude of stupidity must one possess to get that wrong? Argh!

 

[Ming the Merciless]

Fixed a puncture whilst it was snowing last winter. Realised after an hour that I’d left the pump behind. Returned and only just found it in the snow.

 

[Rusty Nails]

Just remembered another expensive mistake I made when getting into working on bikes.

Forgot to take that BB square taper bolt off the drive side, put a lot of effort into getting the crank remover to screw into the alloy crank and stripped the thread. I had to cut the crank off. I've not repeated that one.

 

[TheDoctor]

I've done that.
Twice...
Spannering after a glass or three, I once managed to fit the entire SS drivetrain on the left hand side of the bike.

 

[tyred]

I put the bottom bracket spindle of my Raleigh Trent in the wrong way around so the chainring was hitting the chainstay and I spent ages wondering why as it hadn't done that before I serviced the bottom bracket.

 

[rogerzilla]

I've probably done them all over the years. A highlight from my teens was trying to use a crank puller, not realising that there was a washer involved and it was still on the spindle (cheap bikes always had nutted spindles).

A more recent one was having a frame with a Raleigh fork reamed and faced for a new headset. The shop used an ISO reamer. Not many people know, even professionals, that Raleigh cups are JIS sized and will rattle in an ISO head tube. I shimmed them with beer can strips. Eventually I bought an ISO fork and fixed the issue completely.

 

[T4tomo]

one the not tightening up properly theme....

I was chatting as I unfolded my Brompton, didn't quite get the handlebars in the right position as I tightened the clamp, set off, and abruptly somersaulted over the collapsing handle bars...into a perfect judo break-fall roll and stood up again!

 

[Jameshow]

I've just discovered why I'm having trouble rebuilding the rear wheel of the DeMayo. Whichever idiot originally built it, did so using the thicker spokes on the non drive side. What magnitude of stupidity must one possess to get that wrong? Argh!

That's interesting my dad has a demoyo not a common make! I'll ask him for a picture?

Do you have a picture of it.

 

[EltonFrog]

one the not tightening up properly theme....

I was chatting as I unfolded my Brompton, didn't quite get the handlebars in the right position as I tightened the clamp, set off, and abruptly somersaulted over the collapsing handle bars...into a perfect judo break-fall roll and stood up again!

The fragrant MrsP did that last week, but her recovery wasn’t as decorous. I have audio visual evidence.