Stupid mechanic errors you have made

[Dogtrousers]

Ok...

The previous time I did a job like that involved tapping out knackered bearings and very carefully tapping in the new ones (I don't have the right tools to do it properly).

I had just finished and put the wheel back on the bike when I spotted a rather important spacer left sitting on my table! That spacer is supposed to sit on the axle between two sealed bearings so they can push against each other.

I had to tap out a brand new bearing without damaging it, insert the spacer, and then tap the bearing back in. I fully expected to damage the bearing doing that but somehow managed to do it successfully.

I suppose it would have been a better 'stupid mechanic error' if I actually had killed the bearing doing that!

Getting stupider ...

Reminds me of a time last year when I'd just put a cassette onto a back wheel, and was trying the gears in the stand. It was all over the place. Obviously this was going to require fiddling with the cable tension. I hung my head and sighed and stared sadly at the floor.

And then I noticed, on the garage floor, next to my foot - the spacer that I'd fogotten to put on before the cassette.

 

[T4tomo]

Getting stupider ...

Reminds me of a time last year when I'd just put a cassette onto a back wheel, and was trying the gears in the stand. It was all over the place. Obviously this was going to require fiddling with the cable tension. I hung my head and sighed and stared sadly at the floor.

And then I noticed, on the garage floor, next to my foot - the spacer that I'd fogotten to put on before the cassette.

I didn't get quite that far when fitting a mates new wheels, He was supposed to have stripped tyres and tubes of the old ones before i got there but hadnt.. so was rushing a bit and he was passing me bits and pieces as I refitted tyres and tubes.

I whipped the cassette off the old wheels (which must have been max 10 speed) popped in on new ones and tighten it up only to find it was still wobbling.
"did these come with a spacer in the box?"
"Oh that's what this thing is then, you mean you need that?"

doh!

 

[cougie uk]

Oh I've missed putting on my own spacer on my wheels. I think I'd taken the cassette off to clean for a race abroad. Put the bike back together again in Germany and the cassette was jingling. Had to find a bike shop to put on the missing spacer the day before the race.
Doh ! Never rush things !

 

[Jenkins]

Not me, but a reputable bike shop. I'd ordered a new bike and requested a different cassette to the one supplied as standard. When the bike arrived the gear changing was completely out and I just couldn't get it to index correctly until I double checked the cassette - they had supplied the correct ratio cassette, but the 10 speed version, not the 11 speed to go with the rest of the groupset.

 

[Gillstay]

Did a job on the car. Very pleased it went well. Jumped in to test it and ran straight over my socket set that was just out of sight.

 

[Profpointy]

I once accidentally rode into a deep narrowing rut on a fast MTB descent. I couldn't escape from it and eventually the rut came to an abrupt end. The bike stopped dead, upended, and launched me forward over the bars. I landed on my feet and ran down the hill to keep my balance. I eventually came to a safe stop and trudged back up the hill to retrieve my bike!

In a similar vein years ago I was walking down some snow covered station steps; really really covered, buried even, not just a layer. Anyhow I slipped, and ski'd down the whole flight on one heel, the other foot raised in front and one hand for balance sliding down the handrail. Hit the bottom and bounced onto both feet. Sadly no one saw this great feat, which I doubt I could do again no matter how many times I tried it.

 

[HLaB]

I haven't done it for over 10years touch wood but when I was new to mechanics a few times when threading the chain through the jockeys I missed feeding it through the cage retainer or whatever it is called. It was ok with my KMC chains you'd simply reopen/ rejoin them, but my mate insisted on using a shimano chain and I had to push out the retaining pin and reinsert it after. I did that easily enough but he only got two rides before it snapped at that point ☺

 

[cougie uk]

Oh I remember another one.
Mate of mine noticed his front wheel QR was undone.
About 50 miles into a ride and that was after a three mile descent.

No lawyers lips in those days either !

 

[presta]

Forgetting to hook the straddle cables back on after I finished servicing it.

 

[Fastpedaller]

Did one of the most stupid things you can do with a fixie. Mickling the chain, but holding the chain at the bottom whilst spinning the crank forward - hand/fingers get dragged towards the rear sprocket - fortunately I was going slowly, otherwise I'd be missing the end of a finger. It has happened to people.

Yep - I did that once. Those of us that do it, only do it once!..............

 

[ColinJ]

Mate of mine noticed his front wheel QR was undone.
About 50 miles into a ride and that was after a three mile descent.

No lawyers lips in those days either !

Good job he didn't try bunnyhopping any potholes or cattle grids then!

 

[cougie uk]

Good job he didn't try bunnyhopping any potholes or cattle grids then!

Isn't it just !!

 

[Fastpedaller]

One on a car 40 years ago.... I drained the oil and put a new filter on. Went in for lunch. You've guessed this already haven't you? Came out and put the new oil in, and then found the sump plug next to my toolkit! All the new oil mixed with the oil in the container under the car.
One on another car 25 years ago........ Did some work on the car, put the wheel back on and went around the block to ensure everything was good: it was, except that I couldn't find the '3-pin socket' for the anti-theft nuts (1 on each wheel). It was then I realised I'd left it on one of the nuts, so it was somewhere on my 1 mile circuit. I thought all was not lost, as I still had the original box with the key number. Telephoned the manufacturer who kindly said they'd send a replacement socket. A week later a box arrived with 4 new nuts and a socket, saying they gave me a new set because they couldn't supply the original. It was then I found out how easily a thief could remove the anti-theft nuts without the correct tool and without causing damage to the wheels.

 

[Houthakker]

I fitted a new Garmin speed and cadence sensor, spent ages geting the gaps to wheel and pedal magnets just so, then went out for a test ride and couldnt change gear. I'd only cable tied the gear cable to the frame!

 

[JhnBssll]

The most time consuming and embarrassing error i made was working on my old track car. I was swapping the clutch out and had just wrestled the gearbox back in to place and was putting the bell housing bolts back in when I got thirsty and stopped for a break. As I walked back through the garage I noticed the brand new thrust bearing still sitting on the bench so it all had to come out again - I was not pleased with myself!