choddo

Is it just me who does things like this or have other people messed up? I rode bikes a lot as a teenager, had very basic tools and could keep mine just about going but knew my limits. I didn’t touch a bike from the age of 20 to about 40 and got into it again properly and still like fixing / servicing things myself when I can. This can lead to cases of “a little knowledge being a dangerous thing”.

A couple of years later they introduced the massive Ride London event which used roads I knew well and I was lucky enough to get a place.

I stripped my bike down to clean it properly and was very proud of how shiny it was. The first 40km are very flat and then you hit a hill that’s about 10%. 1km or so before the hill I happened, among the huge crowds, to start chatting to a very nice young lady and was doubtless impressing her enormously with my knowledge of the upcoming hills and associated tactics.

We hit the gradient and I changed to the small ring for the first time that day, only for the chain and crank to instantly seize up and my bike and I to rapidly decelerate into a scattering crowd of riders. I had time to utter a quick “oh dear, I wonder what that is” as my credibility drained and she cruised off up the hill. I managed to just about unclip and get to the side of the road without causing anyone else to crash. Took me close to 15 minutes to get the chain out from between the chainrings and I had to ride the entire rest of the ride in the big ring. Pop quiz: Anyone want to guess what I’d done wrong?

And I think the incident somehow caused damage to my rear mech too because two weeks later, in a paceline at 40kph, it did this


Not a very good clue for what went wrong though because I still can’t figure out how the two are related. Maybe coincidence.

RoadWearier

I once put the rear brake caliper on my Triumph Bonneville on backwards. Got 10 feet and then the brake line snapped and spilled brake fluid all over my driveway. Not "bicycle" related but (motor)bike related. Now I always take pictures of everything while I'm dis-assembling.

Shadco 

Dropped the barrel nut on the saddle clamp down the roval seat post on my Aethos.

.

Steel Charlie

Too embarrassing to even consider relating

base2 

I've never done anything to be embarassed about. That said: "No more mechanicals, Base2! " Did become sort of an inside joke in the cycling group. It was always something innocuous and not ride ending, Thank Goodness. Unexpectedly rotating handlebars did get quite a laugh that one time, though.

If you are looking for a dumb mechanical mistake, I cross threaded a bottom bracket once. And one time I cranked down a Hollowtech II bottom bracket preload bolt way, way too tight. $50 and 500 miles later I figured it out and learned my lesson. (I've never told anyone, even my wife...It's a secret.)

wheelreason

Mounted a Conti Ultra Sport on it.

choddo

Haven’t had the pleasure.

88ss

Well if the cranks were put together with the wrong spacing between the front rings the chain may drop down between them, then if they jammed between the chain-rings and you kept pedaling and wound up the chain around the crank it would take up all the range the rear derailleur had by pulling on the bottom run of chain which usually has no high tension, and maybe put enough force on it to strain or bend the derailleur or it's hanger in some way.

Now that I am an old man, I have learned the hard way that I have to make sure I do not have a lot of distractions when I am doing mechanical work or I may forget something, you have to take your time and make sure your mind is on and enjoying what you are doing and not thinking about anything else. Yours or someone's life may depend on it. I don't mind if I kill myself, but I am not enthusiastic about working on other people's things as when I was young as I do not want to be responsible for them. A friend asked me if I would install a water-heater in their house a while back and my reply was "When your house burns down because of a gas-leak would you rather have had me install the water-heater or a licensed, bonded and insured plumber/contractor that you can get a settlement from or sue for damages and/or loss of life?

maddog34

forgot to glue a sew-up tire in place on my Mitzutani Super Lite racer... had a flat on a ride, just slipped the spare on, and rode home,,, two days later i was racing my neighbor(he had a peugeot p-10) i went into a not-very-tight right hander at full speed ahead... then went sideways into a white picket fence at about 40 mph..

i never neglected to glue a sew up on after that........ the road rash was epic... gravel, splinters and all that fun stuff... a rose bush or briar got involved too... or both.

i had to fix the fence the next day.. fresh paint included... i was still bleeding a bit......... i paid mom back for the wood and paint.

Specialized Turbo high pressure clinchers came out the next year.... thank gawd. i overheard two guys talking about them at Phil's Schwinn Cyclery, B-H Highway, Beaverton...
a month later, i had bought and laced up a pair of clincher rims......

choddo

Classic sorry, I shouldn’t laugh.

choddo

That may well be what happened. I remember the mech was in a very strange position.

The mistake I made was putting the small ring on the wrong way round. I didn’t know the teeth were directional and “lean” slightly towards the big ring… or away from it if you install it the wrong way, allowing the chain to jam between the rings.

delbiker1 

I'm still working on it.

Chuck M 

I was trying to remove a crank arm last night and it was really stuck. I figured I better remove my puller and investigate. When I did I realized in my rush I didn’t remove the nut. No damage to anything except my pride.

88ss

The other way to do it is to drop the chain behind the big cog out back so it jams the freewheel, now you effectively have a fixed gear rear wheel pulling the bottom run of chain tight and bending the derailleur and/or hanger. I made a real mess out of a few bikes, once after crashing hard and remounting dazed and trying to start moving again, and once by taking a new to me used bike for a ride before checking the rear derailleur adjustment, turned both derailleurs into knots and bent the hangers. Was able to straighten the hangers out because they were steel, but in both cases had to install new derailleurs. Either way from or back pulling on that bottom line of chain doesn't do anything any good on a multi-speed bicycle......

maddog34

meh... it's long history now... Wes' dad was "clocking us" in his shiny gold, brand new, Pontiac Grand Prix... he almost hit me when i bounced off the fence... my mom would have, most likely, made me pay to repaint his car too.

PS.. i laugh about it now too.... a small piece of that gravel finally worked it's way out of my right elbow about 15 years ago....

maddog34

they do come loose much easier with the nut removed... speaking from experience...

SurferRosa

Worst mechanical screw up? Hmm... I once ran into a parked car on a test ride and bent the fork.

SoSmellyAir

Come on, I had used a pair once; they are reasonable training tires.

That does not sound like a mechanical screw up.

* * *

I run a Prestacycle Uniblock (12-28) cassette which comes with its own lock ring, which does not have a crush spacer behind it. I must have torqued the lock ring insufficiently, because it worked itself loose and got jammed up tight against the RD hanger bolts, causing the freehub to lock up relative to the frame, and thus locked up the crank too. This happened during a fast descent earlier this year, so my pedals were near the 3 and 9 o'clock positions. At the time, I was still almost a complete noob at clipless, and I had a very difficult time unclipping from those pedal positions; I usually unclip my foot at bottom dead center. I thought I was going to crash but thankfully just managed to avoid that. When I got home I tossed the aftermarket lock ring and ordered Shimano Ultegra lock rings for a 12T smallest cog.

Sierra_rider

Nothing too insane, but I've forgotten to put the spacer ring that goes behind 11-speed shimano cassettes a couple times. Also left one of the spacers out between the cogs before...I probably adjusted my rear derailleur about a dozen times before I saw my mistake. It was on brand-new fancy wheels on my gravel bike, so I was all sorts of pissed at the crappy shifting...then felt like a complete dumbass afterwards.

Another "doh!" moment occurred on my first internally-routed bike. I put some new bars on and the bars were designed for the cables to partly go inside the bars. I went to pull the rear derailleur cable out and absent-mindedly pulled the cable and the internal liner out as well. Getting the cable back through was a real PITA, until I realized that you could guide the cable with a magnet.

maddog34

it sounds more like a mechanic screwed up..

i once clipped a curb with a sidecar wheel while making a tight right-hand turn during a test ride... it was mounted to a nearly new 1500 gold wing.... luckily, there was no oncoming traffic, and i knew enough to turn into the roll direction.... but it was close... real close... felt like about 45 Degrees lean before recovery... with a whallop... Jim (Service Manager) spotted the scuff mark on the SC tire sidewall... he just shook his head, told me to check the bike's lean angle, and went back to work...

capnjonny 

Maybe not a screw up / you decide.
Took an old mountain bike out of the pile at the Bike Exchange and started to go through it. Cleaned, greased, and assembled everything. Just as I was about to say 'Job done', I noticed that the chain stay was sheared all the way through just aft of the bottom bracket. The bike was toast.

There is nice end to the story though.
One of our volunteers was painting a mural on the wall of the shop just inside the front doors and we used the bike as part of it. I removed the off side crank arm, cut one side of the handlebars off and hung the bike on the wall about 8 ft off the ground.

jadmt

not so much a mechanical as a brain fart from being in lazy, I will spare the major details but it resulted in drilling an 1/8" bit thru my left ring finger pad straight thru the center coming out the middle of the finger nail. Worst part was I had to put the drill in reverse to get it back out. dewalt 20V angle drills go through fingers like a hot knife through butter.

dedhed

I have spent hours trying to remove a "seized" pedal by turning it the wrong direction.

choddo

BTinNYC 

I don't consider my AFOAM (amazing feats of absent mindedness) as screw-ups. Most screw-ups are mistakes I can learn from, whereas not tightening the NDS crankarm...

I don't remember not tightening it, so maybe it was the garage goblin.😜