Road Bike Racing - First Crash in 20 Years

Hi,

I know that many of you will say that if you don't crash you aren't trying hard enough, but I have enough scars on my legs and elbows from my earlier years in cycling to say that I don't like hitting the ground.

Anyway, I was at the velodrome on Thursday night for a weekly training session. I've had a low level cold for about two weeks so I decided to ride with the slower group on the pole line instead of the fast group on the stayer's line. We were literally about a mile into the controlled warmup when a friend up in the fast group had his pedal unscrew from his crank. This caused him to lose control and the rider behind him hit him and went down too. They both slid down the track and hit my teammate who was right in front of me. I thought that I was going to be able to slip by on the inside, but I just glanced off of one of the original crashers and down I went too. :(

My Garmin showed 22 MPH just before it went to zero. When I hit the ground I landed on my back and slammed the back of my head on the wooden apron. Net result, a bruise just above my left glut, my right shoulder blade slightly tweaked, a broken helmet, and a few splinters in my skinsuit. The next morning my neck muscles and lower abs were (and still are) sore.

I had not been telling anyone exactly how long it had been since my last crash as I didn't want to jinx myself, but now that the streak is over... :rolleyes: Oh, all of the other crashees were able to get up and walk away.

BTW, I have had numerous close calls over the last 20 years, but I had managed to avoid actually hitting the ground. Oh well. I guess that the new streak begins now. ;)

Yep, the last time I crashed was about a month ago. Every time I ride my MTB I crash it. I just go too fast and don't have enough technical skillz.

Here's to another 20 crash-free years.

my lone crash on the bike was when i was just riding around, trying to get my girlfriend to ride a bike with me. i was going about 10 mph and managed to flip over head first coming over the slight curb into my driveway. luckily i was clipped in and managed to keep my bike over my body save for the bars, which got no more than a scuff on the tape.

most embarressing/hilarious moment ive had on the bike.

im sure ill crash alot more often now that im going to be racing most weekends though.

I know that many of you will say that if you don't crash you aren't trying hard enough
Not me. You can't win the race on the ground, and my most exhausting efforts have been in time trials (without a crash)



I thought that I was going to be able to slip by on the inside
You probably already know this, but you generally want to go around a crash on the outside on a velodrome whenever possible, because gravity has them sliding down towards the inside.

Not me. You can't win the race on the ground, and my most exhausting efforts have been in time trials (without a crash)


You probably already know this, but you generally want to go around a crash on the outside on a velodrome whenever possible, because gravity has them sliding down towards the inside.

Hi,

I was waiting for someone to bring that up. ;) Unfortunately, since everyone on the high line was scattering, the only room to "escape" was low. :( It was the usual slow motion kind of thing. I saw my friend losing it and then I saw the other guy hit him. Then I saw people behind scattering (my friend was ahead and above) and then I saw my teammate go down. The whole time I'm thinking, where can I go to miss this?

I really thought that I was going to clear them but then... :o

Yeah, it's hard to tell in the moment. Looking back, was there anything you think would have worked better? If not, then you were just meant to go down. Sucks.

when a friend up in the fast group had his pedal unscrew from his crank.

That ain't supposed to happen........Pedal threads are self-tightening as the crank spins or something like that.

It was just your day, I guess.

I definitely know what you mean about not wanting to hit the ground when you get older. I mean, I didn't like it when I was younger but now...

Glad you're ok.


:beer:

That ain't supposed to happen........Pedal threads are self-tightening as the crank spins or something like that.

This is actually EXACTLY how it's supposed to happen. If a bearing in your pedal seizes, would you rather have the fixed gear unscrew the pedal or wrap your ankle around the crank 10 times until you roll to a stop?

This is actually EXACTLY how it's supposed to happen. If a bearing in your pedal seizes, would you rather have the fixed gear unscrew the pedal or wrap your ankle around the crank 10 times until you roll to a stop?

Actually pedals are designed to be self-tightening due to precession (the same thing that keeps a gyroscope upright) but if a bearing did seize up it probably would unscrew.

That said, if the pedal seized on a fixed gear you would probably just going into a skid rather than wrap your ankle around the crank. Actually, the force would probably un-stick the bearings before skidding the wheel.

I always thought they were self-tightening. The only time I've ever had a pedal detach from the crank arm was when I pulled a classic bonehead and rode a bike I was building before actually screwing the pedals in. Even then, as I recall, they didn't unscrew so much as strip the crankarm threading.

Anyways, the main thing is that the OP got through his first crash in 20 years (now that's impressive) w/o serious injury.


:beer:

If you guys take half a second to look at the way pedals are threaded on, you'd realize that they are prone to unscrewing themselves. The right pedal, for example, screws on clockwise. As the crank spins clockwise, the pedal has to spin counter-clockwise to stay upright. You're mistaking pedals with older Volkswagon lugnuts.

I had a teammate unclip from his pedals right in front of me while doing jumps on the velodrome. Scary, but yes I'd rather have that that the pedal wrap my leg around.

Actually pedals are designed to be self-tightening due to precession (the same thing that keeps a gyroscope upright) but if a bearing did seize up it probably would unscrew.

They were designed to unscrew with a seized bearing because all bikes used to be fixed gears. After some number of people were crippled for life, they reversed the threads on the left pedal.

Unscrew your pedals halfway and go for a long ride. Tell me if they tightened or loosened during the ride.

OK, let me weigh back in on this diverging topic. ;)

Yes, a loose pedal will unscrew by natural pedaling action. Put you bike on a workstand, loosen the pedal, hold on to the axle, "pedal" the bike, and see what happens. :)

What bothers me most about this accident (other than the end of my streak) is that many people don't pay enough attention to the maintenance of their track bikes. I think that it's because they are so simple -- what could go wrong? :eek: Well, now we know. :(

They were designed to unscrew with a seized bearing because all bikes used to be fixed gears. After some number of people were crippled for life, they reversed the threads on the left pedal.

Unscrew your pedals halfway and go for a long ride. Tell me if they tightened or loosened during the ride.

Can you back that up with facts? Because I have information* that says left pedals/cranks are reverse threaded so they don't unscrew themselves when you pedal.

True, a loose pedal will come off as the bearing friction will probably be great enough to overcome procession, but a properly tightened pedal will actually exert a tightening force (clockwise on the right, counterclockwise on the left) while pedaling.

*http://www.sheldonbrown.com/gloss_p.html#pedal
*http://en.wikipedia.org/wiki/Bicycle_pedal#Attachment_to_crank_arm

What bothers me most about this accident (other than the end of my streak) is that many people don't pay enough attention to the maintenance of their track bikes. I think that it's because they are so simple -- what could go wrong? :eek: Well, now we know. :(
Well, you know not all athletes are known for their brains. It does bring up something interesting. In auto racing, a car has to pass a tech inspection for safety before it's allowed on the track. I wonder how hard that would be for cycling.


Can you back that up with facts? Because I have information* that says left pedals/cranks are reverse threaded so they don't unscrew themselves when you pedal.

True, a loose pedal will come off as the bearing friction will probably be great enough to overcome procession, but a properly tightened pedal will actually exert a tightening force (clockwise on the right, counterclockwise on the left) while pedaling.

*http://www.sheldonbrown.com/gloss_p.html#pedal
*http://en.wikipedia.org/wiki/Bicycle_pedal#Attachment_to_crank_arm
I think everybody is arguing the same thing, but leaving the seized bearing as a variable.

Well, you know not all athletes are known for their brains. It does bring up something interesting. In auto racing, a car has to pass a tech inspection for safety before it's allowed on the track. I wonder how hard that would be for cycling.

They do this for Keirin races in Japan, but that's a multi-million (probably billion) dollar industry.

Can you back that up with facts? Because I have information* that says left pedals/cranks are reverse threaded so they don't unscrew themselves when you pedal.

True, a loose pedal will come off as the bearing friction will probably be great enough to overcome procession, but a properly tightened pedal will actually exert a tightening force (clockwise on the right, counterclockwise on the left) while pedaling.

*http://www.sheldonbrown.com/gloss_p.html#pedal
*http://en.wikipedia.org/wiki/Bicycle_pedal#Attachment_to_crank_arm

Interesting, there don't seem to be many facts on either side. I did a patent search, and none is claimed. Sheldon and others say that the Wright Bros appear to be credited with the invention, but that hasn't been substantiated either. It appears that precession works in a bike stand, but I haven't tried it.

One day my right pedal became loose, and I had to pull over and finger tighten it every 5 minutes, and it came completely out twice. Precession was not working. At all. That pedal was one of the Shimano Look clones from 1992, and it was the smoothest pedal bearing I think I've ever owned. I still have it, and it's still perfect.

The same thing has happened to others I've been with on group rides.

So, I started thinking about the unscrewing thing, and the broken ankles made the most sense to me. Say you're riding around on a high-wheeler, strapped in, and the rust finally takes over in the left pedal. I think you'd invent a left-threaded left pedal that night in the hospital. A decade later, I read about that theory in a forum somewhere.

Anyway, precession makes sense on paper, and I can see it working in experiments on the bike stand, but I've also seen it not help at all out in the field.

Speed play has a history timeline of the pedal. The first toe clip was invented in 1868 though it seems like it wasn't much like the clips and straps of today (which weren't invented until 1900). The safety bicycle was invented in 1885. The first clipless system was invented in 1895. The freewheel was commercially viable by 1898.

It is unlikely that there were many ordinary bikes that had anything other than platform pedals. It's possible they had stirrups but your foot would slip out of those if your pedal was binding.

If broken ankles were the reason for left-threading pedals it probably would have come about in the early 1900s, after the safety bicycle and freewheel had been invented.


On a non-historical note, I think the reverse threading on the BB provides good evidence for self-tightening. A bottom bracket is going to have twisting force applied to it in the opposite direction as the pedal spindle and the BB is reverse threaded on the drive side. I know that I've had an Italian BB (clockwise threading on both sides) unscrew itself on the drive side and I know that many people have experienced this problem as well. The reverse threading causes the BB to tighten, not loosen.

I've had pedals come loose on me and they definitely do NOT tighten themselves. I can't speak for why one is threaded one way or another, but pedals do unscrew if not tightened properly. In my case my aerolites came with standard (i.e. measured in inches) thread, almost identical to whatever a metric pedal axle is threaded but not quite. The standard axles were a bit oversize, sort of like how Italian BBs and English BBs are threaded the same pitch but the threads are actually taller. I ruined a bunch of cranks with jammed aerolite pedals so one day I didn't force the pedal in quite so hard. Screwing in an oversize axle feels like you're turning a pedal axle in a crank with nylock inserts, so I figured it'd stay put. My mistake and luckily no one went down (including me) - it came out a couple hundred meters from the end of a crit. I tightened the pedal hard, sacrificing the crank, and raced the next race 15 minutes later.

Ditto English BBs - I've had cups unscrew (and been on rides where others' BB cups are unscrewing). If you snug it up it just loosens again. I would use a hammer on the end of a BB wrench to tighten the fixed cup and the lockring. If I was using a Campy tool kit, I'd crank the heck out of the tool.

When taught how to build bikes by a bike guru type person, he told me that when I start putting a pedal on, I put it on all the way. To quote him, "I don't care if the Pope walks in the door, you tighten that pedal before you kiss his ring."

never kissed the Pope's ring,
cdr

Well, you know not all athletes are known for their brains. It does bring up something interesting. In auto racing, a car has to pass a tech inspection for safety before it's allowed on the track. I wonder how hard that would be for cycling.

The reason why USA Cycling doesn't do this is that by inspecting a bike, it implies they also pass it. This makes them liable for any technical failure. USA Cycling, back in the USCF days, used to check tubular tires to make sure they didn't roll. It's a big deal still if you roll a tubular - automatic 10 day suspension (your first 'warning' comes when you sign up for a license).

At the Harlem Crit in NYC the inspectors were particularly ferocious - they'd roll *clinchers* off of wheels and DQ guys at the startline due to that. They yell at the guy "You got 3 minutes to get another wheel" and most of them would be SOL. I figure they rolled 20% of the tires they checked, and you better believe that no one rolled a tire at Harlem. However, most inspectors were not as vigilant, and when guys inevitably rolled a tire, someone would sue the USCF. And win.

So the USCF announced that they would no longer inspect tubular tires. And you see guys roll them here and there.

cdr

In a way I'm sorry I started this diversion but it is interesting.

The way I've always understood it is that a properly tightened pedal should not be able to work loose as the rotation is self-tightening. Like Yoshi I'd think the rotational forces would make even a seized bearing rotate. The important caveat is "properly tightened" and I improperly left that out when I created the segue way up in post #7. I had a pedal that I stupidly only hand tightened and not even all the way into the crank arm come out. Though that pedal "pulled out" (taking the crank arm threading with it) as much as unscrewed.

To the OP i doubly feel your pain as it's possible your impressive streak came to an end for preventable reasons.

CDR's explanation of why inspections have been discontinued is educational and sad at the same time.


:beer:

Hi Cleave. I, too, had my first crash in 20 years this past October, but mine was on the mtb, and I can't blame anyone but myself. I underestimated a rock/hole in a steep downhill and did a faceplant, then fell off the side of the trail and bounced 40 feet to the bottom of the gorge. Might need to have surgery on the right shoulder, but it doesn't bother me on the bike, so I'm still riding. 20 years ago I had surgery on the left shoulder, odd.
Hope we can ride together sometime soon.

The reason why USA Cycling doesn't do this is that by inspecting a bike, it implies they also pass it. This makes them liable for any technical failure.
Makes sense, but SCCA doesn't have that problem. If your car has a mechanical, it's still your fault. I wonder if it has to do with wording in their bylaws.

"Self-tightening" isn't really the proper words, what I really mean is that properly tightened pedals won't unscrew themsevles from pedaling because the forces applied to the threads when they are properly tightened are in the tightening direction.

A loose pedal will mostly like come unscrewed.

Makes sense, but SCCA doesn't have that problem. If your car has a mechanical, it's still your fault. I wonder if it has to do with wording in their bylaws.

I was wondering about that, because a car breaking on a track day would probably cause a lot more damage than a bike breaking. Perhaps it was something to do with liability? It was back in the days of the first ANSI helmets. Actually there's a very depressing bit of info written by one of the USCF guys from those days, velonews named it site of the day, I think it's called cyclops (Les Earnest wrote it). To think there are races commemorating a lot of the guys he named. Of course it's one sided but still.

Okay, I'll stop being lazy. Here's the link:
http://www.stanford.edu/~learnest/cyclops/

cdr

Yep, I remember back in the day (as you kids put it) when you had to get your bike inspected before you could start. Inspection included things like trying to rip your tubular tires off the rim, twisting you handlebars to see if they were tight on the stem and if the stem was tight on the steerer tube, and squeezing your brake levers to see if you cables were adjusted properly.

I also heard that these inspections ended due to liability issues.

So in all my years of racing I have:

Rolled a tire once
Had my bars slip (rotate) during a race
Had my stem break (at the handlebar clamp)
Had my seatpost start slipping into the sunset twice

All of these failures, except one seatpost slip, occurred when we had inspections. So much for usefulness of inspection. :o

All I know is that my loose pedals don't tighten, so precession makes no sense as a reason to re-engineer the left threads back in the early 1900s.

I found another article, this one is unrelated to bicycles:

http://en.wikipedia.org/wiki/Precession_%28mechanical%29

Oh, and again, loose pedals will loosen probably due to bearing friction being greater than the precession + thread friction. Tightened pedals, however, will not loosen due to precession.

It makes perfect sense for people to re-engineer pedals due to precession if they discovered that a properly tightened left-pedal kept unscrewing itself.

Now since theory and practice are two different things, I'll tell you what - I'll swap the crank arms on my fixed-gear and flip my wheel around. I use eggbeaters on that bike so I can use the left pedal with my right shoe and vice versa. I'll report back on my findings.

Sounds like a good test. My unscrewing pedal was smooth as silk though, so not likely to be higher friction than the threads and precession.

I totally get the precession mechanics. No trouble believing that, but in practice, I've not seen it working.

Sounds like a good test. My unscrewing pedal was smooth as silk though, so not likely to be higher friction than the threads and precession.

I totally get the precession mechanics. No trouble believing that, but in practice, I've not seen it working.

Many pedals use bushings as one of their bearings instead of roller bearings. Cheaper Looks do this while the more expensive ones use needle bearings intead of bushings. The bushings, if properly lubricated, are smooth as any roller bearing, especially when unloaded.

Now then, to tie this all up, bushings don't display precession -- any friction, be it from rubbing of the bearing against the bushing or from fluid friction coming from the grease, will be in the direction to unscrew the pedal. The old pedals used two ball bearings, one at either end of the axle, so precession will be the main unscrewing force, just as it is in a well maintained bottom bracket. Modern pedals, if they are of a two bearing design, which covers most of the pedals except for the most expensive, have one ball bearing to absorb axial loads as well as radial loads, and one needle bearing or bushing to bear the brunt of the radial loads of the pedal strokes.

Take your pedal apart and I'll bet that you'll find a ball bearing close to the threaded end of the axle that holds the pedal body captive and a bushing further inside the pedal body to carry the brunt of the load.

Many pedals use bushings as one of their bearings instead of roller bearings. Cheaper Looks do this while the more expensive ones use needle bearings intead of bushings. The bushings, if properly lubricated, are smooth as any roller bearing, especially when unloaded.

Now then, to tie this all up, bushings don't display precession -- any friction, be it from rubbing of the bearing against the bushing or from fluid friction coming from the grease, will be in the direction to unscrew the pedal. The old pedals used two ball bearings, one at either end of the axle, so precession will be the main unscrewing force, just as it is in a well maintained bottom bracket. Modern pedals, if they are of a two bearing design, which covers most of the pedals except for the most expensive, have one ball bearing to absorb axial loads as well as radial loads, and one needle bearing or bushing to bear the brunt of the radial loads of the pedal strokes.

Take your pedal apart and I'll bet that you'll find a ball bearing close to the threaded end of the axle that holds the pedal body captive and a bushing further inside the pedal body to carry the brunt of the load.

This one has balls on both ends (just popped it open). 1992 Shimano 105, Look licensed.