chasm54

Jesus, can't we keep the helmet debate in A&S? I'd be happy to re-educate you helmet Nazis in the appropriate forum, but this isn't it.

OP, I'm not at all surprised. There's a reason great time-triallists used fixed gears. I've recently bought my first fixie at the ripe old age of 55 and in the appropriate terrain I am faster than on my geared bike. You are quite right, it is perfectly possible to be efficient over a wide range of cadences.

Racer Ex 

Hardly a lack of understanding and I'm not the one who brought it up in the first place; so perhaps YOUR reply would have been best stated "over there".

I've ka-banged my noggin enough with and without. My test cases reflect real world scenarios and only someone utterly lost in statistics would deny that a helmet can provide a benefit in those test examples. The belt sander reflects a typical abrasive injury seen in helmetless accidents. The banging of the head on asphalt blunt force trauma. A helmet provides a protective layer against the former and energy dispersal for the latter.

Where the helmet doesn't help is in accelerative brain injuries. In a few cases it can exacerbate those injuries but not generally in the type we see in cycling, that's more common in auto racing where the additional weight of the helmet come into play in accelerating the speed before impact. In any case they do little to protect from concussions.

There's really a wealth of information out there on this subject that's far more complete and scientific than any of the statistical analysis I've seen. Please don't have let those monkeys die in vain.

Racer Ex 

Stop being a helmet Holocaust denier and we could have an educated discourse.

And again, I don't give a flying pony ride if you want to wear one or not. What I do give a flying pony ride about is mis information regarding the subject and the characterization of people who disagree with your opinion as folks who would stuff a few million people in ovens for the sake of political scapegoating and genetic purity.

Racer Ex 

And BTW, I know you guys in the UK are dealing with this as a nanny state political question. I read the Brit mags. FWIW I think if you're "of age" it ought to be your call.

Back to the fixed gear TT thing:

I actually considered it for a couple of courses here. Biggest issue is most of our stuff is "out and back" and we're often dealing with 10-30 MPH wind on our head or tails on the different legs. In one case the "out" leg took me 30 minutes, the "back" leg 10. Just too big a change in cadence to make that work.

Biggest benefit I can see from a fixed wheel TT bike is it's forced discipline; you have to keep positive pressure on the pedals, in doing so you're keeping a positive wattage and for some people it no doubt smooths their effort. I've looked at a lot of TT power files and most are pretty jagged...people lose concentration or take mini "breaks" on downhills. Never a great thing for time.

The negatives would be a less than optimal power output. Again, I've dissected a lot of TT files and you'll generally see the highest power is developed in an 8-15 RPM band. It can be a linear to severe drop off (I'm in the latter group). I'm not sure you can train around this; my track experience so far has shown most people gear to their range for the crucial part of each event.

Worth reading Obree's book for some insight as to when he went fixed or geared. Of course he was a little daft but there's some interesting stuff there.

rruff

I didn't bring it up either.

Me too. The parts you are missing are a) the natural tendency of a person to protect their unprotected head, and the tendency to not protect it if it is deemed "safe". When we crash the head is the only thing that *is* protected at all. And b) the difficulty in tucking and avoiding a significant head impact with an extra 2-3 inches of dimension added to the head. In my numerous cycling crashes, the only time I hit my head would likely have not happened without the helmet.

But this is really anecdotal anyway. If population studies, and studies of pro cyclists show no benefit due to helmet wearing, then my money is on it doesn't help... whatever the reason.

Nate552

Based on your studies, would Jens have benefited by not wearing a helmet during his crash in the Tour de France 2009?

https://www.metacafe.com/watch/3086720/nasty_crash_2009/

Dean V

I used to do our local 10 mile TT on a fixed gear almost 20yrs ago. I have just started doing it again but have been using gears so far. I am going to try it with a fixed gear next time out. Always used to really like riding it on the fixed gear. What length cranks are you using? I had 165mm, mainly because that is what was on the bike. Had a best of 22.05 for the 10 miles back then, and now the best so far is 23.07. Used to ride a 51/14 or 51/15. Did basically identical times with either.

Racer Ex 

Actually I'm not.

I don't wear a helmet for the many crashes when I can instinctively protect my head, which is your natural reaction, helmet or not. I do it for when I can't.

My one concussion on a bicycle came from a Jens similar moment when I was unprepared and hit an object that threw me over the bars. I landed on my back hard enough to crack my helmet into five pieces (the hard plastic shell held it together); Semi conscious I dragged my head along the pavement long enough to shave a fair bit of helmet off. My best efforts would not have prevented my head from impacting the pavement hard, I've little doubt I would have had significant scalp injuries and possibly a skull fracture with the helmet.

In another I was struck from behind during a crit; similar outcome sans concussion, but with a broken rib. I've written off three motorcycle helmets, two from race accidents and one from being struck by a car; one of the race accidents was at a speed not uncommon for cyclists who live in hilly areas.

If I drop you on your head from 5 feet at 45 degrees, one or two inches is less than a second at best worth of avoidance or in lack of acceleration. It's a fraction at 25 MPH.

This is the case in most head impacts. You don't choose to strike your head. Physics chooses and in those cases the fractional distance change between a helmet and not is insignificant. If you could have prevented your head from hitting with an inch to spare in both cases you will not be injured. To claim a helmet would cause an injury in this case is absolute garbage physics.

Any protective instincts are hard wired. During a crash no one makes a conscious decision NOT to protect their head if they are wearing a helmet. That's an instinctive reaction; go up to any cyclist wearing a helmet and swing a tennis racket at their head...they will duck and cover.

But saying you don't need a helmet or they are minimally effective because you naturally protect your head is exactly like saying you don't need seatbelts or airbags because you naturally steer away from a direct impact (an argument that was used during hearings about making seatbelts mandatory BTW). It presumes absolute control over how and when you crash. That's a poor premise on which to base your choice of safety equipment.

However if you are saying you don't like helmets or are willing to accept the statistically small risk of hitting your head and ride without one, I've no quarrel.

rruff

Have you ever fallen with a fragile object in your hands? I have a few times... and I don't behave the same as when I'm holding nothing. You don't have to make conscious decisions... you believe that your helmeted head is fairly well protected and you act accordingly.

You are missing the point... helmets have been statistically *proven* ineffective for cycling. *Why* they are ineffective is another topic entirely. If seatbelts were statistically proven ineffective, then there would be no case for using them either.

caloso

Very nice. I did my last triathlon on FG, just for ****s and giggles, and posted the 5th fastest bike leg (and a PR).

Basil Moss

Can you people PLEASE stop whining about bloody bicycle helmets? That isn't what this thread is about. I'm not trying to tell you what to wear, or belittle you for your choice of headgear, so can you please extend the same courtesy to me? In the UK there are just a few people who try to tell you you should wear a helmet, but when they realise that you've made your own decision, and that it isn't just because you hadn't considered how immensely dangerous cycling is, they let the subject drop. Perhaps you could be polite enough to do the same thing. For what it's worth, I smoke the odd cigar, and a pipe now and then. I eat red meat, drink wine and beer, and like my breakfast fried in butter. If you want to take issue with my personal choices, that's all well and good, but perhaps you could direct your hate towards my PM box where it won't clog up this thread which is about FIXED GEAR TIME TRIALS. Thankyou.

The front wheel is a mavic CXP 30 built on an Ultegra hub. I'm using 175mm cranks, because they suit my gangly legs better. I was thinking about trying 180's, but that was before I grounded a pedal two laps in succession in a road race yesterday (not riding fixed there of course!). My best in a 10 is now 20:57, I set it on our fastest course using a 52-15. This Thursday I ride the same course again, I'll use 54-15 just to see what happens. No pressure to set a pb this week though, I'm in the middle of a tough training block, so don't expect to have super legs by Thursday. I've not tried anything with a 14 cog yet, but maybe will give it a try next year.

I think you are partly right about fixed forcing discipline- you basically can't make it easier by changing gears, all you can do is think "faster!" and try to do it. I become very focused on my effort, because it only changes quite gradually with terrain and wind, so it's quite easy to nudge it as close as possible to the red line without the risk of going over it.

Most of our courses are out and back, I've not ridden one with a truly raging headwind yet, but in moderate headwinds I do very well, probably because there's no option of gearing down, so I just have to push on. I imagine that would knacker the legs after a while though- they are pretty much shot after a 25 on a big gear. I've ridden with a howling crosswind though, last Thursday, and recorded a course best time. That improvised disc wheel seems to do the job!

Grumpy McTrumpy

I agree with the OP. This isn't a helmet thread.

Nate552

I agree with the mentality of the FG. Is that course relatively flat? Would you consider FG on a rolling or hilly course ?

botto 

^
iirc stuart dangerfield won a few hill climbs on a fg. or perhaps it was a single speed. can't remember. this was +/-15 years ago.

Basil Moss

The hillclimbs are still regularly won on fixed. The national was year before last. As I said, most of our courses are rolling, and I still get better results on fixed. The flat ones are where I set pb's of course, but I have set awesome course bests on fixed.

caloso

I should set up a 39-25 fixed for Mt. Diablo.

Racer Ex 

No evidence to support that helmeted riders behave differently in a crash. Zero. Plenty of video from Moto GP guys crashing; when they are sliding (not tumbling) the one constant is they hold their "protected" head off the ground.

And again the "statistical" evidence is poorly done and the conclusions questionable. The lab work on what and how a bike helmet protects from impact is not.

So I presume you no longer wear one?

No. And if you read any of my posts I support your right not to wear one so don't go off on some pointless "it's my choice please respect it" when I've already said I did. And my guess is RR does also. And I'd point out that you proceeded to write a paragraph about helmets after asking us to stop. And also the helemt conversation IS NOT ABOUT YOU.

Unless WR died and made you a moderator, I'll post about my socks in here if I want to. You're the guy talking about magic fairy dust and how there's no way you could push a freewheeel as fast as a fixed gear. I was nice and cut you some slack but you know what, if you can't push a freewheel as fast as a fixie, that's on you.

And BTW, here's a repost of what I wrote that pertains to that subject, apparently in your hissy fit you missed it:

Back to the fixed gear TT thing:

I actually considered it for a couple of courses here. Biggest issue is most of our stuff is "out and back" and we're often dealing with 10-30 MPH wind on our head or tails on the different legs. In one case the "out" leg took me 30 minutes, the "back" leg 10. Just too big a change in cadence to make that work.

Biggest benefit I can see from a fixed wheel TT bike is it's forced discipline; you have to keep positive pressure on the pedals, in doing so you're keeping a positive wattage and for some people it no doubt smooths their effort. I've looked at a lot of TT power files and most are pretty jagged...people lose concentration or take mini "breaks" on downhills. Never a great thing for time.

The negatives would be a less than optimal power output. Again, I've dissected a lot of TT files and you'll generally see the highest power is developed in an 8-15 RPM band. It can be a linear to severe drop off (I'm in the latter group). I'm not sure you can train around this; my track experience so far has shown most people gear to their range for the crucial part of each event.

Worth reading Obree's book for some insight as to when he went fixed or geared. Of course he was a little daft but there's some interesting stuff there.

Dean V

I am not sure that analysing TT power files from a geared bike would be completely accurate with regard to the power vs cadence. I find that when you have gears you tend to use them. That may sound obvious but what I mean is that when your cadence starts to get out of your "zone" instead of concentrating on spinning faster or pushing harder as would be required with a fixed gear you just move the gear lever. Subsequently you may not get a true indication with regard to what you are really capable of with regard to power output over a range of cadences.

chasm54

I'm not so sure about that. There's something about the dynamics of riding fixed that is different, and unless you have a perfect pedalling action - very few do - I'd be inclined to believe that at similar cadences one is inherently more efficient on fixed.

Of course that begs the question about terrain, and whether one could maintain optimum cadence over an undulating course. But on a flat course, I'd back the FG rider with the appropriate ratio against a freewheel rider.

Obsessional, no doubt. Eccentric, certainly. A long way from daft, though.

pjcampbell

there is a flat half ironman I would consider doing on my track bike... it is pancake flat.
not sure if it is legal even with a front brake?

brianappleby

That simply isn't true. The ONLY time fixed differs from a freewheel is when you're coasting. If there is positive pressure on the pedals throughout the entire pedal stroke, your body can't tell whether your bike is fixed or free. It's in your head.

Dean V

A fixed gear must be more efficient than a derailleur system. There is perfect chain alignment and no pulleys that the chain has to snake through. As to what the % difference is I don't know. Must be some data somewhere.

chasm54

Re-read what I said. I said "unless you have a perfect pedalling action" FG was more efficient.

The point is that very few people do have a perfect pedalling action. The vast majority, even among experienced riders, cannot maintain a consistent positive pressure - it may be constant, but it isn't consistent, there is a deadish spot at the top of their stroke. So what you say is true in theory but only rarely so in practice, IMO. It isn't just in the head.

brianappleby

The pedal stroke doesn't have to be perfect, just good enough so that the freewheel never disengages. An inconsistent pedalstroke on a fixed gear or a freewheel will have the same result: small surges on the power strokes, and small lulls in the dead spots. This would exist on a FG just as much as it would on any other bike.

chasm54

We'll have to agree to disagree, but the experience of riding a FG leads me to conclude that it ain't the same. The FG imposes a maintenance of momentum that the freewheel does not, so in the latter case an imperfect pedal stroke seems to me to cause a greater deceleration, or "lull" as you describe it, than on the FG. Short of a laboratory test we aren't going to be able to prove our point, I'm afraid.