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-   -   500M TT: Track Bike or Road Bike Faster? (http://www.bikeforums.net/track-cycling-velodrome-racing-training-area/882900-500m-tt-track-bike-road-bike-faster.html)

refthimos 04-08-13 03:38 PM

500M TT: Track Bike or Road Bike Faster?
 
500M time trial.
Standing start.
333m outdoor concrete track.
You can ride either track bike or road bike.
Assume track bike has slightly better aerodynamics (solely due to lack of drivetrain components, brakes, cables, etc).
Assume track bike is slightly lighter.

So does the track bike's power transmission and other slight advantages overcome the road bike's ability to shift gears and keep the powerband in an ideal cadence zone?

Brian Ratliff 04-08-13 04:25 PM

You don't get to shift gears on your road bike during a track time trial. At least not where I come from.

refthimos 04-08-13 06:08 PM

Quote:

Originally Posted by Brian Ratliff (Post 15486249)
You don't get to shift gears on your road bike during a track time trial. At least not where I come from.

Your "response" is not responsive to the question. I am more than aware of how track events are run, I ride both road and track, have both road and track bikes, yadda yadda yadda. This is a special event where both road bikes and track bikes are allowed. Thus the question.

Nagrom_ 04-08-13 06:16 PM

If you can shift the road bike it's not really a contest. Especially with a standing start, at only 500m. A road bike would have a quarter lap advantage right from the gate, and would easily be able to keep it all things equal.


No amount of minor aerodynamic/weight advantage is going to trump the ability to shift.

refthimos 04-08-13 06:43 PM

Quote:

Originally Posted by Nagrom_ (Post 15486695)
If you can shift the road bike it's not really a contest. Especially with a standing start, at only 500m. A road bike would have a quarter lap advantage right from the gate, and would easily be able to keep it all things equal.


No amount of minor aerodynamic/weight advantage is going to trump the ability to shift.

This was my inclination as well - I do feel like a fixed gear track bike also transmits power better and makes spinning a higher cadence easier, but being able to shift and keep at a more efficient cadence seems to be the way to go.

Anyone think differently?

Brian Ratliff 04-08-13 07:12 PM

Quote:

Originally Posted by Nagrom_ (Post 15486695)
If you can shift the road bike it's not really a contest. Especially with a standing start, at only 500m. A road bike would have a quarter lap advantage right from the gate, and would easily be able to keep it all things equal.


No amount of minor aerodynamic/weight advantage is going to trump the ability to shift.

Bingo. Anyone with a brain will bring a road bike. Who needs cadence when you can start on a 75" gear and end in 100+"? It's not even a question.

And I apologize for bringing up the issue of a standard race... I thought you were just confused (you neglected to outline the context for your question). The advantages of shifting are so overwhelming, especially in a start-dominated race like the 500m, I didn't think the question was serious. To equalize, you need to de-emphasis the start advantage of the geared bike: so 2k or longer pursuit.

brawlo 04-08-13 09:06 PM

My idea in this is that a track bike would be faster in the 500TT.

Despite the better start gearing, 500m gives time to wind up a track gear. Thinking of the standing start body positioning, sure you could start well on a roadie, but you have to compromise the positioning to change those gears, meaning you can't apply the same amount of torque for the same duration. Then from a personal perspective, I can't spin my road bike well at anything over 120rpm. Yes you can push harder gears, but you are using torque rather than power. When you're pushing for speed, you want power, and that power, from what I've read, comes at 120-130+ rpm. I can go into that range on my track bike and sit there for at least 100m. From doing top speed runs at training, I know it takes me around 250m to wind up to my top speed in a 94.5 gear and I can hold it for 100-150m, so then I just have to hold on for 100m. From longer sprints on my road bike, I know I can hit higher speeds, but that takes a leadout, and it also takes longer in terms of distance to do it.

I would think of it like a chariot race. Those that can get up to speed quickly and be able to hold it until the end can usually finish first. Those that are on higher gears are spending too much time winding up, and although they finish faster in speed, they take too long to get there.

Then of course you only get one chance with a track bike, pick the wrong gear and you're gone. The road bike is adaptable in this respect. Riding a track bike will mean doing your research/training to know what gear suits you best.

Brian Ratliff 04-08-13 10:22 PM

Power is torque times speed. You can trade one for the other. Turning 120" gear at 90rpm takes the same amount of power as spinning a 90" gear at 120rpm.

carleton 04-09-13 02:42 AM

The track bike would be faster in a 500M standing start, hands down. Probably in a Kilo, too.

carleton 04-09-13 02:56 AM

...the key being, as Brawlo mentions, is that you can't stay on the torque and shift gears.

For sprinters, the 500M is a very violent event :)

ochizon 04-09-13 08:03 AM

am i nuts for thinking the road bike has is at a DISadvantage on the launch? I would break my bike and fall over if i tried to launch my roadie like i do my track bike. Launching is a skill with much technique, and a road bike would mess with all the mechanics of a standing start (imo).

And in a 500m race, launch is everything.

Nagrom_ 04-09-13 08:16 AM

You definitely wouldn't need to start in a similar fashion on a road bike. That's what the gears are for. You can also still shift under power, it may not sound pretty, but you can. This isn't the 80s.

TMonk 04-09-13 10:07 AM

or you could let of the gas for the fraction of a second that it takes to shift...

i see where youre coming from carleton but on a road bike you can accelerate so much faster starting from a lower gear

McRussellPants 04-09-13 10:36 AM

I vote track bike.

If you had a two speed that'd be different, but you'd have to go small ring to big ring, which would take forever or drop through 5-9 gears on the cassette. I don't see a fast way of doing it and staying at a max effort.

Brian Ratliff 04-09-13 10:47 AM

Quote:

Originally Posted by McRussellPants (Post 15489094)
I vote track bike.

If you had a two speed that'd be different, but you'd have to go small ring to big ring, which would take forever or drop through 5-9 gears on the cassette. I don't see a fast way of doing it and staying at a max effort.

Why small ring to big ring? A 75" gear is a 53/19. That's plenty low enough to produce a really screaming start and only three shifts of the cog away from a 102" gear on an 11-25 10 speed cassette. Even starting in an 84" (53/17) or 89" (53/16) - depending on the cassette spacing - and shifting down just one or two cogs to a 95" (53/15) or 102" (53/14) would give you both a huge start and a high top end. Multiple gears means not having to compromise. This is, of course, assuming the bike stays in one piece. As Carleton said, the 500m is a pretty violent event.

That said, I think you'd want to go and practice these gear shifts to make sure you kept the rubber side down during the gear transitions, and I would be nervous with a road bike at all on a tight track such as my home track, Alpenrose. It would be a totally different strategy from starting a track bike and you'd have to practice it.

refthimos 04-09-13 10:47 AM

This is really interesting stuff, since there is no consensus, with some thinking the road bike would be the way to go while others would stick with the track bike.

I wonder if opinions are divided among roadie/trackie lines, i.e. are those who would prefer the track bike primarily track riders as opposed to road, and vice versa...

VanceMac 04-09-13 10:55 AM

I tend to go with Carelton here. Not as black and white as it appears on paper. For really strong sprinters who are experienced on the track, I think they will do better on a track bike. For roadies without much track experience, they are going to do better on a road bike (especially with a little coaching on selecting a starting gear where they only have to shift ONCE).

At the club event to which the OP refers, they allow road bikes in order to be inclusive. It's a lot of fun, and for many people, their first exposure to track. All the trackies use their track bikes. Last year, out of 70+ riders, the top 9 times were all track bikes (that in itself doesn't tell us anything, really... selection bias)... and the top road bike time was 4 seconds off the fastest time.

Spoonrobot 04-09-13 11:00 AM

What's really something is that I think the result depends on the rider. If Chris Hoy is going to compete against himself, is he faster on his road bike or his track bike?

But if you assume it's a baller track cyclist versus equally baller road cyclist, I think the track cyclist is going to win.

Hermes 04-09-13 11:17 AM

I am a 500 meter guy. What is missing from the discussion is the starting technique and the ability of a racer that executes it properly to accelerate a bike fast in a big gear. The human engine is pretty good at high torque at zero speed.

Also, a road bike is not going to work very well accelerating in the turns. In fact, it will be all over the lane and not feel right. When the bike does not feel right, I tend to ease up which is the kiss of death in a 500. Road bikes are great going straight putting in a lot of power out of the saddle but not so great turning while putting in power out of the saddle which is where you will be standing for the high torque high power portion of the 500 on a 333.

The rear dropouts of a road bike and quick release skewers are not designed for 500 meter high wattage starts at zero speed. Pro road sprinters can do 2000 watts but it is at higher rpm. So it is very likely that if one can do a great standing start on a road bike, the rear wheel may pull out and damage the bike. Track bikes have beefy horizontal dropouts and the rear wheel is bolted on. On occasion, trackies twist the rear wheel even on a track bike.

How is the shift in practice going to take place and what is the gearing sequence. Let's assume you get three cracks at a gear change.

Assuming one has a 53/39 on the front of the road bike, let's assume we use the big ring. If we start in a 53/17 or 84.2 gear inches, our next shift is 53/16 or 89.4 inches and the finishing gear is 53/15 or 95.5 gear inches. With each shift, the racer will load up his legs and there must be a reduction in power to make the shift. And one will be out of the saddle when doing this. The loading of the legs and shifting will cost time.

If I started in 84.2 gear inches, I would be spinning 95+ rpms out of the first turn. So for me, I would get a fast first few pedal strokes which would be good but I would need a gear change right away. 89.4 gear inches is not going to be enough and 95.5 too much. I will blow throw 89.4 quickly. So for me, this sequence of gearing would be a disaster time wise. I will do much better starting in a 92.5 and keeping it the entire race. My start will be fast but slower than the smaller gear but my acceleration out of the first turn on the straight away rapid. However, trackies train to accelerate leg speed. So with each pedal stroke, I unload my legs. So the acceleration is fast and I do not lose time shifting and I do not load up my legs with a shift.

A 500 meter racer is a sprinter and the time will be a function of strength, leg speed and weight. A geared bike provides overhead that cannot be used effectively in practice. The track bike is faster for a trackie. A road bike will be faster for a roadie until he becomes a trackie.

Hermes 04-09-13 11:23 AM

A 500 meter race is a full gas all out effort. There is nothing measured. When I am in the starting gate I am thinking full commitment full gas. Thinking about a gear change and when to shift adds mental overhead as well.

Nagrom_ 04-09-13 11:29 AM

This is a good thread, and I don't think there is a concrete answer.

Great discussion.

McRussellPants 04-09-13 12:36 PM

Quote:

Originally Posted by Brian Ratliff (Post 15489158)
Why small ring to big ring? A 75" gear is a 53/19. That's plenty low enough to produce a really screaming start and only three shifts of the cog away from a 102" gear on an 11-25 10 speed cassette. Even starting in an 84" (53/17) or 89" (53/16) - depending on the cassette spacing - and shifting down just one or two cogs to a 95" (53/15) or 102" (53/14) would give you both a huge start and a high top end. Multiple gears means not having to compromise. This is, of course, assuming the bike stays in one piece. As Carleton said, the 500m is a pretty violent event.

That said, I think you'd want to go and practice these gear shifts to make sure you kept the rubber side down during the gear transitions, and I would be nervous with a road bike at all on a tight track such as my home track, Alpenrose. It would be a totally different strategy from starting a track bike and you'd have to practice it.


I'm thinking of limiting shift times, I don't think a chainring shift would be effective in practice at all.

If you could jump from 75-110gi in one shot I think it would be easy for the geared bike, but having to click down through 5 to 9 speeds on the rear cassette you'll be off power so long the track bike could come back.

500 is too short I think, Legs are like electric motors, they make the most torque at 0rpm, the only reason to push 120rpm is the mechanical advantage is better than a gear pushing 40rpm and you wont wear out as fast. I'm thinking that its such a short time to blow yourself out, that just hammering through that tall gear from a start would get you to the finish line faster.

Road bikes are really set up for sub maximal efforts, and the 500 is still short enough to be mostly about the best maximal effort.

carleton 04-09-13 02:21 PM

Quote:

Originally Posted by Nagrom_ (Post 15489407)
This is a good thread, and I don't think there is a concrete answer.

Great discussion.

No. There is a concrete answer...you just refuse to acknowledge it :)

Nagrom_ 04-09-13 02:39 PM

Quote:

Originally Posted by carleton (Post 15490213)
No. There is a concrete answer...you just refuse to acknowledge it :)

I just acknowledged that my own answer may not be the answer, which could be acknowledgement that your answer may be the answer.

Maybe... Haha. I'm not convinced yet.

Hermes 04-09-13 02:54 PM

Nagrom, Do you compete in the 500 meters at the track?


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