Wednesday, July 06, 2016

Racing - Throwing Your Bike (Pictures)

I wrote a post a while back about throwing your bike, meaning doing a bike throw at the finish of a sprint. I know that I'm somewhat obsessive about bike throws, even doing bike throws when I'm well clear of the field.

However, my livelihood doesn't depend on it. I still do them, just because I want to do the best I can with what I have. I do bike throws because I don't want to leave something to chance.

It's a very minor one, I thought I was clear so I threw the bike out of habit.
I'm not way over the back wheel.

This is a pretty poor bike throw, I've gained maybe 6-12 inches forward travel on the bike. My head would normally be over the bars, or even in front of them in an all out sprint, not behind them. If I had to really reach I could have gotten another 6 inches of reach I think.

The picture below shows just how safe I was playing that finish.

That's me up ahead, the speck below the red and white tent awnings.
Like I said, I threw the bike just to be safe.

And today, July 5th, 2016, in the Tour, I think that Direct Energie's Coquard had the sprint in the bag. He simply could not finish it off with a good bike throw.

Bryan Coquard's finish in Stage 4 of the 2016 Tour de France.
Picture from BH Bikes USA, Facebook.

The significant thing here is that Coquard is sitting on his saddle.

This means he did not do a bike throw at the finish.

Remember that you're classified as finishing when your bike breaks the plane of the finish line. I think if the bike is crashing then it's not necessarily the front tire, but in a normal sprint you're looking to put the front tire to the line before anyone else. That's key because it means that you're not as concerned about your head, your torso, etc. It's the front tire of the bike.

The way a bike throw works is the rider moves momentum/inertia from one part of the bike/rider unit to another. Since the rider, even a skinny Tour racer, is heavier than their bike, a racer can shove themselves backward on the bike to move the bike forward. If you shove the bike forward relative to your body you will momentarily slow your body. In return your bike will accelerate.

Say you weigh 160 lbs. Your bike weighs 16 lbs. If you move your body back one inch, your bike will move forward 10 inches. This means that if you move your bike forward, relative to your body, just an inch or two, you'll gain half a wheel in the sprint.

Okay, that's not totally accurate. There's wind resistance, there's friction, and there's the fact that part of your body is moving with the bike (your hands, feet, some of your arms, most of your legs). Plus there's the whole "how long are your arms" question - if you can't reach further forward then your bike isn't going forward any more.

The reality is that if you move your hips back about 8-10 inches you'll realistically get your bike forward maybe 12-18 inches. It's not ten to one ration between yours and your bike's movement, it's more like three to two. Still, though a foot is significant if you're losing the sprint by a an inch.

The wrong way to do a bike throw is to simply straighten your arms. You don't move your body relative to the bike so the bike doesn't leap forward. This is what Coquard did at the end of Stage 4.

The right way to do a bike throw is to extend your arms as you drop your pelvis behind your saddle. By pushing your pelvis behind your saddle you're moving the most mass possible as far back as possible.

This thrusts the bike forward.

This is the bike throw that basically started the blog.

Once I realized I could sprint on the bike I started looking at how to optimize my sprint. I learned about bike throws, figured out the physics thing (thanks to school), and from then on I was doing bike throws all the time. Easy ride? Throw my bike to whatever shadow was in front of me. Waiting in the parking lot for a group ride? Bike throws to empty parking spot lines. Group ride? Bike throw at town line sprint.


Bike throws for sure.

Over the course of 30-odd seasons I don't think it'd be unrealistic to say that I've done maybe 10,000 bike throws. If I did 300 a year that would be about 10,000. I probably had single days where I did 50 or 75 or even 100 bike throws. I even had bike throw mishaps, like when I went out on a ride on my Aerolite equipped bike with slippers on instead of cycling shoes.

For a long time I never thought I'd really use a bike throw because I seemed to get shelled all the time. Eventually though I started sprinting, started placing, and started doing bike throws for real.

I did get an interesting place in the Tour of Michigan due to a bike throw. We were sprinting curb to curb, about 10 riders across. I was stuck in the second row. The first row was somehow, magically, sprinting at basically the exact same speed, within a foot or two of one another.

The second row was soft pedaling, waiting for someone to blow, waiting for that gap to open to allow them to surge past that blowing up front row and win the race.

The gap never happened.

At the line I thrust my bike forward as far as I could. My front wheel ended up at or past some of the front row riders' pedals and cranks. I thought I might lose my wheel to those spokes.

There were 10 riders in the first row of sprinters. I got 11th in the race.

Fast forward about 11-13 years. I was one point behind Morgan in the overall in the Bethel Spring Series. I had to beat him in the sprint, and get top 7, to win the Series overall. As a sprinter I was definitely one step behind Morgan. He could beat me straight up; I was close only because he skipped a race, I think because it was raining and he'd used himself up in the Masters race.

Coming into the sprint I followed Bethel Cycle's four man leadout train. They had two sprinters, Stephen G and Bryan H. Both of them would win the Series overall in other years - they are both very good riders. I sat on their wheels, waiting for the right moment to pounce.

I jumped very late, trusting in my jump to give me the best chance against Morgan. We sprinted at similar speeds (he a bit faster) but in the jump I possibly had an edge.

I sprinted towards the finish. I'd jumped hard I thought I had it made. I was debating if I should raise my hands or not. Then, just before the line, to my right, I sensed something.

I looked.

To my horror it was Morgan. He'd gotten boxed in going into the sprint (when one or both of the Bethel sprinters blew up), had to back out of that spot, and was now closing with a fury. He was sprinting noticeably faster than me. I had to get to the line before he passed me for good.

I did a couple more pedal strokes and desperately threw my bike at the line. I threw the bike so hard I lost my grip on one side of the bar, causing me to veer crazily toward the left curb.

But, in all that, I'd done a good bike throw. I'd won the race, and with it, the Series.

You can see here that I'm only slightly ahead of Morgan.

I'm rapidly slowing in the sprint at this point. It's hard to see in the pictures but in the video you can see that I'm not going as fast as Morgan.

However I'm already getting into the bike throw at this point.

As my body extends back my bike moves forward.
I'm trading my body's position to gain bike movement.

At this point I'm going to win the race. I'm deep into my bike throw, I'm still not fully extended, but my front wheel is already ahead of Morgan's wheel.

I'm still extending, trying to get my hips down.

At this point I'm still getting further back on the bike. My head is coming down really hard, hard enough to hit my helmet to my stem. I can feel the saddle in my stomach and I'm hoping that I don't fall back into my own rear wheel.

The finish.

I'm fully extended and on the edge of losing control. The saddle is firmly in my stomach and I have marginal control over the bike.

However, if you look at Morgan, you can see he's really only raised himself up out of the saddle. If he'd thrown the bike forward it would have been a closer race. I always compare head position relative to the line - my head is forward of Morgan's so I think I'd still have won. However it would have been much, much closer.

His hips are basically in the same place as mine, and if he had a similar torso length as me, I think his head would have been about even with mine. It would have been even a closer race.

Bike throws are quick. In pictures they look nice and neat, but in reality it's a little spurt and that's that.

The bike throw for the 2005 Bethel Spring Series (go to just before 6 minutes into the clip for real time, 7 minutes in for slow motion):

Coquard, in the sprint for Stage 4 today in the Tour, didn't move his bike forward relative to his body. If he had done so he realistically would have taken the stage.

The last kilometer, courtesy the Tour (no commentary):

 I did notice that virtually no one threw their bikes at the line, even Kittel. It might have been that the uphill drag was particularly tough. However that's even more the reason to throw the bike, because if only one rider throws his bike...

For all us normal racers the bike throw is an easy skill to practice, you can do it all ride long on easy rides, you can do it warming up for races or group rides, you can even do bike throws when you're testing riding your bike (or someone else's bike). It's a skill that you should master and use. You never know when it'll come in handy.


F16F22 said...

Hi Aki, nice post. Did you see the finish on stage 3 where Cav narrowly beat Greipel? In that case, it looked like Cav got in an extra half pedal stroke prior to his throw. I think that was the difference in that one.

Aki said...

I didn't see it. I looked at the Tour's last KM clip (seems the best to review with no commentary, very short, etc) and you're right, Cav pedals through his bike throw. I do what Greipel did. I think, based on their pedal position, Cav got most of an extra full pedal stroke in.

Greipel is one of the guys that does good bike throws, meaning he ends up far behind the bike.

Sometimes I've come up to the line and do the bike throw a bit early because I'm so blown. When I'm feeling better in the sprint I'll go right up to the line and do a throw - it's super quick and over in a flash. I remember one race where I threw the bike so early I think I did about 10 feet coasting with the front wheel hanging out in front of me. The officials even commented on it - why did you throw the bike so early?? I think I didn't beat anyone in that throw, probably out of 4 other riders I was last, and it wasn't even for the win. In that case I was so blown I didn't think I could get to the line pedaling so I just did a bike throw.