skinnyone

or a big no-no... I have often been in this situation when I sprint. I hate to be in a gear where I have to use a lot of power to even spin up to 80/90 rpm. I mostly settle on a gear where I have to use a good first step to turn over the cranks and then spin up in the next 5-10 strokes but I run the risk of spinning out... I am scared to upshift at this point - you can the thud-creak under the strain put on the chain and casette and it does affect your handling a bit as the chain throws to a smaller cog..

To shift or not to shift is the question...

[p.s - As a rule I never shift when out of the saddle... ]

TheKillerPenguin

you can do it and do it smoothly provided the cog jump isn't too large. If you're sprinting you'll most likely only be losing 1 tooth when you downshift. I do it when i need to, although i try to select a good sprinting gear that I wont need to shift out of.

ETQC

I finally found out how I could shift so well while out of the saddle yesterday.

I time it so that my shift is when my left pedal is at 10 o'clock, as seen from the right. This is pretty much a dead spot in power. At that point, I shift my weight a little bit to the left, causing my hips to rotate to the left, which stores some energy.

This is done while pedaling the whole time, the hip twist (damn, can't believe I'm actually writing this) just allows the shift to go trough while very little torque is put on the drivetrain.

Another way to see this : I "push" a little bit more on the downstroke from my dominant leg (right, in this case), which shifts my weight to the left, and while in the dead spot, the shift does trough.

It actually feels pretty natural.

Elvish Legion

Shiftting out of the saddle scares me, my chain has a habbit of wanting to slip on a shift of the big cog and I'm worried I'll come down hard one day.

TheKillerPenguin

that can be fixed with a few twists to the barrel adjuster.

Elvish Legion

Yeah I know, I'm taking it in for its 100mile check in prolly this weekend, and I'll complain to the mechainic haha, well not really. But they told me to bring it in soon as my wheel is coming out of true...Alx275s...I can't remember if those are the bad ones....

my58vw

You should not have to shift when out of the saddle.

Sprinting mechanics...

1. Standing... 10 - 15 pedal strokes, high gear i.e. 11-14, gets momentum going maybe 30 - 31 MPH range, sit at cadence at say 90 RPMs in the drops

2. Sitting... the spin up. Spin the same gear to about 120 - 130+ RPMs while in the saddle and in the drops

3. Holding or shifting... Hold the cadence for the remaining of the sprint or shift up and re spin up in the saddle.

This all happens in 15 - 20 seconds, very fast. There is no problem shifting under high load if the cadence is high (i.e. 110+ RPMs). Personally I have shifted in a prime sprint but not in a final sprint. It is all about technique, personally I have never gone above a 53-12 in a sprint, actually even a 53-13 at about 125 RPMs.

WaitUpForMe

What cadence are you usually at that you have to spin up to reach 80 or 90?

It might help if you practice jumps; you can randomly sprint for signs or phone poles during a ride, or you can do a couple sets of x repetitions as a specific workout. Downhills are good for developing the leg speed to get your RPMs up.

DannoXYZ 

I usually start my sprints at 90rpms minimum for maximum acceleration. Out of the saddle up to about 105rpms or so, then sit and spin up to 130rpm. Shift up, out of the saddle for a couple strokes to really crank on it, sit and spin up to 130-140rpm, shift and stay in the saddle and spin up to 130rpm. I'm usually right at 41-43mph at this point and gotta keep the spin as high as possible to maintain that speed because i'm already pushing as hard as I can on the pedals all the way around, the only way to generate any more power is with more RPMs.

I've found that with my track-riding, I've gotten much, much smoother with my pedaling motion and can actually sprint in the saddle almost as fast as out (not as efficient). Cool part about sprinting in the saddle is that no one realizes you're moving so fast until you've gapped 20ft and still pulling away... heh, heh...

Remember that power=F * D / t, or power = F * RPM, once you're pushing on the pedal as hard as you can, you're maxed out as far as power-output. The only way to increase it is to spin faster. Another way to look at it is if you've got two evenly matched guys who can both push on their pedals with 200lbs force all the way around, one guy pushs 200lbs @ 90rpm and the other pushes 200lbs @ 110rpm, the 2nd guy's gonna be going faster and pulling away...

'nother

Wow, yeah, this is exactly what I do. Thanks for expressing it in words, I never examined it at that level of detail because:

skinnyone

I usually stay btw 75-90 odd RPM and I should have said I have trouble in a high gear to get spinning up to 90/100 rpm.... After the first stroke you take, my cadence drops a wee bit and then with subsequeent strokes I spin up... I have heard a lot about doing jumps, that it helps the whole sprinting process and coordinates your first step etc... I will try that out..

Thanks for the advice all around.

PolishPostal

A 53-13 @ 125 RPM is 39.8mph. Your pretty good.

divekrb

This year I did some sprint drills with a top level Pro 1/2 guy who wins a lot. He wouldn't agree with you, and based on several wins, primes, and the prizes that went along with them thanks to those drills I wouldn't either.

RC2

Gotta love the downhill finishes.

krazyderek

i have up shifted(stupid term, cause the chain is going down hill on the cassett) when sprinting, if you're doing sprints from a slow start (strategic) then its hard to do the whole sprint in one gear, after a certain point you just can't spin any faster, but if you start in a harder gear, it'll take to long to get up to speed from a coasting start.

If you're confident on your bike you shouldn't have any problem shifting when standing, sprinting, or climbing. It's all about timing and just getting used to easing off the preasure and just balancing your weight on both crank's for an fraction of a second.
When you're sprinting, as someone already said, cadence is usualy already pretty high around the 120's so the shift happens so quick that it almost doesn't require any compesation, by the time you start worrying about weather or not the chain is going to skip and cause you to blow up in a ball of fire, the resistance on the pedals has already increased and all you are(or should) be concentrating on then is pushing harder and faster to get ahead of the guy you're trying to sprint past/attack.

skinnyone

Reading the responses, it occurs to me that a sprint in a race is way different from sprinting for a town line... Obviously I havent raced yet but I am assuming that in a race you have a leadout, whereby your cadence is already high, and then you go crazy and put your head down.

Town line sprints, at least the ones I am part of, are pretty much reacting to the first attack and shooting for the line.. There is no spinning at a high cadence and the second coming after being out of the saddle.. Maybe I need to practice this...

I after all intend to start racing next year and for a guy who is 140 I need all the good technique I can develop...

TheKillerPenguin

Try initiating townline sprints farther out by getting up to a near sprint speed in the saddle. If others want to win, they'll follow! The stuff you do now is good practice for when you'll have to chase down attacks and catch faster trains, since you're going from a cruising pace to a sprint. I always forget we do town sprints in my group and the result is a late jump in too big a cog, hence me being used to shifting while sprinting.

Smoothie104

Skinnyone krazyderek has some good points....


The sprint for the town line, and the finish line in a race are the same, the reason they seem different is that you dont have 50 plus guys all trying to get to the town line to win $35.00 With their parents and significant others watching/judging etc..

That being said, learning to win from a small group is a valuable skill to have, so don't pass up the opportunity to practice.


But Yeah, this standing, sitting, spinning, standing again is not what some would consider spriting. The sprint is all out for the last 100 meters or so, anything prior is just positioning, or attacking and holding it.


This is one of the reasons that a good lead out is essential, It keeps the speed high, to discourage attacks, and allows you to sprint without worrying about having to ramp up to sprinting speed.

You can shift while standing, if you do it carefully. just a slight softpedal while the chain flicks over.

You may lose a little momentum however, so If you are coming up to the finish line, you are best to stay in the gear you are using. If its to gain position of jump on the wheel of an attacking rider, then do whatever you have to do.

Ideally, you want to follow wheels till the last 200 meters of less, so once you stand up to try and get around everyone, you only have 10 seconds or so. Maybe one cog higher than you are using when sitting on the wheel in front of you, maybe 2, It depends on the wind, the finishing grade, the distance etc.


Be wary of big dopey guys like my58vw, they tend to start sprinting in way to big a gear. I used to love the cat 5 races where coming out of the last corner, guys are basically going backwards while they try to wind up that big gear with tired legs, and half of them are skipping thier chains all over the place.

The pros talk about slamming it into the 11 cog and giving it the stick, but remember these guys are hauling ass to begin with, and they can put out 1800 or more peak watts and weigh less than 170lbs. So even if they start in a higher gear than they should have, they are able to get up to speed quickly. Also the leadout is at 36mph or higher.

You can train your sprinting muscles through intervals, and short power hill work, but training your sprinting brain is tougher. If you have guys you ride with who shoot for the city limit signs like we do, try and grab the wheel of the guy who is the best at this. Early too, not when he attacks, but before that, and go with him, hold on and try to come around.

roadfix

OK......who here can shift while sprinting using downtube shifters while out of the saddle?

Smoothie104

I used to be able to slam it into the high gear with a knee.

And fixer brings up a good point, before brifters, you had to choose your gear wisely.

Sadly another lost art.....

CPcyclist

I think Smothy nailed it. It is easy to know what to do for the sprint. I know how to spin it up and follow a wheel. But sprinting is as much if not more about the mind game of who to mark and when to go. A good lead out helps with these descisions.

Train your Brain.

TheKillerPenguin

Holy crap! Dont all DT shifters work off friction too (i've never used em)? Talk about control...

CPcyclist

Sorry Penguin Index shifting predate STI/ERGO.

TheKillerPenguin

knew that. i was just testing ya

krazyderek

i did a sprint day with a guy that is 30lbs lighter then me, one thing i learned really quick was not to let him get away in the first 4 or 5 seconds, you little guys have the edge when it comes to accelerating, so i'd sujjest you work on your strategy aswell, waitting till the very last moment to sprint or get out front and then watch your back, cause once us big guys get up to speed we're like freight trains, and that momentum just helps to reel you in I won a sprint this way snuck up behind him at the last second and took it by a tire this is why you'll often see guys attack with 1k to go instead of sprinting it out the last 150meters they can put out the power, sometimes just not at the flick of a switch like the lighter guys.