Bigger ring riding

Thursday, 24 February 2011

Hoy Sireau

Here’s a post to satisfy fans of BigRingRiding.com. The latest edition of Vélo magazine has an interesting take on track cycling, reporting on the gears used over the years by the sprinters.

1970 Daniel Morelon 48×14 7.32 metres
1999 Florian Rousseau 49×14 7.47 metres
2001 Arnaud Tournant 50×14 7.62 metres
2011 Kévin Sireau 52×13 8.54 metres

Note the gradual progress of an additional tooth on the chainring until you get to Sireau who adds two teeth, plus the game-changing 13T sprocket on the back. Sireau also uses 172.5mm cranks.

But the change isn’t due to Sireau and the French team. “In 2006, after having filmed the English [sic] we understood they were using a bigger gear than us” track coach Gérard Quintyn told Vélo Magazine.

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{ 13 comments }

grolby February 24, 2011 at 5:11 pm

For what it’s worth, the effect of longer cranks is to slightly reduce the gear ratio, so 172.5 mm cranks, if anything, ameliorate the bigger gear. But it’s such a small change that it doesn’t really matter.

It is interesting, though. I do think that sprinting is exactly where you would expect to see bigger gear ratios. Perhaps in pursuiting as well. I would be surprised to see a similar trend in the mass-start endurance events.

Starr February 24, 2011 at 6:24 pm

52×13? I suppose he’ll have a bit more control, not having to flail at super high rpms, but still seems to heavy for jumping without a leadout. He can’t be hitting more than 130 rpms.

Touriste-Routier February 24, 2011 at 6:28 pm

Historically gear selection also depended on the track. Most notably the lap length; the longer the lap, the longer the straightaway, the bigger gear you can use. In Los Angeles we used larger gears in all events on the 333m Olympic Velodrome vs using smaller gears on the 250m Encino Velodrome

The Inner Ring February 24, 2011 at 6:42 pm

grolby: we’ve seen gears on the road go up, riders can now use 55×11 when 53×12 was a big gear only 10 years ago.

Starr: apparently he does 145 RPM!

Touriste-Routier: thanks, that makes sense but I’d never thought of it.

A February 24, 2011 at 6:59 pm

This will run counter to what Touriste-Routier says, but the shapes of tracks and resulting tactics are driving some of this. In Morelon’s day tracks were generally 333.3 – 400m where passing is relatively straight forward. A smaller gear allows you to sit in and then make a quick jump with 150m (or so) to go and pass your opponent.

Now that 250m tracks are the new standard tactics have changed. The short distance, sharper turns, and steeper banking gives far fewer opportunities to pass. Sprints now tend to be long drag races rather than a slow roll for 2 laps and then a furious jump for the final lap. This means they need a gear that they won’t spin out and can stay on top of for the duration of the sprint.

Touriste-Routier February 24, 2011 at 8:00 pm

A,

An interesting counter argument!

Yes, the smaller tracks give fewer possibilities to pass on the straights, since you are in the turns more often/relatively longer. Once leaving “turn 4″, the longer tracks typically have further distance to the finish line, and hence more opportunity to accelerate, hold top speed longer, and pass. Once you are out of turn 4, you typically are at or near top speed. While a smaller gear does allow one to accelerate easier, if you are close to max speed or spun out, it doesn’t help all that much.

In the Pro/1/2 races at the Olympic Velodrome we’d typically use 90 – 94 inches (depending on your strength and preferred cadence); at Encino it would be 88 – 90. It was just too hard to get the larger gears up to full speed on the smaller track (whose banking was only 28, compared to the 33 of the Olympic track). Riders using over 90 inches at Encino would get bogged down, and would lose that deadly 2nd/final acceleration. The surface was also better on the Olympic track. On the 166m indoor tracks in Germany, we were slightly under 88 inches; sprints would begin with ca 2 laps to go. The years I am referring to are the early – mid 90s.

I also didn’t mention track width can also could come into play. The smaller tracks are also usually narrower, also yielding less passing opportunities.

I imagine the longer drawn out races of today are largely due to the larger gears; it takes longer to get up to speed, especially on the smaller tracks. I haven’t checked, but i imagine 200m times are down over the same period, due to the riders being stronger/faster.

Of course, I could be all wrong, and my experiences (too long ago) not relevant to today…

grolby February 24, 2011 at 11:09 pm

Sure, there are bigger gears on the road today, but there aren’t too many pros riding something as big as a 55×11 in a mass start road race. As I said, I would be unsurprised to see bigger gears in pursuiting (as we do in road time trials), but much more surprised in mass start endurance events. Upon some reflection, this probably has more to do with the different tactics needed in a time trial vs. a sprint vs. a mass start race than it does with the length of the event. It’s been pointed out before that, for all that cyclists promote spinning as a better technique for the reason of efficiency, most riders actually achieve maximum aerobic efficiency well below 90 RPM. In race formats where abrupt and/or frequent changes of pace are required, such as a typical road race or mass start track race (or a track sprint in the 1970s, perhaps), a lower gear is necessary to be able to respond. In faster, more constant-paced events like a time trial, pursuit or, possibly, a modern track sprint, maxing out the gear gives bigger returns than spinning faster.

Touriste-Routier February 25, 2011 at 4:02 am

Grolby, the other thing to consider is the time it takes to get a gear up to speed. You can lose precious seconds even in a pursuit if you don’t get up to tt speed in time; in a kilo, it is even worse. Too big a gear/too slow a start easily can be the difference between winning or not; tenths of seconds count!

Starr February 25, 2011 at 4:16 am

145 rpms on that gear is a tad over 75kph.
Are you telling me Kevin is sprinting over 46 mph without being lead out?
I’ll have what he’s having!

A February 25, 2011 at 2:52 pm

Starr–
For the curent crop of world-class sprinters on a high-quality indoor track: yes, that’s about right.

beev February 26, 2011 at 11:47 am

just thought i would add my tuppence worth re track lengths and straights – i read the finish line in the london velodrome will be over 5 metres further down the straight (to favour sprinters). Brailsford, rarely misses a trick – “marginal gains” as he would say…..

beev February 26, 2011 at 11:48 am

…..over 5 metres further down the straight (to favour sprinters) with respect to Manchester…..

ASiegel993 February 26, 2011 at 2:06 pm

I was sitting in the stands at Manchester this weekend and can tell you that cadence was well above 130. Sireau did 9.98 in his flying 200m time trial. According to my gear chart (the GearCalc app for iPhone, which deserves a mention here) that would translate to an average of 143 rpm for the duration of the effort. And yes, that’s a about 45mph. And Manchester is not a particularly fast track. It’ll be interesting to see how fast he goes in Moscow come May. Perhaps break his own world record (9.572s, or 149 rpm on a 52×13 or the same 143rpm but on a 54×13.)

As for the debate on track length and gear size, I’d have to side with A on this one. For what it’s worth, I grew up on a 400m track and always left my sprint tactics ’til the bitter end. Moving to a 333m later on I started to prefer to lead sprints out. Now I’m riding on 250m tracks and have quickly learned that taking the lead early tends to be the better strategy unless you’re considerably faster than your opponent. There are still obviously ways to win from behind, but we’ve seen a dramatic shift in the way sprints occur over the last 10-15 years, with an early jump becoming the norm. Because of that, sprinters are now aiming for top speed and long sprints (usually involving some version of the razor, usually in the back straight), which are done more easily on massive gears. So, all eles equal, smaller track means bigger gear. Another factor is that you actually go faster in the banking. A flying 200m on a 250m track takes you through the turns twice. On a 333m or larger, only once. So yet another reason you may be on a bigger gear on a shorter track. Of course, a track like FCV near Toronto is so short that it may be different. This all assumes that the corners are well designed and don’t actually slow you down (as I think they do at Burnaby, for instance). As for Touriste-Routier’s comments about track width, banking, and smoothness, those will also have a massive impact on gearing. The higher up the track you can get, the better. Usually shorter tracks have more banking, but L.A. seems to have been an anomaly. I can almost guarantee Sireau will be on an even bigger gear in Moscow, which is a 333 but extremely wide and thus very very very tall. That height is the reason it’s so fast, not the length. Well, that and its ventilation system that is apparently set up to create a permanent tailwind! For the actual sprint events he’ll probably come back down to his normal race gear because the height is so immense that I don’t think they take advantage of all of it in a normal race. So, I would contend that a longer, wider, steeper, smoother track will ALL encourage a big gear.

Finally, re: beev’s comment – I think having the line further down is actually an impediment to the British boys. Watch their tactics (or lack thereof) in races. Get to the front early, lay down the hammer and hold everyone off. The longer the straight, the more opportunity for opponents to make a run down the home straight and nip them on the line. Riders trying to come over the top always get a little boost out of turn 4 from the banking, but it’s usually a trade-off between that and the possibility of running out of time to take the lead. This improves the prospects for that type of strategy. So the 5m extra will make for some more exciting racing, I think, but it’s not an advantage for all sprinters by any means. It’s a zero-sum game of sorts and I think that a rider like Hoy actually loses out in this case. So it favors sprinting, but not British sprinters.

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