Compact vs Standard double for sprinting

[sogood]

Back to the CT vs Standard double chainring debate, and one that relates to sprints and sprint training.

For us in the amateur ranks, does it really make a difference whether our bikes are equipped with CT or Standard chainring when it comes to sprint training and race performance?

With the same cassette in the rear, the difference b/n CT 50 and Standard 53 is exactly 6%. And given the top end pros like Cavendish and Hushovd only has 53/11 to play with at the top end, do riders in the mid amateur ranks (often with 25+% discount in peak sprint power) really need that 53 in a sprint? OR should the average amateurs train for higher cadence on a lower gear rather than over-stressing on 53/11 at a low cadence?

[philip]

I think it rarely matters at our level. I started riding club A grade with a 50/11 and didn't have trouble in sprints (not that I can win them, but gearing isn't the issue ). If it was a downhill sprint or big tailwind then I might've spun out but I don't think I've ever come across a downhill sprint. 50/11 is a bigger gear than 53/12 which a fair few guys with a 53 use anyway.

[sogood]

I concur Phillip. But there seemed to be a prevailing misconception out there that CT chainsets are "slow". Or there seems to be a mentality that only the Standard double are for serious riders.

However, it's of interest to see if there are alternate argument for running standard double ie. 53 ring, for this specific purpose. I am particularly interested in well supported and scientifically justified argument. Does power meter data show any differentiation?

[Alex Simmons/RST]

gear inches are gear inches.
they don't care via what combination of chainring/cog they are attained.
all you do by going compact is choose one smaller tooth cog at rear and you pretty much have exactly same gear:



given most trackies will do sprint training in gears from 82-96", then you are well covered by either.

[sogood]

gear inches are gear inches.
they don't care via what combination of chainring/cog they are attained.
all you do by going compact is choose one smaller tooth cog at rear and you pretty much have exactly same gear:

given most trackies will do sprint training in gears from 82-96", then you are well covered by either.

Thanks Alex, but some out there don't seem to understand this.

So for doubters' benefit, based on your knowledge of amateur rank road racers (up to club A-B level), do they really need that 53/11 for sprints? Is there any advantage by sprinting or carrying out sprint training on 53/11? Are races won or lost due to absence of that 53/11 as opposed to 53/11 (apart from downhill sprint finishes)?

[rkelsen]

Are races won or lost due to absence of that 53/11 as opposed to 53/11 (apart from downhill sprint finishes)?

Hey SoGood,

I'm sure Alex can explain the science better than I can, but according to my calculations the difference between 50/11 and 53/11 at 70 kph is 7 rpm. That is, to do 70 kph with a 53/11 gear, you need to spin at 115 rpm. With a 50/11 gear, you'd need to spin at 122 rpm.

I might be talking out my hat here, but surely that difference would be insignificant to any seasoned cyclist?

[foo on patrol]

A big gear is totally useless to you, unless you can push it. No science in that!

We only ever had a top of 112inch when racing and slip streaming semis at 60mph.

[Le Velo]

Are races won or lost due to absence of that 53/11 as opposed to 53/11 (apart from downhill sprint finishes)?

Hey SoGood,

I'm sure Alex can explain the science better than I can, but according to my calculations the difference between 50/11 and 53/11 at 70 kph is 7 rpm. That is, to do 70 kph with a 53/11 gear, you need to spin at 115 rpm. With a 50/11 gear, you'd need to spin at 122 rpm.

I might be talking out my hat here, but surely that difference would be insignificant to any seasoned cyclist?

I don't know many people that spin at 70kph around here ..at best of times we push it up in the 50s and cruise in the high 30 to low 40 .... If the difference at 70kph then I would assume that for every day cyclist it would mean squat ..... I think it's what you are comfortable with and what you can push.
I ride compact myself and can push it as good as what other guys can or climb in traditional gears

[winstonw]

I imagine one's ring preference is influenced by relative comfort of higher power vs higher cadence. Some of the factors I imagine influence this are cross sectional cycling muscle mass, neuromotor recruitment factors, cardiovascular fitness, phosphogen energy system for sprints, age. Anecdotally, one of the better sprinters in our group is shorter with proverbial tree trunk legs, and always operates at a slower cadence than the rest of us.

Crank length may also influence preference. There's some evidence smaller circles are more comfortable on older hips and knees, and soft tissue.

It might also be more difficult for recreational cyclists when sprinting, to achieve efficient higher cadences out of the saddle, which may bias some towards 53.

[open roader]

For us in the amateur ranks, does it really make a difference whether our bikes are equipped with CT or Standard chainring when it comes to sprint training and race performance?

I say it makes little difference for 'average' riders. We all have varying 'engines' some of us can really grind taller gears and achieve competitive speeds, but some of us can't do this and prefer to keep the revs up and spin shorter gears faster to achieve some speed.

I run 34/50T cranks on my road bike (and a 12-29T 11 speed cassette).

A pure speed example :- There are a few long, steep roads on my rides where I can really get some serious (fun) speed up on - like 75-85 km/hr. I have a very short gearing set up but at a cadence of just above 100 RPM I have never run out of gears to propel my bike down down those hills at my max. comfortable speed of around 80km/hr.

A realistic example :- for sprint training on relatively flatter gradients I hardly get get through 2/3rds of my short gearing set up holding 45km/hr at 100RPM - if I had a bigger engine I still would have those next 3 or 4 cogs to drive for more speed - but I can achieve realistically a modest power output only for longer periods and simply don't use or need the taller gears of "standard cranks" to get the speed I want and I'd suggest most riders are in my basket. My ability to sprint or perform sprints from slower speeds is in no way limited by my option to run compacts and shorter gears

However, I choose compacts and short gears for hill climbing more so than simply avoiding "standard" crank ratios because I can't drive them to thier limit.

[sogood]

I imagine one's ring preference is influenced by relative comfort of higher power vs higher cadence. Some of the factors I imagine influence this are cross sectional cycling muscle mass, neuromotor recruitment factors, cardiovascular fitness, phosphogen energy system for sprints, age. Anecdotally, one of the better sprinters in our group is shorter with proverbial tree trunk legs, and always operates at a slower cadence than the rest of us.

It might also be more difficult for recreational cyclists when sprinting, to achieve efficient higher cadences out of the saddle, which may bias some towards 53.

I think there's no question that higher power output would be able to leverage higher gears for higher speed. But working back from pro sprinters (Cavendish, Hoshovd, Petacchi etc), they are typically limited to 53/11 gearing combo for their 70+km/h sprints. And given their massive power output, something I'd guess are at least 20% greater than a decent club racer. Then the question is what justifications do the less power riders have to say they need 53/11? Yet we regularly hear amateur club racers stating CT cranks are too slow for them. Physical truth or perceived opinion?

[ni78ck]

i know this doesnt answer your qustion sogood, but there seams to be a shift to cc to my knowledge.
cervelo have released 5 different groupset combinations for their S5 and three of the five come with compact cranks!

[winstonw]

And given their massive power output, something I'd guess are at least 20% greater than a decent club racer.

I understand there's several A graders in my club with a max sprint speed in the 70s, but obviously presume their 5 and 10 second power falls away more steeply than a pros.

I also guess some A graders attain their shorter duration 70kph at lower cadences than a pro, because they just don't have a pros superior technique nor cardiovascular conditioning (recalling for the same power output, a higher cadence has a higher heart rate.) My general impression is amateurs are not as comfortable as pros with higher cadences. I presume comfort at higher cadence takes hours and hours of saddle time, optimal skeletal frame, and superior physiology - stuff amateurs are less likely to have. Though an amateur could still grunt out the power for a short period.

Accepting some club guys can 70s sprint speeds, but for shorter duration, and lower cadence, that supports them preferring a bigger gear.

All assumptions though.

[winstonw]

i know this doesnt answer your qustion sogood, but there seams to be a shift to cc to my knowledge.
cervelo have released 5 different groupset combinations for their S5 and three of the five come with compact cranks!

Was talking with an Aussie Shimano rep a few months ago who said there's a move to compacts on high end roadies to accommodate the higher uptake by older people, with the money to buy them, and the time to ride them. Though presume cc's are required by many young people with minimal riding under their belt. One of my reasons for upgrading my bike last year was to get a cc. Some of the hills around Brisbane were just too hard on my heart with a 39. Interestingly, my max sprint speed with the 50t is 49 but on my previous 53t it was 51...but I was 2 years younger and a few kg lighter then.

[fenn_paddler]

No good flogging this dead horse sogood - I think you well know the answer to whether it's fact or perceived opinion that compact is too slow for club racers. Compact criticism is just another form of elitism. Which is common in road cycling...

[Alex Simmons/RST]

I wasn't aware that compact gearing was criticised/ridiculed?

A gear inch is a gear inch. Again, it doesn't matter how you arrive at it.

The 53x11 is useful for going downhill, not for sprinting. Unless you have a downhill sprint or have a monster tailwind. It's for those that think winning the sprint at Sutherland means something.

Please, hands up all those here who on flat ground with no wind can hit 70km/h in both directions on any given stretch of road?

The answer will be very, very few people.

Peak power typically occurs at more like 130-140rpm.

For training purposes, the gear ratios that you would use to develop neuromuscular power and anaerobic capacity are well within the ranges of both standard and compact gearing.

[Alex Simmons/RST]

So for doubters' benefit, based on your knowledge of amateur rank road racers (up to club A-B level), do they really need that 53/11 for sprints?

No.

I've won A grade on the Eastern Creek downhill sprint and was in the 53x13.

Is there any advantage by sprinting or carrying out sprint training on 53/11?

Not really. Indeed it might be counter productive.

Are races won or lost due to absence of that 53/11 (apart from downhill sprint finishes)?

No.

[Alex Simmons/RST]

Are races won or lost due to absence of that 53/11 as opposed to 53/11 (apart from downhill sprint finishes)?

Hey SoGood,

I'm sure Alex can explain the science better than I can, but according to my calculations the difference between 50/11 and 53/11 at 70 kph is 7 rpm. That is, to do 70 kph with a 53/11 gear, you need to spin at 115 rpm. With a 50/11 gear, you'd need to spin at 122 rpm.

I might be talking out my hat here, but surely that difference would be insignificant to any seasoned cyclist?

None. If you can't hit 70km/h, it not because of the top gears listed (122rpm is relatively low for sprint efforts). It's because you don't have the power.

[Alex Simmons/RST]

But working back from pro sprinters (Cavendish, Hoshovd, Petacchi etc), they are typically limited to 53/11 gearing combo for their 70+km/h sprints. And given their massive power output, something I'd guess are at least 20% greater than a decent club racer. Then the question is what justifications do the less power riders have to say they need 53/11? Yet we regularly hear amateur club racers stating CT cranks are too slow for them. Physical truth or perceived opinion?

Pros sprint power at end of these long races isn't massively superior to what a really good club rider could do (I have plenty of masters aged trackie mates that have higher sprint peak power output than say Henderson or Griepel). Cav's peak power isn't all that high either (quite modest in fact).

It's the fact that they've ridden 200+ km over tough terrain at 45km/h and holding superior maximal aerobic power for the 5 or so minutes before the sprint that sets them apart. Then examine their 1-minute power before the finish.

Pro road sprinting is actually just another time trial, albeit a short one - it's all about position, when to launch (i.e.pacing) and power to aero drag ratio.

[sogood]

No good flogging this dead horse sogood - I think you well know the answer to whether it's fact or perceived opinion that compact is too slow for club racers. Compact criticism is just another form of elitism. Which is common in road cycling...

Seriously, my impression is that it's a perceived opinion, but I can't be 100% sure and hence the interest in discussing the matter further.

One question is, what's the impact of power development at a cadence of 110 vs cadence of 120 (the gap is a tiny bit larger than the CT vs Standard difference of 6%). I understand that one starts to fail to develop power properly when one's cadence goes beyond some upper point, so does 110 to 120 sits on this down-slope curve? Instinctively I wouldn't have thought so as just about all serious and competitive club riders should able to spin in that range or higher. But I have not personal experience nor hard data to consider this view.

So I don't think it's a dead horse, maybe almost, but not just yet.

[sogood]

Peak power typically occurs at more like 130-140rpm.

For training purposes, the gear ratios that you would use to develop neuromuscular power and anaerobic capacity are well within the ranges of both standard and compact gearing.

Thanks Alex! That's the exact data that'll help fill my data void on this question. I think I am satisfied with the logical argument on this issue now.

[philip]

I understand that one starts to fail to develop power properly when one's cadence goes beyond some upper point, so does 110 to 120 sits on this down-slope curve

Alex already said:

Peak power typically occurs at more like 130-140rpm.

So unless something crazy goes on, typically it would be going up

[sogood]

Pros sprint power at end of these long races isn't massively superior to what a really good club rider could do (I have plenty of masters aged trackie mates that have higher sprint peak power output than say Henderson or Griepel). Cav's peak power isn't all that high either (quite modest in fact).

That's interesting! Thanks.

[sogood]

A pure speed example :- There are a few long, steep roads on my rides where I can really get some serious (fun) speed up on - like 75-85 km/hr. I have a very short gearing set up but at a cadence of just above 100 RPM I have never run out of gears to propel my bike down down those hills at my max. comfortable speed of around 80km/hr.

I understand that on those massive descents where speed gets up to 70-100km/h, the predominant barrier to going even faster lies with one's aero position. The 6% top end gearing difference b/n CT vs Standard and the power one can add is trivial compared with air resistance. Better to tuck real close than try to spin legs and increase one's air resistance.

[ft_critical]

I have raced the same two courses on both a 12-25 and an 11-23 on 172.5 cranks and a 39/53 Chainring set. Both times I raced the 12 I ran out of gearing. At West Head, solo, chasing the break into Salvation Creek and a second time at Eastern Creek in the sprint finish (68kmh, 158rpm is my best sprint here on a 11-23 by way of reference.)

One consideration is that I am more of a power sprinter than a speed sprinter. I can’t spin out that fast so I need the bigger gear. The second is, both cases where I ran out of gear, were either downhill or slightly downhill. Running the bigger gear, 11, I did not run out in the same circumstances (and I have raced both courses a few times.) It does make me wonder what would happen on a 10?