# Racing with a compact crankset?



## Gnarly 928 (Nov 19, 2005)

I trying out a compact this season, attempting to increase my climbing speed by climbing at a higher cadence. I was racing and training on a 39/53 and train on a 12/25 cassette, sticking on cassettes to match whatever course I raced.. 12/21 has worked for me in crits, 11/23 or 25 for mountain RRs or events with a big downhill. Pretty much had gearing that crankset down..but now....

I'm on a 34/50. I've been finding my 11/23 is a good "all around" combo for the 'vertical' area where I train. Long sustained climbs and downhills abound. But what about crits and sprint finishes in the flats? Can I use a 12 and still be ok in a sprint? "Old guy Masters class is where I usually race"...or some cat 4s (I do about an hour 40k TT time)...so I am not sprinting against guys like Cav. 

I'd love to have the closer gear spacing for flatter races and crits, but sprinting is where I get my few podiums. I calculate about 40mph at 110 with an 11 and 36mph with a 12/50...I know on the downhills the 50/12 combo doesn't get it..can't keep up, gets spun-out. but in a sprint? 

What are you guys using as cog sets for flatter races with compact cranks? 

Thanks


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## bmxhacksaw (Mar 26, 2008)

I spun a 50-12 up to 44.49 mph drafting behind a truck last Friday


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## den bakker (Nov 13, 2004)

It's only on the internet people spin out their 50/12 in flat sprints 



Gnarly 928 said:


> I trying out a compact this season, attempting to increase my climbing speed by climbing at a higher cadence. I was racing and training on a 39/53 and train on a 12/25 cassette, sticking on cassettes to match whatever course I raced.. 12/21 has worked for me in crits, 11/23 or 25 for mountain RRs or events with a big downhill. Pretty much had gearing that crankset down..but now....
> 
> I'm on a 34/50. I've been finding my 11/23 is a good "all around" combo for the 'vertical' area where I train. Long sustained climbs and downhills abound. But what about crits and sprint finishes in the flats? Can I use a 12 and still be ok in a sprint? "Old guy Masters class is where I usually race"...or some cat 4s (I do about an hour 40k TT time)...so I am not sprinting against guys like Cav.
> 
> ...


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## CHT (Mar 1, 2001)

My new (to me) race bike came with a compact crank. I trained on the compact the whole winter and I've been racing on a compact 12/23 every week for over a month now. I've never used a compact before, and it would not have been my first choice for no other reason than I had it in my mind that real racers don't do compacts (I'm also more of a climber and never had an issue with a standard 12/23 or 25 for serious hills). The price for the bike was too good to pass up, so I figured I can always get a standard crank later. 

So far, it's working for me. The only limitation on the sprint has been me, not the gearing. Full disclosure though, all of my crits have had uphill finishes and you really only need to be between 30-35 mph to place well going uphill. I have spun out on some downhills, but generally it's fairly close to the point that I would be tucking in for the descent. I think if you are a really strong sprinter, maybe a downhill sprint would create an issue of spinning out depending on your tolerance for high cadence.

Putting aside what some may feel about the optics, gear inches are gear inches - just compare the gear inches between a standard 53/12 and a 50/11 - you are not giving up much but gain way more on the other side 39/25 vs. 34/25). I also have an 11/23 conversion cassette (Campy drivetrain) which I plan on using as well with a different wheelset.

Since I'm more of a climber and don't really need the compact, I think the greatest benefit is it has allowed me to stay in the big ring while going up a lot of hills which eliminates the shift back and forth as your start and then crest the hill.


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## Wookiebiker (Sep 5, 2005)

Well....considering a 50x11 is bigger than a 53x12....you are not losing much top end speed compared to somebody running a standard crank.

On the other side of things you don't lose anything in the climbing gears and may be able to spin longer and not run out of gears getting bogged down on some climbs.

I ran a compact my first year of racing and was just fine. In fact some places it helped because I could stay in my big ring instead of having to drop down to the small ring up front which lowered the risk of a dropped chain in the middle of a race.

If you can stay with the pack and put your self in place to win...it doesn't matter what gear or gearing you are running.


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## Gnarly 928 (Nov 19, 2005)

Wookiebiker said:


> Well....considering a 50x11 is bigger than a 53x12....you are not losing much top end speed compared to somebody running a standard crank.
> 
> On the other side of things you don't lose anything in the climbing gears and may be able to spin longer and not run out of gears getting bogged down on some climbs.
> 
> ...



I should have been a little more specific. Can you sprint with a 50X12 combo?

I know about the "other end" of a compact. In our group, on weekend rides if you have a 50X12 you will get dropped because we can't find routes without long up and down hills. 

Wookie, you are familiar with Seven-Mile Hill from the Cherry Blossom stage race..You can actually use a 53-11 there, or descending from Parkdale down a long (13 miles) highway behind a bunch of 2s, 3s and Z-team masters.

So Yeah, a 50X11 will keep you up in a bunch...but it'd be nice to have the closer spacing of a 50X12 during a crit or a long flat-ish race with a sprint finish....if the gearing wouldn't leave you spun-out, like it does when you are descending in a pack with 'strong normal crank guys willing to hammer'..


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## CHT (Mar 1, 2001)

Gnarly 928 said:


> II calculate about 40mph at 110 with an 11 and 36mph with a 12/50...I know on the downhills the 50/12 combo doesn't get it..can't keep up, gets spun-out. but in a sprint?


Isn't that the answer? It really is course specific and what you need to contest a win. If you need to be greater than 36mph for any extended time to contest a sprint, and will likely feel like your "spinning out" over 110, the 50/12 combo will not work for you. The gear jumps with the 11 are still fine which would take you to 40mph.


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## Wookiebiker (Sep 5, 2005)

Gnarly 928 said:


> I should have been a little more specific. Can you sprint with a 50X12 combo?
> 
> I know about the "other end" of a compact. In our group, on weekend rides if you have a 50X12 you will get dropped because we can't find routes without long up and down hills.
> 
> ...


Yea, I'm familiar with seven-mile hill  With that said, much of it has to do with leg speed and how fast you can spin. 

Myself...I could get by with a 50x12 if needed at least for road racing/group rides (not so much for TT's where keeping a steady cadence and low body are more important than spinning fast and even then I ran a 52x12 for a long time on my TT bike).

I've spun a 48x12 to over 53 mph on a geared bike. 

On my single speed with a 46x17 I've been over 36 mph before and been in rotating pacelines at 26-28 mph for long periods of time on my single speed. 

On my trainer, which has cadence, I wanted to see how fast I could spin so I went all out for 10 seconds and held over 180 RPM for those 10 seconds and hit a high of 195 RPM...So I running 130+ RPM for extended periods of time isn't that big of a deal for me.

I'm however more the exception than the rule....though if one can carry high RPM's for a long time then gearing isn't as important on the top end.

The other factor is if you are with guys who have the big gears, it's just a matter of tucking in behind them and using their draft to get you down the hill faster...unless you are on a really curvey road and can't stay with them through the corners....then :idea: 

With all that said...a 53x11 does make it easier on downhills by not working your cardio system so hard


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## Number9 (Nov 28, 2004)

Gnarly 928 said:


> I should have been a little more specific. Can you sprint with a 50X12 combo?


Yes, but I normally sprint in a 48x15 on the velodrome. But what you really need to be asking is, "can I sprint with a 50x12 combo?"

Since you have a 11-23 cassette, why don't you slap that on and just figure it out empirically. Warm up, shift to 50x12 and roll up to 30 or so, get on the gas for 10-15 seconds and then check your power meter/speedometer/whatever. Rest, repeat in 50x11 and see which gives better results. If the power/top-end is similar then the 50x12 is fine. If one is clearly better than the other, that's the one you want.

BTW, I hit 50mph going down San Marcos Pass spinning a 50x12, so to me, that's plenty of top end, even for descending.


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## Gnarly 928 (Nov 19, 2005)

Number9 said:


> Yes, but I normally sprint in a 48x15 on the velodrome. But what you really need to be asking is, "can I sprint with a 50x12 combo?"
> 
> Since you have a 11-23 cassette, why don't you slap that on and just figure it out empirically. Warm up, shift to 50x12 and roll up to 30 or so, get on the gas for 10-15 seconds and then check your power meter/speedometer/whatever. Rest, repeat in 50x11 and see which gives better results. If the power/top-end is similar then the 50x12 is fine. If one is clearly better than the other, that's the one you want.
> 
> BTW, I hit 50mph going down San Marcos Pass spinning a 50x12, so to me, that's plenty of top end, even for descending.


 Shoot! I shoulda thought of that, just doing a couple without going into the 11 cog. Me go there, now.
Thanks everyone.


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## ericm979 (Jun 26, 2005)

I use a 50/34 and 12-27 in all races (except the Everest Challenge where I use a 12-30).
I can't sprint in a 50x13 let alone the 50x12. If I don't stay in the draft on non-technical descents, I am off the back no matter what gearing I have. I can't really turn over a 50x11 anyhow.

As I slowly get stronger it sometimes seems that I could use a slightly taller gear than 50x12. I may switch to 52/36 gearing this year.

One of the downsides to a 50/34 or 52/36 is the wide range between chainrings. I think that a reasonably wide range cassette goes the best with them. If there's not a good overlap between the gear ratios on the two chainrings you will be forced to shift between them a lot on rolling terrain. With a 12-27 I can use the 50x24 a lot of the time and avoid shifting to the 34t.


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## tjib13 (Aug 11, 2008)

The 11-23 includes- 11,12,13,14,15,16,17,19,21,23
The 11-25 includes- 11,12,13,14,15,17,19,21,23,25
The 12-23 includes- 12,13,14,15,16,17,18,19,21,23
The 12-25 includes- 12,13,14,15,16,17,19,21,23,25

from Comp Cyclist site in ref to Shimano cassette.

If you are talking about sprinting the first 5 or 6 gears on the cassette are the same so why not run the 11-23 with the compact the whole time?

If you can sprint with a 53x11 then you should not being using a compact. If you can sprint with a 53x12 then 50x11 is more than adequate 

I am not sure why you would want to take off the 11 t for a 12t for a flatter race when the difference between the two cassettes is above the middle of the cassette


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## Seven Wonder (Oct 13, 2009)

Have you looked at getting a 52 tooth chainring for the front, while still keeping a 34 or possibly a 36? I have a team member who has been using this setup with no problems. It seems like it would be the best of both worlds. It also depends on what type of cranks your running as well. I know Sram and FSA compacts both have this ability.


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## ericm979 (Jun 26, 2005)

You can do that with any 110mm BCD crank.

52x34 would make for difficult shifting both up and down. 52x36 has the same difference as 50x34 and would shift the same.


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## Gnarly 928 (Nov 19, 2005)

It's been a week now and I've been trying all different cassettes. I think I am going to train on an 11-25, which gives me a good spin going uphill in a couple of gears and yet allows me to mash downhill. A 12-23 seems to work better on the 'flatter' rides and 11-23 comes good on a few hills or with a tailwind, but it requires 3 rear changes for each chainring change, where the 11/25 is just two gears..I did fabricate a 'chain-keeper that hangs on my front derailleur mount...I now shift without concern between my chainrings knowing it's impossible to 'toss the chain'

I have a flat crit coming this week...probably with 20-40mph headwinds and a downwind finish...I am going to pre-ride that course trying a 12-21...but it will probably be the 12-23 that gets raced...for the 16 cog I like to use sometimes.

Having a 25/34 going uphill has really changed my climbing...I now can spin in a few gears rather than mashing in a 23-25/39 and letting my cadence drop to under 50 and the lactate build to excruciating levels in my quads and glutes...


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