Aerodynamics of Road vs. Cross bikes
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What I would do, in your shoes, is rent a few road bikes you would be interested in having, and rent a power meter. (Yes you can rent them.) Ride each bone a couple days, record speed and power. Ride the same route with each, try to control as many variables as possible.
#27
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Go but a few bikes, problem solved.
What I would do, in your shoes, is rent a few road bikes you would be interested in having, and rent a power meter. (Yes you can rent them.) Ride each bone a couple days, record speed and power. Ride the same route with each, try to control as many variables as possible.
What I would do, in your shoes, is rent a few road bikes you would be interested in having, and rent a power meter. (Yes you can rent them.) Ride each bone a couple days, record speed and power. Ride the same route with each, try to control as many variables as possible.
I think if I'm being honest, I'm just sort of brainstorming/daydreaming about this right now. Realistically a new aero road bike would probably be a for next spring kinda purchase. This year maybe I'll do a GPS thinger and maybe an on bike power meter. I've been thinking about tackling a few longer rides...heading out to Saugatuk or Grand Rapids Michigan...GPS would be handy for that.
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Get the power meter first. Then get me a competent proofreader, send this one to the lions!
#29
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Those erg mode intervals work by the way haha! Just hanging in the group on this ride last year nearly killed me. No way I could have even attempted taking a turn on the front.
#30
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No no, I like the current proofreading just fine lol
I have been thinking more about tthe power meter. I'm spending more and more time outside now; the incentive to stay in my basement to get structured workouts in is waning very quickly.
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I'm on the JRA training plan. With a hill or a boulevard that doesn't see much traffic, I can get my intervals in. No erg mode outside, but hills keep you honest. So does motivation, and you've obviously got that in spades. PM can be real useful outside for regular training purposes. It's also useful to know how much TSS you racked up. I imagine it'd be nice to have a record of your energy demand during a race, if you want to geek out.
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A typical cross bike does not have the gearing to run with a road bike at top end. Apologies if this has been mentioned. I haven't read through all the posts.
#33
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What gearing do people think cross bikes have??
#34
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Just replying to say that I love your screen name and if you are indeed the Sausage King of Chicago (who can lunch at Chez Quis) I’m sure you can afford a new bike.
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While you're not running along at 40 mph you're going to be rolling along at 25-35 pretty consistently and considering your largest gear requires you to spin at 120 in order to even reach 40 mph - it's under geared.
I resort back to one of the best stories I've heard that illustrates this. Back during the Superweek era Rich Smott showed up to a race up in Wisco that had a long or steep descent. He was talking to one of the pro mechanics before the race (he was a 2 at the time I believe). Said mechanic saw his 52 or 53T chainring and went to his van, pulled out a 54 or 56T and tossed it to him. "Don't get dropped on the downhill, kid."
We can sit here and debate all the differences all day but I live in both the road racing and cyclocross racing worlds. We don't ride the same bikes in both. We pick the right tool for the right job. Road bikes are made to go fast, make small changes at high speed and have amazing stability and control at those speeds. Cross bikes are made for handling well at mid to super low speeds and having the gearing range that makes the most sense for mixed terrain use.
In other words a basic production sedan might be able to go 120 mph but it sure isn't like driving a car that is designed to go 120 mph. It's isn't all about the aerodynamics either.
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A bunch of years back we had a competition during the Chicago Cyclocross Cup for a few of us in the industry. We had to race and we had to wear skinsuits - (affectionately referred to as sausage suits as when you stuff overweight industry people into them they look like sausages with casings that are ready to pop). We raced head to head each week and did interviews with everyone in the contest. At the end of the season we had a public vote. Winner was dubbed "Sausage King of Chicago". Rich Smott won the first year. He was our pactimo rep so he had them sponsor the thing by doing a custom skinsuit that was done to look like Ferris Beuller (Bugle Boys, Cardigan, Leather Jacket, etc). On the back it just said, "Sausage King of Chicago".
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#37
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A bunch of years back we had a competition during the Chicago Cyclocross Cup for a few of us in the industry. We had to race and we had to wear skinsuits - (affectionately referred to as sausage suits as when you stuff overweight industry people into them they look like sausages with casings that are ready to pop). We raced head to head each week and did interviews with everyone in the contest. At the end of the season we had a public vote. Winner was dubbed "Sausage King of Chicago". Rich Smott won the first year. He was our pactimo rep so he had them sponsor the thing by doing a custom skinsuit that was done to look like Ferris Beuller (Bugle Boys, Cardigan, Leather Jacket, etc). On the back it just said, "Sausage King of Chicago".
#38
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It's not a matter of capable top speed. It's a matter of the right gear inches in the right range where you can make slight step changes in the correct cadence band. It's raises it's head with cross gearing because the chainring is so small that the gear inches jump in even 1 tooth cog jumps is too high for high speed work in a pack.
While you're not running along at 40 mph you're going to be rolling along at 25-35 pretty consistently and considering your largest gear requires you to spin at 120 in order to even reach 40 mph - it's under geared.
I resort back to one of the best stories I've heard that illustrates this. Back during the Superweek era Rich Smott showed up to a race up in Wisco that had a long or steep descent. He was talking to one of the pro mechanics before the race (he was a 2 at the time I believe). Said mechanic saw his 52 or 53T chainring and went to his van, pulled out a 54 or 56T and tossed it to him. "Don't get dropped on the downhill, kid."
We can sit here and debate all the differences all day but I live in both the road racing and cyclocross racing worlds. We don't ride the same bikes in both. We pick the right tool for the right job. Road bikes are made to go fast, make small changes at high speed and have amazing stability and control at those speeds. Cross bikes are made for handling well at mid to super low speeds and having the gearing range that makes the most sense for mixed terrain use.
In other words a basic production sedan might be able to go 120 mph but it sure isn't like driving a car that is designed to go 120 mph. It's isn't all about the aerodynamics either.
While you're not running along at 40 mph you're going to be rolling along at 25-35 pretty consistently and considering your largest gear requires you to spin at 120 in order to even reach 40 mph - it's under geared.
I resort back to one of the best stories I've heard that illustrates this. Back during the Superweek era Rich Smott showed up to a race up in Wisco that had a long or steep descent. He was talking to one of the pro mechanics before the race (he was a 2 at the time I believe). Said mechanic saw his 52 or 53T chainring and went to his van, pulled out a 54 or 56T and tossed it to him. "Don't get dropped on the downhill, kid."
We can sit here and debate all the differences all day but I live in both the road racing and cyclocross racing worlds. We don't ride the same bikes in both. We pick the right tool for the right job. Road bikes are made to go fast, make small changes at high speed and have amazing stability and control at those speeds. Cross bikes are made for handling well at mid to super low speeds and having the gearing range that makes the most sense for mixed terrain use.
In other words a basic production sedan might be able to go 120 mph but it sure isn't like driving a car that is designed to go 120 mph. It's isn't all about the aerodynamics either.
I mean perhaps I'm giving up a watt or 2 (or a half watt....) by making the chain make slightly sharper bends going around a 46 rather than a 53, and maybe being always down a cog or so in back.On the other hand...I'm fairlly sure I would consistently have a better chain line than most people with my setup, working generally in the middle of the outer half of my cassette.
I'm still of the opinion that what I'm giving up is predominantly aerodynamics, followed by an unknown (to me....) loss of handling.
Last edited by Abe_Froman; 05-06-19 at 03:08 PM.
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A standard road crank set has a 53 tooth big ring w/ 11 cog and a compact has a 50X11. My new mid-compact has a 52X11. So, from my point of view you are out-gunned, gearing wise. FWIW, I have a 1 mi. Strava segment that is pretty flat. My PB is 25.7 mph. I'm 73. You can go faster.
If you are actually doing 40 mph at 120 rpm, how long can you spin like that and how much does it take out of you? I can spin at 120 but typically spin at 100 rpm and last longer. There really are a lot variables.
Last edited by bruce19; 05-06-19 at 03:12 PM.
#40
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I can spin 120 and put a lot of watts out while I do it. But not for very long. I'm sure you don't need to maintain 40 mph in a race, but if you're willing harder to overcome your gearing, it's not helping you.
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Not trying to be argumentative. And I don't disagree obviously that for road riding, a road bike is the best tool for the job. However...I DO disagree with the fact that (at least around Chicago), the issue is decidedly NOT gearing. I've got a 46,36 double, 11-28 cassette. Anything over 20mph, I've got 1 tooth cog jumps from the 15 down to the 11 tooth.
I mean perhaps I'm giving up a watt or 2 (or a half watt....) by making the chain make slightly sharper bends going around a 46 rather than a 53, and maybe being always down a cog or so in back.On the other hand...I'm fairlly sure I would consistently have a better chain line than most people with my setup, working generally in the middle of the outer half of my cassette.
I'm still of the opinion that what I'm giving up is predominantly aerodynamics, followed by an unknown (to me....) loss of handling.
I mean perhaps I'm giving up a watt or 2 (or a half watt....) by making the chain make slightly sharper bends going around a 46 rather than a 53, and maybe being always down a cog or so in back.On the other hand...I'm fairlly sure I would consistently have a better chain line than most people with my setup, working generally in the middle of the outer half of my cassette.
I'm still of the opinion that what I'm giving up is predominantly aerodynamics, followed by an unknown (to me....) loss of handling.
Fast riding in a pack is a matter of tiny changes in accelerations that come from tightly managing your gearing and cadence. You don't have that option. You on a road bike with road bike gearing will turn in faster performances over the same terrain than on your cross bike with cross gearing.
I have argued this with riders for years. Everyone who starts in cross and wants to bridge over to road just ends up losing it when the surges come. Riding along at speed in the pack is fine but cornering and surges and they're just - gone. They pull all the mental gymnastics trying to explain it. Then we get them on a road bike with adult gearing and all of a sudden they have no problems.
Reality is your really small gearing is causing you to ride outside of efficient cadence ranges in order to maintain the speeds the pack is going. Each jump of 1 tooth sends you through wider cadence range than those with tighter gearing. That's was less efficient with the body.
Example and proof - you say yourself you have enough gearing to go faster than everyone - then go faster than everyone. The wind isn't holding you back - you're drafting someone. You're working 30% less than them anyway. It's that the cadence you're running at isn't as efficient for you.
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#42
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We'll see. Maybe some of the race venues I go to will have steeper/longer descents than the rides and races I've done previously. If that's the case...then I can always spring for a bigger chainring. Hasn't been an issue yet though.
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...and the speed of your setup at 100 cadence is 29.5mph. You start creeping above 100 cadence and you start burning your fuse. 29.5mph is going to be a common surge in any road ride around here.
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I've showed up to plenty of fast road/groad with a 46/36 on my gravel bike and held my own. Now running a compact on it because I did spin out on steep descents but I do miss the fast shifts in bumpy terrain. I am kind stupid though, and show up with 38c gravelking slicks on a regular basis so take it for what you will
#45
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Speaking as a 100% soloist, hanging with speed surges of 29-30mph in a pack is meaningless in terms of aerodynamics and power production. Mid-pack might be 150-160W. Gimme a good draft and I can hold 30mph all day, on a CX bike on 35s. Like say... behind a Honda Civic.
Anything that happens in the draft is only indicative of the draft. Most of the group guys I've been around flounder out in the open-- they can hold those speeds for minutes, or less.
Anything that happens in the draft is only indicative of the draft. Most of the group guys I've been around flounder out in the open-- they can hold those speeds for minutes, or less.
#46
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I also now have a built in excuse for getting dropped on the first lap of your crit
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What I was trying to say. Once you get up to those speeds there's a lot to be said for aerodynamics too. Anytime I try to go fast it's on my own little TT. Riding in a group with my club is a whole different story.
#48
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Tour int in their latest issue showed the difference between an aero road bike (Canyon Aeroroad on zipp 404s), std road on aero wheels (Tarmac on same 404w), and std road on modern stock wheels (Tarmac on DT Swiss R411 db) is about 28w at 28mph (45kph ~12% improvement). The difference between the training wheels and 404s was 13w (~5%). This was with a half dummy pedaling with spinning wheels.
Now, the aero road bike did not have a bottle and cage on it, so a lot of the aero differences are the downtube, handlebars, and seat post. A bottle and cage neutralizes the downtube advantage. The seat post operates in dirty air at all times. So, in the real world, a standard road bike with aero handlebars and wheels about the same as an aero bike.
The difference between a cross/gravel bike and standard road bike isn't that great. The cx bike will have a thicker fork that's wider (but only 10mm on each side at the top, bottom is the same). It'll also ride worse on road tires (my 2014-ish crockett was brutal on road tires on the stock seatpost - roadbike.de confirms with their frame test #s ) and have lower gearing. You can obviously change the gearing easily. If you're on a 1x bike, you'll be riding in the smaller 11-15t cogs of the cassette a lot, so you'll lose 2-3w there.
I'm slow, an 18mph solo type, but Strava doesn't notice the difference between my Emonda ALR, old Crockett CX bike, and my new fat down-tubed Checkpoint SL on the same wheels/tires. Running 1x on the gravel bike, I'm only in trouble over 30mph running a 42t ring on a group ride. I really only have two bikes to have shorter gearing on one and so I can have one down for maintenance. I like 1x for bumpy gravel and the proper road bike rides a bit better.
Handling wise, the proper road bike zig-zags a bit better, but they corner the same.
If you're going to one bike, it might make sense to get a second set of wheels, tires, cassette (so you don't have to change it), and maybe a second crankset with lower gearing. If you're 1x, I'd buy a second crank with different gearing on it. I'd totally put aero bars on a CX bike having tried them. My SRAM medium cage RD isn't too fussy about whether I have an 11-28 or 11-36 on it.
Now, the aero road bike did not have a bottle and cage on it, so a lot of the aero differences are the downtube, handlebars, and seat post. A bottle and cage neutralizes the downtube advantage. The seat post operates in dirty air at all times. So, in the real world, a standard road bike with aero handlebars and wheels about the same as an aero bike.
The difference between a cross/gravel bike and standard road bike isn't that great. The cx bike will have a thicker fork that's wider (but only 10mm on each side at the top, bottom is the same). It'll also ride worse on road tires (my 2014-ish crockett was brutal on road tires on the stock seatpost - roadbike.de confirms with their frame test #s ) and have lower gearing. You can obviously change the gearing easily. If you're on a 1x bike, you'll be riding in the smaller 11-15t cogs of the cassette a lot, so you'll lose 2-3w there.
I'm slow, an 18mph solo type, but Strava doesn't notice the difference between my Emonda ALR, old Crockett CX bike, and my new fat down-tubed Checkpoint SL on the same wheels/tires. Running 1x on the gravel bike, I'm only in trouble over 30mph running a 42t ring on a group ride. I really only have two bikes to have shorter gearing on one and so I can have one down for maintenance. I like 1x for bumpy gravel and the proper road bike rides a bit better.
Handling wise, the proper road bike zig-zags a bit better, but they corner the same.
If you're going to one bike, it might make sense to get a second set of wheels, tires, cassette (so you don't have to change it), and maybe a second crankset with lower gearing. If you're 1x, I'd buy a second crank with different gearing on it. I'd totally put aero bars on a CX bike having tried them. My SRAM medium cage RD isn't too fussy about whether I have an 11-28 or 11-36 on it.
Last edited by jfranci3; 05-10-19 at 10:54 AM.
#49
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The human body makes the largest aero difference
My Scott cross bike has a high stack, wide bars, low and narrow is not it's thing, it rides great, not stiff at all
Aero bike, long pulls @25mph+ it's a noticeable difference
Last edited by RedBullFiXX; 05-10-19 at 02:09 PM.
#50
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Spend a fraction of the money on instrument (power meter + drag meter) which you would otherwise spend on all the bikes.
You'll be able to measure the drag coefficient (aerodynamic) with less than $1000. They would be the best thing to improve your power and ride positions.
CdA meter:
https://velocomp-llc.myshopify.com/p...-and-cda-meter
Power meter: (one of many. possibly one of the best you may get at this money.)
https://cycling.favero.com/assioma
You'll be able to measure the drag coefficient (aerodynamic) with less than $1000. They would be the best thing to improve your power and ride positions.
CdA meter:
https://velocomp-llc.myshopify.com/p...-and-cda-meter
Power meter: (one of many. possibly one of the best you may get at this money.)
https://cycling.favero.com/assioma