Why aren't road bike wheels tiny? Planned maintenance scheduled April 23, 2019 at 23:30 UTC (7:30pm US/Eastern) Announcing the arrival of Valued Associate #679: Cesar Manara Unicorn Meta Zoo #1: Why another podcast?Advice on aero wheelsWhy are hand-built wheels considered to be better than machine-built wheels?Does group riding negate the aero benefit of deep rim wheels?Why are wheels so important for racing?Road bike frame for offroad/cx wheelsWhy no wheels with rope instead of spokes?Where does aero wheels noise come from?What's the difference between road bike disc brake wheels /cyclosross wheels?Can it be estimated when it would actually be beneficial to increase drag in tailwind?Why do deep section front wheels get pushed around in crosswinds?
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Why aren't road bike wheels tiny?
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Why aren't road bike wheels tiny?
Planned maintenance scheduled April 23, 2019 at 23:30 UTC (7:30pm US/Eastern)
Announcing the arrival of Valued Associate #679: Cesar Manara
Unicorn Meta Zoo #1: Why another podcast?Advice on aero wheelsWhy are hand-built wheels considered to be better than machine-built wheels?Does group riding negate the aero benefit of deep rim wheels?Why are wheels so important for racing?Road bike frame for offroad/cx wheelsWhy no wheels with rope instead of spokes?Where does aero wheels noise come from?What's the difference between road bike disc brake wheels /cyclosross wheels?Can it be estimated when it would actually be beneficial to increase drag in tailwind?Why do deep section front wheels get pushed around in crosswinds?
My understanding is that air resistance is where most of the pedal power goes to at high speeds, and that this is a concern not least for the wheels: What you pay for in a road bike wheel is aerodynamic and/or light wheels, not so much to other losses like rolling resistance and bearings.
So if air resistance is the thing to optimize a wheel for, the wheel should be tiny. Obviously in width, but also in radius, because even shortening the length of a surface reduces boundary layer drag. Has anybody thought of this?
Postulate: The faster angular speed of a small wheel is irrelevant to air resistance: If the forward speed is given, every point on the wheel at a given fractional wheel radius has a speed compared to the ground that is independent of the wheel radius. In other words, shrinking the wheel does not speed up any point on its surface; you just get less surface. Which should be good!
wheels aerodynamics
New contributor
add a comment |
My understanding is that air resistance is where most of the pedal power goes to at high speeds, and that this is a concern not least for the wheels: What you pay for in a road bike wheel is aerodynamic and/or light wheels, not so much to other losses like rolling resistance and bearings.
So if air resistance is the thing to optimize a wheel for, the wheel should be tiny. Obviously in width, but also in radius, because even shortening the length of a surface reduces boundary layer drag. Has anybody thought of this?
Postulate: The faster angular speed of a small wheel is irrelevant to air resistance: If the forward speed is given, every point on the wheel at a given fractional wheel radius has a speed compared to the ground that is independent of the wheel radius. In other words, shrinking the wheel does not speed up any point on its surface; you just get less surface. Which should be good!
wheels aerodynamics
New contributor
552 mm wheels are probably UCI legal in road races. Fore and aft same wheels of same diametre are required though
– gschenk
4 hours ago
1
Uh, what is the single largest (by far) source of both weight and wind resistance for a bicycle (that's being ridden by a human)?
– Daniel R Hicks
4 hours ago
And concoct an adult-sized bike with 16-inch wheels. Take it out on a highway and ride it 50 miles. Then come back and explain why wheels should be small.
– Daniel R Hicks
1 hour ago
add a comment |
My understanding is that air resistance is where most of the pedal power goes to at high speeds, and that this is a concern not least for the wheels: What you pay for in a road bike wheel is aerodynamic and/or light wheels, not so much to other losses like rolling resistance and bearings.
So if air resistance is the thing to optimize a wheel for, the wheel should be tiny. Obviously in width, but also in radius, because even shortening the length of a surface reduces boundary layer drag. Has anybody thought of this?
Postulate: The faster angular speed of a small wheel is irrelevant to air resistance: If the forward speed is given, every point on the wheel at a given fractional wheel radius has a speed compared to the ground that is independent of the wheel radius. In other words, shrinking the wheel does not speed up any point on its surface; you just get less surface. Which should be good!
wheels aerodynamics
New contributor
My understanding is that air resistance is where most of the pedal power goes to at high speeds, and that this is a concern not least for the wheels: What you pay for in a road bike wheel is aerodynamic and/or light wheels, not so much to other losses like rolling resistance and bearings.
So if air resistance is the thing to optimize a wheel for, the wheel should be tiny. Obviously in width, but also in radius, because even shortening the length of a surface reduces boundary layer drag. Has anybody thought of this?
Postulate: The faster angular speed of a small wheel is irrelevant to air resistance: If the forward speed is given, every point on the wheel at a given fractional wheel radius has a speed compared to the ground that is independent of the wheel radius. In other words, shrinking the wheel does not speed up any point on its surface; you just get less surface. Which should be good!
wheels aerodynamics
wheels aerodynamics
New contributor
New contributor
New contributor
asked 4 hours ago
user2394284user2394284
1091
1091
New contributor
New contributor
552 mm wheels are probably UCI legal in road races. Fore and aft same wheels of same diametre are required though
– gschenk
4 hours ago
1
Uh, what is the single largest (by far) source of both weight and wind resistance for a bicycle (that's being ridden by a human)?
– Daniel R Hicks
4 hours ago
And concoct an adult-sized bike with 16-inch wheels. Take it out on a highway and ride it 50 miles. Then come back and explain why wheels should be small.
– Daniel R Hicks
1 hour ago
add a comment |
552 mm wheels are probably UCI legal in road races. Fore and aft same wheels of same diametre are required though
– gschenk
4 hours ago
1
Uh, what is the single largest (by far) source of both weight and wind resistance for a bicycle (that's being ridden by a human)?
– Daniel R Hicks
4 hours ago
And concoct an adult-sized bike with 16-inch wheels. Take it out on a highway and ride it 50 miles. Then come back and explain why wheels should be small.
– Daniel R Hicks
1 hour ago
552 mm wheels are probably UCI legal in road races. Fore and aft same wheels of same diametre are required though
– gschenk
4 hours ago
552 mm wheels are probably UCI legal in road races. Fore and aft same wheels of same diametre are required though
– gschenk
4 hours ago
1
1
Uh, what is the single largest (by far) source of both weight and wind resistance for a bicycle (that's being ridden by a human)?
– Daniel R Hicks
4 hours ago
Uh, what is the single largest (by far) source of both weight and wind resistance for a bicycle (that's being ridden by a human)?
– Daniel R Hicks
4 hours ago
And concoct an adult-sized bike with 16-inch wheels. Take it out on a highway and ride it 50 miles. Then come back and explain why wheels should be small.
– Daniel R Hicks
1 hour ago
And concoct an adult-sized bike with 16-inch wheels. Take it out on a highway and ride it 50 miles. Then come back and explain why wheels should be small.
– Daniel R Hicks
1 hour ago
add a comment |
2 Answers
2
active
oldest
votes
You also have to count for stuff you can get over - that's why 29-inch wheels are so popular with the mountain bike crowd these days. They suck at cornering, and that's why they came up with 27.5's. Smaller wheel diameters are great for accelerating quicker, hence the popularity of 650C wheel sets for triathlons. Scooters have tiny wheels because they ideally are ridden on paved roads or sidewalks, and can therefore get by without hitting any major potholes or bumps. At some point, people got together and determined an ideal threshold for wheel size that would prevent accidents by their sole ability to get over stuff. That's the best explanation I've got!
add a comment |
Assuming a bicycle with a conventional rider position, the rider cannot be positioned any lower because there has to be a certain amount of clearance between the cranks and the road. As wheels shrink, the frame has to extend downwards to reach the axles, so you are not really removing structure that causes drag, you are replacing it with something else.
Smaller wheels have higher rolling resistance, at some point that become significant compared to aero drag.
There are a host of other practical reasons, for instance:
As the driving wheel decreases in size the gear ratios have to increase to maintain the same distance travelled for a turn of the cranks. This is why folding bikes have huge chainrings.
Small wheels are less stable, as anyone who has ridden a Razor scooter knows.
add a comment |
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2 Answers
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You also have to count for stuff you can get over - that's why 29-inch wheels are so popular with the mountain bike crowd these days. They suck at cornering, and that's why they came up with 27.5's. Smaller wheel diameters are great for accelerating quicker, hence the popularity of 650C wheel sets for triathlons. Scooters have tiny wheels because they ideally are ridden on paved roads or sidewalks, and can therefore get by without hitting any major potholes or bumps. At some point, people got together and determined an ideal threshold for wheel size that would prevent accidents by their sole ability to get over stuff. That's the best explanation I've got!
add a comment |
You also have to count for stuff you can get over - that's why 29-inch wheels are so popular with the mountain bike crowd these days. They suck at cornering, and that's why they came up with 27.5's. Smaller wheel diameters are great for accelerating quicker, hence the popularity of 650C wheel sets for triathlons. Scooters have tiny wheels because they ideally are ridden on paved roads or sidewalks, and can therefore get by without hitting any major potholes or bumps. At some point, people got together and determined an ideal threshold for wheel size that would prevent accidents by their sole ability to get over stuff. That's the best explanation I've got!
add a comment |
You also have to count for stuff you can get over - that's why 29-inch wheels are so popular with the mountain bike crowd these days. They suck at cornering, and that's why they came up with 27.5's. Smaller wheel diameters are great for accelerating quicker, hence the popularity of 650C wheel sets for triathlons. Scooters have tiny wheels because they ideally are ridden on paved roads or sidewalks, and can therefore get by without hitting any major potholes or bumps. At some point, people got together and determined an ideal threshold for wheel size that would prevent accidents by their sole ability to get over stuff. That's the best explanation I've got!
You also have to count for stuff you can get over - that's why 29-inch wheels are so popular with the mountain bike crowd these days. They suck at cornering, and that's why they came up with 27.5's. Smaller wheel diameters are great for accelerating quicker, hence the popularity of 650C wheel sets for triathlons. Scooters have tiny wheels because they ideally are ridden on paved roads or sidewalks, and can therefore get by without hitting any major potholes or bumps. At some point, people got together and determined an ideal threshold for wheel size that would prevent accidents by their sole ability to get over stuff. That's the best explanation I've got!
answered 52 mins ago
M. HernandezM. Hernandez
464
464
add a comment |
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Assuming a bicycle with a conventional rider position, the rider cannot be positioned any lower because there has to be a certain amount of clearance between the cranks and the road. As wheels shrink, the frame has to extend downwards to reach the axles, so you are not really removing structure that causes drag, you are replacing it with something else.
Smaller wheels have higher rolling resistance, at some point that become significant compared to aero drag.
There are a host of other practical reasons, for instance:
As the driving wheel decreases in size the gear ratios have to increase to maintain the same distance travelled for a turn of the cranks. This is why folding bikes have huge chainrings.
Small wheels are less stable, as anyone who has ridden a Razor scooter knows.
add a comment |
Assuming a bicycle with a conventional rider position, the rider cannot be positioned any lower because there has to be a certain amount of clearance between the cranks and the road. As wheels shrink, the frame has to extend downwards to reach the axles, so you are not really removing structure that causes drag, you are replacing it with something else.
Smaller wheels have higher rolling resistance, at some point that become significant compared to aero drag.
There are a host of other practical reasons, for instance:
As the driving wheel decreases in size the gear ratios have to increase to maintain the same distance travelled for a turn of the cranks. This is why folding bikes have huge chainrings.
Small wheels are less stable, as anyone who has ridden a Razor scooter knows.
add a comment |
Assuming a bicycle with a conventional rider position, the rider cannot be positioned any lower because there has to be a certain amount of clearance between the cranks and the road. As wheels shrink, the frame has to extend downwards to reach the axles, so you are not really removing structure that causes drag, you are replacing it with something else.
Smaller wheels have higher rolling resistance, at some point that become significant compared to aero drag.
There are a host of other practical reasons, for instance:
As the driving wheel decreases in size the gear ratios have to increase to maintain the same distance travelled for a turn of the cranks. This is why folding bikes have huge chainrings.
Small wheels are less stable, as anyone who has ridden a Razor scooter knows.
Assuming a bicycle with a conventional rider position, the rider cannot be positioned any lower because there has to be a certain amount of clearance between the cranks and the road. As wheels shrink, the frame has to extend downwards to reach the axles, so you are not really removing structure that causes drag, you are replacing it with something else.
Smaller wheels have higher rolling resistance, at some point that become significant compared to aero drag.
There are a host of other practical reasons, for instance:
As the driving wheel decreases in size the gear ratios have to increase to maintain the same distance travelled for a turn of the cranks. This is why folding bikes have huge chainrings.
Small wheels are less stable, as anyone who has ridden a Razor scooter knows.
answered 26 mins ago
Argenti ApparatusArgenti Apparatus
38.2k23995
38.2k23995
add a comment |
add a comment |
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552 mm wheels are probably UCI legal in road races. Fore and aft same wheels of same diametre are required though
– gschenk
4 hours ago
1
Uh, what is the single largest (by far) source of both weight and wind resistance for a bicycle (that's being ridden by a human)?
– Daniel R Hicks
4 hours ago
And concoct an adult-sized bike with 16-inch wheels. Take it out on a highway and ride it 50 miles. Then come back and explain why wheels should be small.
– Daniel R Hicks
1 hour ago