How much faster can one expect with an upgraded bike?

[skydive69]

I ride a Specialized Sequoia Elite which weighs about 24 pounds (Shimano 105 equipped). If I upgraded to a "high end" road bike that weighed about 7 pounds less and is equipped with top-of-the-line goodies, how much more speed could I reasonable expect to achieve with the same effort under the exact same conditions? Let's assume, for example, that I averaged 19 mph for thirty miles. If I repeated that course under the exact same conditions, what speed could I expect to average with the typical high-end road bike?

As long as we are discussing this, what could be expected to be the difference between the two aforementioned bikes, and a high end time trial bike ridden over the same course under the same conditions?

Thanks for your replies.

 

[BanditManDan]

I ride a Specialized Sequoia Elite which weighs about 24 pounds (Shimano 105 equipped). If I upgraded to a "high end" road bike that weighed about 7 pounds less and is equipped with top-of-the-line goodies, how much more speed could I reasonable expect to achieve with the same effort under the exact same conditions? Let's assume, for example, that I averaged 19 mph for thirty miles. If I repeated that course under the exact same conditions, what speed could I expect to average with the typical high-end road bike?

As long as we are discussing this, what could be expected to be the difference between the two aforementioned bikes, and a high end time trial bike ridden over the same course under the same conditions?

Thanks for your replies.

I'm not an expert but my experience says that it depends. It depends on the hills because the lighter weight bike will make hill climbing easier and down hill's slower. If we are talking about flat surfaces using the lighter bike I would guess that you might expect to finish a 30 mile ride around 30 to 60 seconds faster than with a bike weighing 7 pounds heavier. Of course I don't have calculations to back this up but I've reasearched this question before and that's about what I remember reading.

Perhaps some physics guy can chime in and give us a more scientific explaination.

Dan.

 

[skydive69]

I'm not an expert but my experience says that it depends. It depends on the hills because the lighter weight bike will make hill climbing easier and down hill's slower. If we are talking about flat surfaces using the lighter bike I would guess that you might expect to finish a 30 mile ride around 30 to 60 seconds faster than with a bike weighing 7 pounds heavier. Of course I don't have calculations to back this up but I've reasearched this question before and that's about what I remember reading.

Perhaps some physics guy can chime in and give us a more scientific explaination.

Dan.

Thanks Dan. Candidly, I was expecting more input in that I would assume that upgrading bicycles is something that everyone thinks about. Assuming that your current bike is comfortable and reliable, one of the reasons to upgrade would be increased performance - there is certainly no big difference in looks between my bike and one costing thousands more. If I can't go faster, I don't need to upgrade.

My primary interest is difference in speed. My local bike shop owner told me that I could expect another 2 mph by upgrading to a Specialized s-works bike. I am a bit skeptical about that statement.

 

[gruppo]

You may want to look at this article. It is a little more complicated than just weight vs. speed:

http://www.bikemania.biz/bikehighway/weight/weight.htm

 

[skydive69]

You may want to look at this article. It is a little more complicated than just weight vs. speed:

http://www.bikemania.biz/bikehighway/weight/weight.htm

Interesting article, but bottom line is that I am still a bit confused. I guess the specific question I am trying to answer is this: I am on a flat surface, zero wind, cranking along at my LT. Let's say for arguments sake, I am doing 28 mph on my heavier bike with heavier components. Now I upgrade to say a Trek Madone. How much faster will I be going with exactly the same energy expenditure under those conditions? The assumption is that both bikes are precisely fit to me.

 

[Breliswell]

Thanks Dan. Candidly, I was expecting more input in that I would assume that upgrading bicycles is something that everyone thinks about. Assuming that your current bike is comfortable and reliable, one of the reasons to upgrade would be increased performance - there is certainly no big difference in looks between my bike and one costing thousands more. If I can't go faster, I don't need to upgrade.

My primary interest is difference in speed. My local bike shop owner told me that I could expect another 2 mph by upgrading to a Specialized s-works bike. I am a bit skeptical about that statement.

Check out this page, author gives a pretty good explanation of teh forces involved, their magnitude
http://www.gugly.com/Archbikewindroll.htm

 

[gruppo]

The only data I have found suggests the following:

At 0% grade, and at 100 watts output, the difference between a 6.8 kg bike and 9 kg bike is 6.3 seconds/km.

At 0% grade, and at 400 watts output, the difference between a 6.8 kg bike and 9 kg bike is 4.1 seconds/km.

That data is summarized from "High Performance Cycling" by Jeukendrup.

 

[Daremo]

There is no answer to that ...........

Yeah, I'm sure there is some formulae that you can use to calculate speed per distance based on weight, but the reality is much different.

A lighter and better equipped bike will be faster because of psychological reasons more than flat out physics at the recreational/amateur level.

Climbing will be better because weight savings has a more significant effect when you start changing altitudes.

But then again, if YOU weighed seven punds less, it would have the same effect .............

Buying a better bike and trying to justify it based on physics is the wrong reason. You buy a better bike to have better components and to have something that you will be happy with for a long time.

But do us a favor, don't be another Fred that goes out and buys a Madone ....... shop around and get a better bike/value ......

 

[gruppo]

OK, I'm sure a physics professor would blow holes in this analogy, but it may be reasonable for practical use:

You have a fixed amount of power which is moving a fixed amount of weight. If you are looking at saving 7 lbs, we could estimate the savings as:

Body weight = 140 lbs
Savings = 7 lbs
Saving % = 5 %
28 MPH + 5% = 29.4

or

Body weight = 175 lbs
Savings = 7 lbs
Saving % = 4 %
28 MPH + 4% = 29.12

 

[Joe Faust]

I ride a Specialized Sequoia Elite which weighs about 24 pounds (Shimano 105 equipped). If I upgraded to a "high end" road bike that weighed about 7 pounds less and is equipped with top-of-the-line goodies, how much more speed could I reasonable expect to achieve with the same effort under the exact same conditions? Let's assume, for example, that I averaged 19 mph for thirty miles. If I repeated that course under the exact same conditions, what speed could I expect to average with the typical high-end road bike?

As long as we are discussing this, what could be expected to be the difference between the two aforementioned bikes, and a high end time trial bike ridden over the same course under the same conditions?

Thanks for your replies.

You can get a good estimate of the 7 pound improvement at Analyticcyling.com Plug in some figures and run a model for the change in parameters.

 

[BanditManDan]

The bottom line is the bike is "not" the biggest factor in cycling performance, the rider is. I was once told that I shouldn't worry too much about the bike unless I was losing races by a few feet, otherwise I needed to improve the engine (me).

2 mph difference that your LBS told you is perhaps a max speed difference but does nothing for you average speed. I would say that it's best to train yourself first and then look at the bike second.

Always remember: "It's not about the bike."

Dan.

 

[JohnO]

I've been running some informal tests of a 70's vintage Falcon racer (21 lbs, 531 frame, Campy NR) against my reasonably modern Trek Y-Foil (17 lbs, OCLV carbon beam frame, Campy Chorus), photo of the Foil is my avatar.

Results so far have been interesting. On the flats, not a great deal of difference, maybe a 1mph advantage to the Foil. Keep in mind that these are the results of a weekend cyclist who is lucky to hold a 20 mph average for 20 miles on the flats. Your mileage may vary.

Climbing - if I discount the Foil's 10 speeds on the rear versus the Falcon's 5, and keep both bikes in the same size gear, not much difference. Having the 10 speeds on the back makes it easier to find the 'right' gear for a climb.

Downhill - definite advantage to the modern bike. On a moderate downhill, in a power on descent, the Foil maxes out at 48 mph (I'm trying for 50), while the Falcon tops out at around 42.

Interesting to note that when I swapped out the aero wheels on the Foil for a more conventional wheel - 32 spoke 3 cross laced, non aero box rim section, the Foil lost 3-4 mph on the downhill. You could definitely feel less resistance when sprinting downhill with the aero wheels, especially as the speed got above 40.

Keep in mind that the biggest difference between these two bikes is the aero wheels, the extra gears, and aerodynamics on the frame. The old Falcon's frame is quite stiff, as befits a British built competition frame of that era, so I don't think much was lost due to frame flex. (the Foil's frame is very stiff) The Chorus brakes work better than the old NR brakes, but brakes don't make you go faster.

If you're comparing upgrade to buy new costs - you might think about getting a set of lightweight aero wheels. They can always be moved to another bike. 105 is respectable componentry, going Ultegra/DA/Campy won't get you a noticable increase in performance. You might lose half a pound in weight - about as much as a loaded water bottle. How much faster do you go when you leave the water bottle off? The only other area of possible improvement is the frame, if your current one exhibits flex. No reason you couldn't pick up a used 5200 frameset and move your gear over. Or a Foil frame, if you can find one.

 

[davidbod]

If were talking level ground, already at speed, then the weight difference will make absolutely no difference in performance. At that point the only thing acting on you and the bike are wind and rolling resistance and your legs pushing against the two of them. On level ground the weight difference only comes into play during acceleration and decceleration. Hills are a different story and add gravity into the equation.

 

[gruppo]

If were talking level ground, already at speed, then the weight difference will make absolutely no difference in performance...

Is this just opinion, or do you have data to support this claim?

 

[skydive69]

I've been running some informal tests of a 70's vintage Falcon racer (21 lbs, 531 frame, Campy NR) against my reasonably modern Trek Y-Foil (17 lbs, OCLV carbon beam frame, Campy Chorus), photo of the Foil is my avatar.

Results so far have been interesting. On the flats, not a great deal of difference, maybe a 1mph advantage to the Foil. Keep in mind that these are the results of a weekend cyclist who is lucky to hold a 20 mph average for 20 miles on the flats. Your mileage may vary.

Climbing - if I discount the Foil's 10 speeds on the rear versus the Falcon's 5, and keep both bikes in the same size gear, not much difference. Having the 10 speeds on the back makes it easier to find the 'right' gear for a climb.

Downhill - definite advantage to the modern bike. On a moderate downhill, in a power on descent, the Foil maxes out at 48 mph (I'm trying for 50), while the Falcon tops out at around 42.

Interesting to note that when I swapped out the aero wheels on the Foil for a more conventional wheel - 32 spoke 3 cross laced, non aero box rim section, the Foil lost 3-4 mph on the downhill. You could definitely feel less resistance when sprinting downhill with the aero wheels, especially as the speed got above 40.

Keep in mind that the biggest difference between these two bikes is the aero wheels, the extra gears, and aerodynamics on the frame. The old Falcon's frame is quite stiff, as befits a British built competition frame of that era, so I don't think much was lost due to frame flex. (the Foil's frame is very stiff) The Chorus brakes work better than the old NR brakes, but brakes don't make you go faster.

If you're comparing upgrade to buy new costs - you might think about getting a set of lightweight aero wheels. They can always be moved to another bike. 105 is respectable componentry, going Ultegra/DA/Campy won't get you a noticable increase in performance. You might lose half a pound in weight - about as much as a loaded water bottle. How much faster do you go when you leave the water bottle off? The only other area of possible improvement is the frame, if your current one exhibits flex. No reason you couldn't pick up a used 5200 frameset and move your gear over. Or a Foil frame, if you can find one.

Very interesting John - thanks for your input. Of course 1 mph would be a substantial increase in speed for same effort after a two mile ride. Theoretically, one would be two miles farther down the road with the same effort!

 

[skydive69]

Check out this page, author gives a pretty good explanation of teh forces involved, their magnitude
http://www.gugly.com/Archbikewindroll.htm

Interesting piece! Thanks

 

[skydive69]

OK, I'm sure a physics professor would blow holes in this analogy, but it may be reasonable for practical use:

You have a fixed amount of power which is moving a fixed amount of weight. If you are looking at saving 7 lbs, we could estimate the savings as:

Body weight = 140 lbs
Savings = 7 lbs
Saving % = 5 %
28 MPH + 5% = 29.4

or

Body weight = 175 lbs
Savings = 7 lbs
Saving % = 4 %
28 MPH + 4% = 29.12

Interesting, but as you say, the physics of the problem would not sustain that theory.

 

[skydive69]

If were talking level ground, already at speed, then the weight difference will make absolutely no difference in performance. At that point the only thing acting on you and the bike are wind and rolling resistance and your legs pushing against the two of them. On level ground the weight difference only comes into play during acceleration and decceleration. Hills are a different story and add gravity into the equation.

If I am reading you correctly then David. If I jumped on a Madone with my twin riding alongside me on my Specialized Sequoia, and we were putting out the same steady state effort, then we would be doing the same speed. If true, it shoots down any motivation to upgrade in that there is nothing I dislike about my Sequoia. I am willing to upgrade only if, for example, I could complete a 40 mile, flat ride quicker with the more expensive bike. I am not into having things to impress my friends and neighbors (fellow riders).

 

[Jitensha Joe]

If I am reading you correctly then David. If I jumped on a Madone with my twin riding alongside me on my Specialized Sequoia, and we were putting out the same steady state effort, then we would be doing the same speed. [ .. ]

Theoretically, the wind and rolling resistance David correctly mentions, may be less on the more expensive bike - more aerodynamic riding position perhaps, slightly better wheel and crank bearings, slightly harder tyres|tires. If so, in theory your legs would have to do slightly less effort to overcome this wind and rolling resistance, or conversely, for the same power input, you would go slightly faster. How significant "slightly" is is debatable endlessly.

So .. mass of the bike on level ground at steady velocity is not going to have any effect in theory, outside of anything already accounted for in rolling resistance ( ie, a pedant may argue that a higher mass bike may squash the tyres|tires slightly more into the road, slightly increasing rolling resistance .. but, well ... life is short )

Steady velocity implies no change in direction, even at the same speed - if you turn, even maintaining exact speed, the mass makes a difference. So .. the theory is that the effect of a bikes mass, ceteris paribus, on a rider travelling at constant velocity ( straight line effectively ) is zero.

I guess the thing to do, rather than the theory, is try and borrow a 17lb bike over your usual route..

Warning: even if its not faster, you might still want it

JJ

Tied an anchor to my saddle loops and it made no difference

 

[skydive69]

Theoretically, the wind and rolling resistance David correctly mentions, may be less on the more expensive bike - more aerodynamic riding position perhaps, slightly better wheel and crank bearings, slightly harder tyres|tires. If so, in theory your legs would have to do slightly less effort to overcome this wind and rolling resistance, or conversely, for the same power input, you would go slightly faster. How significant "slightly" is is debatable endlessly.

So .. mass of the bike on level ground at steady velocity is not going to have any effect in theory, outside of anything already accounted for in rolling resistance ( ie, a pedant may argue that a higher mass bike may squash the tyres|tires slightly more into the road, slightly increasing rolling resistance .. but, well ... life is short )

Steady velocity implies no change in direction, even at the same speed - if you turn, even maintaining exact speed, the mass makes a difference. So .. the theory is that the effect of a bikes mass, ceteris paribus, on a rider travelling at constant velocity ( straight line effectively ) is zero.

I guess the thing to do, rather than the theory, is try and borrow a 17lb bike over your usual route..

Warning: even if its not faster, you might still want it

JJ

Tied an anchor to my saddle loops and it made no difference

Thanks for the interesting reply> I wonder if there is in fact anyone out there with first hand experience who traded up, and noted a difference in his logbook of faster average speeds over the same route?

The local bike shop has a loaner of one of the bikes I am interested in, and perhaps I will take it out and test it. There is one strip of road in my neighborhood that I typically do a sprint at the end of the ride with the intention of hitting top speed. One test will be to see if I can break my record on the test bike. Admittedly, there will be a zillion variables.