How much faster can one expect with an upgraded bike?

[el Ingles]

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.

As the pros only tend to use superlite bikes in the mountains you have to wonder what the advantages really are when most people could shed several kilos in weight for little if any cost and don´t ride in the mountains - remember that rolling resistance is overtaken by wind resistance at 28 kph .
now if you start talking about 10 kg - 20 kg less weight THEN the change in weight will have significant effects in the amount of POWER needed to maintain 45 - 50 kph - it is much less significant at 30 kph .
Weight matters going uphill ( 5% +) but unless you ride mountains ( 30 mins + of climbing and remember that in le Tour they climb for 20 or 30 km with gradients of up to 20 % ) you probably won´t notice a difference in speed but you may find a difference in the feel and handling ( a higher c of g ? ) , lighter wheels always feel faster but in reality ?

if you´ve got the money and want to spend it reality really isn´t what matters is it ?

 

[skydive69]

As the pros only tend to use superlite bikes in the mountains you have to wonder what the advantages really are when most people could shed several kilos in weight for little if any cost and don´t ride in the mountains - remember that rolling resistance is overtaken by wind resistance at 28 kph .
now if you start talking about 10 kg - 20 kg less weight THEN the change in weight will have significant effects in the amount of POWER needed to maintain 45 - 50 kph - it is much less significant at 30 kph .
Weight matters going uphill ( 5% +) but unless you ride mountains ( 30 mins + of climbing and remember that in le Tour they climb for 20 or 30 km with gradients of up to 20 % ) you probably won´t notice a difference in speed but you may find a difference in the feel and handling ( a higher c of g ? ) , lighter wheels always feel faster but in reality ?

if you´ve got the money and want to spend it reality really isn´t what matters is it ?

Thanks for your interesting input!

 

[davidbod]

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

Exactly. If your looking at mass only, then a difference in weight will only come into play during acceleration, decceleration and change in elevation. There will be some difference due to higher rolling resistance for a heavier mass, but with modern high pressure tires you can negate this.

There are other factors to consider though. Acceleration is one for sure. In a sprint or trying to catch a break the lower the mass the less force required to accelerate. Turning the bike is a form of decceleration / acceleration and a lower mass helps here as well. Also higher quality equipment will mean less resistance in the drive mechanism leading to more of your force applied to move you forward and not wasted as drag. A Madone frame with its shaped tubes will be more aerodynamic leading to less wind resistance.

Turning the bike, accelerating, braking and changes in elevation will all require less force with a lower mass bike+rider.

 

[Breliswell]

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!

No, depending on base speed you would be about 550-600 feet further down the road. At 20 miles per hour it would take you 6 minutes to go 2 miles, at 19 MPH it would take you 6.3 minutes. (.317 min.)* )*(1 hour/60 min.)*(20 miles per hour)*(5280 ft. /mile) = (.317*20*5280)/(60) ft. = 555.8 ft. the distance increases as speed goes down. between 18 and 19 miles per hour it would be 586 ft. And that distance far exceeds anything that the physics indicates that one should expect so I will suggest that the 1 mile per hour increase is overly optimistic

 

[meehs]

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!

You mean after a 2 hour ride right? After a two mile ride the lighter bike would only be about 700 feet (704 feet to be exact) farther down the road, assuming a 15mph speed for the heavier bike.

Okay, I'm a geek...

UGH! Someone beat me to it! See above. LOL!

 

[skydive69]

No, depending on base speed you would be about 550-600 feet further down the road. At 20 miles per hour it would take you 6 minutes to go 2 miles, at 19 MPH it would take you 6.3 minutes. (.317 min.)* )*(1 hour/60 min.)*(20 miles per hour)*(5280 ft. /mile) = (.317*20*5280)/(60) ft. = 555.8 ft. the distance increases as speed goes down. between 18 and 19 miles per hour it would be 586 ft. And that distance far exceeds anything that the physics indicates that one should expect so I will suggest that the 1 mile per hour increase is overly optimistic

I meant to say after a 1 hour ride. If you are going two miles an hour faster then one would be 2 miles farther down the road after 1 hour

 

[skydive69]

Exactly. If your looking at mass only, then a difference in weight will only come into play during acceleration, decceleration and change in elevation. There will be some difference due to higher rolling resistance for a heavier mass, but with modern high pressure tires you can negate this.

There are other factors to consider though. Acceleration is one for sure. In a sprint or trying to catch a break the lower the mass the less force required to accelerate. Turning the bike is a form of decceleration / acceleration and a lower mass helps here as well. Also higher quality equipment will mean less resistance in the drive mechanism leading to more of your force applied to move you forward and not wasted as drag. A Madone frame with its shaped tubes will be more aerodynamic leading to less wind resistance.

Turning the bike, accelerating, braking and changes in elevation will all require less force with a lower mass bike+rider.

Very informative David.

 

[phinney]

Very informative David.

Well, as others have pointed out, if the bikes are aerodynamically the same then they'll be going the same speed on that long flat ride. There is a huge emphasis on weight and "the bike" in cycling. It's fun and the technological innovation is interesting. That said a few pounds here or there doesn't amount to much compared to the variability possible in the rider.

I have a pretty light and pretty aerodynamic race bike. I also have a 40+ pound tandem with some touring accessories attached to it. Sometimes I take the tandem out for a solo ride to make sure it's tuned up and working good. Over an hour loop with some mellow climbs I'm probably a couple minutes slower on the tandem. The tandem has wider tires, is far less aerodynamic, etc.

 

[skydive69]

Well, as others have pointed out, if the bikes are aerodynamically the same then they'll be going the same speed on that long flat ride. There is a huge emphasis on weight and "the bike" in cycling. It's fun and the technological innovation is interesting. That said a few pounds here or there doesn't amount to much compared to the variability possible in the rider.

I have a pretty light and pretty aerodynamic race bike. I also have a 40+ pound tandem with some touring accessories attached to it. Sometimes I take the tandem out for a solo ride to make sure it's tuned up and working good. Over an hour loop with some mellow climbs I'm probably a couple minutes slower on the tandem. The tandem has wider tires, is far less aerodynamic, etc.

Thanks - that is fascinating information. Obviously, a tandem is a considerable difference than a light road bike, and yet the difference is surprising little for the difference. I guess the difference between my Sequoia and a bike costing a couple thousand more (on the flats) would be mimimal. I am still anxious, however to hear a comparison by the owner of two road bikes over the same loop (one in the just over a thousand category and the other in the multi K category).

 

[el Ingles]

Not sure the aerodynamic argument really holds water for us - for the track or a closed road time trial more so but , and it´s a big but , all the figures talk about still air - and how much of that do we get on the open road ? turbulence from traffic , side winds and what about the turbulence caused by the movement of our legs and feet ? " aero " wheels and frames ( a cannondale springs to mind here ) can get a bit squirally in a side wind and riders in pro races that start on aero rims and finish on standard wheels due to punctures and replacements from neutral service don´t seem to be any slower.

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