69chevy

Knowing my average speed and my average grade....

If I dropped 5lbs off of my bike, I would be .1 MPH faster.

If you wonder how much faster a lighter bike would make you and you know your average speed and grade (or power) you can use this calculator to get an approximation. Aero gains can't be calculated here. Just weight differences.

Bike Calculator

Dan333SP

Thanks for sharing.

Edited to add something useful-

Bicycle Speed (Velocity) And Power Calculator

This one gives you all sorts of numbers and allows you to adjust rider drag, rolling resistance, elevation, ect.

Not sure how accurate it is, though. Says that, holding the same power (250 watts as an example) on a flat road, going from riding on my hoods to the drops would cause me to accelerate from 19.4 mph to 21.9. There are a lot of variables involved in that (drop depth, elbows bent/straight, back flat, saddle-bar drop, ect.) so I'd take any of these calculators with a huge grain of salt.

BoSoxYacht

Ask a physics professor that is a cyclist. They might be able to explain to you how the question you are asking has too many variables to answer easily.

Smokehouse

I would say at least 3a faster...if not 5q. Me? I ate a large lunch so I'd probably only be 2.6n faster.

grote

This is very true... For example, you can change your speed by .1 mph just by consistently riding on the painted stripe of the road. That little bit of extra smoothness created by the paint makes a difference you can actually feel.

(Not exactly a practical piece of advice though since you might swing out into traffic!)

Dan333SP

But what if the paint is fresh and sticky? Do we have a formula we can use to determine tire drag based on a given type of road paint's drying times in various environments?

PepeM

Are white and yellow paint the same?

Wheever

0 to 60 in 3.5 seconds faster.

caloso

Conduct an experiment. Take your current bike and add 5 pounds. (It's a lot easier to add weight than to subtract it, just use water in backpack). Ride around, collect data. Add another 5 pounds, ride around, collect data. Repeat. Graph out your findings, draw conclusions. I bet you could win a ribbon at the middle school science fair.

bbbean 

Duh! You'd be 5 lbs faster!

Dan333SP

Only if your tri-fold poster board game is strong.

PepeM

What if there is no lbs in my small town?

Dan333SP

@PepeM great question!

Here's another quality science experiment with relevant data for cyclists-

DaveLeeNC

FWIW, I wrote an Excel based bike simulator simply to answer questions like this. The motivation was to understand how much, if any, performance improvement was available by doing stuff like new wheels, lighter bike, etc. It saved me some money :-)

Given my personal riding style/habits and the areas where I ride, dropping 5 pounds would net me less than a 0.1 mph improvement (according to the simulator). Why yes, I'd love to have another piece of chocolate cake :-)

dave

colnago62

It is very expensive to put my bike on a diet. Much cheaper putting me on a diet.

motorthings

41% faster

kc0bbq

Loosing 100 pounds on a climb I do often would net me 5.6mph with no extra effort and a Strava KoM. Is 75lbs too unhealthy for someone who is 6'2"? I think I can do it without losing any strength.

69chevy

Using the dollar/gram weight weenie thumb rule (a grams weight savings is worth a dollar) I employed my calculator skills and concluded that for me...

A 1 mph gain would result in spending $22,680 and I would end up with a -30lb bike.

I guess you measure negative weight with lift, so I'm going to invent a wingset that will lift some of my weight off of the road.

FrozenK

Are we talking how much faster you'd be using real world physics or 41 physics? Because with 41 physics you'd be slower on the lighter bike.

69chevy

Or I'll just buy this one.

69chevy

You wouldn't be too skinny.

DaveWC

That rule only applies to mere mortals.

Dan333SP

I love the sign sneaking in on the left there... "Please pardon our progress" indeed.

FrozenK

I forgot, you need a pro license to gain any speed from a lighter bike!

DaveWC

Not falling for that again. The last time we did this exercise we all diligently calculated the time/speed gain that various scenarios produced & then the flat earthers came out & told us that a) it only applies to pros b) even though the time gained was easily calculated, it was a wash when other factors were extrapolated c) time differences of 20-30 seconds are impossible to calculate.

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