Does the weight of your bike really make a difference?

pblakeney

I love it when people post without reading the thread.

blueturtle

I have two summer bikes, a Cervelo r3sl weighing in at 5.8kg and a Pinarello f8 weight 6.7kg . My weight is 60kg. The Cervelo is definitely quicker up climbs but slower on descents than the Pina. The Cervelo is more of a handful on the descents whereas the Pina is well planted descending. On the flat the lighter Cervelo is more responsive with respect to short bursts of acceleration when riding on group training rides, something which i am grateful for when trying to close small gaps! If i where on the other hand riding a time trial then the Pina would be the steed of choice as once up to speed the aero effect comes into play ( the Cervelo is about as aero as a wet paper bag!) Ask yourself this question. When preparing a car to race trackside you not only tune the engine but remove all the excess weight you can, why? to make the car accelerate more quickly. To sum up the weight of your bike certainly makes a difference but as usual its horses for courses.

pblakeney

I'd suggest that there are more factors coming into play than a simple 0.9kgs weight difference.

leskenn

blueturtle said:

I have two summer bikes, a Cervelo r3sl weighing in at 5.8kg and a Pinarello f8 weight 6.7kg . My weight is 60kg. The Cervelo is definitely quicker up climbs but slower on descents than the Pina. The Cervelo is more of a handful on the descents whereas the Pina is well planted descending. On the flat the lighter Cervelo is more responsive with respect to short bursts of acceleration when riding on group training rides, something which i am grateful for when trying to close small gaps! If i where on the other hand riding a time trial then the Pina would be the steed of choice as once up to speed the aero effect comes into play ( the Cervelo is about as aero as a wet paper bag!) Ask yourself this question. When preparing a car to race trackside you not only tune the engine but remove all the excess weight you can, why? to make the car accelerate more quickly. To sum up the weight of your bike certainly makes a difference but as usual its horses for courses.

Surely any cheap TT bike that puts you in a proper aero position would beat the F8 on a TT. That's why people have TT bikes after all.

I'm guessing you have deep rims on the F8 ? If they were on the Cervelo - you'd be as fast downhill ?

blueturtle

I was just making the comment regarding riding the Pina. rather than the Cervelo in a time trial with regards to the effectiveness of weight vs aero effect. While not a time trial bike per se the Pinarello does have aero attributes which the Cervelo does not. The f8 is shod with Enve 3.4s or dura ace c35s. With regards to your second question , you have obviously never ridden a Cervelo r3sl on a fast descent. Believe me the f8 is far safer going downhill fast than the Cervelo. This is my experience gained during ascents and descents of Ventoux. As well as other climbs in the Pyrenees. To sum up , If i was racing to the top of Ventoux i would ride the Cervelo, but if the the race was up and down Ventoux then my steed of choice would be the f8.

ugo.santalucia

blueturtle said:

I was just making the comment regarding riding the Pina. rather than the Cervelo in a time trial with regards to the effectiveness of weight vs aero effect. While not a time trial bike per se the Pinarello does have aero attributes which the Cervelo does not. The f8 is shod with Enve 3.4s or dura ace c35s. With regards to your second question , you have obviously never ridden a Cervelo r3sl on a fast descent. Believe me the f8 is far safer going downhill fast than the Cervelo. This is my experience gained during ascents and descents of Ventoux. As well as other climbs in the Pyrenees. To sum up , If i was racing to the top of Ventoux i would ride the Cervelo, but if the the race was up and down Ventoux then my steed of choice would be the f8.

Nice to have that choice... I can choose between a Dolan Dual shod with a mix of unmatched components or a Brompton 2 speed, I'd probably go for the former in either case...

blueturtle

ugo. santalucia Brought a smile to my face !! Each to their own . My first bike had wooden blocks on the pedals so i could reach them! Now its all the gear and no idea.

fenix

Didn't Sastre ride a R3SL when he won the tour ? Can't be that bad for descending surely
What were the Schlecks on when they were complaining about descents in the Tour ?

blueturtle

Yes Sastre did ride a R3SL in Le Tour as did the Schlecks. They are obviously better bike riders than me. What i have described is my personal experience having ridden both bikes over the same terrain. My bike handling skills may not be on a par with the professionals but i can still feel the difference between the two bikes and in my opinion going round a hairpin bend at speed feels more comfortable on the f8 rather than the Cervelo. It may be the geometry ( the R3SL has a wheelbase approx. 20mm shorter than the f8 amongst other things). As an aside any inerrant problems will be magnified by an amateur rider rather than a professional who can use his skills to get himself out of awkward situations as they arise.

mr_mojo

imposter2.0 said:

mr_mojo said:

For me it all depends where the weight is on the bike. Worst place to have excessive weight is the wheels, that is if you are climbing.

Much previous discussion on this topic. It actually makes little or no difference where the weight is.

I don’t entirely agree. I certainly can feel the difference when climbing on my lightest bike at 6kg with its 1.1kg wheelset compared to my 7.5kg aero bike with its 1.8kg wheelset.

fenix

This study shows it does make a difference but perhaps not as much as you might think.

https://www.training4cyclists.com/how-much-time-does-extra-weight-cost-on-alpe-dhuez/

imposter2.0

mr_mojo said:

imposter2.0 said:

mr_mojo said:

For me it all depends where the weight is on the bike. Worst place to have excessive weight is the wheels, that is if you are climbing.

Much previous discussion on this topic. It actually makes little or no difference where the weight is.

I don’t entirely agree. I certainly can feel the difference when climbing on my lightest bike at 6kg with its 1.1kg wheelset compared to my 7.5kg aero bike with its 1.8kg wheelset.

Of course a lighter bike will feel better on a climb than a heavier bike. But that isn't what you said. The point I was making was that wheel weight is largely incidental when viewed in the context of overall bike (and rider) weight.

larkim

https://www.youtube.com/watch?v=0QDnUkUaQfk&t

According to this, a 400g saving on the wheels would shave a massive 4s off a ride up a Cat 1 7% climb of just short of 10k. If you can feel that difference you're senses are akin to Peter Parker's.

Maybe the impact of 1.5kg on the bike is bigger than 4x400g would suggest, but it's still going to be in the range of human-undetectable, surely? Or maybe all you feel is the impact of acceleration, and what you don't sense is the difference in decceleration on each stroke?

ugo.santalucia

larkim said:

https://www.youtube.com/watch?v=0QDnUkUaQfk&t

According to this, a 400g saving on the wheels would shave a massive 4s off a ride up a Cat 1 7% climb of just short of 10k. If you can feel that difference you're senses are akin to Peter Parker's.

Maybe the impact of 1.5kg on the bike is bigger than 4x400g would suggest, but it's still going to be in the range of human-undetectable, surely? Or maybe all you feel is the impact of acceleration, and what you don't sense is the difference in decceleration on each stroke?

If you climb at 4W/kg up said col, then 400 g is a bit less than 2 watts, not a lot... 4 seconds seem a slight underestimate, I would think it's more like 15-20 seconds, but yes, in recreational riding is not a lot.

If you do a hill climb and go up at 6 W/kg, then it's nearly 3 Watt, which up a typical Cat 4 hill means 1-2 seconds. It seems very little, but these races are very tight and you can easily find yourself 10 places down for the small matter of 2 seconds.
Even in terms of club ride bragging rights, if your wheel is ahead of your mate's then you are faster than him...

pblakeney

We are fortunate today in that we can actually/virtually test these things for ourselves. Simply indulge in a bit of digital doping/testing for yourself to find out.
I found out that if I lost 20kgs and got down to 65kgs then I'd be 12-1/2 minutes quicker up Sa Colabra for the same power output. I doubt that can be directly extrapolated to 1-1/4 minutes for 2kgs but you have the ability to find out for yourself next time on the turbo.

ugo.santalucia

pblakeney said:

I doubt that can be directly extrapolated to 1-1/4 minutes for 2kgs but you have the ability to find out for yourself next time on the turbo.

It can, going uphill has an almost linear correlation between mass and speed (inverse, obviously)... things get distorted by drag as you get faster and very distorted when drag is pretty much the only force you have to overcome. Sa Calobra is steep enough for drag to be overlooked

teisetrotter

I'm at 60kg and 168cm. So a lighter bike makes quite a bit of difference ..... if you are 200Cm and 90kg then statistically it's a lot less. Just moving from my normal 60kg to race weight at 58kg and maybe even less is a third of a watt per kg, which is some difference and boy do I notice it. So if I drop 2kg and move to my lightweight summer bike which is 2.5kg lighter ...... that's nearly 10% drop in my overall system weight. That's why my 200cm mate always moans about me drafting on the flat, just before I drop him on a climb

joe_totale-2

larkim said:

https://www.youtube.com/watch?v=0QDnUkUaQfk&t

According to this, a 400g saving on the wheels would shave a massive 4s off a ride up a Cat 1 7% climb of just short of 10k. If you can feel that difference you're senses are akin to Peter Parker's.

Maybe the impact of 1.5kg on the bike is bigger than 4x400g would suggest, but it's still going to be in the range of human-undetectable, surely? Or maybe all you feel is the impact of acceleration, and what you don't sense is the difference in decceleration on each stroke?

As stated here in an article written by the same gentleman as in the video:

https://www.cyclingweekly.com/news/latest-news/at-what-point-does-aero-become-more-significant-than-weight-316952

A pro will still feel the aero benefit more on a 7% climb but an amateur on the same climb would benefit more from a lighter bike. Sure Oliver Bridgewood is no pro but he rides bikes for a living, recently trained for an hour record and has a number of KOM's in my local area so he's probably fitter than most of us.

It'd be interesting for the study to be run again with a rider with more modest abilities.

mpatts

Utterly subjective, but there are so many other things which are more important than outright weight - starting with things like contact points, and very definitely tyres.

I have a '78 raleigh Ti amongst more modern stuff, and it just rides unbelievably well, and does not feel its heft.

shortfall

It doesn't make any difference to the 99% of us who aren't racing or doing chaingangs with a club. It's just a number that sounds good in the pub or when somebody picks it up outside the cafe and gasps at how light it is. Same with bhp figures for cars and power to weight ratios with motorbikes, it's just an ego trip for the owner unless he's got the talent to exploit it. Now there's nothing wrong with buying what you want with your own money don't get me wrong, but spvnking ££££s on a super light bike thinking it's going to make you materially faster is a bit pointless unless you're going to shed the weight off your body and put in the training graft as well.

larkim

Instinctively that feels right to me shortfall. I ride a £300 bike that's 10.6kg in weight. It matters not one little bit to me whether I could be 5 minutes faster up an alpine climb by riding a £1500 bike at several kg less, especially when I know that the choice of whether to ride with 2 full bidons and / or stopping to get a drink or not is the same as spending ££££ on a lighter bike.

But that's also because I don't have £1500 to spend. If I had it, no doubt I'd have a nice, lighter bike with better kit on it. What I've got is fine.

But I do think the "science" is interesting. w/kg in reality should be expressed as the whole system, shouldn't it - rider + bike + clothing + unconsumed fuel / water - as teisetrotter above posted, for some riders the equation of where to save weight (the bike or the rider) will be differently skewed if absolute performance is important.

ugo.santalucia

larkim said:

w/kg in reality should be expressed as the whole system, shouldn't it - rider + bike + clothing + unconsumed fuel / water - as teisetrotter above posted, for some riders the equation of where to save weight (the bike or the rider) will be differently skewed if absolute performance is important.

No, it shouldn't. It provides a number which is independent on how much water you carry with you, whether you are wearing summer clothes or a winter jacket, whether you have a heavy or light bike. It basically defines you as an athlete.

davep1

ugo.santalucia said:

larkim said:

w/kg in reality should be expressed as the whole system, shouldn't it - rider + bike + clothing + unconsumed fuel / water - as teisetrotter above posted, for some riders the equation of where to save weight (the bike or the rider) will be differently skewed if absolute performance is important.

No, it shouldn't. It provides a number which is independent on how much water you carry with you, whether you are wearing summer clothes or a winter jacket, whether you have a heavy or light bike. It basically defines you as an athlete.

My w/kg is defined by the equation not enough/too much...

larkim

ugo.santalucia said:

larkim said:

w/kg in reality should be expressed as the whole system, shouldn't it - rider + bike + clothing + unconsumed fuel / water - as teisetrotter above posted, for some riders the equation of where to save weight (the bike or the rider) will be differently skewed if absolute performance is important.

No, it shouldn't. It provides a number which is independent on how much water you carry with you, whether you are wearing summer clothes or a winter jacket, whether you have a heavy or light bike. It basically defines you as an athlete.

OK I take the point, those other items (the bike, the water, the clothing) can't add power to the equation and in racing if you compromise those things you've only yourself to blame when a competitor with a lower w/kg than you rides faster because you've loaded up with more water etc.

But to get 80kg up a mountain in X minutes takes the same amount of watts whether 65kg of that weight are the rider or 73kg is the rider, doesn't it?

ugo.santalucia

larkim said:

But to get 80kg up a mountain in X minutes takes the same amount of watts whether 65kg of that weight are the rider or 73kg is the rider, doesn't it?

Broadly speaking yes...
Then of course lighter bikes tend to be higher end ones, with stiffer frames and better power transmission all round... which might account for some difference

webboo

I wonder how many of the folk who say a light bike makes no difference have ridden a sub 7 kilo bike for any length of time.

ugo.santalucia

webboo said:

I wonder how many of the folk who say a light bike makes no difference have ridden a sub 7 kilo bike for any length of time.

Never been lucky enough to own one... but on the other end of the spectrum, for a while all I had was an 11 kg bike and it was shit uphill... it even gave me tendonitis after doing the Etape Cymru

mpatts

webboo said:

I wonder how many of the folk who say a light bike makes no difference have ridden a sub 7 kilo bike for any length of time.

I tested a willier zero once, which I think was 6.8kg. Obviously designed for doing 450w up a 5% climb for an hour, because on everything else it was awful.

Oh, and I can do 450w for about 45 seconds.

shortfall

webboo said:

I wonder how many of the folk who say a light bike makes no difference have ridden a sub 7 kilo bike for any length of time.

I don't see anybody claiming it makes no difference, just a few of us questioning how much difference it makes in the real world to people who aren't racing. If you have <10% body fat and you're well trained then you're going to buy the lightest bike you can afford because it might make the difference in a race. If you're that middle aged guy with a bit of a paunch who averages 14 mph and you just want a really light bike because you can afford it, then knock yourself out, just don't expect to start dropping your mates on every climb like you're Pantini.

ugo.santalucia

shortfall said:

webboo said:

I wonder how many of the folk who say a light bike makes no difference have ridden a sub 7 kilo bike for any length of time.

I don't see anybody claiming it makes no difference, just a few of us questioning how much difference it makes in the real world to people who aren't racing. If you have <10% body fat and you're well trained then you're going to buy the lightest bike you can afford because it might make the difference in a race. If you're that middle aged guy with a bit of a paunch who averages 14 mph and you just want a really light bike because you can afford it, then knock yourself out, just don't expect to start dropping your mates on every climb like you're Pantini.</p>

What if you are somewhere in between? What if you are nearly 50 but the body fat is 13% and you drop all your mates easily and routinely are in the top 2-3% of meaningful segments on Strava? Should you aim for a nice light bike or you shouldn't because ultimately you are not going to win any race?