If you're so clever and I'm so wrong it would take no time to destroy my arguments...but you've not advanced anything other than references to your article...which concludes against you from what I can see.
...you could do it tomorrow morning break time?
What am I supposed to be proving exactly?
That lighter wheels accelerate faster, handle better, stop quicker, and let your suspension work more efficiently.
Whereas heavier wheels accelerate slower, handle worse, stop slower, and cause your suspension to work less efficiently.
Do you expect me to show you all that in formulas?
And please stop trying to be offensive, it doesn't suit you 😆
y time will be 0.385% quicker, which over 90m equates to 0.347% = 20 seconds
Doing the maths on this, that means 90m (metres?) originally took you 96 minutes?? (0.347% of 96 minutes is 20 seconds)?
🙁
Skywalker...You're telling me I'm wrong without explaining why. Your last post shows you don't even understand my point, no matter how simply I make it. That's enough for me, you lose.
H...90 minutes.
Lighter wheels accelerate faster, we already agree on that right?
They handle better because of the reduced gyroscopic effect. You can notice this by simply putting on slightly lighter tires!
They stop quicker for the same reason they accelerate quicker.
They cause your suspension to work more efficiently because the suspensions job is to keep the wheel in contact with the ground. The wheel is forever being bounced up and down by rocks/roots/bumps etc. The heavier the wheel, the more work the suspension has to do to keep in contact with the ground. The less unsprung weight it has to deal with, the better it can do its job.
All this combined makes saving weight on your wheels worth while.
Not really much to argue about is there?
Gotta laugh at smart ass Al's change of stance, it was only last year he was saying:
Look up moment of inertia.If acceleration didnt matter then you wouldn't know the difference between a light and heavy bike
do try harder!
LOL you are arguing this without even understanding the physics?
Let me help you. I'm not saying it's significant - just that gram for gram you'll feel weight loss more at the rim/tyre than static weightyou're probably trolling anyway.
Most of your factual points are correct...you've also expressed a few opinions which are subjective and so incapable of being proved either wrong nor right.
But that's not really against what crikey and I were saying, so you've changed your point 🙄
Being offensive suits you BTW...and it appears to be all you've got.
Run along now!
Nice selective quote these Doug, the older thread is actually a year old, and in it I even say the difference in time/speed is insignificant - my present position.
Flattered you're spending time on it tho...haterz gon' hate...
Be nice if you could contribute something to the thread other than attempts to bring of down...says all about you and nowt about me.
Most of your factual points are correct...you've also expressed a few opinions which are subjective and so incapable of being proved either wrong nor right.
No, they are all correct and can be proven so by simple physics.
But that's not really against what crikey and I were saying, so you've changed your point
I haven't changed my point, I was originally saying that you were wrong for saying this;
Rotating mass in bicycle wheels has an insignificant effect, however often the myth is repeated.
If anyone can show it makes a difference, rather than claiming it does, I'm open to having my opinion changed.
TBF crikey me sober chum, so does non-rotating weight.
And
Being offensive suits you BTW...and it appears to be all you've got.
I haven't been offensive, you two were the ones being childish and resorting to insults.
Run along now 😆
skywalker
...All this combined makes saving weight on your wheels worth while
...is subjective. Problem is, so was my "insignificant" tho you chose to ignore my re-phrasing of my point.
Even then it's all about degree and other factors which affect the simple formula in your wiki article (and even it later concede's that's balls...funny you've nothing to say about those eh?
Of course you have been offensive...calling someone "stupid" isn't?...and you've been obnoxious from the start.
Oh well...at least I know what to expect of my first day volunteering in primary tomorrow...
Oh and Duggie...nothing to say? 🙄
This thread is great!
I would rather have light wheels if I could afford it end off! The only thing I would put it down to is how much stick I give my wheels. For and Enduro I would stick the lightest wheels my wallet could afford. Save weight on all the parts. It always comes down to money balls to the science.
Al you are wrong, face it.
I have said [i]nothing[/i] that can't be backed up by physics.
Lighter wheels are worth while, for the points I outlined up there ^
If you don't believe me, buy the heaviest tires you can find, and some of the lightest ones, and see how much better your bike rides with the lighter ones.
Have fun tomorrow, being surrounded by 30 people of higher intelligence.
Nighty night, don't let the bed bugs bite 😆
[img] 
[/img]
LOL...you still don't even get it!
Anyway....why are you 2 so obsessed with putting me down? Did you get mixed up in the crossfire of some flame a thon?
Minnows like you really shouldn't try to mix it with the big hitters until at least your voice has broken.
Al and Crikey:
a fairy comes along and you have a free wish to have either taken 500g from your wheels or from you frame. With no other than the weight effect. So no more or less flexibility, durability etc.
What would you choose?
LOL...you still don't even get it!
No grandad, you still don't get it. You must have forgotten to take your alzheimer's medication for the past few days because you seem to have forgotten what you are even arguing about.
Anyway....why are you 2 so obsessed with putting me down? Did you get mixed up in the crossfire of some flame a thon?
You started it old boy, I have only been giving as good as I was getting.
It seems that when you don't have the answer to the undeniable facts, you resort to petty name calling.
Minnows like you really shouldn't try to mix it with the big hitters until at least your voice has broken.
Calling yourself a big hitter 😆 it gets better and better. Not only are you confused by simple physics, you have to resort to blowing your own trumpet because no one will do it for you.
😆
[img] 
[/img]
[i]Al and Crikey:
a fairy comes along and you have a free wish to have either taken 500g from your wheels or from you frame. With no other than the weight effect. So no more or less flexibility, durability etc.
What would you choose?[/i]
It would make no difference where you lost the weight from.
How much faster are you with a full water bottle or an empty one?
How much effect does losing 500g from a total weight of 100 kg make you?
A big wee is about 250 mls; how much faster are you after having a wee?
You are assuming that changing the weight of your wheels will have a greater effect than changing weight elsewhere, please explain why.
You are assuming that changing the weight of your wheels will have a greater effect than changing weight elsewhere, please explain why.
It would make no difference where you lost the weight from.
Err, yes it does.
I explained all the reasons up there ^, if you care to read them again it would stop everyone repeating themselves.
Also the analytic cycling website has models and graphs which clearly show the benefits of lighter wheels in different situations.
What they don't take into account though is the effect lighter wheels have on suspension performance, handling and braking.
If you add up all these benefits, you will find saving weight at the wheels is worthwhile.
[i]Err, yes it does[/i]
Theoretically, there is a very very very small effect. In the real world? No.
[i]The miracle of light wheels (compared to saving weight anywhere else in the bike/rider system) is hard to see.[/i]
This is a quote from the article that [b]you[/b] are using to support your theory that [i]you will find saving weight at the wheels is worthwhile.[/i]
Let me spell this out for you; the source for your theory says that your theory is [b]not correct[/b].
See?
No.
Like I said, you two are only looking at the effect on accelerating and maintaining speed. If you look at the whole picture (accelerating, braking, handling and suspension performance) it is significantly worthwhile.
Why do you think manufacturers try so hard to reduce the sprung and unsprung weight of downhill bikes? If you and Al were right, they would build heavier bikes to keep momentum, but like I said you are not looking at the whole picture.
Edit: That quote is taken out of context, read the whole thing FFS.
Plus it isn't taking into consideration braking, suspension and handling.
[i]If you look at the whole picture (accelerating, braking, handling and suspension performance) it is [b]significantly[/b] worthwhile[/i]
In the interests of the provision of enough rope, perhaps you could actually explain this bit, because you haven't done so yet.
Lighter wheels are easier to accelerate. This is a fact.
But you aren't just accelerating the wheels...
So come on, Professor, give it your best shot.
ratio of sprung to unsprung weight has s significant effect on the suspension performance - one reason why motorcycle racers use the lightest wheels they can.
Lighter wheels accelerate faster, we already agree on that right?They handle better because of the reduced gyroscopic effect. You can notice this by simply putting on slightly lighter tires!
They stop quicker for the same reason they accelerate quicker.
They cause your suspension to work more efficiently because the suspensions job is to keep the wheel in contact with the ground. The wheel is forever being bounced up and down by rocks/roots/bumps etc. The heavier the wheel, the more work the suspension has to do to keep in contact with the ground. The less unsprung weight it has to deal with, the better it can do its job.
All this combined makes saving weight on your wheels worth while.
Not really much to argue about is there?
I already explained on the last page young grasshopper.
You don't even have an argument, I really don't see why you are still going on, you are just making yourself look silly.
Edit: Thanks you TJ, finally someone with some brain power.
..Ok, now apply this to the real world, and lets see the actual effects rather than the 'makes your skin smoother' comments.
Tell me the effect of reducing the weight of your wheels by 500g on a mountain bike ride of 3 hours.
I think that if you did the ride 5 times with 'heavy' wheels, then did the ride 5 times with 'light' wheels, the difference between the two would be less than the difference between your fastest and slowest ride on each wheelset.
You're hammering a theoretical issue, one that is simply lost in the noise of mountain bike performance. It's a great marketing tool, because at heart, there is a small, imperceptible gain, but in the real world it makes no difference at all.
Especially when the rider of these 'light' wheels is wearing baggy shorts, and carrying a Camelbak with 3 litres of water and a load of crap, riding a full sus, upon which his 'acceleration' is severely limited by the bouncing and the squidging and the big fat tyres....
[i]You don't even have an argument[/i]
Lol.
You've plucked a wikipedia article out that DISAGREES with your assumptions....
Bedtime for you sonny Jim.
cricky I actually suspect the difference is more than you seem to be saying as you do spend a lot of time accelerating and braking as well as going over bumps and turning - all of which are affected by the lighter wheels.
However its almost impossible to quantify as you say it will be lost in the "noise".
Going between extremes of tyres on the tandem - from the DH ones to the touring ones is nearly a kilo and a half 🙂 Drag as well in that of course as well as differnt profiles but that makes a noticeable difference
...and you still think that 'light' wheels can be accelerated [b]on their own[/b]
Look at your bike, the wheels are connected to the bike, which you sit on.
This is why
[i]How can it be that wheel inertial forces are nearly insignificant, when the advertisements say that inertia is so important? Quite simply, inertial forces are a function of acceleration. In bike racing this peak acceleration is about .1 to .2 g’s and is generally only seen when beginning from an initial velocity of 0 (see criterium race data in Appendix D ). Furthermore, the 0.3kg/0.66lb difference in wheels, even if this mass is out at the rim, is [b][u]so small compared to your body mass that the differences in wheel inertia will be unperceivable[/u][/b]. Any difference in acceleration due to bicycle wheels that is claimed by your riding buddies is primarily due to cognitive dissonance, or the placebo effect (they paid a lot of money for the wheels so there must be some perceivable gain).[/i]
this is said here;
http://biketechreview.com/reviews/wheels/63-wheel-performance
TJ, there is no doubt that lighter wheels are noticeable, but this does not translate into a performance improvement. It's a bit like changing the colour of your bike; everyone can tell, but it doesn't go faster.
Crikey, no offence mate, but no matter which way I explain it too you, you aren't going to understand. You can't even be bothered to read the wiki link correctly, instead you are just quoting out of context.
There is no marketing in there whatsoever, just plain facts.
Like I said before, http://www.analyticcycling.com/ have models and graphs proving you wrong.
...Anyway, enough.
Our opinions differ, I'll leave it there.
jeebus...
this has been a fantastic read!
FWIW, I would summarise as follows:
Skywalker has quoted some mathematically correct equations which demonstrate (quite correctly), that in isolation, when considering moving a body around from one place to another, that includes a rotating mass, there is more kinetic energy involved.
Crikey/Al have demonstrated that in the grand scheme of mountain biking over variable terrain in variable conditions the actual measurable difference is quite small. How small depends largely on all those other variable factors that have not been defined or described. In some circumstances lighter wheels may be of benefit, in others they are not so much, and in some cases a wheel with a little more mass can actually be a good thing.
You have all demonstrated that arguing on the internet is pointless, but amusing 🙂
-------------------------------------------------------------------
In case anyone accuses me of not understanding or having read the articles etc. I have read all the links you guys posted, plus others, I have also conducted my own real world experiments, admittedly more for my own curiosity than to generate any usable data, and I have a masters degree in Physics, and I still wouldn't say lighter wheels make you faster.
I like that summary!
Evening minnows, you'll have to wait a little for more factual and well reasoned "big hitter" input...me phone's running out of battery
Right so, when I buy a new hope hoop wheelset should I go for crests or flows for general XC/trail centre riding?
Flows with dual ply tyres and DH tubes, you wont notice the difference 😆
I've been involved in testing on motorcycles previously. I can't remember the exact figures but the difference between standard cast aluminium wheels vs carbon ones was striking - something like 1.5secs on a 1.10s lap. On a racing motorcycle that's a massive difference.
The bike accelerated quicker, stopped in less distance, was easier to turn at high speed and gave the improvement in lap times, plus the rider gets less fatigued due to less effort to turn the bike (a large amount of rider input is required to turn a motorcycle at high speed).
It's not just about the total wheel weight though but it's moment of inertia. Regardless of total wheel weight, a wheel with a lower moment of inertia will require less force to accelerate and have reduced gyroscopic effect making it easier to turn. Generally this means a lighter rim and spokes (the hub weight has almost no effect).
POST-A-GEDDON
neninja...interesting...cast alloys must weigh a ton tho, and the speeds, forces, gyroscopic effect are likely orders of magnitude higher than mtbs...where we are discussing 500g off a ~3.5kg wheelset, part of a 90kg rider & bike.
skywalker - Member
What they don't take into account though is the effect lighter wheels have on suspension performance, handling and braking.
None of which you have referenced any formulae or data for...so your only guessing.
skywalker - Member
Why do you think manufacturers try so hard to reduce the sprung and unsprung weight of downhill bikes? If you and Al were right, they would build heavier bikes to keep momentum, but like I said you are not looking at the whole picture.
Your logic is crap, that would not follow from our argument, in fact in DH where there's a fair bit of accelerating & change of direction, and races are very very tight, these factors [i]may[/i] matter.
Anyway back to your sacred article, here are the salient quotes about light wheels...
In other words, a mass on the tire has twice the kinetic energy of a non-rotating mass on the bike. There is a kernel of truth in the old saying that "A pound off the wheels = 2 pounds off the frame."[14]...
Another place where light wheels are claimed to have great advantage is in climbing. Though one may hear expressions such as "these wheels were worth 1–2 mph", etc. The formula for power suggests that 1 lb saved is worth 0.06 mph (0.1 km/h) on a 7% grade, and even a 4 lb saving is worth only 0.25 mph (0.4 km/h) for a light rider. [u]So, where is the big savings in wheel weight reduction coming from? One argument is that there is no such improvement; that it is "placebo effect".[/u] But it has been proposed that the speed variation with each pedal stroke when riding up a hill explains such an advantage. However [u]the energy of speed variation is conserved; during the power phase of pedaling the bike speeds up slightly, which stores KE, and in the "dead spot" at the top of the pedal stroke the bike slows down, which recovers that KE. Thus increased rotating mass may slightly reduce speed variations, but it does not add energy requirement beyond that of the same non-rotating mass.
Lighter bikes are easier to get up hills, but the cost of "rotating mass" is only an issue during a rapid acceleration, and it is small even then.[/u]...
There are two "non-technical" explanations for the effects of light weight. First is the [u]placebo effect[/u]. Since the rider feels that they are on better (lighter) equipment, they push themselves harder and therefore go faster. It's not the equipment that increases speed so much as the rider's belief and resulting higher power output. The second non-technical explanation is the [u]triumph of hope over experience—the rider is not much faster due to lightweight equipment but thinks they are faster. Sometimes this is due to lack of real data, as when a rider took two hours to do a climb on their old bike and on their new bike did it in 1:50. No accounting for how fit the rider was during these two climbs, how hot or windy it was, which way the wind was blowing, how the rider felt that day, etc.*below[/u]
Another explanation, of course, may be marketing benefits associated with selling weight reductions.
Many many people on here suffer from *above.
I love how you say we don't understand your argument. We understand it perfectly, and have showed that, whereas you've not even responded to points made by me 2 pages ago! If you had, you'd have some credibility.
Anyway this is too easy...like eating minnows in a barrel. Night, hope you're tucked in!
Right so, when I buy a new hope hoop wheelset should I go for crests or flows for general XC/trail centre riding?
It doesn't matter mate. Buy the heaviest wheels and tires possible, it won't make a blind bit of difference
😆
Actually Al its all similar magnitude
a couple of kilos off a wheel set that weighs a few kilos and a bike and rider weighing 200 kgs - thats the sort of range. speeds are higher yes but not orders of magnitude higher.
so actually quite relevant to get some idea of the time / effort savings which in the case of the motorcycle a couple of %
I would expect the motorcycle effects to be higher with the higher speeds but an mtb is accelerating for more of the time probably.
so I would expect overall a similar magnitude of difference of a couple of %
ywalker - Member
It doesn't matter mate. Buy the heaviest wheels and tires possible, it won't make a blind bit of difference
LOL...as if I've said that...keep deflecting...
TJ...speeds - 200mph vs 20mph...power is easily at least an order of magnitude higher.
but an mtb is accelerating for more of the time probably.
I doubt it...the race bike is pretty much accelerating all the time, bar when braking hard and briefly for corners? (and the losses are only that of rolling resistance and friction for the mtb as the mumentum is otherwise maintained)
