Why do people spend so much to make bikes lighter?

rich_teague

The only problem is that lighter stuff doesn't tend to be as strong as some of the heavier stuff, and I'm tough on components. Very tough.

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Speed_King

can someone tell me where i can get the bolts tht are lighter as i want to change all of them on my speciallized rockhopper pro disc, and is it best using titainium as the lightest option? Quick rplies greatfully recieved

Thanks

milese

So from a speed / handling point of view can someone answer me this question.

If I upgraded, for arguements sake, my frame and saved 5lbs in weight. Then stuck 5lbs of fluid in my camelbak would there be any performance increase?

I've been looking into change to a FS frame and dont like the idea of the extra weight, but an extra 3lbs is nothing at all in comparison to the whole package of bike, rider, clothes and loaded bag!

Sir HC

Milese wrote:

So from a speed / handling point of view can someone answer me this question.

If I upgraded, for arguements sake, my frame and saved 5lbs in weight. Then stuck 5lbs of fluid in my camelbak would there be any performance increase?

I've been looking into change to a FS frame and dont like the idea of the extra weight, but an extra 3lbs is nothing at all in comparison to the whole package of bike, rider, clothes and loaded bag!

You will always have that 5lbs of water though.


Lighter = Faster. Simple rules of physics, A=F/M (F=MA). If you can either increase F (the force propelling the bike), or reduce M (Mass). Then A (acceleration) will increase.

There has to be a balance between lightweight and durability. As to finish first, first you have to finish. There is also the issue of flexy components bending, wasting useful energy. The same goes with using tyres that have just enough grip for the surface.

My Inbred is 23pounds, built up for around the £700 mark. Running 2.3 Conti verticals, XM719 Wheels on XT hubs. Could of gone for a lighter wheel and tyre setup, but I wanted wheels that I could trust.
Quick round the trails, since I've built it, I've only had to replace the chainring bolts (aluminium chainring bolts are rubbish). When the 6 year old specialized Strongarm cranks and square taper bb break, I'll replace them.

Discopooh

I took my bike from a 34lb heavy weight to 28lb and it made such a differance,sprites and hill climbs are no longer the crusher than they use't to be to me. lighter rules

L60N

My bike is failry light, but im unfit as hell, so im still snail slow :P

Made a mental not to myself last weekend at dalby, "Let some air out before you hit the trails" I commute at around 55psi. I set off on the trails and was completely knackered after 30-45 mins, slowing riggght down. thought it was the beer from the night before, but later it occured to me in my slow brain that the bike tyres were PUMPED! it was very skittish, and rebounding off everything, throwing me all over the place. I pulled over, let a gob full of air out of each making the tyres "squidgey" after that it rolled smooth as silk, I was then able to put in an extra 2 hours no problems

Went a bit off topic there but hey. Im daft.

milkywhite

Milese wrote:

If I upgraded, for arguements sake, my frame and saved 5lbs in weight. Then stuck 5lbs of fluid in my camelbak would there be any performance increase?

I may be wrong (it does happen occasionally) but as far as i can work out, in this situation, there would be no increase in performance. The F=M*A thing obviously relates to the rider+bike+gear, and as the overall weight wouldn't have changed the formula remains unchanged. What there woud surely be is a small (possibly unnoticeable) change in handling, as the centre of gravity of you+bike has changed, due to the shift of mass from the bike up into your camelbak. If anything this would result in a loss of performance due to higher C of G.

Like I said, I may be wrong.

breezer

Weight on the rider is far easier to move around. Weight on the bike is not. Only situation where the speed would be the same is on a smooth uphill (talking about the weight in camelbak or the bike itself), rest of the time the lighter bike setup would be quicker as it would be easier to move around, get over obstacles, accelerate etc.

sam1234

I can climb quicker on my 30lb hardcore hardtial than I can on my brothers sub 24lb hardtail. Fair enough the frame are diffrent angles etc so that may have made a diffrence. As for descending I just can't get on with my brothers bike despite choseing smooth lines etc (we do ride diffrently etc)

I can see why people you ride in XC races reguarly want lighter bikes but they not for me.

To be really put the cat in with the pigions. When in my LBS the other day talking to them and a rep. The LBS and rep said the only reason people want light MTBs is to say they have got one and they only ride them down the road as a sort of fashion statement.

But lets turn the debate around why do people want 6in+ AM rigs are these really essential to have for the majority of riding people do or are these for show.

At the end of the day ride want you, not what others tell you to.

P.S I do like my brothers 16lb ti road bike though very nice to ride and fast.

Sam

sam1234

P.S what did make me faster though was losing weight myself and getting fit.

Aux1

I think most people actually don't really understand the real reason why they would need something better, but buy it out of fashion...

However, I do have a question. Has someone ridden a lighter and a heavier bike on the same course and timed the difference? Would be interesting to know how much difference it makes.

BikerDan

Lets get back to the original question. Why do people spend so much? Surly there are cost effecient ways of getting rid of weight?

Aux1

BikerDan wrote:

Lets get back to the original question. Why do people spend so much? Surly there are cost effecient ways of getting rid of weight?

Well, I was told a lighter wheelset makes lots of difference. If I remember physics correctly, a moving object has kinetic energy but the one that rotates as well also has the rotational energy. So lighter wheels would require less energy to lift their mass from a lower to a higher place, and also less energy to spin them. Therefore, an ammount of wheel weight would make more difference than the same ammount of frame weight or something else that doesn't spin. Hope I'm right.

toasty

Milese wrote:

So from a speed / handling point of view can someone answer me this question.

If I upgraded, for arguements sake, my frame and saved 5lbs in weight. Then stuck 5lbs of fluid in my camelbak would there be any performance increase?

I've been looking into change to a FS frame and dont like the idea of the extra weight, but an extra 3lbs is nothing at all in comparison to the whole package of bike, rider, clothes and loaded bag!

Yes, it would realistically improve you a lot. If you and your bike were one fixed unit, glued to the seat, then obviously no.

The purpose of the light bike is to move around under your weight, bouncing up and down to some degree over the bumps. By the time the forces get to your body you need to have damped as much out as possible, firstly in tyres, then suspension and the remainder in your legs/arms. If your keep your body keeping in the smoothest line possible you'll maintain your momentum.

Sit down and ride over a bumpy area, you'll be slow, every bump has to accelerate your entire mass all over the place, eating tons of force. Stand up and ride over the same area, absorbing as much as possible in your legs to keep your body smooth. You'll be fast! Keep wheels and frame weight down so it can accelerate quickly and you'll lose less velocity.



Back to the original question, why not save weight? You can go out and ride faster and harder, then come back feeling fantastic. I enjoy it more. I've not bought anything as a fashion statement, soley for function, hell, my Stumpjumper currently has a set of Suntour forks on! :P

I can climb quicker on my 30lb hardcore hardtial than I can on my brothers sub 24lb hardtail. Fair enough the frame are diffrent angles etc so that may have made a diffrence.

What exactly are you arguing here? That heavier bikes go faster? If you knocked 6 pounds off your bike without changing the geometry you would go even faster.

sam1234

[/quote]I can climb quicker on my 30lb hardcore hardtial than I can on my brothers sub 24lb hardtail. Fair enough the frame are diffrent angles etc so that may have made a diffrence.[/quote]

[/quote] What exactly are you arguing here? That heavier bikes go faster? If you knocked 6 pounds off your bike without changing the geometry you would go even faster.[/quote]

I'm not arguring that at all (I’ve probably explained it in a bad way) except I found myself climbing quicker on my bike but I think main reason is that Im more comfy on my bike. Were as on my brothers bike I couldn't get comfy on it when climbing and just found my self wandering around the trail on it, plus its got flat bars and bars end which I hate (personal preference).

Yes if I knock six pounds of my bike I would properly be a lot faster but it would cost a fortune and would be hard to do because of the frame weight.

But why would I want a lighter bike? , I may go faster but I can do 20 plus miles at a speed I'm happy with and in a time I’m happy with. I don’t race and don’t wish to either so I don’t see the point or need to go light. (This may sound to contradict myself) I did upgrade my wheels and forks which were lighter and it did make a difference, but I wanted something with better performance rather lighter weight.

That’s just my thoughts on the subject. Sorry if you don’t like my thoughts on the matter, but Hey we all enjoy same thing at the end of the day riding bikes; for me that’s a 30lb hardtail for you it may be a 18lb carbon race bike or 36lb freeride rig.

Yes and you probably would beat me to the top of a climb on your light weight bike but do I care .

Sam