Ultra Light Wheels

[chickenstrip]

Just curious, as I'm far from being the wealthiest person on the planet...

I recently replaced my old, tired rear shock with a nice new item from an R6. It made such a difference to the handling (as I knew it would); even to the extent that I now think I can detect a bit of flex in the front forks that I didn't notice before. Well, that's ok, I'm planning an R1 USD upgrade, maybe next year now, so hopefully that'll be sorted too.

But it got me to wondering (as you do) how far I could go with my heavy ol' road bike (FZS1000). So I was wondering, anybody out there changed from stock to carbon/magnesium/super-ultra-light-weight wheels? So you're reducing un-sprung weight, how much does this affect the handling and in what way? Enough to be worthwhile on a bike that only gets road, albeit recreational, use?

TL;DR Carbon/magnesium wheels - how much would you notice the difference from stock, handling-wise?
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[Musketeer]

It would improve handling yes. In Snetterton I had a chat with a guy who had carbon wheels on his bike and he said many positive things about them if you are thinking about getting those for your road bike then I wouldn't bother. Light carbon wheels will be very expensive.. we are talking about 4 digit numbers here. Not worth spending that much on a road bike. Same with the 520 sprockets and chain.
If you do this to a race/track bike then that makes more sense.
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Current Bike: Yamaha XSR900 Previous bikes: Honda CBR1000RR Fireblade, Kawasaki ZX-6R Ninja, Aprilia RS125 2-stroke

[chickenstrip]

[Musketeer]

[chickenstrip]

No, it doesn't seem to handle badly at all (for what it is). Leastways, I don't have trouble keeping up with most other riders no matter what bike they're on. It's just something I want to know a bit more about.

On the other hand, I do love my bike and enjoy doing mods that have a purpose or improve it. It's just we often do, isn't it? It wouldn't be the first time I've upgraded suspension and performance on a bike; maybe just to give it what the manufacturer held back with for cost reasons or whatever. The aftermarket industry is alive and well, so I'm not the only one

I do like to ride them Welsh roads (while I still have a license ) where there's far less risk of being thrown into a hedge by monumental pot holes, and many roads have less hazards like lots of traffic, junctions etc, so such mods seem worthwhile to me.

So for the moment, I want to ignore the cost, and just find out how effective a change it would be.

("It's just we do, isn't it?" ??!! See, I'm turning Welsh, isn't it? )
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THERE'S MILLIONS OF CHICKENSTRIPS OUT THERE!

[c_dug]

LukeVFR, or whichever iteration of his name he was on before his demise, had carbon fibre wheels on the road for a while. Might be worth searching for a thread about them, maybe he said something insightful.
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[lihp]

Lighter wheels will accelerate faster, stop faster and turn faster.

However, all that can probably done with a bit more skill from the rider also on nearly all bikes on the road.
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[chickenstrip]

[ajag]

[BigDan1190]

They're weaker. Potholes will destroy them.

Not worth it on a road bike

[chickenstrip]

[chickenstrip]

Ok, am I on the right track: A lighter wheel means less gyroscopic effect, so the wheel has less tendency to want to stand itself up, ergo, less effort to get the bike around a corner?

Still want to know about the mechanics behind reducing unsprung weight though, as I assume this is a seperate thing? Apart from an overall weight reduction and the benefits that brings. Is it to do with less loading on the tyres?
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[lihp]

There really isn't many areas where you get a benefit of unsprung vs sprung mass reduction on a road vehicle. Off road, there may be a benefit in having less unsprung mass.

The primary differences in weight reduction are:

1. Rotational Mass
2. Sprung and Unsprung Mass

With rotational mass, when you have something spinning the "effective" mass increase in relation to it's angular velocity. So losing 1kg from a wheel or a brake disc will have a greater effect than losing 1kg from the chassis.

This is also true for other spinning and moving components, crankshaft, camshafts, chain, sprockets, gearbox etc. But the wheels, breaks and chain & sprockets are the most cost effective to change.

However, paying to reduce the weight of the bike that is non-rotational is largely irrelevant as you will pay a lot of money to save 1 or 2kg, but most of us are quite capable to lose more body weight than that for free, and gain just as much of an advantage.

So to answer your question, for most circumstances, there is no benefit to removing unsprung weight over sprung weight. But there is a significant difference in removing rotational mass vs non-rotational mass.
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[barrkel]

[nowhere.elysium]

[Kris]

[nowhere.elysium]

[RhynoCZ]

Light weight parts won't make you faster, not being fat will. Yes, in top moto sport it gives you advantage of a few milliseconds per lap, but it's just not worth the money in the real world.

So, lose the fat and keep the money for petrol.
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'95 Mercedes-Benz w202 C200 CGI, '98 Mercedes-Benz w210 E200 Kompressor

[sickpup]

Luke, X, XA0s or whatever he called himself in the end had a front Carbon wheel which I believe fell apart. You would be able to see his thread except his profile was sanitised after his death for reasons none of us understood.

[stevo as b4]

Here's a genuine question on the same subject then. Can a 250kg bike safely use lightweight forged alloy or magnesium wheels or even carbon ones, or is there a set weight limit that these wheels can be used for safely?

TL:dr Lightweight wheels on a V-max possible?

[lihp]

[Kickstart]

Hi

Reduced rotating mass will make it easier to change direction. Reduced unsprung weight allows the suspension to work more easily (the force to move the wheels when a bump or pothole is hit will change with weight, plus it is also working against the weight of the bike hence the ratio of sprung to unsprung weight is important).

Make any real difference and you will probably need to change the spring rates and damping.

That said, a wheel isn't that heavy. Pair of brake disks are probably a bit more, and the tyre is probably heavier as well.

All the best

Keith
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[Wafer_Thin_Ham]

[chickenstrip]

[drbaig]

It is impossible to find anything luke posted on bcf as it has all been deleted.
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