weight of wheels

[ben]

Ok sad as i am i went and weighed a jconcepts rear wheel and a proline rear wheel. The jc one weighed 17 grams. The proline 21 grams.
Does this make any difference to the way the car handles? Like rotating mass or something?

Ben

[Garry Driffill]

Homo

The Pro-Line wheel was probibly Yellow - They are "Phat" making them heavier..

[bigred5765]

any unsprung weight is bad for the car, so to answer your question Ben yes

[Lee]

But you wont notice it.

Just to confirm what Gary said



Now go and buy a touring car if your going to carry on doing crap like that

[ben]

Originally Posted by Garry Driffill

Homo

The Pro-Line wheel was probibly Yellow - They are "Phat" making them heavier..

Nahh garry it was white.

[ben]

Originally Posted by Lee

Now go and buy a touring car if your going to carry on doing crap like that

Fair point

[Chrislong]

Yeh, the weight of the wheels makes a difference. So, try cutting all the spikes off the tyres, cut the ribs off the inside, don't use glue and drill holes in your inserts. Proper dialled.

[sparrow.2]

That's 16 grams of rotating weight! And it's unsprung too! If you're running Lipo and building your car to the weight limit you could be underweight with a change of tyres...

I feel dirty now...

[Northy]

Maybe that's why Ben Riley is having blow outs with the JC wheels?

G

[Chrislong]

Originally Posted by Northy

Maybe that's why Ben Riley is having blow outs with the JC wheels?

G

LOL, yeh, but the weight is even less for him as he has no vinyl stuck to them either now.

[SlowOne]

On a more fact-filled note...

Unsprung weight is bad, as it prevents the wheel following the terrain. Rotating weight is not always bad. High rotating weight prevents the car accelerating as quickly as low rotating weight. On a high-grip surface, high rotating weight will give less acceleration, but on a low-grip surface, this can help prevent wheelspin, and might be an advantage.

Since unsprung weight consists of everything below the spring (so most of the shock, part of the wishbone and most of the hub and axle) another few grammes on a wheel makes very little difference. And rotating weight consists of everything from the motor armature (or BL rotor) right through the gearbox, driveshafts, layshafts, belts, etc., again, another few grammes makes little difference. However, rotating weight makes much more difference the further it is from the centre of the axle/shaft. IF you want to save rotating weight, a few grammes off the tyres makes more difference than a few grammes off the wheels - the tyres are further away from the centre of the axle.

I have to know this stuff for a living, so like Lee says, if you're this worried about your hobby, go TC racing!! HTH

[glypo]

The above definition of unsprung mass is a little misleading in the wording. As technically anything below the spring could mean the chassis etc, which obviously is all sprung mass. I always think the clearest way to define unsprung mass is anything attached directly to the wheel or hub is totally or partially unsprung.

I recently read a book on vehicle dynamics when I was considering working for McLaren who had vaccancies in the field. After seeing the pay (I think it was only £26k?!?!) and realising what a dry and dull subject it is, I soon thought wiser...

Anyway on topic.

Ben yes it will make a difference. But in good and bad ways, as the mass is rotating in the longitudinal axis it will give lateral stability. Basically gyroscopic style stability, keeping the car true down the straights. However the disadvantage is at high speed corners, you lose a bit of turning due to the increased stability. Low speed corners won't matter. So that's the first trade-off.

Secondly, and something you don't get with touring cars, jumps! People (incorrectly) say that you can change the cars attitude (nose-up/down) in the air due to gyroscopic effect of the wheels. It is in fact the Polar Moment of Inertia that allows this. Cutting through the science, more weight in wheels and tyres - means more control in the air. Whoop!

So yeah, of course you will get get slower acceleration also as said above, but I'd rather set an expo on my throttle rather than use heavy tyres or wheels to control wheelspin personally, so I don't really consider there to be a plus side in this point, only a downside on acceleration. I say the plus side is momentum, the extra weight will keep the wheels spinning, using less power down the straights and at high speed.

Anyway, if you can't be arsed to read all the crap I wrote up there (I don't blame you, I can type forever) then I would basically say that it makes no difference. What people will gain on certain areas of weight, can be lost elsewhere... and it basically evens itself out. 4 grams isn't an awful lot either.

p.s. I don't think people will believe me if I said I don't drive a touring car. So I do, and I love it. *goes to hide*

[ben]

I read it. Thanks for the explanation.

[Neil Skull]

It is most important to balance your wheels.
A lot of the top guys do it makes a big difference, you especially need to do for cheaper wheels and for bigger classes like 1/8th

[Col]

If I ever see anyone in 10th off road balancing their wheels/tyres, I'm going to stand on their cars, and then their heads so that everyone can see exactly how little there is inside

[ben]

Col if i remember right craggy has balanced his wheels in the past. And i remember tom Cockerill balancing his wheels at batley national

[Garry Driffill]

I can see why they would do it on on-road as its all flat and super consistant lines through and through like scalelctric. But off road is soo random even on a consistant line indoor and outdoor especially.

Aswell with the huge tryre walls on they 1/10th and 1/8ths i would have thought that that would have played some difference in cornering with sag and stuff on grip/bite into corners also 'wollowy' suspension.

Ben with you saying Tom and Neil Cragg doing that with wheels i see it being at a natonal too obviously outdoor. Tom doing this at Batley which is mainly grass too can it make that much of a difference or is it more psychological? Im not dibbin at the guys for doing it in all fairness somthing thats true-er will work better merchanically but in off road it cant make that much difference!

Im with Col

[daz]

Whats the f***s going on? Ben im gonna bitch slap you! Get them gay stupid looking j c s*ite spokes off your car, give your head a shake. As for chuffing being arsed to put them on scales that need another kicking and give your head another shake. And buy some nice SOLID yellow wheels.






P.s Is your momma asking about me?

[bigred5765]

Originally Posted by Col

If I ever see anyone in 10th off road balancing their wheels/tyres, I'm going to stand on their cars, and then their heads so that everyone can see exactly how little there is inside

bens right neil wheels are quiet often balanced, and yes it makes a huge differents,a old wheel hub and some plastercine is all thats needed,easy pessey

[bigred5765]

Originally Posted by Garry Driffill

I can see why they would do it on on-road as its all flat and super consistant lines through and through like scalelctric. But off road is soo random even on a consistant line indoor and outdoor especially.

Aswell with the huge tryre walls on they 1/10th and 1/8ths i would have thought that that would have played some difference in cornering with sag and stuff on grip/bite into corners also 'wollowy' suspension.

Ben with you saying Tom and Neil Cragg doing that with wheels i see it being at a natonal too obviously outdoor. Tom doing this at Batley which is mainly grass too can it make that much of a difference or is it more psychological? Im not dibbin at the guys for doing it in all fairness somthing thats true-er will work better merchanically but in off road it cant make that much difference!

Im with Col

have you tried it??
i have and no the truth