British engineering genius strikes again!

[aNOBLEman]

Originally Posted by 2ndclasscitizen

Ta Daa! Magic, that's how!

I'm thinking that the titanium bolts are what hold the rim to the hub.

[h00t_h00t]

Originally Posted by fpv_gtho

You'd lose steering response from the taller sidewalls like that though

The response is the same, it just doesn't feel like it because the tyres give more over bumps etc. Fitting larger wheels can also upset the suspension as it has been set up for smaller wheels and tyres. BMWs with the M-sport suspension and 18in wheels suffer from a harder ride because of this, opting to keep the 17s makes the car handle better overall.

[KnifeEdge_2K1]

Originally Posted by h00t_h00t

The response is the same, it just doesn't feel like it because the tyres give more over bumps etc. Fitting larger wheels can also upset the suspension as it has been set up for smaller wheels and tyres. BMWs with the M-sport suspension and 18in wheels suffer from a harder ride because of this, opting to keep the 17s makes the car handle better overall.

it isnt, shorter sidewalls flex less and make the steering more instantaneous

the wheels dont really affect the suspension geometry at all, the suspension has no way of knowing what inch wheels you have, it's the unsprung weight that matters, there are so many different wheels on the market it's possible to go up a couple sizes yet still go down in weight

[RacingManiac]

Originally Posted by KnifeEdge_2K1

it isnt, shorter sidewalls flex less and make the steering more instantaneous

the wheels dont really affect the suspension geometry at all, the suspension has no way of knowing what inch wheels you have, it's the unsprung weight that matters, there are so many different wheels on the market it's possible to go up a couple sizes yet still go down in weight

inertia though, changes with bigger wheels. Which hurts braking, accelerating...etc. As with bigger wheel although it may be lighter, places more mass further away from the center and thus may still be increasing rotational inertia.....

again a full carbon wheel(including the spokes) has been done before, at least on a FSAE scale. TU Munich showed up in Formula Student this year with one piece carbon fiber wheels that weights a tad over 4 lbs, compare to the aluminum counterpart that we run that weighs 8 lbs....The only metal was used at the hub fastening face where a billet aluminum block was bonded in the wheel to accept the lugnuts(as carbon does not provide any bearing support)....

[RacingManiac]

Some of the examples of the carbon fibre wheels in the competition, including the one piece one....

The common one is to use existing wheel center(ie BBS) then make custom carbon fibre rim section for it. Others use custom designed wheel centers....

[KnifeEdge_2K1]

Originally Posted by RacingManiac

inertia though, changes with bigger wheels. Which hurts braking, accelerating...etc. As with bigger wheel although it may be lighter, places more mass further away from the center and thus may still be increasing rotational inertia.....

again a full carbon wheel(including the spokes) has been done before, at least on a FSAE scale. TU Munich showed up in Formula Student this year with one piece carbon fiber wheels that weights a tad over 4 lbs, compare to the aluminum counterpart that we run that weighs 8 lbs....The only metal was used at the hub fastening face where a billet aluminum block was bonded in the wheel to accept the lugnuts(as carbon does not provide any bearing support)....

a bigger wheel doesnt neccesarily increase rotational inertia

there are so many wheel designs that it is quite possible to increase in rim diameter yet lower the weight

wheels themselves weigh alot too, though not as much as the rims themselves, but you also need to remember the wheels are farther away from the axle then the rims and thus adds quite a bit to rotational inertia

there is a limit to how large the rims can be, but also a limit to how small they can be

the upper limit would be defined by reaching a point where the sidewalls become so short they no longer have any give in them, or a point where the wheel/tyre assemble becomes too heavy

the lower limit would be defined by the caliper clearance and the height of the sidewall, too thick a sidewall and your suspension wont work as it was designed to work since the widewalls flex too much

[ZeTurbo]

That is really quite impressive!

[Equinox]

indeed it is!

[cmcpokey]

Originally Posted by KnifeEdge_2K1

a bigger wheel doesnt neccesarily increase rotational inertia

there are so many wheel designs that it is quite possible to increase in rim diameter yet lower the weight

yes you can make lighter larger wheels, but the larger the weel/tire assembly, the longer the moment arm. the longer the moment arm, the more force it takes to accelerate it. a comparably weighted 15" wheel will accelerate faster than a 17" wheel.

but with the larger wheel/tire comes more surface area touching ground, so more grip. its all a series of tradeoffs.

[mee]

Originally Posted by cmcpokey

but with the larger wheel/tire comes more surface area touching ground, so more grip. its all a series of tradeoffs.

well, actually the area of contact patches are determined by the width of the tires also, not solely on the diameter. and also, taller sidewalls flex more. it absorbs energy better, which translates to less slip, less overspin (which results in quicker launches), and those wheel/tire setup on F1 cars proved to work just fine..
but are tires always lighter than the rims?
well on slim-low sidewalled tires they are, but what if the proportions are like those F1 wheels?

[h00t_h00t]

With F1 cars the wheels and tyres have to be that big. Tyres almost always weigh less than the wheel unless its an F1 car, the magnesium alloy wheels they use are REALLY light.