Wheels thread

[noone]

Thanks for the opinions.

So anything directly between the 16s and 17's? When I did this to by Soobie, the ride got harsh. This was with stock springs but the tyres were thrown in with the package, so probably the poor tyres made it worse.

[pologti18t]

Anyone catch topgear last night? HSV R8 + Supercharger laptime was 3 seconds a lap faster after they ditched the overlarge 22 inch wheel/tyre combo for the stock 20 inch setup.

Maybe something to consider for all those people wanting to go for a 18inch wheel/tyre combo on the Polo.

[VW GTI]

Anyone catch topgear last night? HSV R8 + Supercharger laptime was 3 seconds a lap faster after they ditched the overlarge 22 inch wheel/tyre combo for the stock 20 inch setup.

Maybe something to consider for all those people wanting to go for a 18inch wheel/tyre combo on the Polo.

That would mainly be the weight.

If you go 18s on a Polo, make sure you get light ones - or you don't care about how fast your car is.

[philthy]

That would mainly be the weight.

If you go 18s on a Polo, make sure you get light ones - or you don't care about how fast your car is.

Weight? How so? Whats difference is an extra 10kg's in wheel weight going to make on a 1200kg car?

I suppose the unsprung weight of the wheel could affect the ability of the suspension to keep the tyres on the road.

The force required to rotate a wheel compared to that required to propel the car would be bugger all.

[Chipped]

he,he rip out your spare wheel and ur rear seats go for a quick drive - that makes a difference.

[seangti]

I suppose the unsprung weight of the wheel could affect the ability of the suspension to keep the tyres on the road.

The force required to rotate a wheel compared to that required to propel the car would be bugger all.

Correct on the first bit, incorrect on the second. minimising unspring weight brings many benefits: more accurate steering, generally speaking better bump absorption/control, better acceleration and vastly improved braking. This is also another reason I would NEVER put a chrome wheel on a car (mainly around the braking dynamics). Heavy and don't dissipate heat.

[Petrina Polo]

That would mainly be the weight.

If you go 18s on a Polo, make sure you get light ones - or you don't care about how fast your car is.

My 18s are lighter than the stock wheels. But you have a valid point. I compared my 18s against some others who were double the weight of my set.

I dont know how it can ruin the gearbox though??? who said that??

My car is as quick or quicker with the 18s than the standard wheels.

[VW GTI]

Weight? How so? Whats difference is an extra 10kg's in wheel weight going to make on a 1200kg car?

The engine is trying to turn the wheels, whereas the rest of the car weight is just increasing the weight that needs to be moved. An easy example is spin a cocktail umbrella, then spin a real umbrella. The cocktail it easy to spin because it's light, but it takes a lot more effort to get the actual umbrella spinning. Same theory with wheels - same with slowing them down too.

My 18s are lighter than the stock wheels. But you have a valid point. I compared my 18s against some others who were double the weight of my set.

I dont know how it can ruin the gearbox though??? who said that??

My car is as quick or quicker with the 18s than the standard wheels.

Adding heavy wheels does put more stress on the gearbox, how much extra stress is hard to say, but there is definitely some.

[Desmo]

. An easy example is spin a cocktail umbrella, then spin a real umbrella. The cocktail it easy to spin because it's light, but it takes a lot more effort to get the actual umbrella spinning. Same theory with wheels - same with slowing them down too.

Thats half the story and lighter wheels only help to a point, this is due to something called Moment of Inertia, do a wiki search for a full explanation.

Here is an Excerpt;

... consider two discs, A and B, made of the same material and of equal mass. Disc A is larger in diameter but thinner than B. It requires more effort to accelerate disc A (change its angular velocity) because its mass is distributed farther from its axis of rotation: mass that is farther out from that axis must, for a given angular velocity, move more quickly than mass closer in. In this case, disc A has a larger moment of inertia than disc B.

Thats why I still run 16's, also the fact that the ride handling compromise is shocking. Oh and I only use my car for weekends and track days...

[VW GTI]

Thats half the story and lighter wheels only help to a point, this is due to something called Moment of Inertia, do a wiki search for a full explanation.

Here is an Excerpt;

... consider two discs, A and B, made of the same material and of equal mass. Disc A is larger in diameter but thinner than B. It requires more effort to accelerate disc A (change its angular velocity) because its mass is distributed farther from its axis of rotation: mass that is farther out from that axis must, for a given angular velocity, move more quickly than mass closer in. In this case, disc A has a larger moment of inertia than disc B.

Thats why I still run 16's, also the fact that the ride handling compromise is shocking. Oh and I only use my car for weekends and track days...

But... then there are tyres - and the rolling diameter should be the same as the bigger the wheels, the smaller the tyres... So really, it's overall weight of the package (wheel and tyre).

So sticking to 16s for that reason...

[Chipped]

I have a clutch kit with a singlemass lightweight flywheel.
I definately noticed "easier" or what I perceive as "lighter" acceleration as a result. I would suspect he same would apply (if only slightly) to lightweight rims...
Try Speedywheels Lite Fin7 or Gmax Drift6 for local lightweight rims...

[Desmo]

But... then there are tyres - and the rolling diameter should be the same as the bigger the wheels, the smaller the tyres... So really, it's overall weight of the package (wheel and tyre).

So sticking to 16s for that reason...

The reason for my post is to inform that there is a trade off in increasing wheel size, not just weight, can I suggest you go and reread my post and the article I mentioned. The issue is where the weight is situated, as much as the total weight of the wheel and tyre. Sometimes the difference will be small but are worth noting.

By having a larger wheel and a lower profile you move more of the mass to the perimeter, this is not ideal. Also, all the 17 or 18 inch wheels I have seen on Polo's, are also WIDER, anything from 7-8inch, over the standard 6.5..the only upside is the associated increase in track, though this is also due to offset differences.

As posted previously by others, the proof is in the TG Aus segment on the clubbie, they went from 22's to 20's and picked up 3 secs a lap. Not to mention better compliance when not on a track. Super low profiles are more about aesthetics, and separating people from their money, than performance.

Thanks for you helpful advice on wheel size choice, but I will keep the 16s, light weight wheels with R spec's for track and STD rims for the road. I can understand why 17's are popular, they look good, bigger choice of tyres, but I want to dispel the myth that its going to be some big performance advantage, when in can be the opposite, epeccially when taken too FAR (18's) especially on a bumpy road.

My mantra is big enough to cover the brakes, wide enough to take a tyre that won't rub, any more is a waste.

[Petrina Polo]

There is nothing wrong with the 16 inch wheels we have.

There is nothing wrong with my 18 inch lightweight wheels I also have.

I notice no difference whatsoever in acceleration performance between the two sets.

Yes the 18s are a fraction harder and soak up less bumps etc. But the difference is so what!!

On the track I dont know as I have not taken my car round a track as yet. The 18s have 215 tyres, a little wider than the stock set so maybe they are better on the track.

For the look of them, its hands down winner to the 18s.

I just wanted my car to look a little better than standard, thats all.

[Petrina Polo]

I saw a Polo gti this morning, a silver one. It had 17 inch version of those incubus wheels. black/polished 5 spoke finish.

I thought it looked OKish.. Not really my style but it was ok. The car was lowered, looked really nice on the road.

I think the black cars like mine miss out on the different look the black front has in conjunction with a colour

[RhysQ]

The reason for my post is to inform that there is a trade off in increasing wheel size, not just weight, can I suggest you go and reread my post and the article I mentioned. The issue is where the weight is situated, as much as the total weight of the wheel and tyre. Sometimes the difference will be small but are worth noting.

Your article was about a bigger and a smaller disc (assuming they are the same weight - the bigger being thinner). It was basically implying a larger disc is harder to spin, which is true.....but, this has no relation to car wheels (wheels and tyres) as they have to be the same overall diameter as Sam said. As for adding tyres, I'll put money on my 40 profile tyres are significantly lighter than your 45 profile tyres, so weight is lost there.

By having a larger wheel and a lower profile you move more of the mass to the perimeter, this is not ideal. Also, all the 17 or 18 inch wheels I have seen on Polo's, are also WIDER, anything from 7-8inch, over the standard 6.5..the only upside is the associated increase in track, though this is also due to offset differences.

My 17's (7.5" on the front, 8" on the rear...both with low offset) weigh 6.5-7kg each, compared to the 10-11kg each from the standard 16" wheel. Add my lower profile, stiffer sidewall, wider, and lighter tyre, along with my much wider track (about 60mm wider than standard) and I would guarantee my track times are quicker.

One huge problem with our cars is torque steer on the gas out of corners. My 7.5" fronts have significantly increased cornering stability and hugely decreased torque steer issues.

As posted previously by others, the proof is in the TG Aus segment on the clubbie, they went from 22's to 20's and picked up 3 secs a lap. Not to mention better compliance when not on a track. Super low profiles are more about aesthetics, and separating people from their money, than performance.

20" and 22" inch wheels can not be compared to our cars. The 20" standard wheels from memory have the same tyre profile as our cars running 17's. The 22" wheels they used would have had a 30 profile.....which is ridiculous. It is wrong to apply a rule where the smaller your wheel the better your performance. Yes it is to a degree, but too much and sidewall issues arise. The smaller your wheels, the larger your profile, the more flexible your sidewalls become.....meaning cornering stability is diminishing. If that Superclubbie had 16" wheels on I would bet it would be slower around the track than on the 22" wheels. And don't bring up the argument about the tyre profile on F1 cars as they are specially made tyres with extremely stiff sidewalls....very little movement. Same as any race car really... as TG Aus fail to mention.

Thanks for you helpful advice on wheel size choice, but I will keep the 16s, light weight wheels with R spec's for track and STD rims for the road. I can understand why 17's are popular, they look good, bigger choice of tyres, but I want to dispel the myth that its going to be some big performance advantage, when in can be the opposite, epeccially when taken too FAR (18's) especially on a bumpy road.

Lightweight 16's and R-spec tyres are a good choice for track because of the overall weight and stiffer sidewalls. Try putting your standard wheel and tyre combo on at the next track day and tell us how they go.

17's on our cars aren't really for show, but the stiffer sidewalls, decreased torque steer and wider I would imagine would make for a better result on a track time. Try to find someone with lightweight 17's and R-spec tyres for your next track day and swap wheels for a few laps. I think you would be surprised.

The 22's on the Superclubbie would be heavy as all hell, which is where the inertia theory is relevant. It would be comparable to us running a 19" wheel with a 30 profile tyre.....stupid.

Cheers,
Rhys