55 replies to this topic

[fredeuce]

A call to all of you engineer types out there , what is wrong with the extreme camber exhibited on the vehicles in this video clip?

This came up for discussion on another forum I frequent. There are some that attempt to defend the practice on the basis that you have to understand Japanese car culture. If you don't understand it you don't get it.

I say bollocks to that. It has nothing to do with Japanese car culture . It so happens they are Japanese cars in Japan. That is an irrelevance.

By any objective standard the wheels fitted to the cars at the extreme angles of camber shown are not fitted as intended by the manufacturers of the wheels and tyres.

I take the view as a mechanic and legal practitioner that such a modification will sooner or later lead to a catastrophic failure of the tyre. Any damage flowing from the failure is not going to be covered by your insurance as the modification has contributed to the loss. Any insurer in Australia would deny cover if they had not approved the modification.

The defenders also seek to argue that tyres these days are designed to deal with greater levels of camber.

Over to you tyre engineers to articulate what the limits of camber are on tyres these days.

http://www.youtube.c...player_embedded

[Magoo]

Evidently, camber has attained its high maniera phase in this culture. At these angles, tire life and suspension dynamics are no longer considerations. These cars are barely driveable, which is a good thing because they won't be going very far in this state anyway. This is nothing more or less than art for art's sake. There is no other purpose here.

I snagged this still from the video.

Edited by Magoo, 02 April 2013 - 22:10.

[Magoo]

Over to you tyre engineers to articulate what the limits of camber are on tyres these days.

To answer the question specifically, on a production road car with an expectation of something approaching normal tire life, no more than a degree or two.

[Greg Locock]

To answer the question specifically, on a production road car with an expectation of something approaching normal tire life, no more than a degree or two.

Static camber settings at kerb tend to be exceeded on the road as most suspensions (not macpherson) have some camber/roll compensation. An extreme example is one model of Australian taxi which has been praised by many popular figures who don't buy their own tires. That has -2 at the back (looks like more than that to me).

[Tony Matthews]

This sort of cartoon may have something to answer for! Copyright Wicked Artz Cartoons, posted without permission, so I'll probably rot in Hell. Meet friends, have a laugh...

[fredeuce]

Magoo,
I have to agree with that. These cars are nothing more than comic book ideas that should have remained just that. As art, well, maybe. However, there is good art and bad and that is another whole area of debate.

Evidently, camber has attained its high maniera phase in this culture. At these angles, tire life and suspension dynamics are no longer considerations. These cars are barely driveable, which is a good thing because they won't be going very far in this state anyway. This is nothing more or less than art for art's sake. There is no other purpose here.

I snagged this still from the video.

[GreenMachine]

Would these cars actually be legal? Is that a consideration in Japan, or does anything go?

We would need an engineers certification that the mods were roadworthy, can't see that happening any time soon ...

[desmo]

Hotrod modders have never let engineering or reality stand in the way of "a look" that's in fashion have they? This is hardly sillier than a lot of what I've seen done over the decades.

[Canuck]

As a high-school kid I wanted nothing more than to replicate Rick Dobbertin's Pontiac J2000 with it's twin-turbo, twin-supercharged mill and custom super-wide tires with just 8" between (inner) sidewalls. Practicality? What's that? That said, I'm sure this is more offensive - this cartoon camber thing while rockin' the stretch. Looks like a tire pooping a wheel.

[Fat Boy]

What you're seeing here has nothing to do with performance. It's just a look thing.

Having said that, I have been 5+ degrees negative on certain tires with a fast race car on an oval. Back when I had a street-racer type car my 'street' setup was ~-2.3 degrees on the front. The tires actually still wore the outside edges.

[MatsNorway]

Camber and wrong rim.. impressive that its air tight.

[Lee Nicolle]

As a high-school kid I wanted nothing more than to replicate Rick Dobbertin's Pontiac J2000 with it's twin-turbo, twin-supercharged mill and custom super-wide tires with just 8" between (inner) sidewalls. Practicality? What's that? That said, I'm sure this is more offensive - this cartoon camber thing while rockin' the stretch. Looks like a tire pooping a wheel.

To put it bluntly these are just stupid wankers that have no idea.it supposedly looks fast! The Japanese car culture has instigated this. The 'stretched' tyres as pictured along with 5+ degrees of camber. It comes from drift where they do not want any side grip.
And yes all of it is highly illegal and causes dozens of defects a month here in SA yet alone the rest of the world.
Also if you have an accident you may well find yourself uninsured. both compulsory third party as well as comprehensive.
For a racecar 2-4 degrees is normal,, or 6 deg for HRT in Thupercar and they wonder why the tyres delaminate !! DooOH.

Just recently I am getting all the 'wanker' enquiries here. I sell tyres and rims [as well as most automotive parts] and I am getting people who want to put 295 wide tyres on 10" rims on a Corrolla, Not quite so bad a Torana. Or 4" front rims on a V8 Torana. Or 8" wide rims on an early Monaro without rolling the guard lips.[Something that is impossible] And that is just this week!

I try not to deal with the drift mentality, though do seem to sell quite a few tyres, both new and used as well as radiators etc for the burnout fraternity. Though one wanted me to build him an engine. I declined!!

[Tony Matthews]

Is 'wanker', like 'bowser', a word that is unfamiliar to some/many?

The fad of tarting-up your car to make it look fast/individual/sexy is nothing new of course, and most things seem to reduce the performance whilst increasing the noise or ruin the handling. Although I'm not sure if it is possible to ruin the handling of a Vauxhall Nova, a popular UK car for modifying, I think they come factory pre-ruined.

[Dmitriy_Guller]

In my experience, ruining your car is a cultish following.

For a very short time, I tried being part of the VW Vortex forum. I joined just to get to know more things about my car, the best places to get it serviced, etc. I quickly found out that it's a forum where young "adults" encourage each other to spend a lot of money on modifications to lower the car, camber the tires out to extremes (beyond what you would get from lowering the car to ridiculous levels), getting huge rims so that the tire is just a narrow ill-fitting band of rubber, and so on.

When I suggested that not everyone is interested in spending money to modify the car they already paid money for into a condition where it's no longer road-worthy, where every speed bump or a moderate pothole threatens to total your car, and any other piece of slightly uneven road scrapes your undercarriage away, I was effectively run out of the forum. The most infuriating thing I've read there is how someone ripped out the whole engine from the car after striking the pothole, was reassured by other forum members that any car would've ripped out its engine there, and actually got paid by the insurance company (my insurance company, in fact).

Edited by Dmitriy_Guller, 03 April 2013 - 14:11.

[Fat Boy]

For a racecar 2-4 degrees is normal,, or 6 deg for HRT in Thupercar and they wonder why the tyres delaminate !! DooOH.

Ya, I've destroyed tires as well. I didn't wonder why the tires delam'ed, but the tire guy said it would be OK prior to the race. When he just shrugged and said, "I guess I was wrong." I was less than impressed.

[Canuck]

In my experience, ruining your car is a cultish following.

For a very short time, I tried being part of the VW Vortex forum. I joined just to get to know more things about my car, the best places to get it serviced, etc. I quickly found out that it's a forum where young "adults" encourage each other to spend a lot of money on modifications to lower the car, camber the tires out to extremes (beyond what you would get from lowering the car to ridiculous levels), getting huge rims so that the tire is just a narrow ill-fitting band of rubber, and so on.

When I suggested that not everyone is interested in spending money to modify the car they already paid money for into a condition where it's no longer road-worthy, where every speed bump or a moderate pothole threatens to total your car, and any other piece of slightly uneven road scrapes your undercarriage away, I was effectively run out of the forum. The most infuriating thing I've read there is how someone ripped out the whole engine from the car after striking the pothole, was reassured by other forum members that any car would've ripped out its engine there, and actually got paid by the insurance company (my insurance company, in fact).

There's nothing like a cohesive forum and a perspective-challenging interloper to generate a keyboard-cowboy lynch mob. Pointing out that stroke does not make torque was the beginning of my end, eventually culminating in them dismissing the formulas of Prof. Blair, CF Taylor (and everyone else) while trotting out their own excellence (I used to drag race so I know what I'm talking about). I suspect building two equal-displacement / different b/s engines to prove them wrong would still not have convinced them.

[indigoid]

There's nothing like a cohesive forum and a perspective-challenging interloper to generate a keyboard-cowboy lynch mob. Pointing out that stroke does not make torque was the beginning of my end, eventually culminating in them dismissing the formulas of Prof. Blair, CF Taylor (and everyone else) while trotting out their own excellence (I used to drag race so I know what I'm talking about). I suspect building two equal-displacement / different b/s engines to prove them wrong would still not have convinced them.

Hilarity, not. I've heard both of the below:

- V-twins "make more torque" than four-cylinder engines because they have less cylinders
- V8s "make more torque" than four-cylinder engines because they have more cylinders

Once I even heard both in the same conversation, from the same person! I'm pretty sure they trotted out the tired old crap about long-stroke engines as well. Boggles.

I'm a huge fan of BMW's K1200 (the later transverse-mounted ones!) and K1300 engines. Abundant low-end torque (in city riding I rarely needed more than 2500rpm!) and a heady rush of top-end power. Abnormally miserly on fuel, too. They're a gem, IMHO. I'm told Suzuki's Hayabusa engines are even better.

[munks]

Aesthetically, I'm more offended by the size of those rims than the camber. But certainly one would be worried about tire failure if they were used in hot weather or at high speed; hopefully these folks are just cruising around parking lots at low speed and picking up chicks (or scaring them off).

[Scotracer]

I'm not much of a tyre guy but I'm guessing stressing the sidewalls like that with the stretch would lead to pretty impressive failures? I'm not sure of the lateral components of load they are designed to withstand...

[Lee Nicolle]

Ya, I've destroyed tires as well. I didn't wonder why the tires delam'ed, but the tire guy said it would be OK prior to the race. When he just shrugged and said, "I guess I was wrong." I was less than impressed.

In my experience IF you have the correct size tyres for the rims 4 deg should always be enough, maybe a touch more for qualifying if you are that serious. The wide tyre culture even persists in road racing. American manufacturers in particular love wide tread tyres. Then you need more camber just to make the bloody things turn and usually the steering effort goes through the roof.

I had this on my Sports Sedan, the tyres I had been using were discontinued as not enough were sold, Then I had a choice of tyres an inch wider that rolled all over the rims and were slower. Because I was effectivly running on tyres narrower as the rolled on the rims.Less real contact patch instead of more. And the rears were on the maximum permitted rim

[Lee Nicolle]

The 'stretched' tyres seem to be creeping into 'proper' motorsports too. I competed at a hillclimb this weekend and there was several examples of too small a tyre on rims. These being proper semi slick race tyres.
Though needless to say it was Jap imports they were on.
There was a few examples of too big a tyre on small rims too though the other way was more prevelant.
But no stupid cambers at least. Though 6 deg was not uncommon. Though for a hillclimb on soft tyres that may work well.
Interesting car that was winning when I left. What used to be a 260Z with a very strong 410 Chev running through Hilux gearbox and diffs, complete with 6 stud proper alloy racing wheels.
Another aside, an Evo9 crashed [they bin one a year at this event] It hit a bank hard and broke the wheel through the spokes. Breaking the rim is understandable but the spokes?? Speedline, not a good add. Though the impact broke the wheel, not the other way around.

[MatsNorway]

Lucky shot!

http://lh5.ggpht.com....jpg?imgmax=800

Edited by MatsNorway, 07 April 2013 - 10:38.

[Tony Matthews]

Ha ha! Amazing! I'd want my money back...

[carlt]

Lucky shot!

http://lh5.ggpht.com....jpg?imgmax=800

I knew we shouldn't have fitted those 6 pot calipers

[Canuck]

Some structural adhesive and some buffing compound and it'll be right as rain again.

[desmo]

Some structural adhesive and some buffing compound and it'll be right as rain again.

Parts buffed to a high polish never break.

[Lee Nicolle]

Lucky shot!

http://lh5.ggpht.com....jpg?imgmax=800

Shades of the wheel from Sunday, similar style.

[MatsNorway]

Ive picked up some hate against rota rims anyone having experience with them here?

[Tony Matthews]

They came looking for you - I said you'd gone away, I didn't know where, or when you'd be back.

[MatsNorway]

Ah yes. bad grammar matched with fast typing.

Must be a virus because i am unable to get rid of it.

When i looked at the photos i got this idea that a tightly meshed rim would do better than a say a 5 spoke. Surely a tight mesh would distribute the load more directly and therefore have a better potensial to take loads. Or be lighter.

Edited by MatsNorway, 08 April 2013 - 18:02.

[NeilR]

Lee I never knew you ran at Bryant Park.
Are you going to Malcolm Oastler's talk?

[Lee Nicolle]

Lee I never knew you ran at Bryant Park.
Are you going to Malcolm Oastler's talk?

I ran at Mt Alma in SA. A long fast fun event,,, if you drive within yourself unlike EVO drivers seem to do.

[Greg Locock]

When i looked at the photos i got this idea that a tightly meshed rim would do better than a say a 5 spoke. Surely a tight mesh would distribute the load more directly and therefore have a better potensial to take loads. Or be lighter.

For a couple of years my main job was wheel design engineer. This basically involved taking the pretty model made by the pony tailed guys to the drafting office, where somebody would draw it, and then taking the drawings to our supplier, who would suck his teeth and make some changes, which I'd take back to Styling, and off we go again. Finally we'd have a design that everyone could live with. Note how much 'engineering' content was involved. Then they'd make a wooden pattern and give us some gravity cast wheels which i'd arrange to be tested on the SAE durability rig, and some strength tests and so on on the car. If we passed (unlikely) then they cut the low pressure steel dies and away we go into pre-production testing and sign off and production. More likely it would fail, and having decided whether the imperfections at the site of the cracks were impossible in production (voids and inclusions are the main reason you use low pressure die cast for wheels rather than gravity cast) we'd beef up the sections, maybe even do some of that new fangled FEA, and try again. Dead easy on a wooden pattern, just add a bit of body filler where needed. These days of course the whole job is FEA right the way through.

In my experience simple disc shaped wheels are less troublesome than spoked wheels, because the flow through the mould is better. A few large spokes are better than many small ones. BUT, if you want high camber stiffness in your wheel (yes you do Virginia) then you need the depth of section provided by spokes, not discs

These were mine with 5 deep U section spokesspokes, they were an excellent design stiffness and strength wise and they look hot.
http://www.carsguide...93_buyers_guide

These are pretty good, the spokes are deep, but the wall thickness of the solid spokes is greater than the rims which is a slight no no

http://www.gumtree.c...tion/1016575451

These are easier to make as they have fewer bigger U section spokes unfortunately Mr Aesthetics has left the building

http://www.gumtree.c...dore/1015459201

These are very easy to make but won't be so good in camber stiffness, and the rim may need to be thicker as it isn't well supported.

http://www.gumtree.c...ires/1017267168

Incidentally steel wheels are much harder to get right than alloys if you are trying to get a minimum weight design that is durable. The rim is easier, the spider (disc) is a mass of conflicting requirements.

[indigoid]

These were mine with 5 deep U section spokesspokes, they were an excellent design stiffness and strength wise and they look hot.
http://www.carsguide...93_buyers_guide

awesome, I always liked those wheels too! (but not the rest of the car)

[Lee Nicolle]

For a couple of years my main job was wheel design engineer. This basically involved taking the pretty model made by the pony tailed guys to the drafting office, where somebody would draw it, and then taking the drawings to our supplier, who would suck his teeth and make some changes, which I'd take back to Styling, and off we go again. Finally we'd have a design that everyone could live with. Note how much 'engineering' content was involved. Then they'd make a wooden pattern and give us some gravity cast wheels which i'd arrange to be tested on the SAE durability rig, and some strength tests and so on on the car. If we passed (unlikely) then they cut the low pressure steel dies and away we go into pre-production testing and sign off and production. More likely it would fail, and having decided whether the imperfections at the site of the cracks were impossible in production (voids and inclusions are the main reason you use low pressure die cast for wheels rather than gravity cast) we'd beef up the sections, maybe even do some of that new fangled FEA, and try again. Dead easy on a wooden pattern, just add a bit of body filler where needed. These days of course the whole job is FEA right the way through.

In my experience simple disc shaped wheels are less troublesome than spoked wheels, because the flow through the mould is better. A few large spokes are better than many small ones. BUT, if you want high camber stiffness in your wheel (yes you do Virginia) then you need the depth of section provided by spokes, not discs

These were mine with 5 deep U section spokesspokes, they were an excellent design stiffness and strength wise and they look hot.
http://www.carsguide...93_buyers_guide

These are pretty good, the spokes are deep, but the wall thickness of the solid spokes is greater than the rims which is a slight no no

http://www.gumtree.c...tion/1016575451

These are easier to make as they have fewer bigger U section spokes unfortunately Mr Aesthetics has left the building

http://www.gumtree.c...dore/1015459201

These are very easy to make but won't be so good in camber stiffness, and the rim may need to be thicker as it isn't well supported.

http://www.gumtree.c...ires/1017267168

Incidentally steel wheels are much harder to get right than alloys if you are trying to get a minimum weight design that is durable. The rim is easier, the spider (disc) is a mass of conflicting requirements.

When I advertise my EB wheels I will have to give your recommendation.
The wheel that broke at Mt Alma is a similar style to the ROH in the second pic. And I doubt the ROH one would have broken like this one.

[Greg Locock]

ROH and Castalloy both made high quality wheels when I was involved, 22 years ago.

[Lee Nicolle]

When you say camber strength Greg I presume you mean the inside of the rim that is usually every shape but round on modern cars with low profile tyres. With a LOT more wheel inside than outside of centre.35, 50 even 65P like my Landcruiser wheels.
Though in the past it was often a lot more out than in on aftermarket rims. But they did not seem to bend nearly as much

[MatsNorway]

https://fbcdn-sphoto...962307945_n.jpg
https://fbcdn-sphoto...524473396_n.jpg
https://fbcdn-sphoto...400626313_n.jpg
https://www.facebook...6...pe=1&ref=nf
https://fbcdn-sphoto...765988229_n.jpg

Are we talking Fatigue and expiration "date" on rims? Like a bottle of milk..

Surely there is a expected milage on a rim of higher level design.

Edited by MatsNorway, 14 April 2013 - 10:27.

[Greg Locock]

Are we talking Fatigue and expiration "date" on rims? Like a bottle of milk..

Surely there is a expected milage on a rim of higher level design.

Depends on the loads. There are SAE fatigue tests on them, typically the wheelweight flange collapses. That spoke failure is pretty odd, I wonder if they machined them for brake clearance and left a stress raiser?

Edited by Greg Locock, 14 April 2013 - 22:48.

[mariner]

Greg, do you remember the old Lotus " wobbly web " wheels with the complex bulges towards the centre. Staple diet of 1950/60's then faded from view.

I understood it was a design in response to the foundry's preference for constant section so the bulges provided the stiffness.

In my very limited understanding solid alloy whels - wobbly or Melmag , went out of favour because spokes alowed radiant enegy to escape from the discs - hence the Chapparal wheels which preceeded BBS by many years

[GreenMachine]

Interestingly (and disturbingly, since I have two sets of these wheels), there have been two failures of a particular brand/type of wheel here - one on a relatively high power turbo car, the other on a relatively stock atmo car. Both cars of the same make/model, both incidents at the same circuit within a month or two of each other. As far as I can ascertain, both using R-spec rubber, not slicks. These wheels have been developed for this car, and have been around for some years.

Coincidentally, I have recently developed the habit of pulling the wheels off after each event and having a close look at my spokes ...

Edited by GreenMachine, 14 April 2013 - 22:30.

[Lee Nicolle]

It seems rallycars are breaking wheels more often than I thought. Though obviously it has hit a kerb sideways to do that damage.
One observation is the 98mm PCD on a Subaru would not help.
Though the Lancer I saw with a broken wheel is 114.3 PCD.
I doubt the wheel would be modified for brakes, It seems just poor design or casting is the problem, coupled with very vigorous use ofcourse.
In recent times I have been watching many 40s and 50s 'Specials' that are now using modern road car steel wheels. At a guess a combo of very old rims and modern tyres are breaking them around the stud holes.
At a circuit race level I have seldom ever seen wheel failures though many cars probably keep a very keen eye on them. As many are more than a bit suspect.
For a period in the 90s Sprintcars seemed to break right rears but I have not seen that in a long while.
And some sedans using 'wide 5' hubs were breaking the hubs. Though they were some very poor castings, looked more like concrete than alloy!

[Greg Locock]

Steel wheels fail

-at the mounting face
-in the spider itself
-at the welds to the rim
-in the rim itself

In a modern wheel the rim is made from strip, bent round, welded to form a ring, ground, and then formed. As such the rim weld must be ductile, smooth, and leakproof.

[Canuck]

Is that for manufacturing costs alone or is it a "better" wheel as well?

[Greg Locock]

Is that for manufacturing costs alone or is it a "better" wheel as well?

Is what for what?

[Lee Nicolle]

Steel wheels fail

-at the mounting face
-in the spider itself
-at the welds to the rim
-in the rim itself

In a modern wheel the rim is made from strip, bent round, welded to form a ring, ground, and then formed. As such the rim weld must be ductile, smooth, and leakproof.

Agreed, though for something that is cheap and made by the million are surprisingly good, especially on modern vehicles.
Some wheels always broke, look at 60s tintop enduros anywhere. I see a few cracked in the safety bead area though that has always been through overload, with light truck tyres on passenger rims. Though bent ones on hatchbacks with 50 series tyres are just so common.
Factory alloy wheels seldom cause a problem either though in recent times [last 20 years] I have seen an inordinate amount of cracked broken and bent ones. The cheap Chinese bling stuff is to a degree understandable but not so the Aussie and Euro brand stuff . I have seen quite a lot cracked through spokes, cracked rims yet alone bent ones.
The bent ones however are the product of the stupid low profile tyres so predominant these days. Anything lower than 60 series is stupid on an everyday passenger vehicle. I reckon I see one rim in 4 that are round in 17 18" rims. That includes OEM, the cheapies however don't just bend, they fracture too. And I do see about 80 wheels a month.
The old wheels discussed on the Aussie wheels thread seldom ever do this except for the specialised wheels made from hi magnesium alloy

[MatsNorway]

obviously it has hit a kerb sideways to do that damage.

Perhaps prior to this but not in the pictures shown.

edges like that must be respected. Its like me and a friend playing pool. i won 5-0 because he knocked down the 8 every time. Im not good i just make good rules for myself to play by. Like: i never hit hard either to ensure that the ball stays close to the cups.

Edited by MatsNorway, 15 April 2013 - 14:29.

[Canuck]

Is what for what?

Yeah...I don't know if what I was asking makes any sense. I assume when you say "modern wheels", that implies that steel wheels have not always been made this way. I was asking if the (presumed) change in manufacturing methodology yielded only cost benefits or if the end product is a wheel that is better today than say one made 30 years ago.

[Tony Matthews]

... if the (presumed) change in manufacturing methodology yielded only cost benefits or if the end product is a wheel that is better today than say one made 30 years ago.

Whaaat?

[Greg Locock]

Yeah...I don't know if what I was asking makes any sense. I assume when you say "modern wheels", that implies that steel wheels have not always been made this way. I was asking if the (presumed) change in manufacturing methodology yielded only cost benefits or if the end product is a wheel that is better today than say one made 30 years ago.

Ah, well I only talked about modern steel wheels because they are the ones I used to design. I don't know how they used to make the rims before they developed the welds up to the point where they could withstand the forming process.

Steel wheels are a 'better' product to my mind, at least in the small sizes, than alloys.

Lee- you have to be very careful to differentiate between wheels and tires that are designed for Australian conditions, and those designed for Europe in partiuclar, and even the USA. For example we took a USA 4wd outback, and its poxy tires optimised for rolling resistance all blew within 100 km. Fitted some decent Coopers and no more problems.

Again for wheels both Ford of Australia and Holden have additional strength requirements /way/ beyond overseas markets.

Steel wheels do have a fatigue life at some point they will let go. I'd guess a half a million miles of street use would be a conservative target.

Edited by Greg Locock, 16 April 2013 - 01:32.