When manufacturers design a car....

[Garlick]

....what are the dimension tolerances they work to?

I've just been driving my Lexus and on narrow lanes I wouldn't want a car to be much wider. That got me thinking about whether there is an agreed industry standard that says a car can be no longer than X and no wider than Y, or can a manufacturer simply build a car as big as they like?

OK, so there are exceptions like Hummers, but is there any law to dictate what the roads can reasonably accept? Cars are getting bigger that's for sure, but is there a line?

[S8Demon]

interesting point.

I witnessed a new Jag XJ attempting to park in a car park recently. Not a multi storey, just a regular car park.

It was too wide, in that cars parked perfectly reasonably in the adjoining spaces would have prevented opening the jag doors and it was about 3ft over the line at the rear.

Driver gave up in the end

[ludicrous speed]

They're not going to build some ultra wide thing for a laugh are they, some cars are a lot wider than they once were, but there is a sensible level which manufacturers will stick to.

Pretty sure they can build to whatever they like, practicality will affect sales hugely if they take the piss.

[Garlick]

ludicrous speed said:

They're not going to build some ultra wide thing for a laugh are they, some cars are a lot wider than they once were, but there is a sensible level within manufacturers will stick to.

Not really what I said, but I'm interested to know what the sensible level is that you mention as that was what I wanted to know.

[Huntsman]

There's a lot of ships known as Panamax - the max size that will fit through the Panama canal.

This is in no way relevant!

[kambites]

I don't know but I think they've got it wrong. Many modern cars feel too big to be practicable on our roads, to me. A car being wider than about 1.8m (excluding the mirrors) would be enough to put me off buying it.

Edited by kambites on Wednesday 6th April 13:18

[Proxy]

S8Demon said:

interesting point.

I witnessed a new Jag XJ attempting to park in a car park recently. Not a multi storey, just a regular car park.

It was too wide, in that cars parked perfectly reasonably in the adjoining spaces would have prevented opening the jag doors and it was about 3ft over the line at the rear.

Driver gave up in the end

There's a new(er) XJ (10 plate methinks), that's owned by a guy in one of the units across the street from my work.
When he parks out the front, his car sticks out a whole 2ft further into the road than any other car that's parked here.

There's always a lorry or van delivering something to one of the units here, so you see him out every 2 seconds making sure that nobody's anywhere near it.

That'd just be a huge downer for me

[Matt UK]

I thought the only rules would be around drivers licence class / weight restrictions.

Look at Audi - the Q7 is a beast and when the current A6 was longer than the A8 when launched (IIRC)

I am sure though that consumer research will dictate. I for one do not really want cars getting bigger all the time. The 5 series I used to have was a good size. If I wanted a German exec now I'd go for the current 3 series as the 5 is now too big for my needs.

Edited by Matt UK on Wednesday 6th April 13:15

[fathomfive]

Similarly, how long does an LWB model have to be before it can be called a limo?

Edited by fathomfive on Wednesday 6th April 13:21

[Hugo a Gogo]

presumably you'd want to keep a car under 2m, as that's usually the smallest 'max width' restriction you'd come across

[The Wookie]

I'd imagine there's a common minimum width restriction size (e.g. London) above which it'd start to inconvenience the driver as he'd have to take detours

[Gizmo!]

In Japan the taxation classes always used to be directly related to the size of the car: we knew about the K-cars like the Cappuccino, Beat, Figaro and Sera, but it's a hierarchy of sizes: http://en.wikipedia.org/wiki/Vehicle_size_class#Ja...

Over here though, cars just seem to have been growing ever since I've known. Even "small" cars are huge now - the new Fiesta is almost exactly the same width as the Sierra was - and the 2010 Range Rover is over an inch wider than the Ferrari Testarossa...

[ludicrous speed]

Surely it doesn't come down to a 'common width restriction' but rather just common sense, why would manufacturers build cars wider than the roads they plan to sell the cars for?

[gareth.e]

ludicrous speed said:

Surely it doesn't come down to a 'common width restriction' but rather just common sense, why would manufacturers build cars wider than the roads they plan to sell the cars for?

A lot of cars werent designed for our roads...

Where as the British cars: Lotus, caterham, tvr, etc were

[Garlick]

Tricky isn't it. What works for the chap who lives in (let's say) Milton Keynes where roads are wide, may not work for the chap who lives in rural Yorkshire or Central London.

The Jag story above is a good observation, the poor chap couldn't park!

[blueg33]

[quote=Matt UK]I Look at Audi - the Q7 is a beast and when the current A6 was longer than the A8 when launched (IIRC)

[quote]

I have an A6 and can cofirm it is often too big for multi storey car parking apces in terms of length and width. But it was superb for touring Europe 4 up. People choose the car they need/want and designers try to meet the requirement.

Edited to add

Audi have thought about much in the design of the A6 but have also made some quite big (IMO) errors, like the need to remove the power steering reservoir to change a headlight bulb, an ecu that fails if it gets wet is mounted right under a cup holder.

Edited by blueg33 on Wednesday 6th April 13:50

[Alfa numeric]

Designers don't even seem to consider a front numberplate when penning a new model, so what hope do we have with regards to size? I'm guessing the width of a standard carriageway is the only limiting factor whan it comes to width- when it come's to length there doesn't seem to be a limit.

[Garlick]

blueg33 said:

People choose the car they need/want and designers try to meet the requirement.

I agree with this entirely, but will we see van sized cars one day? Where is the line drawn I wonder. Perhaps it just isn't there at all.

[ludicrous speed]

gareth.e said:

A lot of cars werent designed for our roads...

Where as the British cars: Lotus, caterham, tvr, etc were

There's not much difference in most cars width really though, yeh if you look at biggest to smallest there's a big difference but even the lotus' caterham's and tvr's you talk about would stuggle down many of britains roads if faced with oncoming traffic, these roads just weren't designed for cars.
Is it a problem that some cars are too wide or is it that a lot of roads are just too narrow?
Modern cars aren't designed for these ancient roads and these roads certainly weren't built with cars in mind.

[Crusoe]

Try getting a modern car into a standard single size garage, anything much wider than a mx5 won't fit. New EU laws on percentage size for side mirrors make smaller car wing mirrors much larger too which is usually the widest point.