Handling wise - long or short wheel base?

[300bhp/ton]

What do people think would be a better or preferred setup for a sporting road car (2 seater)?


Option 1:

Total length of 162" with a wheelbase of 95"



Option 2:

Total length of 162" with a wheelbase of 85"



Both vehicles weigh the same (1050kg) and use the same weight engine/gearbox (2.o I4 and 5 speeder with 160hp). They also are the same height (50"), width (65.5") with the same track f/r (55"), and have the same size and type of wheels/tyres. They also use exactly the same suspension, MacPherson front and IRS rear. The vehicle is RWD with a longitudinally mounted engine.

For arguments sake lets say the only differences would be the wheelbase and the overhangs.


Bad drawing to show idea:

Updated pictures to try and add a bit more detail and specifics.

Edited by 300bhp/ton on Friday 4th November 09:16

[Liquid Knight]

Front engine front wheel drive the long wheel base would be roughly the same as my Rover and it hadels pretty well. Front engine rear wheel drive I'd go for longer wheelbase as well. A wheel in the corners would in my opinion handle better than a square platform with overhangs.

[k15tox]

First one.

Wheels as far out in each corner, less overhang.

[paranoid airbag]

the longer one in this case. Always try to minimise overhang.

[wildman0609]

depends on what you want to do with it.

racing it round a very twisty circuit go with the shorter option. drag racing go with the longer wheel base. longer wb will also make it more composed in the fast bends whereas the short wb car will change direction quicker.

[300bhp/ton]

paranoid airbag said:

the longer one in this case. Always try to minimise overhang.

for what reason?

and wouldn't the shorter wheelbase more nimble if more snappy on the limit?

[marcosgt]

Yes, if the length is fixed, the shorter wheelbase can only mean longer overhangs.

If you have overhang it means weight that will impact turn in (on the front anyway) - Sure someone will explain the physics I don't have a clue

If you can shorten the car overall, then the question is whether you want something nimble and quick at direction change or something stable on the sweeping bends (generally speaking).

M

PS You'll also find the front spoiler will scrape on the ground! Biggest problem with the Mk1 Octavia, which otherwise manages its overhang fairly well...

Edited by marcosgt on Thursday 3rd November 15:44

[Snowboy]

Liquid Knight said:

A wheel in the corners would in my opinion handle better than a square platform with overhangs.

I'd agree with this.
That said – it would depend on the car.

An E type is supposed to handle well and the bodywork overhangs more than a Edwardian ball gown.

[300bhp/ton]

Snowboy said:

I'd agree with this.
That said – it would depend on the car.

An E type is supposed to handle well and the bodywork overhangs more than a Edwardian ball gown.

That's partly my thinking, many 60's cars/designs often cited for great handling and feel had fairly large overhangs.

Many modern cars today don't in a stark comparison.

[300bhp/ton]

e.g. a usually cited great handling car, but with fairly largish overhangs:

[Kozy]

wildman0609 said:

drag racing go with the longer wheel base.

Wrong? Shorter wheelbase means more load transfer, more load transfer means more traction for a RWD car off the line. Longer wheelbase is better for braking.

[Liquid Knight]

Snowboy said:

Liquid Knight said:

A wheel in the corners would in my opinion handle better than a square platform with overhangs.

I'd agree with this.
That said – it would depend on the car.

An E type is supposed to handle well and the bodywork overhangs more than a Edwardian ball gown.

The engine and gear box are behind the front wheels and the inbound disc set up at the rear with alloy wishbones meant the mass was centralised so the rear would stick to the road as well.

The long wheelbase picture looks like an MR2, X-1/9 or Stratos set up the short wheelbase looks like a Fiat 600 camper van and would handle accordingly.

[marcosgt]

Did you add the engines later?

That's your answer (or maybe MY answer ) there. With the long wheelbase the weight of the engine is inside the wheelbase, with the short more is over and ahead of the wheels causing understeer.

An old Audi coupe (like the Quattro) is a prime example of the short wheelbase, long overhang with the engine out ahead of the front wheels.

Few would claim a Quattro derived its superiority on rally stages to its format, although to stay competitive they shortened the wheelbase, presumably to make it repond to direction changes more quickly (and save a bit of weight too perhaps?).

M

[Kozy]

doogz said:

You sure about that?

Well I thought I was. Not so sure now.

Long wheelbase is certainly better for braking traction as it keeps the weight transfer down. I assumed it worked in reverse...

[Daniel1]

I always thought it was a longer wheel bass gave you higher stability at speed, shorter wheel bass made the car more maneuverable (at the expense of it being more difficult). I cite the WRC program i watched years ago discussing the Impreza WRC vs the 206 WRC and why the 206 was so successful.

I dont think overhangs are a major problem as long as there isnt much weight in there (i.e. mainly plastic bumpers).

[Kozy]

doogz said:

It's odd. Thinking about it from a sort of logical perspective, what you've said makes sense.

But a quick look at an equation or two, and i've sort of convinced myself otherwise.

Not sure.

Which equations are these then? I like equations...

[Superhoop]

I'm saying option A, but for a slightly different reason to the other replies I have read.

In diagram A, the engine is mounted behind the front axle, so think latest MX-5 and RX-8, both cars which have 50/50 weight distribution, due in the main to the engine being mounted as far back in the chassis as possible

Then think about the Audi RS4, a car that when reviewed is normally noted to be prone to understeer, a trait which is normally put down to the fact that engine is so far ahead of the front axle....

Then you have the Porsche 911, a car that is suppossed to be tricky on the limit, as its engine is so far behind the rear axle....

Or something like that anyway.

[900T-R]

Overhangs don't necessarily mean much if there's not much weight in them.

The biggest problem I see with drawing number 2 is the position of the engine in relation to the front axle line.

Apart from that it's as outlined above - short wheelbase for low-speed corner agility, long wheelbase for straight line/high speed corner stability. Basically.

[Snowboy]

As mentioned above – I think the overhang is mostly important based on the weight.

But, from a drivers perspective, the overhang might disguise the placement of the wheels and the expectation of the turning radius… badly explained – but I'm sure you understand what I'm getting it.

[thiscocks]

First one no question. The second one is a v short wheel base for that length of car and wouldn't handle that well