Weight Distribution

eidolon

eidolon

eidolon

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After reading the supercharged MX5 video it made me wonder just how important weight distribution really is.

I regularly hear about the fabled 50/50 weight distribution of the M3 so I curiously looked up the Elise and found that it was 38% Front - 62% Rear whcih doesn't sound too good to me so why does it handle so well when the weight is all at the back?
 
So does that mean that an M3 is front heavy when you've got a driver in there so BMWs promotional literature is putting a spin on it and their 50/50 stat isn't really worth much
 
tbh I doubt a drivers weight would make much difference to the balance of an m3 as it weighs so much to begin with so the drivers weight will only be a small percentage of the final weight. In an elise however, a driver would add about 10% to the vehicles weight.
 
Hi there

What about the Porsche 911? Its engine is in the boot so surely that must put most of its weight in the rear. It certainly helps on corner exit speeds anyway.

The Mustang GT / Roush / Saleen are 52/48 which is close to the fabled 50/50.

I believe an S2000 is 50/50, am sure Si knows but they handle beutiful.

The Shelby GT500 Mustang however is 58/42 and its definetely nose heavy.
 
Yep that 58/42 one will def feel nose heavy when braking and turning as the front will be even heavier under those conditions as the centre of mavity will obviously be shifted forwards somewhat. 50/50 or slightly biased towards the rear should produce the best handling cars.
 
TBH Id prefer a 60:40 1100kg car over a 1500kg 50:50

The 1100kg will be far keener to change direction even though the 50:50 is the on paper winner if you only look at the distribution.

The S2000, 50:50 which is great, but its not exactly a light chassis, stiff yes but the weight does blunt how quick it could be.
 
Jonnycoupe said:
The S2000, 50:50 which is great, but its not exactly a light chassis, stiff yes but the weight does blunt how quick it could be.
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'Not exactly light' doesn't really cover it - for the size of car, it's pretty badly overweight. The ~2800lbs that it tips the scales at is getting on for Mopar A-body muscle car territory.

I'd love to know where all the weight is in it, as they aren't exactly huge.
 
well the average person probably weighs about 75-80kg, but their weigght wont be pushed right to the front of the car so it will be closer to the middle but still add more forward than aft of the center,

so it probably pushes the elise to nearly perfect distribution under weight of the driver.

in a car weighing 1400kg, the relative addition of the weight will have less of an impact (as stated above tbh) so they can and should be closer to 50/50 because the driver will add less to the mix as a total percentage of the total combined weight.
 
[TW]Fox said:
My car is better than all your cars becuase my cars brochure says its weight distrubution is 50/50.
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But I've met you and therefore know that you weigh almost 30stone, thus ruining your perfect distribution.
 
JRS said:
'Not exactly light' doesn't really cover it - for the size of car, it's pretty badly overweight. The ~2800lbs that it tips the scales at is getting on for Mopar A-body muscle car territory.

I'd love to know where all the weight is in it, as they aren't exactly huge.
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Hi there

I am guessing a lot of the weight is the electric roof as in the mechanicals etc. I suspect a true hard top version would be no doubt quite a bit lighter. I think Spoon did such a version of the car that was race prepped and it was something like circa 150kg lighter but cost a small fortune.
 
eidolon said:
After reading the supercharged MX5 video it made me wonder just how important weight distribution really is.

I regularly hear about the fabled 50/50 weight distribution of the M3 so I curiously looked up the Elise and found that it was 38% Front - 62% Rear whcih doesn't sound too good to me so why does it handle so well when the weight is all at the back?
Click to expand...

Lotus know a thing or two about how to set the suspension up to make a car handle.

The weight distribution of the Elise is more telling in the amount of lift off over steer that the car suffers from, especially the early S1s.
 
eidolon said:
After reading the supercharged MX5 video it made me wonder just how important weight distribution really is.

I regularly hear about the fabled 50/50 weight distribution of the M3 so I curiously looked up the Elise and found that it was 38% Front - 62% Rear whcih doesn't sound too good to me so why does it handle so well when the weight is all at the back?
Click to expand...


Because its all relative.

The elise hasnt got that much weight to split has it?
 
My turbo is 52% front 48% rear. Not bad for a 1978 family saloon :D (yes it's front wheel drive, but it handles suprisingly well :))
 
Nickg said:
well the average person probably weighs about 75-80kg, but their weigght wont be pushed right to the front of the car so it will be closer to the middle but still add more forward than aft of the center,
Click to expand...

I suppose that would change as well depending on where the driver sits in relation to the "balance point" of the vehicle. More weight on the light end helps the balance point shift that way

In a rear engine car, where the driver sits (more or less) equally distant between the axles, the weight distribution may be minimal and the "driverless" weight distribution will be relatively unchanged. This may help the suspension designers as they can develop the car without the dynamics changing much with a heavier (or lighter) driver sitting in there.

With a mid engined car, with the driver pushed further forward, a larger proportion of the drivers weight would be over the front axle, therefore balancing a heavier arsed car to some degree, based on the actual weight of the driver (and that brings into question power to weight of lower powered light cars with some lard arsed pie muncher behind the wheel. For example, I weight over 100kilos (16st), which may affect the balance by quite a bit, but for someone who weighs only 65 kilos (10st), it may affect the balance less, but they would gain 35kilos advantage in weight loss, which may improve performance more than the better weight distribution gained by my blubber)

In a front engined 2 seater car, the classic design is to have the drivers near the rear axle, thus sending the drivers weight to the rear to balance the nose heavy engine. Again, this depends on the weight ratio to begin with, for example, the spitfire has a 4 pot up front and is fairly light with a decent enough distribution, while my GT6C has the 6 pot in the nose and the same layout as the spit, making my car quite a lot heavier in the nose than a "proper" spit, so my car is quite tail happy with poor traction, even with a lardarse like me keeping the rear axle down.

Also, remember where the fuel tanks are and how much that can affect the weight and balance of the car.

Another thing about weight distibution is left/right distribution. For example, the Stag is often criticised for having the battery, washer bottle, petrol tank (with its nice sloshy contents) and driver (with driver requirements like steering column, pedal box, clocks, etc) all on the same side, which means on right hand bends, the center of mavity begins on the right side and is pushed towards the centre of the vehicle as it corners, helping weight transfer onto all four tyres, while in left handers, the center of mavity is actually pushed "outside" the vehicle, putting all the weight on the outside tyres. With a nose heavy layout as well, the front drivers tyre is very heavily loaded in relation to the others, especially if you are low on fuel which pushes the weight balance even further forward... and God help you if you touch the brakes on such a corner :D.
 
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