RE: Light cars are not the answer: Tell Me I'm Wrong

RE: Light cars are not the answer: Tell Me I'm Wrong

Author
Discussion

Hasbeen

2,073 posts

222 months

Tuesday 3rd February 2015
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I don't think the problem has much to do with the weight of cars. I think modern tyres have got too good for most drivers to handle on the road, & the better the car, the less who will be able to handle it as they approach the limit.

I am not talking about slow autocross speeds, or city roundabouts, but at higher speeds, & when a loss of adhesion is unexpected, rather than provoked.

In the old days [60s] you could slide an MG, Simca, Mk2 Jag or a Mk7 Jag around the place, or have them go for a slide unasked, with impunity. The things were so easy to recover at the low limit of the cross ply tyres, only a dolt would have trouble catching them. Today, even an old 3.4L Mk2 Jag, with 8" alloys & modern tyres is an entirely different proposition. Get slack & even old faithful will bite you.

One of the great pleasures of driving a heavy XK140, compared to a Morgan +4, was that with twice the weight, you could take liberties at it's much lower limit, when the same liberties in the light Morgan would get your bum bitten all be it, at a somewhat higher speed.

Robert Elise

956 posts

146 months

Tuesday 3rd February 2015
quotequote all
Hasbeen said:
I don't think the problem has much to do with the weight of cars. I think modern tyres have got too good for most drivers to handle on the road, & the better the car, the less who will be able to handle it as they approach the limit.
True. But cars for most people are moving to failsafe appliances. Unfortunately much of the advancement is negated by a sense of isolation and invulnerability leading to multi-tasking while driving. So, more technology required....
Driving, in the fully active, involving sense of the term, is becoming a voluntary pastime undertaken at weekends.


900T-R

20,404 posts

258 months

Wednesday 4th February 2015
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Robert Elise said:
Unfortunately much of the advancement is negated by a sense of isolation and invulnerability leading to multi-tasking while driving. So, more technology required....
Indeed. At some point we'll need to break the chain - as a society we're simply not rich enough (and very dependent on 'cheap' personal transport as well) to mandate automatised everything to facilitate the lazy and feckless.

'Make something idiot proof and all you'll be doing is creating a better class of idiot'.

ShortBeardy

113 posts

145 months

Wednesday 7th August 2019
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You're wrong!

And I know it had been pointed out already, and I know the idea of the article is to spawn a discussion, but if you are going to make a point and want to base it on physics then get it right.
The F1 car example is just wrong and misleading. A 600kg car with 1000kg of downforce is not equivalent to an equally powerful 1600kg car.

This isn't politics. Your hair probably isn't orange. There is no reason to lose credibility for the sake of a provoking a response - it's as bad as click bait. You can do better.

LennyM1984

639 posts

69 months

Wednesday 7th August 2019
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Well I guess the author has now had 4 years to reconsider his position...

Fastdruid

8,649 posts

153 months

Wednesday 7th August 2019
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I can tell the difference in how well the car handles between a full and empty tank. Let alone with a passenger or two.

While somethings are acceptable to suffer the weight for in a "daily" (a/c, stereo, comfortable seats etc). Lighter is better. Quicker, better handling, less wear on brakes/tyres/suspension.

If I had my way I'd change VED to charge by vehicle mass rather than emissions.

snoopy25

1,867 posts

121 months

Wednesday 7th August 2019
quotequote all
ShortBeardy said:
You're wrong!

And I know it had been pointed out already, and I know the idea of the article is to spawn a discussion, but if you are going to make a point and want to base it on physics then get it right.
The F1 car example is just wrong and misleading. A 600kg car with 1000kg of downforce is not equivalent to an equally powerful 1600kg car.

This isn't politics. Your hair probably isn't orange. There is no reason to lose credibility for the sake of a provoking a response - it's as bad as click bait. You can do better.
Over 7 years you have had your account and your 2nd post is to reply to a thread over 4 years old??

hehe

Grrbang

728 posts

72 months

Wednesday 7th August 2019
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snoopy25 said:
Over 7 years you have had your account and your 2nd post is to reply to a thread over 4 years old??

hehe
This topic must have touched a nerve that 7 years of other threads have not!

He makes an interesting point i hadn’t considered, in that the 1000kg downforce is a speed dependent variable

deadtom

2,557 posts

166 months

Wednesday 7th August 2019
quotequote all
ShortBeardy said:
You're wrong!

And I know it had been pointed out already, and I know the idea of the article is to spawn a discussion, but if you are going to make a point and want to base it on physics then get it right.
The F1 car example is just wrong and misleading. A 600kg car with 1000kg of downforce is not equivalent to an equally powerful 1600kg car.
I’m glad someone picked up on this, this point in the article irked me too.

Force is not the same as mass

RobM77

35,349 posts

235 months

Thursday 8th August 2019
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deadtom said:
ShortBeardy said:
You're wrong!

And I know it had been pointed out already, and I know the idea of the article is to spawn a discussion, but if you are going to make a point and want to base it on physics then get it right.
The F1 car example is just wrong and misleading. A 600kg car with 1000kg of downforce is not equivalent to an equally powerful 1600kg car.
I’m glad someone picked up on this, this point in the article irked me too.

Force is not the same as mass
We covered this on page 12 onwards, but I must admit, I missed that mistake in the original article. As you say, the magic thing about downforce is that you get the additional downward force of a heavier car, but without the additional mass and the problems this causes when accelerating, and by "accelerating" I mean in a true physics sense: increasing speed, braking and cornering. So basically with downforce you get all the upsides without the downsides.

However, with a downforce car you do need stronger springs to cope with the extra downward force. In the above example, you'd need the springs of a 1600kg car to resist that 1600kg of downward force and still keep the wheels in suspension and not bottomed out. The trouble then is with traditional suspension you're then stuck with those springs at all speeds, even when the downforce isn't there. I've not driven a downforce car that gives anywhere near that amount of downforce, so can't comment on the effect that has on handling other than in theory. For milder levels of downforce, such as produced by my Formula Renault (sold a few months ago and owned for 4 years), it all feels quite natural and problems aren't apparent.

ShortBeardy

113 posts

145 months

Saturday 17th August 2019
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I `lurk' and only get to read when I have the time. I am irritated by pseudo science which seems to plague us today. There is enough BS around us that we don't have to put up with it in this, our "hobby".