Speedo or GPS?

Peerzy · 6 Feb 2011 at 18:59

mjt said:
If all components are in good condition, yes. And of course the road is clear, etc.

What about the driver? Brand new Ford Focus can do 130mph or whatever, give it to a 17 year old and that is a perfectly safe speed for him to drive at?

mjt · 6 Feb 2011 at 19:00

Peerzy said:
What about the driver? Brand new Ford Focus can do 130mph or whatever, give it to a 17 year old and that is a perfectly safe speed for him to drive at?

I was talking about the car.

Peerzy · 6 Feb 2011 at 19:02

[TW]Fox;18403685 said:
Are you saying it's a fact that the VMAX in every car in production is a safe speed at which to drive that car?

mjt said:
I was talking about the car.

Surely someone has to drive the car to that speed?

In that case do enough work and I'm sure you can get an old Mini to do 150mph safely in a straight line without taking the driver into consideration?

Skilid · 6 Feb 2011 at 19:03

PMKeates said:
Almost certainly GPS - most speedometers are designed to over-read (though in a modern vehicle the car's systems know almost exactly how fast it is going).

Does annoy me though. Because I've set my speed warning to come on at 85, and it comes on at 85 on the speedo, not when the car is actually doing. I know its designed to, just annoys me.

mjt · 6 Feb 2011 at 19:06

Peerzy said:
Surely someone has to drive the car to that speed?

In that case do enough work and I'm sure you can get an old Mini to do 150mph safely in a straight line without taking the driver into consideration?

I don't care as I'm not getting into this pointless dicussion.
My point was that any car that can do a certain top speed can drive at that speed perfectly safely given that it is in good condition.

Skilid · 6 Feb 2011 at 19:36

I would agree. As long as the driver was alert, and knew how to drive at those speeds. Yes, the cars are capable of those speeds, but the squishy things behind the steering wheel 9/10 aren't.

But if that's not your point then fair enough.

[TW]Fox · 6 Feb 2011 at 19:44

mjt said:
If all components are in good condition, yes. And of course the road is clear, etc.

So you don't think that mass, wheelbase, etc etc have any bearing on stability at high speeds then?

mjt · 6 Feb 2011 at 20:24

[TW]Fox;18406589 said:
So you don't think that mass, wheelbase, etc etc have any bearing on stability at high speeds then?

Of course a little hatchback won't be as stable as a 760Li, but both should be perfectly stable and safe enough to blast along at 130 mph.

FWIW, my Z3 has quite a short wheel base, yet seemed very stable at an indicated 130

Well that's a lie atually. The steering gets very light very quickly at 120+

Barks · 6 Feb 2011 at 20:26

Driving the Mini, the GPS speed is far higher than the Speedo at high speeds. Definitely cannot say the same for the BMW. Even though strictly speaking BMW make both.

Scania · 7 Feb 2011 at 10:35

CaptainRAVE said:
True enough, always reminds me of this -

http://www.wreckedexotics.com/articles/017.shtml

Thats my point in a nutshell, yes.

I must say, the mangled e39 528i in that link made me wince!

CaptainRAVE · 7 Feb 2011 at 11:14

R420LA6X2/4MNA said:
Thats my point in a nutshell, yes.

I must say, the mangled e39 528i in that link made me wince!

Same here - it is made worse when they are cars you own/have driven and at the same speed too.

bam0 · 7 Feb 2011 at 13:08

Burnsy2023 said:
Sat Nav is very accurate as long as you are driving in a straight line at a constant altitude.

Constant altitude? Constant change in altitude maybe (including 0), but all that depends on the sample rate the GPS is using.

Danthus · 7 Feb 2011 at 14:26

Not sure about anyone else but I really wouldn't want to crash in any car on the motorway at 130mph.

ubersonic · 7 Feb 2011 at 17:02

I don't know if its true today but I remember a few years back the accuracy of a gps could vary by a couple of mph due to inclines/declines in the road, not sure if modern ones can account for this now, but yeah their usually more reliable than a speedo.

Overlag · 7 Feb 2011 at 17:23

Peerzy said:
What about the driver? Brand new Ford Focus can do 130mph or whatever, give it to a 17 year old and that is a perfectly safe speed for him to drive at?

im not 17 though I may be relatively new driver (6years) but having done 120ish around multiple race circuits, doing Vmax run of 130mph isnt really that hard.

Like i said, 70mph in a 1.25 entry model hatch is scary, probably more so than 130 in my car. I wouldnt be doing it ALL the time though, its just stupid, a waste of petrol and far too noisy.

Unlimited motorway speeds in this country wouldnt make me suddenly go to Vmax everywhere, i cruise at 75-85 now and probably will be the same if everything was unlimited. Only plus is when im getting tired of the cruise i can blast to 120ish for a bit and not get in any trouble.

Vita · 7 Feb 2011 at 17:26

My speedo is 5mph infront of my GPS. 70mph on speedo is 65 on sat nav.