0 to 60 times, kit car owner delusion??!
Discussion
So ultimately what you (I!) want is a car with a lot of torque that revs like a bike!! That would mean it would have massive bhp then? A Mike Tyson engine!
Sounds like an electric car/bike to me!! Huge torque right from zero revs? I saw a video of a new electric super bike (cant recall the make but was one of the big manufacturers, I'm sure it's on youtube) being test ridden and it was just stupidly quick!! The rider was pretty much freaking out with excitement! No nice noises tho
Sounds like an electric car/bike to me!! Huge torque right from zero revs? I saw a video of a new electric super bike (cant recall the make but was one of the big manufacturers, I'm sure it's on youtube) being test ridden and it was just stupidly quick!! The rider was pretty much freaking out with excitement! No nice noises tho
RemaL said:
Also your 205 rear profile tyre is flat. So has a much larger contact patch then a sports bike 190 rear tyre which is curved.
The bike also generally has:a)Stickier tyres
b)An engine in the middle, not the front.
c)A higher CoG
d)A shorter wheelbase
Which generally means the percentage of weight on the rear tyre for traction is very high indeed. Hence wheelies.
RemaL said:
So as I was talking in general terms (which you may have missed). your not saying a car has less Grip that a bike?
I have only just seen you have a 3 wheeler.
Also your 205 rear profile tyre is flat. So has a much larger contact patch then a sports bike 190 rear tyre which is curved.
Bikes most of the time are quicker than a car. pound for pound, BHP per Kg etc...I'm just talking your normal car and even kit car. not Mega hyper car or F1 car either
Yeah, I missed that.I have only just seen you have a 3 wheeler.
Also your 205 rear profile tyre is flat. So has a much larger contact patch then a sports bike 190 rear tyre which is curved.
Bikes most of the time are quicker than a car. pound for pound, BHP per Kg etc...I'm just talking your normal car and even kit car. not Mega hyper car or F1 car either
The grip that you get from a tyre is independent of the tyre size. Its counter intuitive, but true. As you increase the size of the contact patch you decrease the weight per unit of area and the net result is that grip stays the same.
PhillipM is right, the percentage of weight over the driven wheel(s) is as important as power to weight.
Of course that assumes that all driven wheels are on the same surface and you're going in a straight line. Chuck in a corner with a partially loose surface and of course a 4wd car will do a better job of connecting torques with tarmac than something with just one driven wheel.
mikeveal said:
The grip that you get from a tyre is independent of the tyre size. Its counter intuitive, but true. As you increase the size of the contact patch you decrease the weight per unit of area and the net result is that grip stays the same.
I'm not disputing what you have said Mike as it seems to make logical sense to me, but why in that case do high performance car manufacturers bother with wider tyres? And come to that why do F1 cars have such wide ones too? I have just changed my rears from 195's to 215s and I definitely seem to have more grip both off the line (in a straight line) and on the corners. How is this so?Am I right in saying that grip at the end of the day is just in fact friction? Bigger patch equals more friction but less weight per unit of area equals less friction hence it all balances out? I still don't get why all cars dont just use 175s in that case though (ignoring rubber compound differences of course) and why wider tyres DO seem to give you more grip!
FuryCossieSteve said:
So ultimately what you (I!) want is a car with a lot of torque that revs like a bike!! That would mean it would have massive bhp then? A Mike Tyson engine!
Sounds like an electric car/bike to me!! Huge torque right from zero revs? I saw a video of a new electric super bike (cant recall the make but was one of the big manufacturers, I'm sure it's on youtube) being test ridden and it was just stupidly quick!! The rider was pretty much freaking out with excitement! No nice noises tho
Electric motors do produce maximum torque at 0 rpm. But torque levels fall pretty quickly with RPM. This why the Tesla P85 has very quick 0-60 times but would lose out at higher speeds.Sounds like an electric car/bike to me!! Huge torque right from zero revs? I saw a video of a new electric super bike (cant recall the make but was one of the big manufacturers, I'm sure it's on youtube) being test ridden and it was just stupidly quick!! The rider was pretty much freaking out with excitement! No nice noises tho
Damned if I fully understand fully it. Counter intuitive it really is, but the maths does stack up.
Wider tyres have a different shape as well as a different size of contact patch.
Depending on the tyre pressure and the rigidity of the tyre structure, tyre width may not dominate the size of the contact patch. Eg a highly inflated stiff wide tyre may have a smaller contact patch than a lightly inflated floppy narrow one.
Clearly there will be less wear with a wider tyre. Given the same rigidity and inflation (as a narrower tyre), you will get a larger contact patch with less weight/area.
You'd also expect a larger contact patch to deal better with a loose surface, by averaging out the grip across the entire surface patch.
Probably there's a bunch of complicated stuff related to the shape of the patch and cornering slip angles too.
Some answers here:
http://physics.stackexchange.com/questions/29903/w...
Wider tyres have a different shape as well as a different size of contact patch.
Depending on the tyre pressure and the rigidity of the tyre structure, tyre width may not dominate the size of the contact patch. Eg a highly inflated stiff wide tyre may have a smaller contact patch than a lightly inflated floppy narrow one.
Clearly there will be less wear with a wider tyre. Given the same rigidity and inflation (as a narrower tyre), you will get a larger contact patch with less weight/area.
You'd also expect a larger contact patch to deal better with a loose surface, by averaging out the grip across the entire surface patch.
Probably there's a bunch of complicated stuff related to the shape of the patch and cornering slip angles too.
Some answers here:
http://physics.stackexchange.com/questions/29903/w...
jeffw said:
Its had a lot of money spent on it.
Currently I have a set of double adjustable Protech shocks that I'm fitting, then the indycar anti-roll bar needs to go on. I've got to make a new splitter and sort the rear diffuser. Then figure out why the traction control system isn't playing. After that I need to buy some pneumatic bits so I can get my Xoomspeed paddleshift system working.
Then over the winter I probable need to change the flywheel from 215mm to 184mm with a two-plate clutch (lower interia) and get a roll-cage fitted for MSA regs
So....no, not finished just yet !
I was hankering after a Radical SR8 so if someone made me an offer which was in the mid-£20Ks I'd probable sell it, otherwise it gets upgraded every year
Just watched you on youtube go round Combe at the Dick Mayo sprint. I missed going to that. You were quick!! I am there on Monday at my 1st ever track day. Will be taking it a bit easier than you did!Currently I have a set of double adjustable Protech shocks that I'm fitting, then the indycar anti-roll bar needs to go on. I've got to make a new splitter and sort the rear diffuser. Then figure out why the traction control system isn't playing. After that I need to buy some pneumatic bits so I can get my Xoomspeed paddleshift system working.
Then over the winter I probable need to change the flywheel from 215mm to 184mm with a two-plate clutch (lower interia) and get a roll-cage fitted for MSA regs
So....no, not finished just yet !
I was hankering after a Radical SR8 so if someone made me an offer which was in the mid-£20Ks I'd probable sell it, otherwise it gets upgraded every year
Edited by jeffw on Thursday 13th August 06:36
mikeveal said:
Damned if I fully understand fully it. Counter intuitive it really is, but the maths does stack up.
Wider tyres have a different shape as well as a different size of contact patch.
Depending on the tyre pressure and the rigidity of the tyre structure, tyre width may not dominate the size of the contact patch. Eg a highly inflated stiff wide tyre may have a smaller contact patch than a lightly inflated floppy narrow one.
Clearly there will be less wear with a wider tyre. Given the same rigidity and inflation (as a narrower tyre), you will get a larger contact patch with less weight/area.
You'd also expect a larger contact patch to deal better with a loose surface, by averaging out the grip across the entire surface patch.
Probably there's a bunch of complicated stuff related to the shape of the patch and cornering slip angles too.
Some answers here:
http://physics.stackexchange.com/questions/29903/w...
Physics - I should have paid more attention at school!!!Wider tyres have a different shape as well as a different size of contact patch.
Depending on the tyre pressure and the rigidity of the tyre structure, tyre width may not dominate the size of the contact patch. Eg a highly inflated stiff wide tyre may have a smaller contact patch than a lightly inflated floppy narrow one.
Clearly there will be less wear with a wider tyre. Given the same rigidity and inflation (as a narrower tyre), you will get a larger contact patch with less weight/area.
You'd also expect a larger contact patch to deal better with a loose surface, by averaging out the grip across the entire surface patch.
Probably there's a bunch of complicated stuff related to the shape of the patch and cornering slip angles too.
Some answers here:
http://physics.stackexchange.com/questions/29903/w...
It's not quite linear with tyres, so less lightly loaded tyres (or bigger tyres on the same size car) do give a little more grip - and with less load you can run softer compounds for the same milage etc.
However, 0-60 times are dominated by weight bias (rear engined Beetles are very quick to 20-30mph until they run out of ponies...) and weight transfer (so short wheelbase or high CoG helps).
So bikes are very quick off the mark, but also very tricky to get it to just hover the front wheel without lifting it right up or spinning up the rear first - so they need a good rider to launch a bike perfectly compared to a car, get a good launch and most quick modern bikes will be around 2.5s to 60.
You see things like rwd autograss buggies - where the start is everything - will be rear engine with short wheelbases - they will also wheelie off the line on occasion - if you lift the front all the weight is on the rear tyres after all, so you've as much traction as you would have if they were 4wd (discount above tyre effects and suspension geo differences, etc).
Our buggy has quite a rearward weight distribution, and even with the old engine, it would hit 60mph in 5 seconds, which is quick for most road cars. And it would do it on gravel. With Mud + Snow tyres on.
TL:DR - Weight distribution and transfer is more important than outright power/weight at the levels that are normal these days.
It's also why I have a good laugh when people buy a BMW and then buy into the marketing bull***t about the 50:50 weight distribution being 'perfect'
However, 0-60 times are dominated by weight bias (rear engined Beetles are very quick to 20-30mph until they run out of ponies...) and weight transfer (so short wheelbase or high CoG helps).
So bikes are very quick off the mark, but also very tricky to get it to just hover the front wheel without lifting it right up or spinning up the rear first - so they need a good rider to launch a bike perfectly compared to a car, get a good launch and most quick modern bikes will be around 2.5s to 60.
You see things like rwd autograss buggies - where the start is everything - will be rear engine with short wheelbases - they will also wheelie off the line on occasion - if you lift the front all the weight is on the rear tyres after all, so you've as much traction as you would have if they were 4wd (discount above tyre effects and suspension geo differences, etc).
Our buggy has quite a rearward weight distribution, and even with the old engine, it would hit 60mph in 5 seconds, which is quick for most road cars. And it would do it on gravel. With Mud + Snow tyres on.
TL:DR - Weight distribution and transfer is more important than outright power/weight at the levels that are normal these days.
It's also why I have a good laugh when people buy a BMW and then buy into the marketing bull***t about the 50:50 weight distribution being 'perfect'
Edited by PhillipM on Friday 14th August 14:09
The main problem with 0-60 times is the ability to deliver a consistent time. I've had some very fast cars and I have never, ever, done a brutal 0-60mph launch.
Its also rather irrelevant as the main use for high acceleration is overtaking.
In this regard a 50 - 100 time might be more appropriate, or if you're on track you may need enough power to push towards 130mph. In my experience most super fast, super light kit cars that give stratospheric 0-60 times simply don't have the Kahuna's to push much past 110mph. As areo dynamic drag increases exponentially the amount of power required to give good acceleration past 100mph is quite significant and the weight of the vehicle starts to become irrelevant.
Its also rather irrelevant as the main use for high acceleration is overtaking.
In this regard a 50 - 100 time might be more appropriate, or if you're on track you may need enough power to push towards 130mph. In my experience most super fast, super light kit cars that give stratospheric 0-60 times simply don't have the Kahuna's to push much past 110mph. As areo dynamic drag increases exponentially the amount of power required to give good acceleration past 100mph is quite significant and the weight of the vehicle starts to become irrelevant.
Crippo said:
The main problem with 0-60 times is the ability to deliver a consistent time. I've had some very fast cars and I have never, ever, done a brutal 0-60mph launch.
Its also rather irrelevant as the main use for high acceleration is overtaking.
In this regard a 50 - 100 time might be more appropriate, or if you're on track you may need enough power to push towards 130mph. In my experience most super fast, super light kit cars that give stratospheric 0-60 times simply don't have the Kahuna's to push much past 110mph. As areo dynamic drag increases exponentially the amount of power required to give good acceleration past 100mph is quite significant and the weight of the vehicle starts to become irrelevant.
I was thinking the exact same thing Crispin. How many times if ever do you do a 0 to 60 in the real world? Never most likely! On the road and for defo on track a fast 40 to 80 or 50 to 120 is far more useful to have I'd say? I'm hoping the better aerodynamics of a Fury will come in handy against all the 7s on my track day!!Its also rather irrelevant as the main use for high acceleration is overtaking.
In this regard a 50 - 100 time might be more appropriate, or if you're on track you may need enough power to push towards 130mph. In my experience most super fast, super light kit cars that give stratospheric 0-60 times simply don't have the Kahuna's to push much past 110mph. As areo dynamic drag increases exponentially the amount of power required to give good acceleration past 100mph is quite significant and the weight of the vehicle starts to become irrelevant.
0-60 in a 500ish kilo car with not traction control and good power will always be a bit hit and miss anyway. Much harder to nail a perfect run than in say an M3 or Evo. Its true lots of nonsense is spouted . When I first built my Furyblade back in 2002 times of 3.5 0-60 were banded about, but I doubt it was anywhere near that . I seem to remember some of the Fireblade RGB guys doing some datalogging runs , and I think one did a 3.9. But lets put it into perspective, that was will an £800 engine from a crashed bike and 125 bhp. Quite amazing for the time.
At the Brighton Speed Trails in 2012 my Phoenix ( similar to Jeffs ) with just a 140bhp R1 engine did a 13.2 1/4 mile which I was initially dissapointed with. Until I saw a fully lit Ferrari F40 only managing 13.5 repeatedly.
Production saloon cars are so fast nowdays, and can be cheap, so to the uninformed kit cars are not that fast anymore.
But for me it will always be " It's not how fast you go, but HOW you go fast "
At the Brighton Speed Trails in 2012 my Phoenix ( similar to Jeffs ) with just a 140bhp R1 engine did a 13.2 1/4 mile which I was initially dissapointed with. Until I saw a fully lit Ferrari F40 only managing 13.5 repeatedly.
Production saloon cars are so fast nowdays, and can be cheap, so to the uninformed kit cars are not that fast anymore.
But for me it will always be " It's not how fast you go, but HOW you go fast "
IMO 0-60 times are irrelevant, standing 1/4 mile is much more relevant, If you've ever done a run what u brung event at a drag strip, you'll see this demonstrated, after a 1/4 mile all hot hatches are 100-200 metres behind your average KC after just 13 seconds or so, at least they are compared to my [155bhp] 7 HAHA.
Isn't it interesting that, by and large, people with good 0-60 times like the idea but those that don't. don't. Same applies with the 'you'll never be able to use that much power on the road" brigade whose firm belief is that low power cars are best.
0-100 is a better indication of performance (as is 1/4 mile) as it does away with some of the vagaries of launching a car....but 0-60 is a common benchmark so people will use 'ideal' numbers to show how quick their particular car is.
0-100 is a better indication of performance (as is 1/4 mile) as it does away with some of the vagaries of launching a car....but 0-60 is a common benchmark so people will use 'ideal' numbers to show how quick their particular car is.
jeffw said:
Isn't it interesting that, by and large, people with good 0-60 times like the idea but those that don't... Make one up.
Fixed that for you, Jeff.I've no idea what mine does 0-60 ad no real interest (and too much mechanical sympathy) to find out. It's got 170bhp at the wheels (or 190bhp/125Nm at engine) and weighs in around 550kg with me in it (less if I strip everything out and run the fuel down), revs to 14000, and will hit 72mph in first, which should put it in the 4-4.5 second bracket... So if I'm asked, that's what I say but I don't shout about it.
Gassing Station | Kit Cars | Top of Page | What's New | My Stuff