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No Spare - No Chance !
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rcshott
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PostPosted: Tue Jul 22, 2008 6:45 pm    Post subject: Reply with quote

Dunk wrote:
The difference is tyre widths, front to rear, is to alter the handling characteristics and feel on turn in.

There's also a mild aerodynamic benefit of having narrower tyres up front.

Yes Dunk I know skinny tyes 'assist' turn in...but this is a TRACK thing.

General town/country driving wouldn't make ANY difference. Plus, with same size tyres, I can readily change front to rear for longevity of tyres. Directional or not! Would you drive on the M1 on a spare 'Skinny' with confidence???

C'mon, though Dunk...what possible advantage of aerodynimics could be gained whilst driving a 'block-of-flats' around town (or even normal highway driving), Please tell me I'm dreaming!!!
Ok, ok skinny tyres are cheaper to buy....but not by much!

Unrelated, but same principal;
Look at Aussie Rugby League players, Most have body tatoos which appear New Zealand infulenced. Nothing to do with football!!!

Ditto skinny front tyres!!!

C'mon, someone, give me an intelligent/valid argument. ANYONE?
Jim
P.S. Don't be frrighened to abuse/refute me...I've a tough skin. So go for it...
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Charles
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PostPosted: Tue Jul 22, 2008 7:43 pm    Post subject: Reply with quote

rcshott wrote:
P.S. Don't be frrighened to abuse/refute me...I've a tough skin. So go for it...


Ah! but is it adorned with Maori tattoos?

We need to know, Jim, so that we understand whether we are dealing with an Aussie Rules, Rugby League or Rugby Union type?

Seriously though, I would suggest that the starting point is at the back end. The amount of power to be delivered will define the size of rear tyre/wheel. Then it comes to the front and whilst you could run the big fat tyres at the front (to allow for interchangeability), they would need to beef up the steering and power assistance to accomodate this - thereby adding cost.

From a handling perspective, particularly in terms of driver confidence and accuracy of turn-in, it is better to have narrower front tyres. If you are unsure of this then take a look at modern F1 cars. Also, it is cheaper to fit these and then run them - so cost will be a factor here. You may also find that the basic car upon which the more powerful variant is based has been designed to allow wider rears to fit but wider fronts will foul the wheelarch etc.

All in all, the wider rear/narrower front set-up is a result of cost, engineering integrity and desired handling/feel - but not necessarily in that order. Sure, it compromises the ability to swap wheels/tyres around between front and rear but then, if you fit uni-directional tyres you can't swap side to side anyway (without removing the tyre and refitting it - and as pointed out earlier by you).

It is also a pain when it comes to providing a suitable spare - but in these days of emissions control, the reason why new cars have run flat tyres or repair kits is because the cars are designed without a spare to save weight and reduced weight = reduced emissions.

So, at the end of the day, I would suggest blaming the Government - which is just up your street Jim Very Happy

HTH

Charles

BTW this is coming from a seasoned Rugby Union man without any body art Wink
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Renault Grand Espace - not mine but the wife's!
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Dunk
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PostPosted: Tue Jul 22, 2008 7:59 pm    Post subject: Reply with quote

Jim

I gave you a sensible argument!

If you want the same size tyre front and rear then you're free to do so - but you'll need to change the toe and camber to maintain the best balance on the road.

As for aerodynamic advantage - reciprocating mass plays havoc with aerodynamics, so the narrower you can make it (within reason), the better it is. This is effective from around 60mph upwards - you'll never notice it in outright acceleration, but the Cd will be increased, and you'll have higher fuel consumption.

As an extreme example, look at the late '80s Grp C Endurance Racers which were effectively unregulated aerodynamically - the rear wheels were often faired in, and both ends has huge deflectors and/or venturi underneath on the ground effect to try to keep the airstream away from them.

There's also a brake cooling element to consider - the wider the fronts, the harder it is to dissipate the heat generated within their circumference, although given BMWs prospensity to fit woefully inadequate brakes to things, I doubt this ever crosses their minds.

As for Rugby, well, like Charles I'm a Union man - so I've not the foggiest idea who or what you're talking about there.
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rcshott
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PostPosted: Tue Jul 22, 2008 8:48 pm    Post subject: Reply with quote

CHARLES. TO SET THE RECORD STRAIGHT...
I'M AUSSIE THROUGH 'N THROUGH (APART FROM MY FRENCH DECENT). DON'T LAUGH. MY GR,GR,GR,GRATE UNCLE IS IN THE ENCYCLEPEDA BRITINICA. SO WHERE'S YOURS? HEHEHEHE

LEAGUE, UNION, SOCCER...(IN THAT ORDER) AUSSIE WHAT? THAT CRAPPY GAME WHERE THEY KICK THE BALL TO THE OPPOSITION? I'D LOVE TO SAY MORE BUT POLITICAL CORRECTNESS FORBIDS ME! Bugga!
Kiwi's don't play "football" anyway...they just beat the shit out of the opposition...until a coupla weeks ago when they 'got done' by South Africa at Union...

TATTOOS;
WHO KNOWS WHAT THEY MEAN. JUST SEEMS TO BE THE CURRENT 'FAD'. WE HAVE ALMOST 50% OF LEAGUE PLAYERS FROM NZ (& surrounding islands), BUT THEY CAN NOT JOIN THE "STATE OF ORIGIN", QUEENSLAND V's NEW SOUTH WALES LEAGUE COMP. UNLESS THEIR VERY FIRST GAME WAS AT A PARTICULAR AUSSIE CLUB. BIT OF A JOKE REALLY...IF YOUR SON NEVER PLAYED LEAGUE UNTIL HE CAME HERE, HE WOULD BE ELIGIBLE TO PLAY FOR THE STATE HE FIRST PLAYED IN...AT ANY LEVEL...?

Tyres/power etc, yep I agree with most of what you say. But I make the point again, "For normal driving I think it's plain silly to have different sized tyres. Apart from us "petrol heads", who would know the difference in performance? And I say again, what does it do for "normal, average driving", town OR ccountry? I've tried both...no appeciable difference really.
IMO more negs than pos's. Jim
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Charles
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PostPosted: Tue Jul 22, 2008 11:52 pm    Post subject: Reply with quote

rcshott wrote:
MY GR,GR,GR,GRATE UNCLE IS IN THE ENCYCLEPEDA BRITINICA. SO WHERE'S YOURS? HEHEHEHE


About 6 feet under Wink
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Charles
Teacher of Chemistry and driver of ALPINAs - not necessarily in that order Wink
B3S Touring (49/116) - been to the moon and now on the way back!
Renault Grand Espace - not mine but the wife's!
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rcshott
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PostPosted: Wed Jul 23, 2008 8:38 am    Post subject: Reply with quote

Dunk wrote:
Jim I gave you a sensible argument!


Ok Dunk, points taken & mostly accepted.
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