swapping front tyres for back - why not

[telford_mike]

Bought some nice Yokohama A048R tyres for my last trackday, at great expense to the management I might add. Fronts were totally knackered after half a day, but rears are as new. Ive been told that swapping them round is a bad idea. But why?

 

[Pete]

The theory is you want more grip at the back than the front.

 

[telford_mike]

I want less grip at the back - oversteer is good in a FWD car on the track!

 

[Mike@Rentech]

Back end on a FWD car needs as much grip as possible, the rear is lighter and is more likely to lose traction than the front due to the weight of the engine/transmission.

Something like that anyway.

 

[telford_mike]

Still not convinced. Love that dial-in oversteer that you get by dabbing the brakes when youve gone into a corner a bit too hot.

 

[Pete]

Quote: Originally posted by telford_mike on 27 July 2004

I want less grip at the back - oversteer is good in a FWD car on the track!

Then do it and swap the tyres, itll only be for one track day then the fronts will match again! lol

 

[telford_mike]

True - after one more trackday theyll all be knackered!

 

[JAY172]

on oversteer skid is harder to contol than an understeer skid. so if anything you want the front to give first as its easier to control it than if the back gives way. mike172sport has got a good point also.

 

[telford_mike]

Hmmm yeah - were talking trackdays here remember - I dont use these things on the road (well not often anyway lol). On the road understeer is loads safer, but on trackdays I like to be able to whizz the back around, even if it means I have to catch it with a little opposite lock.

Understeer is much safer on the road, but on the track if you have a chance to provoke some oversteer youve at least got a chance of getting the car pointing in the right direction before putting your foot down for the next straight.

 

[JAY172]

i suppose then you want plenty of grip on the front so you can power out of oversteer if needed.

 

[telford_mike]

OK Im going to try worn rears and nice new fronts at Spa. If I die, Ill blame you lot

 

[CocoPops]

Quote: Originally posted by telford_mike on 27 July 2004
True - after one more trackday theyll all be knackered!


Exactly, normally the fronts wear 4/5 times quicker than the rear.
So most replace only the fronts, otherwise youll need to replace all four instead of just the worn fronts.

 

[Mark@Ritchspeed]

Telford Mike is right in wanting more grip at the front . Oversteer is far easier to control than understeer as you simply dont have many options when a car is understeering , if its oversteering their is plenty you can do . A fwd car needs a bit of slip at the rear for it to tuen in properly .

 

[MarkCup]

Quote: Originally posted by Mark@Ritchspeed on 27 July 2004

Telford Mike is right in wanting more grip at the front . Oversteer is far easier to control than understeer as you simply dont have many options when a car is understeering , if its oversteering their is plenty you can do . A fwd car needs a bit of slip at the rear for it to tuen in properly .

Exactly!!!

Ive been swapping fronts to rears and vice versa on front wheel drive cars to even out tyre wear all my life...never had a problem.

Loads of grip at the rear normally translates to no bite when you turn in, and I like my cars to go where I point them, not push wide and slap my wrist! Youve always got throttle and steering should the back end get a little frisky

 

[Tom]

if you do swap make sure you swap the fronts round when they are on the back

 

[telford_mike]

^^^ sorry Tom explain that a bit more?

 

[MarkCup]

Quote: Originally posted by telford_mike on 27 July 2004

^^^ sorry Tom explain that a bit more?

I think hes referring to tyres that either have to have a particular side facing outwards, or, that have to rotate in a particular direction.

If you had directional tyres, and were swapping them diagonally (which is the best way to even out tyre wear), then youd need to have all the tyres turned on the rims.

 

[Tom]

I just heard you need to do it like this.

No idea why

http://erc.qmuc.ac.uk/cliosport/gallery/full/1090919979__rubbishdraw.jpg

 

[telford_mike]

Only option without having the tyres refitted is left-front becomes left-rear, right-front becomes right-rear. Would be great to swap diagonally though, as most circuits are clockwise so mostly right-hand corners.

 

[RobFenn]

Oversteer is safer and more fun. Do it. Normal road tyres would be better than track focused tyres though.

-Rob

 

[JAF 182]

I was told to only change the fronts and rears on the same side and not diagonally. Apparently the braking forces affect the structure of the tyre and its not a good idea to reverse rotation as the braking forces are also reversed.

 

[MarkCup]

Quote: Originally posted by JAF 182 on 27 July 2004

I was told to only change the fronts and rears on the same side and not diagonally. Apparently the braking forces affect the structure of the tyre and its not a good idea to reverse rotation as the braking forces are also reversed.

I heard that too (but was never fussed about it on my previous non-performance cars). At the Festival of Speed recently I spoke with the technical bods on both the Toyo and Avon stands regarding track tyres and so on. When asked about turning tyres on the rim, or swapping sides so as to reverse the direction, they both gave the exact same response...there maybe a minimal change in "feel", but structurally, there was no reason either could give as to why you shouldnt do it.

 

[telford_mike]

Nice one. Another urban myth blown apart

 

[JAF 182]

Ok that ones blown away! So it all appears marketing bollox - which fits with my intuition. So you can use the tyres any way you want as the limit on forces is the grip between tyre and track and the tyre doesnt know if its accelerating/braking/turning left/right...

 

[MarkCup]

Quote: Originally posted by JAF 182 on 27 July 2004

...So you can use the tyres any way you want as the limit on forces is the grip between tyre and track and the tyre doesnt know if its accelerating/braking/turning left/right...

I guess so, providing of course that theyre turning in the direction they should be, or, the outside of the tyre is where it should be.

 

[Jim172CUP]

Its more to so with breaking in the wet, more grip on the back means less arse end overtaking the front end action.

 

[qwerty]

Dont confuse depth of tread with grip.

In the dry, usually the less depth of tread then the greater the grip.

The opposite when its wet.



Maybe you just need competition front tyres for your track day (leave the rears as standard)?

 

[davyboy]

So in half a days track time you ruined a set of road legal slicks?

How?

Even in my 1400kg Porsche I have got 50 laps of the ring and 6 trackdays and they are still legal.....just!

 

[mark266]

Quote: Originally posted by Tomclio182 on 27 July 2004


I just heard you need to do it like this.

No idea why

http://erc.qmuc.ac.uk/cliosport/gallery/full/1090919979__rubbishdraw.jpg





this is exactly what ive always done tom, ive never had any probs either.

 

[telford_mike]

Quote: Originally posted by davyboy on 28 July 2004


So in half a days track time you ruined a set of road legal slicks?

How?

Even in my 1400kg Porsche I have got 50 laps of the ring and 6 trackdays and they are still legal.....just!

Yup, depends on the track I guess. I like to play about with the car if the track is suitable, and I dont mind taking a few risks. I would never do anything like that at the Nurburgring! With smooth cornering theyd last a lot longer, but I like to explore the limits if its safe to do so.

Tyres are medium compund.

 

[RobFenn]

Quote: Originally posted by qwerty on 28 July 2004


Maybe you just need competition front tyres for your track day (leave the rears as standard)?

Structure of the tyres are completely different, and normally the aspect ratio too. I certainly wouldnt do that.

-Rob

 

[1fast6]

Quote: Originally posted by Tomclio182 on 27 July 2004


I just heard you need to do it like this.

No idea why

http://erc.qmuc.ac.uk/cliosport/gallery/full/1090919979__rubbishdraw.jpg

I dont quite understand why this is required. you certainly cant do it if you have directional tyres as the pattern would be facing the wrong direction.

apart from the tread pattern facing a different way i cant really cant see what swapping the sides would do or what advantages there may be.

 

[MarkCup]

Quote: Originally posted by 1fast6 on 28 July 2004

Quote: Originally posted by Tomclio182 on 27 July 2004


I just heard you need to do it like this.

No idea why

http://erc.qmuc.ac.uk/cliosport/gallery/full/1090919979__rubbishdraw.jpg

I dont quite understand why this is required. you certainly cant do it if you have directional tyres as the pattern would be facing the wrong direction.

apart from the tread pattern facing a different way i cant really cant see what swapping the sides would do or what advantages there may be.

It evens out the tyre wear...as Mike said above...circuits tend to go primarily in one direction, meaning normally, wear is higher on one particular side of the car.

Also, when out on the road, if you like to push your car a bit, and your daily route involves a few roundabouts, then youll often find the front left wearing much quicker than the rest. Swapping them around means you can get them to wear so they all come up for replacement at the same time.

 

[edde]

Ive not read anything anyone posted but whatever you do dont ever ever have low grip tyres at the back you need the best tyres at the back .

It cost me about a grand to learn this DONT make my mistake.

A magazine a while back did a test and proved that the best performer next to having new tyres all round was to have the best ones on the back.

PLEASE learn from other (my) mistakes

 

[qwerty]

edde, of course you should not choose tyres with less grip should others with more grip be available but, given a only 1 set of 4 and 2 have less grip, then for safety for average drivers you may be right.

But for experienced drivers wanting the best lap time then the best tyres should go on the driven wheels.

But since most cars are front wheel drive and all drivers claim to be above average and wanting the best lap time, then they should actually go on the front!

 

[edde]

Quote: Originally posted by qwerty on 01 August 2004

But for experienced drivers wanting the best lap time then the best tyres should go on the driven wheels.
But since most cars are front wheel drive and all drivers claim to be above average and wanting the best lap time, then they should actually go on the front!

Your probably right but I didnt know you were on about track driving which is very different from more normal driving. (your more awake for starters)