Strange tyre story ?

Andy C

Always controversial. Obviously you get shorter braking distance if new tyres gets on the front, but with a slight risk of car spinning back to front if the rear tyres are that bad. If the rear tyres aren't that bad, then I would put the new tyres on front to even out the wear. Then chances are that you could make a discount deal next time for replacing all four.

I suspect there is a bit of tyre industry interest in the "new tyres on the back", statement, since it shortens the time period when the customer needs new tyres and thereby reduces the chances that the customer could get a discount deal on all four. Hence it evens out the tyre business.

Depends what you mean by common sense. If you'd ever been in a situation where the rear wheels locked before the fronts when braking hard, you'd realise the need for the best grip to be on the back.

That's fairly common, especially on cars without ABS, purely because of the weight transfer onto the front end.

I won't go over the details again, but the only serious accident I had was when the back end broke away on my Cavalier and fishtailed until it hit and demolished a stone wall.

This was within a week or two of fitting new tyres on the front, and I admit I did back off instead of powering through it, but at 55-60mph that was VERY counter-intuitive!

Not on any car I've ever owned. Even the original Mini on drum brakes had a pressure restricting valve to the rear brakes.

If you have snow chains on only one end of the car, they have to go on the back[1]. If you have two radials and two cross plies[2], the radials have to go on the back. If you have two new and two old tyres, the new tyres should be on the back. All of these are for the same reason, which is to help keep the car in a straight line when braking.

Steve

[1] Yes, even if it's FWD. [2] I know, a rare beast nowadays the crossply, but presumably the law still applies.

No. The reason crossplies have to go on the front is they develop much higher slip angles when cornering than radials. That means they would produce oversteer if fitted at the back which would make the car unstable during cornering and prone to having the back end step out. It has nothing to do with braking.

You can replicate the situation of crossplies on the rear if you pump the front tyres up very high and let some air out of the back ones. Try 40 psi in the front and 20 psi in the rear. Then go for a drive and see what happens. The car will feel like it wants to point further into a corner than you want it to and the back end wants to step out all the time. As you try to turn into a corner the car moves further in than you want and you have to wind some lock off and it all gets very twitchy. If you push it the car will head off the road backwards. It will however brake in a straight line perfectly normally.

As to the snow chains those go on the back so if the vehicle skids either during braking or cornering it skids from the front end not the rear and doesn't swap ends. Basically the same reason why the better gripping tyres go on the rear.

The purpose of snow chains is to provide traction under arduous conditions. Fitting them to the rear only of a FWD car might be safe but rather pointless. ;-)

Many years ago before the rule about radials going on the back if a mix is fitted, a pal had a MkII Ford Zephyr. That seemed to handle much better with radials on the front, good quality cross plies on the back. Even in the wet. Not that I'd recommend anyone trying it these days. ;-)

Way back when, our company hack in NL was a VW Variant estate. Horrible bloody thing. Rear engine, RWD, front end felt like it was made of rubber bands and watch springs. Studded tyres fitted on the rear because the roads were covered in ice and hard-packed snow gave plenty of traction, but you could scarcely make it turn.

Having the weight over the driven wheels definitely gives the best traction, with a 2 wheel drive. And since you're most likely to need that on a hill, a rear engine RWD will be best. Or reverse up it with a FWD. But that is only to get it moving. Steering and stopping a different matter.

We appear to agree on 2 out of 3 here. I can live with differing on .

Steve

My second car was a 1966, 6 volt one of those. I'd have another anytime. Brilliant car for it's day. I never drove it on snow mind.

Steve

On 1. On 1. Duh.

in garage told me the when they replace front tyres, they swap them with the rear tyres as standard practice so the newest tyres are on the rear.

I'm curious, is there any truth in what he was saying ? The garage certainly had Michelin posters explaining this policy but it seems to go against common sense ?

I was looking through the Volvo handbook out the wife`s car for something tonight and noticed in the tyre section a box headed IMPORTANT. It stated "Tyres with the greatest tread depth should always - irrespective of rear or front wheel drive - be fitted at the rear"

Is that a UK law?

My VW Transporter (FWD) instruction manual states:

"Snow chains may only be fitted on the front wheels - even on the syncro." [4WD model]

John

Common sense should always be questioned, because sometimes it'll lead you astray.

Here's a video explaining why the good rubber should go on the rear:

It's one of those lowest-common-denominator things. Many experienced drivers can handle oversteer competently. But your average driver will likely make a nasty mess of it. Because my wife and daughter also drive my car, the new tyres go on the rear.

John

And that *ought* to be an end to the matter. What's the betting it isn't though? ;-)

Tim