With apologies if this has been covered loads, can someone explain to me why, when replacing 2 out of 4 tyres, the new ones should go on the back?
It seems to me (as a complete non-expert) that the new ones should go on the front: better grip under braking, more tread to clear water in the rain and clear a path for the rears, and if you rotate them at half-life, then probably more even wear. Plus aren´t the rear brakes only used during extreme braking?
Let me just say I´m not advocating this, I was just wondering if anyone had an explanation as to why the opposite would be recommended.
TIA for any enlightenment.
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Good tyres on the back, poorer on the front: car tends to understeer. Corrected by lifting off, and usually caught by most drivers.
Good tyres on the front, poorer on the back: car tends to oversteer. Worsened by lifting off, often snaps round, usually not caught by most drivers.
Of course, it's a pretty fine dividing line, and if you're that close to the limit, you deserve to be going through the hedge backwards..... personally I fit the good tyres to the front of FWD car for best traction.
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RichardW
Is it illogical? It must be Citroen....
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I would tend to agree with RichardW (for FWD or course).
Also, tyres on the front tend to wear quicker. If you leave the old ones on the back you will be keeping the old tyres at the back where you need them the most (see above) and it will be a long time until tread has worn away sufficiently to warrant replacement :(
Put the old ones on the front, wear them out and buy 2 more new ones later when the rear tyres are still newish. That way you will be able to balance the age (and condition) of the tyres front and back better :)
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As far as I'm aware it's been 'best on the front' for donkey's years, but now it's all changed.
I still feel happier with my newer tyres on the the front and had a couple fitted a week or so ago.
Clk Sec
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Buy 2 tyres at Costco & they wont fit them to the front. There is a letter to view quoting the body that recommends this (cant remember who) & there is no getout. Think the reasoning is something about mould release fluids present on a new tyre so its better for these to be removed during initial use on the back rather than the front.
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tinyurl.com/3ah5ns
from TyreSafe - the Tyre Industry Council
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.....Put the old ones on the front, wear them out and buy 2 more new ones later when the rear tyres are still newish. That way you will be able to balance the age (and condition) of the tyres front and back better :)
Hadn´t thought of that!
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Buy 2 tyres at Costco & they wont fit them to the front.
I'd hope they would for some of us, as my front tyres won't fit the back wheel.
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>>>I'd hope they would for some of us, as my front tyres won't fit the back wheel.
That's no excuse, Michael!
Clk Sec
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Plus aren´t the rear brakes only used during extreme braking?
Rear brakes operate at the same time as the front brakes. In a car the degree of braking on the rear is designed to be less than on the front to take into account a lower axle loading and weight transferance from rear to front when actually braking, but that is all.
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L\'escargot.
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I've always "known" that it was best tyres on the rear because that's safest for most drivers - for reasons already given. I'm certainly not aware of that advice ever changing.
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The old style Top Gear did a feature on this some years ago, and proved it in practice, using FWD and RWD test cars.
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Costco are guided by what Michelin say (all their fitters are trained by Michelin):
www.michelin.co.uk/uk/auto/auto_cons_bib_pqr_neuf....p
The reasons make no difference whether the car is front or wheel drive.
My Merc has different size front and rear tyres and they said they wouldn't replace the fronts on their own unless the rears were nearly new.
I do have an issue with rigidily applying this policy as it doesn't make sense if the new tyres are less grippy than the originals. I wanted to replace the original fronts on Mrs BP's Jazz - they're Yokohama Aspec's with a treadwear rating of 200. Costco's Michelin Energy has a treadwear of 400.
Treadwear rating indicates the expected mileage from the tyre, but is also a good indicator of how grippy a tyre is - lower the better. Therefore Costco have fitted the new, less grippy tyres to the rear and put the grippier ones (still on 6mm according to service sheet yesterday) on the front.
Of course I just swapped them around when I got home.
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I've had new tyres on the front and back before, and personally not found it made a jot of difference. Possibly if you were pushing the tyres to the limit it'd affect which end of the car let go of the road first, but for normal day-to-day 30mph driving does it really matter?! I tend to have new tyres put on the front, but if someone wanted to put them on the rear that's up to them.
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normal day-to-day 30mph driving does it really matter?!
It's kind of hard to predict exactly when you might have to swerve or emergency stop suddenly. Any guidance on making your car as safe as possible is surely aimed at the 1 time in 100 when the extraordinary does crop up.
I could use your argument about wearing a seatbelt. Fair enough, it'll stop me going through the windscreen, but for everyday not-crashing-into-anything driving, do I really need to wear it?
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> but for everyday not-crashing-into-anything driving,
This is an unknown concept for me.
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< Ex RF, Ex TVM >
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It's kind of hard to predict exactly when you might have to swerve or emergency stop suddenly. Any guidance on making your car as safe as possible is surely aimed at the 1 time in 100 when the extraordinary does crop up.
I've only lost the back end of my car once, exiting a roundabout. The tyres had all been fitted at the same time, so the rears will have been in better condition (in theory at least). Having more tread on the rears doesn't make the car immune from skidding. Putting new tyres on the front can't be seriously compared to intentionally not wearing a seatbelt.
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The treadwear indicator only indicates the expected mileage BUT isn't comparable between manufacturers - it won't let you compare grip.
The traction indicator might let you compare grip but since all half-decent tyres are rated "A" that doesn't in practice.
There is actually one exception to the "new on rear" advice - 4wd vehicles should have their tyres moved front-back to even wear out and then be replaced in a set of 4. Even marginal differences in rolling radius can wreak havoc with some centre differentials - despite copying with vary speed being one of the reasons for fitting a differential in the first place!
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despite coping with varying speed being one of the reasons for fitting a differential in the first place!
That's what it should have said!
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The treadwear indicator only indicates the expected mileage BUT isn't comparable between manufacturers - it won't let you compare grip.
I recognised that in my post, but there's likely to be some correlation (between wear and grip).
www.honestjohn.co.uk/motoring_answers/index.htm?id...8
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I recognised that in my post, but there's likely to be some correlation (between wear and grip).<<
According to a leading tyre manufacturer's T.V advert, (Michelin) thier tyres are allegedly supposed to "perform from the first mile to the last". This seems to be saying to me that a (M) tyre with 1.6mm tread left is as good as a new one with 10mm tread, the only difference between the tread depth and Grip is tyre lifespan.
Billy
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>>>This seems to be saying to me that a (M) tyre with 1.6mm tread left is as good as a new one with 10mm tread, the only difference between the tread depth and Grip is tyre lifespan.
I would take a lot of convincing. My tyres are replaced long before they get to the legal minimum.
Clk Sec
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The touran fronts went down to betweem 1.6mm and 2mm. There was never a hint of aquaplaning or understeer or lack of grip even during the recent monsoons. I drove it quite hard too, not on the limit true but near enough at times.
When the fronts were changed and were now at 10mm, and the rears were at 4-5 mm it felt just the same as it had before, no issues no problem.
In my experience and circumstances front or rear its a non event.
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< Ex RF, Ex TVM >
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I'd have thought it was fairly obvious the reason why :
Front axle usually carries more weight than the rear, so when going through water the rears are more likely to aquaplane as there's less weight cutting through the water. Hence you want as much tread as possible on the back to reduce the risk.
This has been common knowledge for donkeys years.
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>This has been common knowledge for donkeys
Interesting. Don't you normally replace all four at once on donkeys?
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rears are more likely to aquaplane as there's less weight cutting through the water. Hence
Don't the front tyres push the water out of the way so there isn't much water in front of the rear tyres?
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L\'escargot.
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That might be true going in a straight line but probably not when cornering or going round a bend which is when you really don't want to loose traction.
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New tyres on front.
I'd much rather go through a hedge backwards, I don't want to see what I'm going to hit ;>)
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Wouldn't normally drive at the "limit", whatever that is, but I remember going into a corner too fast in the wet, on twisting B road from Buxton and rear tried to come around. Looked at tyres later: not too worn at rear, but I'd put the best ones on the front. So, swapped around by ATS, who confirmed the advice given to reserve the new ones for the back.
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That might be true going in a straight line but probably not when cornering
Don't rear wheels by and large follow the same path as the front unless you're going round a really tight turn? And in that case you're not going to be travelling fast enough to aquaplane.
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L\'escargot.
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Don't rear wheels by and large follow the same path as the front
The rear wheels NEVER follow the same path as the front unless you are going in a perfectly straight line or you are a train on tracks.
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< Ex RF, Ex TVM >
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I'll accept the idea, of new to the front, BUT...
On Mrs V's Mx5, I switched front to rear at 18k & replaced the set, at 33k, withmore or less an even 4mm tread left.
The originals were Bridgestones & now she gets the extra grippy Toyos - wonder how long they'll last!
&, as I've mentioned before, THE correct method, would be for each tyre, to remain in the precise position it strted from. That way it'll wear to the tollernces of each axle/hub.
VB
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My understanding for putting new tyres on the rear was that the new tyre was unlikely to fail. The older tyre was put on the front so that in the event of failure you had some input so that you could control it. Personally have never had a blow out so don't no what the impact is, but SWMBO had a rear whell blow out in the Z3 in roadworks on the M1 and only found out because the drivers around her let her know. Benefits of new cars? or just complete bunkum. I'll let you decide
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Thanks all - interesting stuff.
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