Both front tyres are worn almost smooth on the outside edge of the tyres on my new motor. I saw this at purchase and I knew I needed two news tyres (although not sure how I test whether they are actually illegal = 3/4s the width has to have tread I recall).
My local tyre place is telling me this is likely to be due to over-inflation. I think this unlikely as there are tyre pressure monitors and I presume it would warn of over-inflation, though the manual only mentions under-inflation. (Pressures are pretty high anyway - 36psi tp 39psi)
Do the panel agree, or do we think it's tracking (like I do)?
I suppose the only way to tell is to have it checked... but I think checking tracking costs money and I'm feeling a bit tight this month!!
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It depends how much difference between the outer edge and the inner.
My experience of either under or over inflating is that it tends to damage symmetrically.
I'd go with tracking. I thought Kwikfit did free tracking tests? Especially when fitting tyres? Just so long as you ignore their conclusions that you need new shock absorbers.
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p.s.
>>3/4s the width has to have tread I recall
The *central* 3/4s I think.
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>> I'd go with tracking. I thought Kwikfit did free tracking tests?
I think *most* places do it for free nowadays. They make their money if the car's geometry needs setting up, and of course like you mentioned, noticing worn shocks, brake pads, and corroded exhausts ;)
Place I use is the local Merityre garage. Free alignment check, and if only the fronts need aligning, they charge less than if all 4 wheels need aligning (that's if the rear tracking is adjustable). One of the few places locally that actually does 4 wheel alignment. With my old Vectra, they only had to make a very minor adjustment, so didn't bother charging me.
Last edited by: VxFan on Wed 16 Aug 17 at 19:19
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Most cars that live in Milton Keynes have extra wear on the outside edge of the front tyres, predominantly the left one. Where did yours come from?
I thought edge wear was symptomatic of under, not over, inflation. But would more likely be symmetrical as NoFM says.
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The legal limit for minimum depth of the tread on your tyres is 1.6 millimetres, across the central ¾ of the tread around the complete circumference of the tyre
Pat
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Regarding the pressure monitoring system. I know there are different systems but if its the one that uses differences in rotation to detect deflation then it wouldn't detect any problem if the tyre pressures were the same across the same axle. i suspect this is true of all systems once you set it up with evenly inflated tyres but soemone on here will know for sure.
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Slight thread drift Smokie, what kind of gearbox is in the Ampera? Is it CVT? Most electric hybrids I see seem to have CVT?
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Dunno. I just put it in Drive, or L mode, select whether I want to drive normally or in sport mode, and off it goes. No gear shifts heard or felt. There is no kickdown cos there are no gears... It is extraordinarily quick off the mark in Sport, and guzzles energy, but after about 30 mph it feels more like a normal car. I suppose it's CVT then.
L mode increases the engine braking. I think the idea was for improved regeneration but the tech heads on the forum say the difference in generated power is minute. What it does do is make the brakes pretty redundant, such that people say Ampera brakes are changed because they have rusted rather than worn out, and there is a tip to coast the car in N (to disengage the regen) and brake reasonably firmly to stop the pads glazing.
Back on topic, the tyres look to me to have plenty of tread across most of the tyre, especially her centre where the groves go round the tyre. I may drop into my local tyre shop to ask if they do a free tracking check and for an opinion about whether they are legal (and safe). I'll also check the pressures manually...
I've just had a warranty replacement of all four wheels approved. It's a common problem, the alloys start flaking. I'll defer the tyres till the wheels have been done.
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It is not a CVT. There is a plenary gear linking the motors and there are three clutches. It is possible for both electric motors to drive (i.e. for performance) although the secondary electric motor is also the generator that gets charged via the ICE.
Last edited by: rtj70 on Wed 16 Aug 17 at 15:16
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Not sure that's right for the Ampera. I understood the wheels are always driven by the electric motor, and the ICE acts as a generator when there is no electric power left. Can't remember where I saw it though...
EDIT: here www.carmagazine.co.uk/car-news/first-official-pictures/vauxhall/opel-ampera-unveiled-at-geneva-motor-show-2009/
Which says, in answer to the earlier query, "There’s no gearbox; the electric motor simply changes direction to select reverse gear."
Last edited by: smokie on Wed 16 Aug 17 at 15:50
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The wheels are driven by one (or both) electric motors. The ICE uses the second electric motor as a generator to charge the battery.
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With the Zoe tpm system, it learns what you tell it. So from factory, it's set to some figure or other. If you then decide to put 42psi in your tyres, you can if you wish hold down two buttons and it then knows that is the new pressure to monitor, only warning if it deviates from 42.
So with mine, you can't rely on a used example "knowing" what you think it ought to. I don't know if the Ampera can do something similar, but if so, it might not trigger on over-inflation.
Last edited by: Crankcase on Wed 16 Aug 17 at 18:47
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I checked them manually and right now they are all correctly inflated - but that's not to say they've always been!! When I have a few mins I will try to get a pic online to show the wear.
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Thread drift - but it's my thread anyway :-)
I asked a question about how the car "works" on the forum yesterday and got some interesting replies about how the different motors interact. It's a very clever piece of kit!! See tinyurl.com/yb7a2ay6 if you are interested.
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>>>thought edge wear was symptomatic of under, not over, inflation
Yep even outer & inner edge wear is usually under inflation and of course over inflation wears out the central tread. Outer or inner wear only so often tracking. Inner wear only also commonly caused by worn suspension bushes. A chopped edge wear is usually shock absorbers but can be worn bushes allowing the wheel to spring between two attitudes.
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You are allowed an 1/8th under 1.6mm on the inner or outer edge with the central 3/4 above 1.6mm. Wear on the outer edge may indicate excessive toe in whereas inner edge may indicate excessive toe out.
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Over inflation will generally cause the middle of the tyre to wear first and under inflation the edges, though if the inner or outer edges are both worn evenly it could be a characteristic of the car and the alignment might be perfect (is the steering wheel straight when driving in a straight line?). So they could possibly be the original tyres and simply need replacing?
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>> You are allowed an 1/8th under 1.6mm on the inner or outer edge with the
>> central 3/4 above 1.6mm. Wear on the outer edge may indicate excessive toe in whereas
>> inner edge may indicate excessive toe out.
I thought it was:
"A minimum of 1.6mm across three quarters the width of the tyre, with visible tread pattern on the remainder"
?
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It used to be, but it changed 5 or more years ago. Tyre can be bald round the outer 1/8th and still be legal - as long as ply / cords are not exposed.
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Vauxhall Ampera - Tyre alignment - No FM2R
