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There was an advert on TV for the Renault Megane, which showed it fitted with an on-board device for monitoring tyre pressures. Out of idle curiosity, does anyone know how this works? Presumably there is a sensor in each wheel, but how does it communicate with the rest of the car? And will it still work at six years old? (I've owned ageing Renaults, so I think I know the answer to the last question.)
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I wonder if this could be an option for caravans, where blow-outs are a perennial problem as loss of pressure does not show up until it is too late.
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You can buy aftermarket pressure sensors, and some for the caravan. Apparently works on a small radio transmitter in each specific wheel fitted when you fit the tyre.
So that b*gg*rs up swapping the wheels round to equalise wear ...
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www.schraderelectronics.fsworld.co.uk/ They take in to account wheel rotation and auto learn which corner thay are on (what about reliant robins then?)
Slightly off issue here, but what do people think about rotating tyres?? Never seen the sense in it myself... open to comments
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Vern,
>what do people think about rotating tyres?? Never seen the sense in it myself...
I'm glad they do........................sorry.
David
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no apology required, why are you glad? I'm always open to be educated.
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Otherwise the car wouldn't move.....
I resisted making a smarta**e comment initially but couldn't hold back..
Sorry Vern....
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dink... or whatever sound a dropped penny makes
:0)
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Big Vern wrote:
>
> no apology required, why are you glad? I'm always open to be
> educated.
Vern
Maybe that nice David W is just too shy to say that he charges customers for rotating their tyres for them!
More seriously, many thanks for shedding so much light on the subject of the pressure sensors.
Ronnie
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Ronnie,
I do rotate customers tyres while still on the car to check for lumps or out of round spots. Michelins are very prone to this at the latter end of their life. I jack each corner up in turn and do this as part of normal service.
What I don't do is swap the position of wheels on the car. Just a personal thing that I don't believe in it.
>"that nice David W" is a phrase I think Mark(Brazil) started when about to post something very cheeky, I suppose it takes the sting out a bit.
David
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My internet connection on go-slow so I haven't time to read all the postings here. Has anyone pointed out that wheels/tyres moved from one position to another should always be kept on the same side of the car, not swapped from one side to the other?
Although not always noticeable, tyre treads wear to a particular shape according to the direction of wheel rotation and swapping to the other side of the car makes them rotate the other way and accelerates tread wear until they 'bed in' to their new position.
Even swapping on the same side of the car can be bad for tyre wear and/or road holding stability in my experience so I go along with David W on this one, i.e. I leave them where they are.
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www.schraderelectronics.fsworld.co.uk/ are the main manufactureres of these, I think they supply most of the monitors used in the states (Seem to remeber a little bird telling me they were to become law following the ford explorer / firestone problems, true / false anyone?)
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tweet tweet!
It is widely expected in the industry that they will become obligatory (in the US) but there's nothing on paper yet.
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I'm sure that calling you a little bird may be considered sexist! :-)
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Not by me. Life's too short.
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Thanks for that, Big Vern. Looks like a neat piece of kit, and unlike most optional extras I would say it is well worth having. I wonder how long before someone does a version for aftermarket fitment?
Pity the site doesn't show how they work. They must have some source of power - either batteries (in which case they will die after a few years) or a miniature generator like the ones in Seiko watches, activated by the rotation of the wheel (in which case they will be awfully expensive to replace when the local tyre fitting gorilla wrecks them.
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Powered by a standard Cr2032 battery (bigger brother of your humble watch battery) Life expectancy of battery in this application 10 years I am lead to belive. Show ne a modern car with a life expectancy of 10 years!!!
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Given average drivers who never checks their tyre pressure, these seem like a good idea ...
I've seen plenty of cars driving along with one tyre half-inflated...
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"I've seen plenty of cars driving along with one tyre half-inflated.."
shouldn't it be one tyre half-deflated.. ;-)
Sorry Ian...
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I believe the tyre pressure monitor for the MINI uses the ABS sensors to determine if a wheel is turning faster than the others whilst driving straight. This will be due to it having a smaller rolling circumference from reduced tyre pressure. It doesn't tell you which one though - so you are 'forced' to check them all (of course if they are all over or under inflated it won't 'know' this, it can only spot the odd one out) and correct the pressure or get the punture fixed.
As for sensors in wheels - quite simple principle, I recall a prototype was knocked up for a university project. However I suspect the monitoring process to avoid reacting to any change in pressure is where the really tricky bit comes in....
Piers
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David
As my finger was poised over the "Post" button, I did wonder whether you had been talking of rotating or swapping - or both! Sorry if I made you sound more mercenary than you are, and I'm with you on both fronts.
Regarding rotation, for some reason, I seem to make tyres last longer the older I get, but I still run regularly my hand round as much of both sides of the circumference as I can to check for oddities or irregularities, just as my Father used to do. As he used to say, it makes your hands dirty, but never forget that those four handprint sized imprints are your only contact with the road!
Regarding swapping, with the degree of wear on a profusion of cars with a combination of front wheel drive, power steering, lots of bhp, increased braking loads and, all too often, the results of haphazard parking, it seems to me that fronts nowadays come in for such a bashing that it is better to change them more frequently as required, whilst making the most of the more "gently" treated rear tyres, than trying to even out wear between them - and the spare of course. Makes more sense with pressure sensors fitted too IMHO.
"Nice" is perhaps an over used adjective, and I should have come up with something better to indicate my appreciation of your substantial contributions to the Back Room. I've even drawn your existence to the attention of several local drivers of the makes/models you specialise in, as well as one in your own area. If I were ever being cheeky, you'd know!
Regards and many thanks.
Ronnie
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Reverting to the original query about how and why, long time readers may recall my sad experience in France. Rented a Laguna, had a blowout, had to go to a Renault dealer for a new tyre (megabucks) because of the tiny sender installed in each valve. Ordinary garage couldn't/wouldn't touch it!
Of course the spare doesn't have a sender, so if you fit it the car looks as if its running on three wheels!
Technology we don't need.
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Colin, couldn't agree more with the technology comment.
Saw the ad with SWMBO, her first comment was ' Well, there seems a lot to go wrong on that.' She must have been having a sly look on here!!
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A great idea, in principle, and in probably in practice. But it makes replacing damaged alloy wheels very expensive. I seem to remember reading of an unfortunate Porsche owner in Autocar whose presurre sensors failed one month out of warranty - he had to pay a cool £16,000 for a new set (yes, sixteen throusand!).
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Yes, David W, and those crappy sensors I keep banging on about are coded to a particular wheel, so youre strongly advised not to change them around side to side or front to back!
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The Smartire system (from Randolph's link) looks like good value at $229, if you run a high performance car with expensive tyres. The senders are attached to the well in the centre of the wheel rims using giant Jubilee clips, so tyre fitters shouldn't have too many problems with them. And it looks as though you can swap wheels around from one position to another without upsetting the system.
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