[Saiho]

I tried searching but didn't find anything remotely similar to my problem.

I've had my car for a month now, and this has only just been happening (3-4 days ago). Whenever I turn my wheel all the way to one side and start moving, the car starts shaking like the front wheels are constantly going over very small speed bumps and you can hear it too.

However, when on the road, everything is normal because I never have to turn the wheel that much during normal drive. Only getting in/out of parked spots do I have to do that and that's when it happens.

When this problem first started there were no warnings, but now whenever I start the car, it'll tell me the there's a "right/left tire fault." I check the tire pressures on the dash and the front wheels are red (below optimal pressure). After a while the pressure readings will turn to green (at optimal pressure) and the warnings don't show up again during the entire drive.

I have even taken a flashlight to look around the wheel and wheel wells and have found nothing visually wrong from what I can see. I don't have the proper equipment to hoist up the car to look underneath, though.

I'm just wondering if anyone has had this problem and if anyone knows what I could do. I have already told my dealer. I would just like to know if there's something I can do myself because they have to fly a technician from Toronto for him to look at it, and that might take a while.

Thanks for reading this long post,

Chris

 

[roundincircles]

When my car is on full lock it shudders and shakes the front wheel, particulary noticeable when the tyres are cold. This is a common and normal experience to do with the .......I forget now but others report this issue.

Once on the move it is OK.

 

[Declan]

a.) The tire pressure should be "green" when the tires are cold. You need to correct this.
b.) When it is cold and the wheels are turned all the way, the tires will be pushed diagonally across the street. This is most probably causing the noise you hear.

 

[andy c]

As RIC says nothing to worry about Chris,perfectly normal and happens on a lot of other cars too.The tyre issue is not connected,it is probably that they are under inflated when cold and when they warm up the pressures increase and your warning goes off,adding a little air should solve the problem,you get the exact opposite when on track as you then have to let air out ,and add again when you let the tyres cool down.

 

[Saiho]

Thank-you everyone for your input. It makes sense now. I will be putting in some air into my tires to see if that solves the issue.

I will also be seeing if the sound/feel is still strange when I turn the wheels all the way to one side while the tires are warmed up.

I'm glad to hear that it's normal and just a minor issue with the tire pressure errors. The technician probably wouldn't be too happy flying down to Vancouver during this weather.

 

[Naranja]

Assuming it's cold where you are, the tyres just do it until they're warm, on lock. It was discussed previously, lots of similar type cars do it. Think its called the Ackernan principal or similar, to do with geometry too. I bet when you did your search you spelt 'tire' like that! (sic).

 

[Naranja]

Here you go...

http://www.mclarenlife.com/forums/mclaren-mp4-12c/1788-great-car-but-things-disturb-me.html

 

[Saiho]

Thanks for the link, it seems it's quite normal when they are cold, which confirms everything said in this thread.

Hmm, it's spelt "tire" where I live. Is it "tyre" in the UK?

 

[kverges]

I will venture a guess. First, the car may have some reverse Ackerman for better handling with significant slip angles. As a result the inside front wheel binds up a bit with large steering input and low speed.

Second, I am sorry, but tire pressure sensors are not a substitute for PAYING ATTENTION TO TIRE PRESSURE. I like to think the buyer of this car is enough of an enthusiast to do the basics like pay attention to fluid levels and tire pressures, know what each should be (hot and cold) and not let any get too low.

 

[Peloton25]

Hmm, it's spelt "tire" where I live. Is it "tyre" in the UK?

Yes, and they put Petrol in their cars instead of Gasoline. They also have a funny way of pronouncing Al-ooo-min-ee-um, among other things.

>8^)
ER

 

[andy c]

Yes, and they put Petrol in their cars instead of Gasoline. They also have a funny way of pronouncing Al-ooo-min-ee-um, among other things.

>8^)
ER

As a matter of interest what is the national language over there??? Is it officially American? Or English

 

[Peloton25]

We don't have a national language Mr Smarty Pants.

>8^)
ER

 

[andy c]

We don't have a national language Mr Smarty Pants.

>8^)
ER

Well how do you understand each other !!

 

[Naranja]

Yes, and they put Petrol in their cars instead of Gasoline. They also have a funny way of pronouncing Al-ooo-min-ee-um, among other things.

>8^)
ER

Ha ha!

It's pronounced as it's spelt; Aluminium. It has five syllables, not four!

 

[Peloton25]

Well how do you understand each other !!

There are plenty of people living in this vast land who I will never understand, and it isn't just a language thing.

>8^)
ER

 

[Saiho]

I will venture a guess. First, the car may have some reverse Ackerman for better handling with significant slip angles. As a result the inside front wheel binds up a bit with large steering input and low speed.

Second, I am sorry, but tire pressure sensors are not a substitute for PAYING ATTENTION TO TIRE PRESSURE. I like to think the buyer of this car is enough of an enthusiast to do the basics like pay attention to fluid levels and tire pressures, know what each should be (hot and cold) and not let any get too low.

I never said I relied solely on tire pressure sensors. The tires looked fine from the outside, and I just checked the pressures and they are all at the recommended pressure. I've had a few cars that gave false errors. All I was asking is if the tire fault message had anything to do with the Ackerman thing I was experiencing.

 

[kverges]

Fair enough and I don't think tire pressure is related to the front Ackerman feel you noticed.