Flat Tyre And Lsd ?

KentIS300 · January 12, 2012

Hello guys,

recently I came across to the following incident ...

I had someone on the motorway right up my !"££$... lets say back while I was overtaking a lorry ... so I decided to give a bit of push on my throttle so kicked down and suddenly the car pulled to the right for 1-2 secs then it corrected it self and no need for me to compensate with the steering ... once I finished overtaking I lifted the foot from the throttle before I pull to the left lane ..and the car acted with the same strange behaviour and pulled left this moment for 1-2 seconds then corrected it self.

I must admit I was a bit scared and thought there was something wrong with my steering as I was due for front lower arm bushes replacement.

I did a few throttles presses and lets goes and same beheaviour and it was getting worse. I decided to pull on the side and have a look around.

My rear right tyre (looking the car from behind) was about 70% flat ... lost air hense all this strange driving...

I replaced it with the funny narrower spare (calling it narrow just because the sportcross has 225 rear and not 215 as the spare is) and everything came back to normal with driving.

Now my question is ... am I right to believe that the car corrected it self while full throttle was applied purely because it has LSD (Limited Slip Diff.) so it compensated the torque between the under-inflated/normal-inflated wheels ....

Is that correct and if so,for the LSD to come into action will take those 1 or 2 seconds?

LexIS200Sport · January 28, 2012

It may well be. Though 1-2 seconds does sound a little long to me for the combined time that it takes the LSD to tighten up and for the suspension arms to take up any deflections in the bushes.

If I'm not mistaken, most moden cars don't like it if one wheel is severely under-inflated compared to the others, as it messes up with the stability control, traction control and ABS, due to the difference in wheel speed sensor readings. Did any of your warning lights appear during this incident?

andyk134 · February 4, 2012

I wasnt aware these cars had lsd, but would benefit from it. Has anyone had one fitted?

KentIS300 · February 5, 2012

It may well be. Though 1-2 seconds does sound a little long to me for the combined time that it takes the LSD to tighten up and for the suspension arms to take up any deflections in the bushes.

If I'm not mistaken, most moden cars don't like it if one wheel is severely under-inflated compared to the others, as it messes up with the stability control, traction control and ABS, due to the difference in wheel speed sensor readings. Did any of your warning lights appear during this incident?

I might exagerate a bit ... it felt to me 1-2secs.... but might have been much shorter, I was still trying in mind to figure out what on earth was happening.

Nope no warning lights on the dash, it would have been easy to notice as it was 10:00 in the night and in the motorway so pitch black.

I would have guessed it was around 15PSI ? maybe ... enough to be seen by the eye as something was wrong with that wheel.