S2 4wd Problem

[JOHNNNY]

hi guys im having a poblem with my S2 attessa 4wd system ,

i have just fitted 2 second hand tyres one on the front pass and

the other on the drivers rear . both tyres have 50% tread and

all 4 tyres are the same size 245/35/19 . now when i drive the car

the 4wd system is coming on under normal driving conditions

front torque gauge reads anywere between 5 kg/m - 10 kg/m

and the car feels as if it is surging . im thinking that maybe because

the tyres are actualy slightly a diffrent rolling dia so therefore the

attessa system sensors are telling it that one of the wheels are spinning

enough to engage the 4wd . im just wondering if anyone has come across

this problem before ??????, there was nothing wrong at all with the car

before the 2 tyres were fitted , and no one touched the car at all while the

tyres were fitted and the guys who fitted didnt break or damage anything

because i watched him like a hawk like i do with anyone who works on my stag

HAHAHA any help will be very much apprciated thanks guys and girls ....

[kidafa]

Mate its deff your problem! Get them off asap to avoid costly repairs to the awd system!

[kidafa]

Ohh and also if you MUST run them put them on the same axle ffs but yeah different tyre sizes and tread depths are a big NO NO on these cars

[chook]

+1, yep, dont risk it, get yourself 4 newies.

[lachlanw]

just put the biggest ones on the back . theyll turn slower and itll be fine

[kidafa]

just put the biggest ones on the back . theyll turn slower and itll be fine

And risk damage to the 4wd system? Good advice!

[mattye]

Dude the diff rolling diameter is defs the prob. As a side not I noticed that the 4wd was kicking in more ofter with just lower tyre pressure (I know of others that this has happened to).

Also as kidafa said dont mix n match tyres from side to side on each axle. Not just for safety reasons but u can damage diffs etc by putting diff size tyres on the one axle.

[lachlanw]

And risk damage to the 4wd system? Good advice!

plesae tell me how it is going to damage it ? the rear wheels wont be turning faster than the front so it wont send any drive to the front . and the overall difference wont be any greater than the difference between wheel speeds when driving around a corner. i put the space saver on the rear of mine and it was a flamin mongrel . sent like ten% to the front . unplugged the green wire and it was happy as

[JOHNNNY]

thanks guys fo your help in conferming what i thought was the problem. i have changed the tyre that was the problem and it has fixed it . but i have booked the car in for 4 new tyres next week so my problem is now ALL GOOD thanks again eveyone who helped out !!!!