XSeries-forum

been getting a noise from front end that sounds like a cv joint knocking at low speed, on full lock, or just pulling away. but after reading some threads I decided to check what tyres I have on
Fronts- Dunlop sp sport maxx 225/60/R17 star rated run flat
Rear Pirelli P7 cinturato 225/60/R17 star rated run flat

Would the mixed combination likely be the culprit?

Hi

Do you know if the width of the front and back wheels the same size or a staggered set up I.e. Wider on the rear?

Reason is you have same width tyres on front and the back which would indicate the same size width wheels but you can check here to be sure

https://www.wheel-size.com/size/bmw/x3/

We know that the earlier E83 definitely is fussy in needing star rated tyres so there is similar in height / rolling circumference to ensure the 4wd system is within tolerance.

It appears to be the same on other models as X5 E53/ E70 to a degree.

A quick check as Horizon has done is actually measure the height and work out circumference as on his E83 X5.

If I remember correctly it was about 30mm out on old tyres causing probs with transfer box which when he replace with new set the prob with skipping in the drive associated with transfer box disappeared.

So probably worth getting a tape measure out and check as it that doesn't cost much, and if the heights and circumference ok then there could be a prob with and if bought from a dealer it's a trip to get them to check it if under warranty.

See link

http://xdrivers.co.uk/forum/index.php/t ... 982.0.html

Hop that helps

All tyres and wheels the same size just different makes on front to the back ones

Is there a wide tread depth variance between font and rear?  Even with the correct tyres that can cause an issue due to the rolling radius being out of tolerance.

CVJs are also known to go and should give you a clicking noise if you have a bad one.

F25...What year?

2010 f25 2ltr diesel auto

Non staggered set up. Does not matter what tyre brand you got as long as wear front/back is similar. Sounds like atc450 (transfer box) is gone. Bad vibration on sharp turn, thats how its starts...Check tyres first, if wear is close to same, you need new transfer box.

Is there any way I can identify if its the transfer box before spending lots of cash?

Disconnect the vtg control module plug.

what is it, where is it, and what will happen if I disconnect it?
Will it mess anything up if I unplug it?

Vtg-transfer box control unit
Front: Engine-gearbox-transfer box
Rwd without vtg plug
You cant mess it up by disconnecting

so what am i looking for when its unplugged?

Sorry as new to this my first BMW auto

Disconnecting the plug stop xdrive system (transfer box), it will be rwd only, so it should drive without any issues you noticed.

ah I see can i ask where its located, i appreciate the help

Underneath the car behind gearbox, unfortunately not easy task to reach it...