Trevor scholes

On 10/10/2021 at 6:05 PM, Greydog said:

Hi Trevor

Mine came with Michelin Diamaris which like wise became like chickens teeth to find. So over the years (7 or 8 sets of tyres) I have fitted Continental, Bridgestone, Dunlop and Yokohama always changed in sets. Mine are 275x40x20R Front 315x35x20R Rear Summer wheels.  I run 255x50c18R Front and Rear Winter wheel set 

The fact that you have had to replace the actuator indicates there have been issues with tyres (transmission wind up causes local stripping of the nylon actuator gear) I would guess the previous owner has had either worn suspension or damage that has caused abnormal rear tyre wear rather than correct it they fitted new rear tyres. This caused a rolling radius imbalance (I have heard 6mm difference) which then starts to stress the actuator through trans wind up. Any odd tyre wear is normally a sign of worn suspension bushes allowing alignment changes (worn inner edges rear with outer edges on the front)

BMW like other manufacturers of AWD's have "recommended" Tyre manufacturers particularly those with staggered set ups (BMW, Mercedes,Audi) so any tyre manufacturer on BMW,s list normally the tyres are within the tolerances needed to protect the transmission.

Dave

Afternoon Dave

think you have settled my mind a little looks like I need not worry to much about the w95 and w96 part of the tire as these to figures seem hard to find in any good make of tyre as a pair again no X3 has ever been fitted with run flats and with sports suspension is a total non starter,  I am taking your sound advice and change all four tyres so long as the size width and height are correct we can vary the load and speed index without any problems yes or have you a different thought 

regards Trevor 

On 10/9/2021 at 8:41 AM, Greydog said:

Morning Trevor

I am 3 years ahead of you age wise 

Is there a reason you are changing just the rears?

Tyres : Different tyre manufacturers while construction is similar tread and final finish will vary the finished size, so if you were to take tyres of the same size from 2 different manufacturers make a chalk mark on the floor and the bottom of 1 tyre then roll it forward 1 revolution and mark the floor, then repeat there is a high chance that the distance will differ in some cases significantly. So say the difference in distance covered by 1 is 25mm greater, doesn't sound much but in a mile that tyre will make 7 or 8 fewer revolutions which if it is across an axel may be absorbed by the Diff. But if front wheels are not travelling the same distance as the rear then there can be damage caused to the transfer case and diffs.

So BMW (and all AWD manufacturers) take great care in selection of tyres and manufacturers to ensure front rear rolling radius's are consistent. BMW also advise changing sets (not always practical) but normally all 4 wear at a similar rate unless alignment is out or of course there has been damage to a tyre.

OEM supply for your car was either Dunlop SP Sport 01 or Pirelli Rosso Asimm Currently BMW approved tyres include Michelin Latitude, Bridgestone, Yokohama. Pirelli Cinturato. (my X5 runs 20" Staggered and currently on Yokohama tyres) 

So try to stick to the same manufacturer (ie: Pirelli) as you will have a better chance of maintaining the rolling radius. After they are fitted reverse on full lock slowly if there is jerking and snatching while reversing it indicates a potential problem with wind up in the transmission.

Dave

PSL I do most of my own car maintenance as well as family and friends always been a "hobby" the only concession to age is things take a bit more planning and sometimes take longer (more tea, coffee and beer breaks) Plus I rope in my sons (younger and bendier) for certain jobs. I do use a BMW Specialist for annual service and on the odd occasion when I either don't have time or (rarely) the inclination

Good afternoon Dave and thank you for the reply.

so us young folks enjoy keeping our cars in good condition, since I bought this car twelve years ago the tyres have always been changed in two’s as this is possibly from the previous owner, I have never had transmission problems apart from upgrading the actuator nylon gear, also upgraded the double vanos seals. and the disa valve pin , however looking at realoem my 19” y spoke wheels have been discontinued and these ran on staggered p zero rossos, realoem now shows both the 235 and the 255 tears as p zero asimm but I cannot find these tyres which end as w95 front or w96 rear, I can fi a rear ending as y96. So still trying for answers from bmw and Pirelli, so will keep you posted.

regards Trevor 

9 hours ago, Greydog said:

Morning Trevor

Welcome to the Forum

From the tyre size you quote I take it that your tyres are same size front and rear? Cars with a staggered set up (Wider rear tyres) generally are more susceptible to transmission damage due to mismatched rolling radius in the tyres front to rear or across axels. 

The important thing is that front to rear rolling radius isn't significantly different, I would think that the Pirelli replacement for the the Rosso's would be fine if going to another manufacturer I would take greater care. 

Dave

Sorry Dave I’m new to this forum am 75 years old and had my x3e83 3.0i msport for 12 years and yes the wheels are staggered, 235/45r19w95 on front never had transmission problems do my own maintaining, done the usual vamps and FISA probs ect, Bmw don’t appear to want to know so in am now about stuck.

thank Trevor

My X3 e83 3.0i m sport has always had Pirelli p zero Rossi’s fitted and no transmission problems, so now I need new rear tyres  and find that Pirelli have stopped making 255/40r19 96w tyres, so what now is our replacement ?