[sandman0615]

i'm gona cut right to the chase

is there any potential damage to the differential or anything if i use 2 different sets of tires? 2 conti RFT on the rears, 2 nokians up front

both are about halfway through their life


not really practical for me to get 4 all new tires every time one blows out and i have the 2 extra contis sitting around

any help is appreciated

[Kalidian]

Tire size is what matters. Post up tire specs and we can tell you whether or not you'll mess up the xdrive.

[thegrinchboy]

As Kalidian said, tire size along with spec e.g. speed rating, AS vs summer, etc.

[sandman0615]

both sets are 205/55/r16 all weather RFT, nokians and contiprocontact.

if thres any risk of damage i dont want to run the setup. if its just uneven wear for a bit until i replace all 4 i can live with that

thanks again

[sandman0615]

bump

[Thorium]

You good on those tires. A bit normal wear diff wont do no harm

[zipstic]

Yeah, you're fine. Assuming you have the WRG2/3 and the ContiproContact SSR these are both at 837 RPM.

[pits200]

The car will ride odd with the different tread patterns from front to back with the different tires.

It probably is a little more unsafe than 4 of the same tire but if the tire sizes are correct and the tread is adequate I guess it shouldn't be a big issue.

[sandman0615]

thanks! always appreciate the help

[sandman0615]

arghhhh

i put on the two continentals up front, but the car is still driving really funky. it does this realllly weird bucking mostly when i'm accelerating in a straight line, but pretty much constantly

is this possible from the two different sets of tires? i first noticed it was driving funny after i got an alignment last week (which is when i blew the first tire), but i havent really driven the car since today

[sandman0615]

it feels like its the differential running. for now i'm not driving the car at all

[thegrinchboy]

What is the speed rating of the tires? Are they the same? Also are the patterns similar?

[sandman0615]

yea both have a v speed rating, same specs. the contis have like an extra mm of tread

[BLKSAPPE92]

Originally Posted by sandman0615

yea both have a v speed rating, same specs. the contis have like an extra mm of tread

your owners manual should state how many 32nds one tire can be off from the rest on xi bmw anything more will damage front, rear diff or transfer case. If cars 2wd they still want you to follow same rule of thumb with front or rear drive axle.

You can buy new tires from tire rack and have them shaved to equal 32nds but you still get awful road noise till tire wears off shave marks.

I sold my Audi cause I was sick of doing the same thing 1 flat equals 4 new tires or a loud new shaved tire from tire rack now. Granted I don't live in Maine or Michigan anymore.

Rwd was for me at worst I have to buy two tires but only on rear and I do t care how fast I accelerate when up north anymore and since I learned to drive in snow with rwd I'm cool with just a good set snows so not buying 4tires a pop so I don't damage drive train

[thegrinchboy]

Originally Posted by sandman0615

yea both have a v speed rating, same specs. the contis have like an extra mm of tread

That is weird, unless 1 set is that that much grippier than the others... Maybe the contis are stickier than nokians (?) Even though both are RFT, one may have softer compound/sidewalls than the others (?)

[BLKSAPPE92]

I have found mix stuff. http://www.tirerack.com/tires/tirete....jsp?techid=18

There are several suggestions that have been offered to drivers who are replacing pairs or individual tires on their four-wheel drive and all-wheel drive vehicles. Some vehicle manufacturers recommend that all tires maintain the same rolling radius and circumference, while others suggest that all tire circumferences remain within 1/4- to 1/2-inch of each other. Other vehicle manufacturers recommend that all four tires remain within 2/32-, 3/32- or 4/32-inch of each other, or within 30% of each other in relative remaining tread depth.

That is link and paragraph is small portion each auto maker is gonna be different and their ABS and Traction Control are different so one manufacture dsc system may be ok with a tire being off 4/32 were another auto maker with more fine tuned dsc may start acting funny if one or two tires are of only 2/32 causing abs or traction control to intervene constantly thinking the one or two wheels are spinning faster then the other 2 or 3 causing your abs to intervene when stopping or traction control to intervene when accelerating.

[sandman0615]

id just like to update by saying the very second i replaced all 4 tires the problem was resolved, so yea even slightly mismatched tires on awd can cause the diff to open

this was off car talk:

"Ray: Here's what happens. On all-wheel-drive cars -- cars that are permanently in four-wheel drive or can be left in four-wheel drive all the time -- there's a part called a center differential. This is a clutch assembly or viscous coupling that's so complicated, we couldn't possibly explain how it works without using our hands. And maybe the hands of at least two or three innocent bystanders.

Tom: When the car is going straight down the road, the center differential doesn't have to do anything. It just sits there. But when the car turns, the front and rear axles need to turn at different speeds to keep the wheels from binding up and the car from flipping over. The job of the center differential is to allow the axles to turn at different speeds.

Ray: The problem is that if the front and rear tires are different sizes, then the front and rear axles are always turning at different speeds. Even when the car is going straight ahead. That means the center differential is always working -- and that wears it out."