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X1 E84 (2011 - 2015)
First generation BMW X1 availbe as a X1 28i with either sDrive (RWD) or xDrive (AWD) or the US exclusive I6 N55 powered X1 35i xDrive.

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  #1  
Old 12-12-2018, 05:24 PM
David Ortiz David Ortiz is offline
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Why 32 - 38?

Due to recent ďslightly coldĒ weather in Florida (low 40s, oh boy ), my left tire pressure light came on (low pressure). So I decided to put some in and check them all while at it. They were all low actually, but what I found strange is the required pressure.

The door sticker calls for 32 front and 38 rear. Really?!?!? A 6psi difference? Why is that? I thought weight was practically eventually distributed. Maybe because itís an xDrive?

Thoughts anyone?


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  #2  
Old 12-12-2018, 06:06 PM
Tommy D Tommy D is online now
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Those are normal pressures for a BMW. My 3 series requires the same pressures. You can increase them slightly to get them closer if you want for personal preferences. Like 33psi in the front and 36psi in the rear. The reason for more pressure in the rear is to induce understeer vs oversteering. This makes the vehicle more balanced to drive on a RWD biased vehicle.

Last edited by Tommy D; 12-12-2018 at 06:08 PM.
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  #3  
Old 12-12-2018, 06:24 PM
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Quote:
Originally Posted by David Ortiz View Post
Due to recent ďslightly coldĒ weather in Florida (low 40s, oh boy ), my left tire pressure light came on (low pressure). So I decided to put some in and check them all while at it. They were all low actually, but what I found strange is the required pressure.

The door sticker calls for 32 front and 38 rear. Really?!?!? A 6psi difference? Why is that? I thought weight was practically eventually distributed. Maybe because itís an xDrive?

Thoughts anyone?


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Is your Bimmer on a square setup or are rear tires bigger than front tires?
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  #4  
Old 12-12-2018, 07:04 PM
David Ortiz David Ortiz is offline
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Originally Posted by DBU View Post
Is your Bimmer on a square setup or are rear tires bigger than front tires?


All tires are the same size.


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  #5  
Old 12-12-2018, 07:06 PM
David Ortiz David Ortiz is offline
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Originally Posted by Tommy D View Post
Those are normal pressures for a BMW. My 3 series requires the same pressures. You can increase them slightly to get them closer if you want for personal preferences. Like 33psi in the front and 36psi in the rear. The reason for more pressure in the rear is to induce understeer vs oversteering. This makes the vehicle more balanced to drive on a RWD biased vehicle.

Thank you Tommy.


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  #6  
Old 12-13-2018, 06:11 AM
briar08 briar08 is offline
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38 in the rear caused tire wear in the center of the rear tires for me. I think 38 in the rear assumes some kind of loading of the rear seat and/or trunk. 32/36 has been working well for me. Its usually just me in the car.
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Old 12-13-2018, 02:12 PM
mcdanielvzw mcdanielvzw is offline
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I've always done the same pressure all the way around. I think I stick with 36-38 all around on my X1.
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Old 12-14-2018, 01:37 AM
David Ortiz David Ortiz is offline
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Why 32 - 38?

Thank you Briar and McDaniel.

Adding more pressure to the front will make me feel more of the road. Gosh, these run-flats are rough riding for sure. I may consider regular tires when due.

Itís also just me in the car 90% of the time (82 round-trip miles daily commute to work x 3 days). The 32/38 is what the door sticker calls for.


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Last edited by David Ortiz; 12-14-2018 at 01:39 AM.
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  #9  
Old 12-14-2018, 08:11 AM
mcdanielvzw mcdanielvzw is offline
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Originally Posted by David Ortiz View Post
Thank you Briar and McDaniel.

Adding more pressure to the front will make me feel more of the road. Gosh, these run-flats are rough riding for sure. I may consider regular tires when due.

Itís also just me in the car 90% of the time (82 round-trip miles daily commute to work x 3 days). The 32/38 is what the door sticker calls for.


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I do it precisely so I can feel the road. I've always slightly over inflated, so maybe that's why runflats never bothered me. I'd rather have that than feel like I'm driving a boat on the ocean and feel disconnected from the road.
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  #10  
Old 12-14-2018, 08:23 AM
Autoputzer Autoputzer is offline
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SUV's are made to haul stuff, lots of stuff. Almost all the weight of the stuff ends up on the back axle. That could be the reason for more pressure in the back.

I've found the decal pressures are almost never the right pressure to achieve even tire wear. My method is to start out at 5% over what the decal says, measured in the early morning when the tires are cold, the air is the coldest of the day, and sunlight has not heated the tires. I measure the depths of the circumferential grooves across each tire when the tires are new, and then right before rotation. I maintain the same pressures through an entire rotation stint. Right before rotation, I take tread depth measurements, calculate the wear on each groove on each tire, and the averages for each tire and axle. From this data, I adjust the pressure for the next rotation stint. This periodic measurement of the tread depths also detects alignment problems before they do significant damage to the tires.

Using this "feedback" method to achieve even tread wear, I can get 40k miles out of high performance tires, and 60k+ miles from "all-season" tires.
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  #11  
Old 12-15-2018, 12:51 AM
David Ortiz David Ortiz is offline
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Why 32 - 38?

Thank you Autoputzer, that was very informative. If I may ask, what pressures do you use?

I checked the depth of my tires using a penny (as suggested on my FIXD app / see image below). However, Iím seriously considering buying a tire depth gauge (theyíre generally pretty inexpensive).
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Last edited by David Ortiz; 12-15-2018 at 12:55 AM.
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  #12  
Old 12-15-2018, 02:00 AM
Autoputzer Autoputzer is offline
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Frau Putzer got a new X3 this year. It currently has 7.5k miles on it. The door decal says 32 PSI Front and 35 PSI Rear. I've been maintaining them at that plus two PSI, measured when the car is cold, in the early morning at the daily low temperatures. But, I'm getting excessive wear in the middle two channels. So, at the next tire rotation, I'm going back to the decal pressures. The tires came "round shouldered" when new, with more tread depth in the two middle channels than in the inner and outer channel. So, my excessive middle wear is squaring the tires back up.

A caveat is that the X3 came with non-RFT's. I've only had one set of RFT's, Goodyear LS2's, and I needed to drastically over-inflate them to get them to wear evenly. Those tires have made me militant about never owning RFT's again.

The X3's non-RFT's are also Bridgestone's. I've found that Michelin's and Bridgestone's need less pressure than Goodyear's or Continental's to achieve even tire wear.

Don't get a digital depth gauge. They only measure in whole 32nds inch. Get a $3 mechanical gauge at any auto parts store. That will allow you to eyeball the measurements to maybe one fourth of a 32nd inch. Being obsessed with this, I'm getting Santa Claus to bring me a cheap machinist's depth gauge so I can get more resolution in my measurements.

I've automated my "tread depth analysis" in a spreadsheet. The spreadsheet calculates the wear in each channel on each tire. It then calculates the average wear, average wear on each tire, on each channel, on each axle, and on each channel on each axle. From this, I can see if my pressures need changing, and also see if I need an alignment. The spreadsheet then takes my tire rotation pattern and shuffles the tread depth data around for doing the calculations again just before the next tire rotation.

Here are some snapshots of the spreadsheet:

The 535i's tread depths at 45k miles showed that my rear pressure was too high (excessive middle wear).

The 535i's tread depths at 51k miles showed that I needed an alignment (after hitting a pothole a few k-miles before rotation). Three tires has excessive outer wear, and the other one had excessive inner wear. The car still tracked straight after hitting the pothole. So, without tread measurements I wouldn't have seen the need for an alignment until it was too late to prevent tire damage.

The X3's tread depths at 3.5k miles showed that my pressures (2 PSI over decal) are too high (excessive middle wear).

The Cobalt's tread depths at 117k miles shows that my pressures are too high. But, that's intentional to get the tread depths back to even all the way across the tires.

To get a meaningful correlation between pressure and wear patterns, it's necessary to stick with the same pressures over a rotation stint. That's because the wear measurement has limited resolution, and you need enough wear to actually be detected. I might be able to do better with my machinist's depth gauge Santa Claus is bringing me. I check and adjust my pressures every two or three weeks, and before and after a day on a road trip.

Here's a downloadable copy of my automotive Excel workbook, which includes the tread depth spreadsheet.

https://onedrive.live.com/view.aspx?...K_x8woBS5-HbWU

At subsequent rotations, you copy the block of cells, leaving one row between it and the previous block. The smaller block of cells are used when you get new tires or a new car.

The E84 X1 didn't offer a spare as an option. So, doing a DIY tire rotation would require a lift. BMW didn't recommend tire rotation when your car was built. But, they've since changed their minds (for BMW's with square set-ups). xDrive still sends 2/3's of the power to the rear wheels. So, your rear tires will wear out faster. Because of the negative camber BMW's uses on the rear wheels (wheels tilted in at the top), they concentrate the wear on the inner part of the rear tires. Rotating your tires will make them last longer, and allow them to all be replaced at the same time. It's important that all the tires have nearly the same tread depths (and therefore the same diameter) on xDrives.

I can't imagine going on a road trip without a spare. Bimmerzone.com sells min-spares most BMW models. We didn't get an E84 or F25 because they didn't come with a spare tire. The G01 offers one as a $150 option (code 300), and it's free if you order the no-cost non-RFT's (code 25X).

I've found that high-performance tires wear faster when new. For all-season tires, the difference in wear rates between new and old are less or non-existent. For high-performance tires, I select a rotation stint by dividing the expected life of the tires by 7.5. That will be the distance for the second and subsequent rotation stints. The first rotation stint will be half that. For all-season tires, I determine the stint distance by dividing the expected tire life by eight. Using these stint distances will put each tire in each corner twice over the expected life of the tires, and they should all have just about identical wear by the end of their expected life.
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  #13  
Old 12-15-2018, 08:47 AM
David Ortiz David Ortiz is offline
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Wow!! Thatís a lot to digest. Thank you for this most informative post. However, Iíll need to reread it a few times to fully gain the benefits of the information provided.

I will buy a tire gauge, thatís for sure.

Thanks again.


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Old 12-15-2018, 09:03 AM
David Ortiz David Ortiz is offline
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Why 32 - 38?

Autoputzer,

I reread your post and this is good stuff. Your post is most interesting.

Also, if I may ask. You measure with your tire gauge in the ďmiddleĒ if the tire thread pattern, yes?

Also, notice on my X1 (xDrive) I have the same sized tires, but different manufacturers (Goodyear front, Michelin rear) thus different pattern. Not sure why theyíd do this, but thatís one of the disadvantages of buying used. Iím hopeful this doesnít cause any adversity.Click image for larger version

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Last edited by David Ortiz; 12-15-2018 at 09:14 AM.
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  #15  
Old 12-15-2018, 02:06 PM
Autoputzer Autoputzer is offline
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Take the measurements in the circumferential grooves, and in the middle (deepest part) of the grooves. Most tires have four circumferential grooves. So, you'd be making four measurements per tire. Taking four measurements per tire gives you profile data, which can tell you if you have an alignment or inflation problem.

It looks like both your Michelin's and Goodyear LS2's have four circumferential grooves. There are "wear bars" in the grooves, little bumps that are 2/32nds inch high. When the tires wear down so that the tread blocks match the wear bars, the tires are legally done. Be careful not to measure on top of those wear bars. That's a trick that tire salesmen will do to make you think your tires have less tread than they really do.

Goodyear LS2's are the tire that cured me from ever having RFT's again. My 535i came with those. I had to over-inflate them 15% to get something close to even tread wear. That made the car ride and handle horribly. I finally had enough and ordered some Michelin Pilot Super Sports (PSS's, ultra-high performance non-RFT's). The PSS's transformed the car.

It looks like your LS2 in the picture is pretty chewed up on the outer edge, but there's still plenty of "meat" in the middle tread blocks. That's the typical under-inflation wear pattern you get with LS2's.

The previous owner(s) probably didn't rotate the tires. So, the rears likely wore out long before the front ones did, and they only replaced two. BMW recommended against rotating tires back when your was built. So, replacing tires two at a time was common. My BMW dealership's building is under renovation. So, the salesman, service writers, and customers are camping out in the MINI dealership next door. MINI's are nose-heavy, front wheel drive cars. So, the front tires on a MINI wear faster than the rear ones. The last time I was in for service, just about every MINI owner/leaser having their car in for service was getting the bad news that they needed two new tires (on the front). Most MINI's don't have spare tires. So, it's unlikely that any of the owners/leasers were doing DIY tire rotations, or spending $20 to have a shop do it.

Having different tread depths causes the tires to have slightly different rolling diameters. This can play Hell with the xDrive. The xDrive logic sees that two tires with less tread are rotating faster, and assumes they're slipping. So, the xDrive partially disengages the clutches sending power to that axle. The operative term is "partially." A partially engaged/disengaged clutch wears out quickly. So, not rotating your tires and the previous owner not replacing all four tires could be slowly wearing out the clutches in your xDrive transfer case. If they go, it's a $3500 to $4000 bill to have the transfer case replaced.

Since you're in south Florida, you really don't need all-season tires unless you make an annual trek up north somewhere for Christmas. As long as you'll never see snow or temperatures below 40F, you'd be a candidate for high-performance tires. If you like flicking your BMW around, they would greatly improve the experience. But, they'd do so at a price. High-performance tires wear out faster, because they use "tacky" rubber. It's sort of like a really good pencil eraser (one with white rubber) wears out faster than a hard one (one with pink rubber).

But, if you do make trips to the great white north in your X1, definitely get all-season tires. High performance "summer" tires stop performing well at about 40F, and can actually become brittle and develop cracks if exposed to 20F weather. Michelin and others make "high-performance, all-season" tires. They're a compromise, but sometimes a necessary one. The all-season tread patterns (with more "sipes" (cuts) in them) are also likely better in the rain.

I have high-performance summer tires on both my 535i and my beater. Really good tires can even make a Chevy Cobalt fun to drive. But, we're moving to Tennessee eventually. When that happens, I'll put all-season performance tires on my beater, and my garage will be insulated and partially heated to protect my 535i's (and hopefully someday a 911's) tires from sub-20F temperatures.

Tires loose pressure over time, some more than others, depending on the smoothness of the rim's surface and how much sealant they used when installing the tire. One of my car's tires lose about one PSI every three weeks. So, an important aspect of "tire whispering" is maintaining the property pressures. So, you'd need a pump. I'm fond of hand pumps, but a high quality one. For just topping off a tire with one or two PSI at a time, they're easier than dealing with extension cords or battery packs. Topeak makes high quality hand pumps for bicycles under their "Joe Blow" product line. For use with a car tire, you'd want their high-volume, low-pressure (75 PSI Max) mountain bike tire pump. Bicyclists are often tree-huggers, and hate generating trash. So, Topeak sells repair parts for their pumps (hoses, O-rings, cups, etc.). A good hand pump can last as long as they sell parts for it, several decades. You also need a high-quality dial pressure gauge.

Tire rotation is easy to do if you have a floor jack, a spare tire (used as a place holder), a torque wrench, breaker bar, and socket. A mechanic's stool makes removing and installing a tire, or even checking and adjusting the pressures a lot easier. Eventually, the savings from extending the life of your tires will pay for all those additional "garage toys."
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  #16  
Old 12-15-2018, 04:02 PM
Yukoner Yukoner is offline
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Ummmmmm, wow. Autoputzer is, hands down, THE authority on tire pressures for BMWs
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Old 12-15-2018, 08:09 PM
David Ortiz David Ortiz is offline
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Thanks again Autoputzer.

However, now Iím going to lose sleep over the different tire thread thing. Hate to have to dispose 4 tires with the thread I have left.

Guess itís cheaper than the alternative.


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Old 12-15-2018, 09:24 PM
Autoputzer Autoputzer is offline
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Thanks again Autoputzer.

However, now I'm going to lose sleep over the different tire thread thing. Hate to have to dispose 4 tires with the thread I have left.

Guess it's cheaper than the alternative.


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Measure the tread depths, and see what a BMW dealer says about differences acceptable with xDrive. My 2014 and 2018 owners manuals don't say anything about it. xDrive's will tolerate a certain amount of difference. BMW sells xDrive's with staggered set-ups (back tire wider) that can't be rotated. So, having tires of different diameter front a back is a normal, unavoidable occurrence with those cars. I ordered our last three BMW's with square set-ups, so I could rotate tires.

I had a $2500 bill one time at my BMW dealer's service department. When I was paying, I asked my service writer if I'd "won" that day's contest for the largest repair bill. She said "Nope, transfer case, $3500."

Last edited by Autoputzer; 12-15-2018 at 09:42 PM.
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Old 12-16-2018, 02:35 AM
David Ortiz David Ortiz is offline
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Thanks Autoputzer-

That last paragraph has me stumped.

Iíll need to look into this. I have a service appointment (my first one) December 21.


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Old 12-16-2018, 06:12 AM
Autoputzer Autoputzer is offline
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Originally Posted by David Ortiz View Post
Thanks Autoputzer-

That last paragraph has me stumped.

Iíll need to look into this. I have a service appointment (my first one) December 21.


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The transfer case is the xDrive hardware behind the transmission that transfers all or part of the power to the front axle, using clutches.




If/when you buy tires you can get a great selection and price from TireRack.com. You punch in the details of your vehicle on the website and it lists all the tires they have that fit your car. You then filter them by the characteristics you want or don't want.

When having low-profile tires installed, it's important to use a lever-less tire machine that doesn't touch the outside of the rim (and scratch it up). Run-flats make scratching a rim with a lever-ed machine even more likely. Tire Rack lists tire installers in your area, an the type of tire machine they use. You can take the make and model of tire machine, google it, and see if it's lever-less. Lever-less tire machines are very expensive, and not all shops have them.
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Old 12-16-2018, 06:50 AM
Autoputzer Autoputzer is offline
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Originally Posted by Yukoner View Post
Ummmmmm, wow. Autoputzer is, hands down, THE authority on tire pressures for BMWs
Thanks, Yuk'. But, the "feedback" method works for all tires.

"Feedback" is when you sample the output of a process or system, and use that output to adjust the controlling input. A household thermostat samples the temperature (output of the furnace or AC) and then uses that data to control the furnace or AC to provide near constant temperature in the house. Modern fuel injection systems use O2 sensors to sample the exhaust (output), and then adjust the fuel flow (input) to provide low-emissions and high fuel economy.

I used to just follow what the door decal said. But, on my 1996 Nissan 200SX SE-R the OE Goodyear's wore as if they were under-inflated. I replaced them with the trick Michelin's of the day (MXXM's?), and those tires wore as if they were over-inflated. That's when I had an epiphany to not blindly trust the door decals anymore.

Racing teams also use the feedback method to adjust tire pressures, but they do it with a pyrometer, measuring the temperature profile across the tire right after the car stops in the pit. My using tread wear instead of temperature is sort of an ultra-slow-motion version (six months vs. six seconds) of what race teams do.

My record for tire life is 79k miles, on Frau Putzer's old V6 Honda Accord. Second place was 74k miles on my Chevy Silverado 1500. I've got over 70k miles out of four sets of tires. I've got over 60k miles out of eight sets of tires, and two of those sets were high-performance tires (the MXXM's on my '96 200SX SE-R, and the OE Dunlop's on my '92 Sentra SE-R).

With the Silverado, I was still getting excessive outside wear even after the warranty alignment. The alignment was within spec's, but just barely. So, at the approximate half-life of the tires, I had a shop flip the tires on the rims to put a fresh edge on the outside. (The tire Bubba never could grasp why I was doing this, and tried to sell me a set of Cooper's for more than a set of Michelin's would cost... after I spent $100 to have the tires flipped.)

When I wear out a set of tires evenly and sometimes all the way down to the wear bars, I want to keep one of the tires as a souvenir and further evidence of my genius. But, there's no room in my garage and Frau Putzer gets pissed when I bring tires into the house.

I've had a couple of friends who were pick-up artists. The reason they hooked up with so many women was that they used... wait for it... feedback. They observed the reactions of their prey, and then constantly adjusted their pitch accordingly. What works well on one woman doesn't work on the next one.

Last edited by Autoputzer; 12-16-2018 at 08:14 AM.
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Old 12-16-2018, 02:02 PM
Yukoner Yukoner is offline
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What works well on one woman doesn't work on the next one.
Is that what I've been doing wrong all these years
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  #23  
Old 12-16-2018, 03:06 PM
David Ortiz David Ortiz is offline
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Join Date: Dec 2018
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Mein Auto: 2014 X1 28i (AWD)
This information is most helpful and appreciated Autoputzer.

Clearly I need to start doing some research. I feel like my car is suddenly a time bomb just waiting to go off.

Itís gotten to the point I didnít drive it at all this weekend. :-(


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  #24  
Old 12-16-2018, 03:20 PM
David Ortiz David Ortiz is offline
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Location: SW Florida
 
Join Date: Dec 2018
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Mein Auto: 2014 X1 28i (AWD)
TireRack. Thoughts? I donít believe these are run flats.

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  #25  
Old 12-16-2018, 04:19 PM
Autoputzer Autoputzer is offline
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Location: NW Floriduh
 
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Mein Auto: 2014 535i + 2018 X3 30i
Measure your existing tires. You might be able to get away with putting the good ones (more tread) on the back. Then as they wear, the diameters will steadily come closer together.

Those ExtremeContact Sports are Continental's replacement for DW's. I'm on my second set of DW's on my beater. Continental is the "second source" that BMW uses for tires for M cars. I bought my DW's because Michelin doesn't a high-performance tire for my beater, except some very expensive one that meets Porsche "N" spec's, and has a lower load rating that what my beater calls for. For $160 in savings, yeah, I'd probably go for the Conti's.

My only gripes with my DW's are that it takes more pressure to keep them wearing evenly than the Michelin's on my 535i and that affects the ride, and they're made in low-wage Brazil. Those non-RFT Conti's will still be a massive improvement in ride over your RFT Goodyear LS2's.

Michelin's for my 535i were made in the U.S.A. Those Conti's in your size are made in Germany, by people who make as much or more than people who work in U.S. tire plants.

Last edited by Autoputzer; 12-16-2018 at 04:30 PM.
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