Suspension fit the same / wheels?

[unluky]

So I have a Xdrive 35i with the 18" tires all around - smallest available. Looking to upgrade, but the front suspension is pretty tight against the wheels/tires now, but I assume all the F15's are the same suspension wise, so as long as I stay within stock sizes and offsets - I should be safe - right?

In other words ALL F15 OEM wheel and tire combos would fit and clear on my car (no big brakes to worry about) correct? IF so that can be my stick to make sure everything would clear.

Like a 375 style 21" x 10" wide with a 285/35/21 with a 40mm offset would clear right, so anything "less" than that would too?

Everything I read says this is right, I'd just hate to find out they hit my suspension when I went to mount them because I was an idiot.

Thinking about a 20" square set up with a 10" wide wheel and 275 tire - as long as my offset is 40 or less - it should fit with no rubbing as long as I choose my tires wisely. Unless I am wrong on this...............

[HJ]

Originally Posted by unluky

So I have a Xdrive 35i with the 18" tires all around - smallest available. Looking to upgrade, but the front suspension is pretty tight against the wheels/tires now, but I assume all the F15's are the same suspension wise, so as long as I stay within stock sizes and offsets - I should be safe - right?

In other words ALL F15 OEM wheel and tire combos would fit and clear on my car (no big brakes to worry about) correct? IF so that can be my stick to make sure everything would clear.

Like a 375 style 21" x 10" wide with a 285/35/21 with a 40mm offset would clear right, so anything "less" than that would too?

Everything I read says this is right, I'd just hate to find out they hit my suspension when I went to mount them because I was an idiot.

Thinking about a 20" square set up with a 10" wide wheel and 275 tire - as long as my offset is 40 or less - it should fit with no rubbing as long as I choose my tires wisely. Unless I am wrong on this...............

Why not just go the traditional staggered setup for the peace of mind not sure what advantage you would have of going a square setup other than rotating tires or getting all season runflats. I have yet to see anyone go 275's squared but Im sure it can be done considering the 611m orbit grey's have a 285/40 squared winter setup with wheels being 20x10 20x10.5. OEM 21 wheels Im not too sure about due to the fact that last year I was interested in getting the 599s but my dealer advised me that it wouldn't be compatible because I had the standard air suspension and not the M adaptive suspension, said it would put a strain to my transfer case causing it to potentially fail which would then be red flagged by bmw and void any warranty that's related. Ive heard mixed feedback on this from others but then again Ive yet to see this happen to anyone but I do recall seeing someone here with under 15k miles had his transfer case go on the jersey turnpike with 612's but had it covered under warranty

[unluky]

You nailed it - rotating. I have had many a staggered set up car and they eat tires like nothing I have ever owned. I also don't have flare and don't want them, so that 315 hanging out the back would look like ass. I have seen a few 275 & 285 squared set ups and they seem to be fine. I just like them flush and not pokeing out which I can fix with a offset, I just want to make sure if I use a 375 wheel front as my "do not cross line" I am using something that will fit on the front of ALL F15's - which I think it would.

If my cals are right, a 375 with a 285/35/21 would put the backside of the tire .36378 further into my wheel well, so I should be able to put a 275 on a 10" wheel and adjust the offset back to that point and clear everything.

Again - if my math is right......lol

[ems328i]

I run 275/40/20 ET40 all round with zero issues. Probably will still order some 5mm spacers for the rear, but without the fender flares I want to stay flush with the fender....

[unluky]

Originally Posted by ems328i

I run 275/40/20 ET40 all round with zero issues. Probably will still order some 5mm spacers for the rear, but without the fender flares I want to stay flush with the fender....

HA! You sent me those photo's via PM awhile back when I was trying to decide if a 275 would look right to me on a 10" wheel! i found them again last night looking through my notes. That is to my taste too - I don't care for that hanging out look. I rather it be a shade too tucked under than sticking out - like you said - you can always use spacers if you want. That front suspension is tight to the tire though. A 275/40 is going to make my speedo off and give me less cushion for ride, but a 275/45 ig going to make it a little off the other way, but make my ride better - IF it does not hit. They are a inch taller and .7" taller than my current tires and I just wanna make sure I don't rub that front arm!

You have plenty of clearance up front?

[ems328i]

Originally Posted by unluky

HA! You sent me those photo's via PM awhile back when I was trying to decide if a 275 would look right to me on a 10" wheel! i found them again last night looking through my notes. That is to my taste too - I don't care for that hanging out look. I rather it be a shade too tucked under than sticking out - like you said - you can always use spacers if you want. That front suspension is tight to the tire though. A 275/40 is going to make my speedo off and give me less cushion for ride, but a 275/45 ig going to make it a little off the other way, but make my ride better - IF it does not hit. They are a inch taller and .7" taller than my current tires and I just wanna make sure I don't rub that front arm!

You have plenty of clearance up front?

275/40 is the stock factory size for the front on 20" wheels, so your speedo will be exactly as it should be, and clearance is also not an issue if you stick to the factory spec of ET40. Don't know if these pics help but I have been running this setup for 2 months and been over some pretty big bumps and it's been fine.

275/40 is perfectly comfortable, my wife doesn't complain (and she would) so it must be ok!

[201]

Originally Posted by unluky

HA! You sent me those photo's via PM awhile back when I was trying to decide if a 275 would look right to me on a 10" wheel! i found them again last night looking through my notes. That is to my taste too - I don't care for that hanging out look. I rather it be a shade too tucked under than sticking out - like you said - you can always use spacers if you want. That front suspension is tight to the tire though. A 275/40 is going to make my speedo off and give me less cushion for ride, but a 275/45 ig going to make it a little off the other way, but make my ride better - IF it does not hit. They are a inch taller and .7" taller than my current tires and I just wanna make sure I don't rub that front arm!

You have plenty of clearance up front?

Not sure in your case but I had the same dilemma a few months ago and I actually think you helped me out on one of my threads. As I was planning on giving my F16 to the wife while getting another car I wanted it to be more practical for her commutes by getting her all season runflats for the 611m's which were the winter grey set that previously had the pierlli snow runflat 285/40r20 squared. As you can imagine there wasn't an OE spec option in all season runflats so I ordered something close which was the pierlli scorpion verde all seasons at 285/45r20 squared Im sure it had something to do with my drop at that time but even with my KW3's at its highest setup the tires would rub at times..ended up returning them and getting conti's dws all seasons 275/40 315/35 and a spare tire kit

[unluky]

Originally Posted by ems328i

275/40 is the stock factory size for the front on 20" wheels, so your speedo will be exactly as it should be, and clearance is also not an issue if you stick to the factory spec of ET40.

40 tire profile is perfectly comfortable, my wife doesn't complain (and she would) so it must be ok!

if 40 is fine....45 would be finer!

275/40/20 would be a shade shorter than my current 18's but not more than 1mph or so. mine is actually fast now by about 2 mph, so 45's would increase the ride AND made my speedo right.

might rub though up front, that would suck.

[unluky]

Originally Posted by 201

Not sure in your case but I had the same dilemma a few months ago and I actually think you helped me out on one of my threads. As I was planning on giving my F16 to the wife while getting another car I wanted it to be more practical for her commutes by getting her all season runflats for the 611m's which were the winter grey set that previously had the pierlli snow runflat 285/40r20 squared. As you can imagine there wasn't an OE spec option in all season runflats so I ordered something close which was the pierlli scorpion verde all seasons at 285/45r20 squared Im sure it had something to do with my drop at that time but even with my KW3's at its highest setup the tires would rub at times..ended up returning them and getting conti's dws all seasons 275/40 315/35 and a spare tire kit

Hmmmm...good to know! 285/45 would be close to a 1/2" taller than a 274/45 and they only rubbed sometimes? but since your not in stock suspension it is hard to say. Your highest setting might be higher than me stock level.

So close, it's hard to say. Unless I can find a used one to mount and test it'd be hard to say for sure. Too many variables.

[ems328i]

Originally Posted by unluky

if 40 is fine....45 would be finer!

275/40/20 would be a shade shorter than my current 18's but not more than 1mph or so. mine is actually fast now by about 2 mph, so 45's would increase the ride AND made my speedo right.

might rub though up front, that would suck.

According to this:https://tiresize.com/speedometer-calibration/

If your speedo is reading 60 mph with your 255/55/18, then with 275/40/20 it would read 59.21 mph.

With 275/45/20 it would read 61.45 mph.

So actually 275/40 would give you a more accurate reading....

This also gives you a good visual indication of the size differences: https://tiresize.com/comparison/

[unluky]

Originally Posted by ems328i

According to this:https://tiresize.com/speedometer-calibration/

If your speedo is reading 60 mph with your 255/55/18, then with 275/40/20 it would read 59.21 mph.

With 275/45/20 it would read 61.45 mph.

So actually 275/40 would give you a more accurate reading....

True, but mine is already fast by about 2 MPH for some reason, so the 45's would help that! LMAO!

[201]

Originally Posted by unluky

Hmmmm...good to know! 285/45 would be close to a 1/2" taller than a 274/45 and they only rubbed sometimes? but since your not in stock suspension it is hard to say. Your highest setting might be higher than me stock level.

So close, it's hard to say. Unless I can find a used one to mount and test it'd be hard to say for sure. Too many variables.

Correct even at its highest setup it was still about .4 lower than stock. It would rub going up incline roads, going up on my driveway, going over bumps could actually hear the tire rubbing noticeably louder if the tire was wet.

[ems328i]

Originally Posted by unluky

True, but mine is already fast by about 2 MPH for some reason, so the 45's would help that! LMAO!

Sorry but that's not how I read it. If you are 2 mph fast with your 18's (ie 62 mph indicated when actually doing 60 mph), then 275/45 would read 63.45 mph indicated when actually doing 60?

[unluky]

Originally Posted by ems328i

Sorry but that's not how I read it. If you are 2 mph fast with your 18's (ie 62 mph indicated when actually doing 60 mph), then 275/45 would read 63.45 mph indicated when actually doing 60?

Right now if I am going 80 by the gauge - I am really going 78. I tested this with 3 GPS (which showed both my other cars as spot on and a friend who is a cop shot me once too......and accidentally 2 weeks ago by the IL Highway Patrol

So if I went from my 255/55/18's to a 275/45/20 that would in theory make my 80mph on the gauge be 81.9mph on the road - but with it being 2 mph fast now it would make it almost spot on.

Again - if it does not rub!

Those picture look like your 275/40 has plenty of room to fit another 1/2 inch in there though - I need to measure mine as it would only be 1/3 inch from mine since the other part of the Dia change goes into lifting the car up.

Might not be as much difference as I had in my head.

[unluky]

Originally Posted by 201

Correct even at its highest setup it was still about .4 lower than stock. It would rub going up incline roads, going up on my driveway, going over bumps could actually hear the tire rubbing noticeably louder if the tire was wet.

Aaaaaa - so even at it's highest setting you were LOWER than stock - ok that gives me some confidence then. I'd only be 1/2" taller than the stock 275/40 and 1/3" taller than my current 18's - so I should be fine.

285/45 would be 2/5ths wider than 275 and the same taller and if you only rubbed some and with your truck lowered - that might help. But I guess the arm I am worried about rubbing on would not be affected by being lowered - so that might not be a safe bet.......I'm not worried about rubbing on the body - but the arm. I'm talking myself in circles here......lol

Still if I went with a 40 offset - and used a 275 - I would be the same depth as ems328i's setup and only be 1/3" taller than I am now and his setup looks like it has tons of room in there for that.

[ems328i]

Good luck with it and let us know how it goes

[unluky]

Originally Posted by ems328i

Good luck with it and let us know how it goes

One thing about me - I don't mind sharing my shit shows!

Whats the good of being stupid if other's can't learn from your mistake........

[ems328i]

Originally Posted by unluky

One thing about me - I don't mind sharing my shit shows!

Whats the good of being stupid if other's can't learn from your mistake........

The very words I live by!