[rich8566]

Originally Posted by AlpsRider

It is normal on the US model M235i to have more heat on the left (drivers side). My car has always had this same issue since it was new. I'm sure it has to do with the extra coolant radiator on the drivers side front grill. On my car the amount of temp difference depends if I'm sitting in traffic, if it's a hot day etc.

Now that's not something that I had not considered yet.

[rich8566]

Originally Posted by Mike_bmw_m235

Mine is garage kept square setup and does it too

I hear you, but why?

[Questofthetune]

When I get back to my 235 this week I'm going to monitor it closely now. I'll even put pressures too just to be sure.

[rich8566]

Originally Posted by Questofthetune

When I get back to my 235 this week I'm going to monitor it closely now. I'll even put pressures too just to be sure.

Thank you!!

[Dylan86]

I didn't think these cars has TPMS sensors anymore. I know they use the wheel speed sensors now (not as effective but no more sensors), or at least that's how my '15 is setup in Canada..

Is there a split or year where they stopped using the sensors themselves?

[doccyber]

It's totally normal. Mine reads high on one side and then higher on the other. I'm not sure what the purpose of temp measure is anyway. I don't trust the readings anyway. Even when it comes to pressure readings I use my handy digital tire gauge every few weeks and adjust the pressure as needed. This is an example of over engineering IMHO.

[morphomeman]

TPMS still used here in US, on both my 2105 M235iX and my wife's 2016 X3.
I scoffed at OP's claim until this morning, when I checked tire pressure and temp. Lo and behold, driver's front tire is consistently 2 degrees F higher than the others, which are all the same!

[Luddy]

My pressures are always pretty similar but my temps are always also higher on the same side. I honestly chalked it up to that being the sunny side while my car is parked at work.

I don't worry about it to much since I always wondered how accurate those are to begin with.

[raleedy]

You can code your car to suppress the tire temperature readout. I recommend this.

[rich8566]

Originally Posted by Dylan86

I didn't think these cars has TPMS sensors anymore. I know they use the wheel speed sensors now (not as effective but no more sensors), or at least that's how my '15 is setup in Canada..

Is there a split or year where they stopped using the sensors themselves?

You are correct - OEM from the factory. I had coding done that displays individual tire pressures and tires temps.

[rich8566]

Originally Posted by morphomeman

TPMS still used here in US, on both my 2105 M235iX and my wife's 2016 X3.
I scoffed at OP's claim until this morning, when I checked tire pressure and temp. Lo and behold, driver's front tire is consistently 2 degrees F higher than the others, which are all the same!

See - I told you. But what's the root cause?

[rich8566]

Originally Posted by raleedy

You can code your car to suppress the tire temperature readout. I recommend this.

On the contrary - I coded my 2014 235i to display the tire temp and pressures.

[XutvJet]

My tire temps vary from 2 to 3 degrees on either side with the drivers side typically having the lower reading. We're talking a 2% to 6% difference in reading on a relatively cheap sensor and that's the easy answer. I wouldn't worry about it.

[xantdieselx]

Plain and simple it has to do with weight and braking. Brakes on most vehicles are larger in the front as the front wheels do most of the braking. Weight is transferred rear to front when braking adding heat to the tires and brakes. With a driver in the car most of the weight is on the left front. Combine this with the fact that the LF wheel is closest to the brake master cylinder and you have the reason for higher temps on the LF. The distance from the master cylinder is shortest from the master to the LF wheel. When applying the breaks fluid reaches the LF wheel first - did you ever notice how the LF wheel tends to be the dirtiest?

[morphomeman]

Great response! I believe you. All these factors (front weight, driver weight, distance from master cylinder) make perfect sense.
Thank you for a very elucidating post.

[harma24]

Originally Posted by xantdieselx

Plain and simple it has to do with weight and braking. Brakes on most vehicles are larger in the front as the front wheels do most of the braking. Weight is transferred rear to front when braking adding heat to the tires and brakes. With a driver in the car most of the weight is on the left front. Combine this with the fact that the LF wheel is closest to the brake master cylinder and you have the reason for higher temps on the LF. The distance from the master cylinder is shortest from the master to the LF wheel. When applying the breaks fluid reaches the LF wheel first - did you ever notice how the LF wheel tends to be the dirtiest?

Not sure I buy this either. I noted the difference on a long run on the highway. Hadn't touched the brakes in hours, and the trunk was loaded with more weight than me in the front seat.

[xantdieselx]

Originally Posted by harma24

Not sure I buy this either. I noted the difference on a long run on the highway. Hadn't touched the brakes in hours, and the trunk was loaded with more weight than me in the front seat.

You don't have to buy it. It's the truth. I worked in the the auto industry for 20 years. Seven of those years were spent as an ASE certified tech specializing in steering and suspension. So not just spitting out what I read on the internets.

[rich8566]

Originally Posted by XutvJet

My tire temps vary from 2 to 3 degrees on either side with the drivers side typically having the lower reading. We're talking a 2% to 6% difference in reading on a relatively cheap sensor and that's the easy answer. I wouldn't worry about it.

I hear you but my left front is consistently 10% hotter than the right front tire.

[rich8566]

Originally Posted by xantdieselx

Plain and simple it has to do with weight and braking. Brakes on most vehicles are larger in the front as the front wheels do most of the braking. Weight is transferred rear to front when braking adding heat to the tires and brakes. With a driver in the car most of the weight is on the left front. Combine this with the fact that the LF wheel is closest to the brake master cylinder and you have the reason for higher temps on the LF. The distance from the master cylinder is shortest from the master to the LF wheel. When applying the breaks fluid reaches the LF wheel first - did you ever notice how the LF wheel tends to be the dirtiest?

Hmmm - I need to see if the left front is dirtiest.

[jgunnz]

My front left is always warmer too, but only since I replaced that tire (nail in the sidewall). Makes sense to me in my case as that tire is newer and grippier. Had never been an issue before.

[Maynard]

Originally Posted by xantdieselx

Plain and simple it has to do with weight and braking......Combine this with the fact that the LF wheel is closest to the brake master cylinder and you have the reason for higher temps on the LF. The distance from the master cylinder is shortest from the master to the LF wheel. When applying the breaks fluid reaches the LF wheel first...

I think this is half right, and it sparked my 'duh moment' - that this probably reflects unequal cross-weights, thus more weight/force to one side or the other on braking (that, plus probably some inherent inaccuracy in the senders).

I don't think that the different distance from master cylinder has a measurable effect on timing of the brakes - I think they move at essentially the same time, otherwise you would consistently pull to the left each time you applied brakes. Surely would not be uneven enough to notice in brake dusting or pad wear, or else you would certainly feel a consistent pull (i.e. even if there is something to this, the engineers must have found a workaround).

[mdputnam]

Well, you could eliminate a few of these suggested problems by swapping the front wheels temporally to see if the off reading follows the wheel or stays on the same side. If it follows the wheel it's a sensor or tire problem, if it stays on the same side its something external.