Rear spring sag noted at 10K km tire rotation

Mike

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#1
Background:

Last night I rotated my tires at 10,157 kms.

I employed my four jacks and used my four jack pads at each of the four designated jacking points.

When the jack pads were first made, the jacks (at the rear jacking points of the car) barely cleared the bottom of the installed jack pads......but they did clear.

Three months and 10K kms later, I had to apply a gentle lifting force under the car to allow me to slip the jack under the jack pads on the two rear jack points.

The jack and jack pad assembly (both rear jack points only) is now about 1/4 inch too tall.

In other words, my rear springs have sagged about 1/4 inch since I have owned the car (since 01 June 2018).

Has anyone else noted a small amount of spring sag at the rear of a TM3 RWD/LR?
 

garsh

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#2
See people, you don't need lowering springs. Just keep driving. ;)

@Mike, does it look awkward at all? Did the front suspension settle with time as well?
If it's bothersome, it's probably worth taking to a service center.
 

Mike

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@Mike, does it look awkward at all? Did the front suspension settle with time as well?
If it's bothersome, it's probably worth taking to a service center.
It does not detract from the looks (yet).

If the trend continues, then I'll address it next summer as I won't be the only one witnessing it and Tesla will have a fix figured out by then.

Being far from a service center, I want to limit any time there to once a year (as/if required).
 

MelindaV

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#6
Good call and I went to have a look.

The TPMS reads within one (1) PSI between all four tires.

My manual tire gauge confirms the similarity of tire pressure for all four tires.
but similar to what the rear tires were previously?
 

racekarl

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#8
When I had new springs installed on my Audi, the installer had me drive around for a while (100 miles or so IIRC) before doing the alignment, to give the springs time to "settle" (his words), so anecdotally at least there seems to be some support for the idea that new springs do compress a bit.

That being said there seem to be way too many variables in your set up to say anything with certainty or to suspect that anything is wrong. Tire pressure and tread wear as mentioned, but also: are you jacking on asphalt? Were you in the exact same place in your driveway or on whatever surface you were jacking from? Are you sure your jack had fully lowered/retracted?

I have an antique car that I have to jack from the differential housing (I have to insert the jack a long way under the car under a very low rear valance) and I notice that sometimes I can get the jack under with no issues while other times I have to finesse it under a bit. This car barely has any suspension at all, so I'm pretty sure the variation has nothing to do with the springs ;)
 

Mike

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#9
When I had new springs installed on my Audi, the installer had me drive around for a while (100 miles or so IIRC) before doing the alignment, to give the springs time to "settle" (his words), so anecdotally at least there seems to be some support for the idea that new springs do compress a bit.

That being said there seem to be way too many variables in your set up to say anything with certainty or to suspect that anything is wrong. Tire pressure and tread wear as mentioned, but also: are you jacking on asphalt? Were you in the exact same place in your driveway or on whatever surface you were jacking from? Are you sure your jack had fully lowered/retracted?

I have an antique car that I have to jack from the differential housing (I have to insert the jack a long way under the car under a very low rear valance) and I notice that sometimes I can get the jack under with no issues while other times I have to finesse it under a bit. This car barely has any suspension at all, so I'm pretty sure the variation has nothing to do with the springs ;)
All good points.

So far, I view this as an observation.

I'm looking for any others that may have noticed the same thing.

The place where I do the jacking of this car is where I always park it, in bay number 3 of my garage, with a concrete floor.

The rear tires (at time of observation) were 1/16" less in radius than when new and all four tires are within one PSI of the book value of 42 PSI.

The springs may have settled as you stated.

I'll know more when it's time to swap my all seasons with my winter tires this November.