Reverse Flatspotting With Warmed Up Tires?

[dwchapmanjr]

Long history but short of it is long standing vibration seems to be related to tire temperature.

 

2015 GMC Yukon.  New Tires (Bridgestone Dueler HL) 1/31/2020 w/Alignment.  They noticed front right strut was leaking and replaced.  Vehicle seemed to drive without issue for at least 2-3 months.

 

COVID-19 hit and I hardly drove anywhere for a few months.  There was a month span where my truck left the garage only a handful of times.  Tires have 3k miles on them despite being 9 months old now.

 

Around July I started driving a bit more and I noticed a pretty bad road vibration and started looking at remaining shocks.  Replaced 2 years and it seemed to help as they were leaking and then remaining front strut as it was leaking hoping this would resolve my issue.

 

Took it to the dealer and they road force balanced and rotated, not finding any suspension or tire issues.  When I drove away, there was a hard pull to the left.  Took it to local shop as I figured it was an alignment but alignment was dead on.  They road force balanced and rotated and pull went away.  I later found out one of the tires had conicity and was replaced and pull went away.

 

This week in Houston we had a bit of a cold front and I noticed it was driving back to normal, like earlier in the year.

 

Yesterday I was driving around and noticed as soon as the tires started to heat up to 38psi (Cold tire pressure is 35psi), the vibration started to get worse so I pulled over and deflated 2 psi.  Next tire got up to 38 and vibration started and I did the same thing and it went away for 10 minutes but came back as the tires seemed to warm up and inflate more due to that.

 

Today I drove trying to reproduce and it seemed to drive better than yesterday and took about 40 mins to get some vibrations that were not even as bad as they have been before.

 

Am I working out some flat spotting?  Or is it possible that some tires that have issues that show when they warmed up?  Or is it possible I have a suspension issue that slightly under-inflated tires are masking?

 

I plan on going back to the dealer and have them run a picoscope to confirm the source of the vibration and look again.  Questions I should be asking them, things I should verify they're checking, etc?  This issue has been driving me crazy for months and seems to be going away on its own due to cold temp (55-60F in the mornings, high of 85F) versus the triple digits we were getting in the summer.

 

Looking back at the Jan-March timeframe it would have been around the same temp here so I'm wondering if I'm exposing a temperature related issue with the tires that shows up when the ambient temp is much warmer or the tires have a chance to get hotter.

 

I have the full story documented here before I even thought it might be tire related

 

 

Edited October 1, 2020 by dwchapmanjr
added info