AZ28driver

I have a new set of 275/40/17 BFG KDW on my car and it feels as though the tires have a flat spot in them. It only occurs on cold mornings when the car has been sitting all night and goes away after 5 mins of driving. Tire pressure (cold) is set at 35 psi all the way around. Has anyone else run into this problem? I never noticed this with the 245/50/16 GSC's that I had on the car. Thanks in advance for your feedback.

Xsta Z 28

iTrader: (2)

Can't say I ever noticed on the Berger, but I realy don't drive it when it is cold.

It is possible that the compounds of the BFG are softer, and when they cool off develope a short term memory.

Brady

iTrader: (3)

Mine do that in cold weather, it usually goes away after 1/2-3/4 mile tho..

laterz
<img border="0" alt="[cheers]" title="" src="graemlins/gr_cheers.gif" />

AZ28driver

WOW. I sent an Email to BFGoodrich and they called me back. I'm impressed! <img border="0" title="" alt="[Smile]" src="gr_stretch.gif" /> They had an engineer call me and he said the feeling of the tire having a flat spot (during initial cold weather driving) is the result of the nylon cord that is used as an overlay on the steel belts. The Nylon cord is there to keep the steel belts cool during high speed driving by shielding the steel belts from the heat generated by the tread and to prevent the steel belts from growing as a result of centrifugal forces as the tire spins faster. He said that the brief feeling of a flat spot inthe tires after the car had sat for a period of time was nothing to worry about. <img border="0" alt="[cheers]" title="" src="graemlins/gr_cheers.gif" />

unfcamaro

How cold are you talking, I have those tires and live in FL and ave never felt that, but I've only had them since July.

scot

Mine are on a 94 Impala and they do exactly as you descibe. Thanks for posting your response from BFG.I'm so impressed with them on the Impala that I'll be getting a set for my Camaro in the spring. I use 38psi. front and 30 psi. rear and it's surpriing how neutral it is.

scot

Surprising how poorly I can type.

AZ28driver

In response to your question Unfcamaro I first noticed this when the morning temp was about 30* F. I bet that is a problem for you in warm FL. <img border="0" title="" alt="[Big Grin]" src="gr_grin.gif" />

unfcamaro

</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by AZ28driver:
<strong>In response to your question Unfcamaro I first noticed this when the morning temp was about 30* F. I bet that is a problem for you in warm FL. <img border="0" title="" alt="[Big Grin]" src="gr_grin.gif" /> </strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">Yeah, I try not to go outside when it gets that cold, haha <img border="0" title="" alt="[Big Grin]" src="gr_grin.gif" />

Quickin

It's the same thing that aircraft get, mainly heavy jets. It always happens on the Learjets that I fly when they are filled with fuel and they sit like that (very heavy) for more than 15 minutes.

It's called "chock effect". The tire contact patch gets flattened from the weight, it just takes a little time and revolutions to stretch back to sherical. We've had captains call in from trips saying that they have a flat spot but can't see it, I would tell them to just taxi to the runway and by the time they get to the hold line it would be gone.

Same thing with car tires.

niphilli

My AVS sports do this and so so my KDWs.