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Jerking on slow turns

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Old 01-05-18, 05:08 PM
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tommyz
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Default Jerking on slow turns

I have a 2017 RCF with about 380 miles on it. It has been jerking when making slow sharp turns particularly when cold. I purchased it in October when it wasn't that cold in NYC yet and all was good. But lately with the 20 degree whether we have been having in NYC lately, when making U turns or backing out of driveways or anything with slow sharp turns the whole cars almost pops or jerks. I dont know if its because of running the pilot super sport tires way below their operating temperature with a LSD or if something is already broken. Anyone have any idea what it could be?
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Old 01-05-18, 06:05 PM
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backing up is normal to feel a skip or a jerk, it has to do with the steering geometry coupled with the low profile tires, and it is apparent on a lot of vehicles, My RCF, my former Camaro, Chrysler 300c, and Mustang all did it. I've read complaints about it on Corvette, MBZ, Challenger, Audi, Caddy, and even Lambo Forums.

It's what happens when you back out with the wheel turned too hard. Just decrease the turn a little and it won't happen. It doesn't happen all the time and will sometimes show up if you hit sand or some other slippery material on the pavement (parking lot stripes for example, or street lane paint). It's part of the price you pay for high performance alignment specs and low profile tires.

personally I haven't noticed it with forward turns, but keep in mind those tires are not designed or safe at temperatures under 35
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Old 01-05-18, 08:16 PM
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Summer tires on cold pavement. Perfectly normal. All three of my cars do this (well, the GS F doesn't now because I put all season Pilot Sports on it).
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Old 01-09-18, 12:18 PM
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Originally Posted by lobuxracer View Post
Summer tires on cold pavement. Perfectly normal. All three of my cars do this (well, the GS F doesn't now because I put all season Pilot Sports on it).
^^^ Have observed the same phenomenon with my other car with the same Michelin PSS tires. After driving a mile or two, no more clunking.
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Old 01-10-18, 04:05 PM
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Yep would agree that its the Pilot Super Sports. Had similar behavior with my previous two vehicles. If you are going to be driving in colder temperatures a lot, the Pilot Sport A/S 3(+) is a great tire. Little comfier of a ride as well.
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Old 01-10-18, 06:05 PM
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Originally Posted by harkirath View Post
...If you are going to be driving in colder temperatures a lot, the Pilot Sport A/S 3(+) is a great tire. Little comfier of a ride as well.
+1 on this approach. This is what I did for the GS F since it's our "family" car now and Atlanta gets into the 'teens from time to time in the winter. PSS can be downright scary in below freezing temperatures.
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Old 01-11-18, 12:33 PM
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Originally Posted by lobuxracer View Post
+1 on this approach. This is what I did for the GS F since it's our "family" car now and Atlanta gets into the 'teens from time to time in the winter. PSS can be downright scary in below freezing temperatures.
Yep got those AS 3+ on the "family" car E class. Much smoother ride than the terrible Bridgestones that I believe it came with. The PSS will stay on the F as I'm not looking for the smooth ride here and they should be able to handle the NorCal rainy season fine. The F will never see snow for me.
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Old 01-13-18, 03:54 PM
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Hell this happens with my GS350 when making slow, tight turns... most noticeable when parking, or backing out and turning around, etc.

Also, running PSS at these temps... not a good idea, even dry. And wet is basically a death wish... so be careful!

-Mike
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Old 01-14-18, 06:41 AM
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Suspension geometry due to the "Ackerman". The inside tire turns at a slightly sharper rate than the outside tire due to the linkage setup. The tires trace at slightly different radii and that is more profound at slower speeds, causing the jerking motion you're referring to, but assists heavily in the handling of the car at higher speeds.
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Old 01-14-18, 01:55 PM
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If it were Ackerman, it would exhibit on any tires. It doesn't. It's only with summer tires in cold weather. The A/S3+ on the GS F have made no noise at all, but the PSS chattered badly in the cold.
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Old 01-18-18, 01:07 PM
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I also think its the cold weather on Super Sports. My car exhibits the same behavior but only when the temperature is below about 40 degrees. My Porsche 911 used to the do the same. Wouldnt worry about it.
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