Understeer, or slippery road?

[eksjay]

Just had a moment when I turned the steering wheel left (to turn into a street), when the car wanted to continue straight. I landed gently on a shallow island divider without incident following gentle braking (no ABS). I had the car in FT 4WD and my speed was slow (GY Silent Armors) tyres have 10k on them with deep tread. The car drove fine the rest of the way. It has been flawless for a 150km drive taking bends and turns fine. Had a look under the hood and the steering box and arm are in the right place, fixed in place. The track rod seems to be moving fine, left and right.

Before I put it down to slippery roads due to the wet, oil slick, grease etc, is there anything that could contribute to random (I.e. could it happen again?) understeer when turning left or right? Today was more like loss of control. What should I check for?

[Mace1]

Originally Posted by eksjay

Before I put it down to slippery roads due to the wet, oil slick, grease etc, is there anything that could contribute to random (I.e. could it happen again?) understeer when turning left or right? Today was more like loss of control. What should I check for?

Dont underestimate the local road surface (wet or dry)....

I have a full set of BFG AT's in very good condition. There are a couple of tight roundabouts I regularly take that are like polished glass - concrete and aggregate surfaces. Ive seen several cyclists fall and cars depart from the correct line while turning (wet or dry), and the Jeep would do the same if I didnt take extreme care when its at all moist.

[awg]

Originally Posted by eksjay

Just had a moment when I turned the steering wheel left (to turn into a street), when the car wanted to continue straight.

Before I put it down to slippery roads due to the wet, oil slick, grease etc, is there anything that could contribute to random (I.e. could it happen again?) understeer when turning left or right? Today was more like loss of control. What should I check for?

If a bitumen road has been dry for ages, like it has been around here, and then gets very wet, as it just has done, all the accumulated rubber, oil & diesel will be washed suddenly to the surface, causing very slippery conditions indeed.

can also cause rear LSD to activate, destabilising the rear on greasy bitumen

[LuluBelle]

"I had the car in FT 4WD and my speed was slow" ???
How come if you were on the street?
_____ooooo
/__l_l_,\____\,___
l_---l_l__l---[ ]llllll[ ]
_.(o)_)__(o)_)--o-)_)

[eksjay]

FT 4WD.

I usually have this Selec-trac setting by default (pre update 4.0L sport, no LSD), especially in rain. It has been bucketing rain in and around Sydney. This incident happened in a quiet suburban Sydney street. I have taken this same corner a million times, and my driving is conservative. After this incident, I drove it home like a grandma. Will ask my mechanic to look over it. I had this happen previously but at freeway speed about 3 weeks ago in semi wet conditions. I managed to keep control of it on a 100k/h zone by applying the brakes carefully but keeping the steering straight on a bend. I was doing 80k/h at the time. Again, I have done this road many times.

Can the power steering pump or some other component give up sometimes, requiring lots of steering input? There is no sign of leaks and I have not noticed the steering wheel getting heavy.

[oldon]

After a long dry spell like we've had it can take a while, a couple of days even before all the slippery stuff gets washed away & can catch you out easy. Just my experience with goodyear tyres mate, but I'd rather have the cheapest chinese tyre on buckled rims than goodyears.

[eksjay]

Thanks Oldon, I suspect it was greasy conditions that caused my scare yesterday. I tried to replicate this understeer on a quiet road closer to home this morning (in the wet), and the car took the correct line every time.

As for the Goodyear Silent Armors, I have used them for many years and found them to have great traction in the wet and dry (even on the JKU). The original good year radials were total crap by comparison, on and off road and I used to aquaplane in small puddles. Off road, the only place they were suitable to run was on sand, they used to melt like butter on gravel tracks.