drewd Posted September 16, 2006 Share Posted September 16, 2006 While driving home last night in the pouring rain the soob started to feel jerky when the rain got heavy...doing about 60 on the highway at times. I know i was hydroplaning at that speed and i could feel it...she stuttered for a bit and then it was ok...very weird. So, what's going on and is this normal? '03 H6 with 60k, no problems otherwise. Quote Link to comment Share on other sites More sharing options...
Manarius Posted September 16, 2006 Share Posted September 16, 2006 AWD doesn't stop hydroplaning; slowing down does. Hydroplaning comes from when your car's tires can't displace enough water to keep the rubber directly in contact with the road. Quote Link to comment Share on other sites More sharing options...
Wayne Boncyk Posted September 16, 2006 Share Posted September 16, 2006 Manarius is right -- and at higher speeds, I've often felt a little "jerkiness" on snow and ice in my Sube as well. If all 4 wheels are slipping, no amount of AWD will help. What you were probably experiencing (this is a guess -- but it seems to make sense) is that you were floating on all 4 wheels for a good portion of that time when the rain was heavy, but occasionally one pair or the other would catch hold of enough pavement to grab a bit. happens to me on ice all the time -- although I'm not usually cruising at 60mph when it happens! Quote Link to comment Share on other sites More sharing options...
dmanaenk Posted September 16, 2006 Share Posted September 16, 2006 Let me guess, still on original tires? AWD/traction control/stability control etc help manage existing traction. Existing traction depends only on tires. Quote Link to comment Share on other sites More sharing options...
jon38iowa Posted September 16, 2006 Share Posted September 16, 2006 Let me guess, still on original tires?AWD/traction control/stability control etc help manage existing traction. Existing traction depends only on tires. I think I would consider new tires. John Quote Link to comment Share on other sites More sharing options...
Dickensheets Posted September 16, 2006 Share Posted September 16, 2006 Hydroplane speed = 9 x sq. root of the tire pres. If pres. differs among tires, hydroplaning will not occur uniformly. rd Quote Link to comment Share on other sites More sharing options...
nipper Posted September 16, 2006 Share Posted September 16, 2006 Tires play a huge part in hydroplaining. AWD helps to some degree, but its mostly tires. When i had the FWD fuse in the car hydroplaned like mad, but after the awd was fixed, it almost disapeared. My tires are 1 year old BFGoogri How many miles and what brand of tires are on the car. nipper Quote Link to comment Share on other sites More sharing options...
drewd Posted September 16, 2006 Author Share Posted September 16, 2006 Stock Potenzas...they have 60k on em. I'm starting to look for tires, but i think i can get another 15-20k on these...they're in pretty good shape. I never measured the depth of the treads, but i can tell you they're far from being bald. Still no answer to the question, though...why was the soob jerking while hydroplaning? Quote Link to comment Share on other sites More sharing options...
Wayne Boncyk Posted September 16, 2006 Share Posted September 16, 2006 Like I said earlier, jerking because the wheels make/break traction in an unpredictable manner when you're riding over top of a thin layer of water. That's my guess. You feel it differently in an AWD vehicle than in 2WDs. Quote Link to comment Share on other sites More sharing options...
nipper Posted September 16, 2006 Share Posted September 16, 2006 Like I said earlier, jerking because the wheels make/break traction in an unpredictable manner when you're riding over top of a thin layer of water. That's my guess. You feel it differently in an AWD vehicle than in 2WDs. what he said. And a tire doesnt have to get bald to outlive its usefulness. 60K is a good run for a set of tires. nipper Quote Link to comment Share on other sites More sharing options...
jon38iowa Posted September 16, 2006 Share Posted September 16, 2006 what he said. And a tire doesnt have to get bald to outlive its usefulness. 60K is a good run for a set of tires. nipper I agree nipper; Moreover, sometimes a particular tire is just not all that good in some areas. I had a set of Goodyears quite a number of years ago, anyhow ( and I like Goodyear) they were like greese on a banana peel in only slightest dusting of snow, and it was rather scarry. I noticed not long after I got rid of them, Goodyear discontinued them. John Quote Link to comment Share on other sites More sharing options...
Setright Posted September 16, 2006 Share Posted September 16, 2006 Hydroplaning is not affected by AWD / RWD / FWD As some people already mentioned, it's only related to speed, tyres, and depth of water. Where AWD does make a difference is on the resulting wheelspin. It will be reduced notably. An FWD car will tend to tug on the steering wheel a lot as the fronts spin indepedently. RWD will fill loose in the rear. AWD will do a bit of both, but less pronounced and more predictable. Quote Link to comment Share on other sites More sharing options...
dmanaenk Posted September 16, 2006 Share Posted September 16, 2006 Stock Potenzas...they have 60k on em. I'm starting to look for tires, but i think i can get another 15-20k on these...they're in pretty good shape. I never measured the depth of the treads, but i can tell you they're far from being bald. Still no answer to the question, though...why was the soob jerking while hydroplaning? Thats what I thought... Many people dump these re92-s right after they buy a car, and for a good reason. I honestly think that any decent tire will not (should not) last past 40k with average use. If I were you - I'd change the tires asap. Your experience says that tread depth is no longer enough to direct water away from contact patch, and it's gonna be getting worse every day. Sure, you can drive these until they become illegal to drive on (and even past that) but if you choose to do so - at least slow down. Quote Link to comment Share on other sites More sharing options...
Ranger83 Posted September 16, 2006 Share Posted September 16, 2006 There are a lot of simplifactions here for a phenomena that everyone has experienced. NTB will give you a tire depth gage, or you can buy one for about a dollar. Most new tire treads are 10/32 or 11/32nd when new. When they are worn down to the wear bars, they have 2/32nds. Some other rules exist in other countries: for example, some countries in the Alps specify that a snow tire with less than 5/32nds tread is no longer legally considered a snow tire. Tread depth is one factor in determining the speed at which you hydroplane. When tires are worn down to 5/32nd or 6/32, while they are still "legal" their ability to evacuate water is diminished. The issue with the RE92's is that they feel a little greasy in the wet, and their breakaway is abrupt. The best rain tires break away very gradually, giving you plenty of feedback as you approach the limit of adhesion. Why Subaru chose a tire that is ranked near the bottom of All Seasons for rain and snow traction for the newest generation Outback is a mystery. Especially considering the OEM Michelins that came on many Gen I cars. How bad is their reputation? I listed my OEM RE92A take-offs (with 500 miles on them - essentially new) on eBay in two auctions of two with a $50 Reserve price - and neither pair sold. They cost about $175 each new....... From: http://www.nhtsa.dot.gov/cars/rules/rulings/TPMS_FMVSS_No138/part5.6.html The conditions that influence hydroplaning include speed, tire design, tread depth, water depth on the road, load on the tires, and inflation pressure. At low speeds (less than about 50 mph), if your tires are under-inflated, you actually have more tire touching the road. However, hydroplaning does not occur very often at speeds below 50 mph, unless there is deep water (usually standing water) on the road. As you get to about 55 mph and the water pressure going under the tire increases, an under-inflated tire has less pressure in it pushing down on the road and you have less tire-to-road contact than a properly inflated tire as the center portion of the tread gets lifted out of contact with the road. As speed increases to 70 mph and above and water depth increases due to a severe local storm with poor drainage, the under-inflated tire could lose 40 percent of the tire-to-road contact area compared to a properly inflated tire. The higher the speed (above 50 mph) and the more under-inflated the tire is, then the lower the tire-to-road contact and the higher is the chance of hydroplaning.Tread depth has a substantial impact on the probability of hydroplaning. If you make a simplifying assumption that the water depth exceeds the capability of the tread design to remove water (which most likely would occur with very worn tires), then an approximation of the speed at which hydroplaning can occur can be estimated by the following formula:Hydroplaning speed = 10.35 x inflation pressure [25] Under this assumption of water depth exceeding the capability of the tread design to remove water: At 30 psi, hydroplaning could occur at 56.7mph At 25 psi, hydroplaning could occur at 51.8 mph At 20 psi, hydroplaning could occur at 46.3 mph. This is presented to show the relative effect of inflation pressure on the possibility of hydroplaning. Quote Link to comment Share on other sites More sharing options...
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