Background. The front tires on our 2007 were wearing much faster than the rears, and the last time I took it in to have them rotated, because the shop was doing other work, they told me that I shouldn't rotate the worn ones to the back. Well, they said this when handing the car back and I had to get going, so fine, but then I forgot about it, and now the front tires are down to the wear bars, while the rears are not very worn at all. Today I went to the store after it had been sprinkling on and off, so the pavement was wet, or at least very damp, but no standing water and definitely no ice, snow, or gravel. Made a right turn from a minor street onto a major street, and gave it a fair amount of gas, and the front end sort of hopped, or bogged down and then released, a couple of times for about a second. The ABS light didn't come on, nor did a CEL. The wife's Accord in a similar maneuver will often spin the inside front tire to the point it chirps. The Prius hasn't done this before though, and there was no chirp. It has done a vaguely similar little dance when one of the tires came off the ground after a one side bump or one of the tires passing over a pothole. Anything that caused one tire to lose contact. Previously that has only happened when going in a straight line, and in every case the ABS flashed for a second. Other than this odd bunny hop the car is driving normally. Seems like it was some sort of traction control event. Any ideas what?
IMHO, your mechanic is lazy and full of it. You want the meaty tires in the front. Warning bars on tires in the rear would potentially allow the rear end to swing out on turns - less weight and less traction. The wheel hop was it trying to grab traction - ease up on the accelerator on damp roads. I've seen a lot of young drivers spin-out on damp and snow covered roads because they're driving like the road is dry..... YMMV
In a car with ABS, sure. But without antilock you'd want your best tread in the rear, even with FWD. Thankfully every Prius has ABS. @pasadena_commut I agree with above; you are requesting more torque than your tires can deliver to the road. Ease up.
Just to be clear, when this happened the car wasn't being floored, the accelerator was around half way down. For me driving this car that is hard acceleration. It has been floored only very rarely, in most cases to avoid being obliterated when merging onto a highway. I think the Bridgestone Ecopias on the front, worn down to the indicator bars, just don't have a lot of grip in the wet. As I understand it the reason one puts the better tires on the back is because it is more difficult to recover from the back end breaking loose than the front.
If your back end is breaking loose, your probably traveling too fast for the conditions your driving in. On a FWD, all you have to do is point the steering wheel where you want to go and 'blip' the accelerator pedal - rear end should fall back in-line. That even works on black ice patches that I sometimes hit, going through the mountains..... I always replace tires just before warning markers stripes touch the pavement. If I can't afford them, the meatiest ones go in the front for grip and stopping power. I don't drive like an idiot any more....
The good tires in the back logic is because 99% of people have no idea how to control oversteer, the situation when the back wheels lose grip before the fronts. I am in the 1% and in over 50 years of driving have never had an accident from an oversteering condition. I have hung the back wheels out, done a 180, and 360 without a scratch. But enough of that . You should replace the tires when the wear bars are close to the tread, in winter or during rainy season if they get close do it earlier. Biomed is on track with the replacement statement but I disagree on the "blip" of the gas. The traction control will play havoc with using power to straighten out, and even without TC the blip can break the fronts loose so you lose steering. A slight increase of throttle can help pull the car into line, but just a bit. A tire has X pounds of grip, which is available for accelerating, braking and cornering. To maintain control one of the first 2 and the cornering grip have to stay less than X. When the cornering force exceeds X the back end skids, comes out, or oversteer happens. All the same thing. When your car "hopped" it might have been a combination of tire slip, road surface, traction control kicking in and worn struts. It definitely was your car telling you to push the gas less or get new tires.
I've never had oversteer problems on the Prius even with spirited driving (which I hardly ever do these days) and remember it isn't a performance sports car where you're trying to go around corners on two wheels. Generic advice is fine, but horses for courses guys! For the Prius, I will always favor the best tread on the fronts which is what naturally happens when you rotate tires as the fronts will always wear faster than the rears.
If you rotate tires regularly, then you keep tread wear "equalized". Posted via the PriusChat mobile app.
