Traction question for car gurus

**Bunni** · 12-10-13, 12:07 PM

If I have a light car (mini cooper), front wheel drive, engine in front... Say I had some worn down front tires and semi worn down rear tires, and got the front's recently replaced, but left the semi-used tires in the back....

For getting the most mileage out of the rear semi-used tires, leaving them in the back would make them last longer (new in the front, old in the back) right?

But to prevent spinning out, wouldn't new tires in the back and the used ones up front be better? From a physics stand point: I already get good traction up front because of the weight of the engine and the front wheel drive... So its the rear that needs all the traction it can get right?

I ask because in all my years of driving I've never spun out... But last week, on a rainy day (hell, rainy week), I spun out coming down a 270deg highway ON ramp doing maybe 30mph (luckily i was the only car and was able to regain some degree of control and only hit the corner of my right rear on the guardrail but still fucked my rear panel up, on my otherwise scratch free baby

)... I've driven this route, for years, and on a hell of a lot rainy days... But for the last two weeks, since I got the fronts replaced, I swear my rear is sliding while I'm on the highway (its been a non stop rainy two weeks)...

Main question: Is it possible, that in getting my front tires replaced, I am in fact seeing less net total friction, causing my rear to slide more than with the worn out front tires (less give and take allow for the rears)? Could be I am just paranoid since spinning out...

Should I go get my tires rotated (no jack hitch for coopers, gotta use a lift, which I don't have)?

Any input will be greatly appreciated!

**deathgodusmc** · 12-10-13, 12:36 PM

The reason they say put the new tires in the front is because that is where your turning begins, its where your weight shifts to during your most needed time of traction ie braking, and if a worn tire blows out its better for that to happen on the back due to the extra drag created from the flat the back will still follow the front. Its more about safety then it is about fuel mileage. Plus they recommend changing all 4 not just 2 but no one does that if two are still good.

Its probably worth saying if it can fit in the bed of my truck its more of a go cart then a car.

**Kanati** · 12-10-13, 01:04 PM

You shouldn't be getting any less traction in the back than you were prior to changing your fronts either.

**dex71** · 12-10-13, 02:24 PM

On a front wheel drive, especially a lil guy like a Cooper, the front tires are absolutely the most crucial. Accelleration, braking , and turning are all done in the front, while the rears are just along for the ride. If the rears are bald enough, they could hydroplane on you in the wet, but otherwise they are just there to keep you from tipping over backwards.

**deathgodusmc** · 12-10-13, 02:53 PM

Throw a couple 80 lbs bags of concrete in the back and call it a day.

**Kanati** · 12-10-13, 02:58 PM

It's a mini. Two bags of concrete might make it wheelie all the time.

**roadhog0** · 12-10-13, 03:09 PM

New tires always on the front, especially FWD. As others said, they do the most braking, they turn, they put power to the ground. You're find with semi worn out tires on the back. Just dont run these on the back and you'll be ok!

**SmokenScion** · 12-10-13, 03:16 PM

Originally Posted by deathgodusmc

Throw a couple 80 lbs bags of concrete in the back and call it a day.

QFT.

The Easiest Solution to Traction.
Maybe Substitute Concrete for Cat Litter.

**RhysJD3** · 12-10-13, 06:34 PM

OK, some additional questions. When you say semi-worn, just how semi-worn are we talking about?

I'm guessing as others have said that your back tires hydroplaned while the front tired were firmly grounded. My dad's been in the car tire business for 50 years. Just asked him and you can hydroplane at almost any speed.

Two solutions that aren't mutually exclusive.

1. Put more weight on the back. With your car, the bulk of the weight needs to be on the front but the engine will take care of that. Having no weight on the back means that the tires aren't pushing down as hard.

2. Proper treads on the rear tire.

So without some level of both solutions, if the tire trends aren't cutting through the water, they will ride on it. Having the rear of the car hydro can be a very very weird experience.

Closest I came to that was in winter. Rear wheel drive car with the idle set higher than it should have been. Everytime I tried to stop, the rear wheels would keep spinning while fronts stopped. Back end of the car would try to become the front. Not fun.

**Phyrelight** · 12-11-13, 09:33 AM

You didn't specify so I will ask. You got new tires on the front, did you spring the extra $$$ for a check of your alignment? If you got new tires and it throws the alignment of your rear tires out you will get pulling to one side of the rear of the vehicle in a hydroplane situation.

If its way off you will even be able to see it by following the vehicle and seeing if the rear is either off right or left while drives straight. I see it all the time in AZ when people buy tires from 3rd party resellers and don't pay for a proper alignment.