I am just wondering if the cobalt as any brake bias between the front and back, side to side and when ABS kicks in? I ask this because I hate driving in snow, touch the brakes and the left rear wheel slows faster then the right rear and you have to [panic] correct it with steering.

Freaking Wisconsin weather...


Regards,

Ryan

 

Brakes are always biased to the front, what it amounts to is weight and weight transfer.

Theses cars weigh very little in the back and when you slow down the weight split for examples goes from 55/45 to 65/35. Even though the brakes are biased to the front, the weight transfered forward off the rear causes the rears to lockup. I see this all the time in autocrossing if I brake hard and start a turn without releasing the brakes soon enough I'll lockup the rear inside tire. I have and LS with no ABS

But with ABS the computer is always going to unlock the wheel.

Simple winter solution, go to home depot or whatever and get a few bags of sand or cement and wrap them in plastic leave them in the trunk. The addad weight will stabilize the car and keep more weight on the rear axle.

 

Thats actually a really good idea, how much sand though? Winter driving can be a lot of fun but scares the **** out of my at times.

Regards,

Ryan

 

Weight in the trunk make these cars handle like a ******* dream...

 

To get a true 50/50 as far as weight goes, you'd need roughly 600 lbs in the back. But that's not really realistic. Even 100 lbs would make a big difference.

 

^^^^ I'd probably start off with like 2 or 3 80lbs bags.

 

That sounds like a good starting point. Also, I know **** will move around from time to time, but try and center them as best you can over the rear axle. Probably directly behind the rear seat would be the absolute best place to start with them.

 

I imagine it would help to put weight in the back of these cars but don't forget one thing, if you are unlucky and get into an accident that weight turns into a missle. A couple hundred pounds of anything in the trunk will break the rear seat latches and fly forward with disastrous results. I would hate to hit something at speed, have the airbag deploy, then a second later have an 80lb bag of something hit the back of my seat, ouch.

When I was a kid a truck driver hit an embankment near my house and the load of pipe he was carrying slid forward and did a cookie-cutter thing on him. They had to dig him out of the pipes. I'll never forget that, that's why I think about things like this.

The odds of this happening, thankfully, are slim, just something to keep in mind. When I drove PUs I made a wooden frame that went over the wheelwells to hold the sandbags in place and hopefully keep them from going forward but I was lucky enough that I never had to test the theory. Possibly some wood could be cut to fit the cobalt trunk the same way, have it go against the back of the wheelwells to possibly hold the bags back there.

just my 2 cents, your reality may differ

 

Best thing to do is to remove the spare tire and put the weight down there.

Also when you think about it though its not much diffrence than carrying a 48 case of beer, or a loaded suit case.
I think of it as being concious of being more careful when driving with items in the trunk. But the unforseen can always occur.

My feelings are the same when it comes to loading up a box speakers and several more pounds of amps. Same principle

 

I would recommend against putting weight in the rear of the car. Not because of the projectile potential, but rather because weight in the back makes a car LESS stable.

It will make the sudden weight transfer less severe, but it will also make the car more likely to rotate (read: spin out) mid corner. In addition, if you do start skidding, it will be harder to correct. The further back the weight sits, the greater the effect.

This is why Porsches are so popular, the rearward weight bias makes them extremely agile, but also extremely unstable. Meaning that if you drive them right, they are very fast, but if you make even a tiny mistake, you're a goner. The reason the Cobalts handle "better" with weight in the rear is because it's easier to rotate the rear to get around a corner. On dry pavement, even with weight in the rear, there is enough traction that you still can't really get close to spinning out, but on snow and ice you are always closer to the edge.

I live in Minnesota so I experience very similar winters. When you say the left rear slows faster than the right, do you mean that the car starts spinning to the right (i.e. you're heading towards the ditch), or to the left (heading into oncoming traffic)?

When you say you "touch" the brakes do you mean, "Grandma slowing for a red-light," "Uh-oh, I'm not gonna beat the yellow," or, "Oh ****! It's Red!"?

Also, since you're selling the GMPP Stage 2 kit, I'm guessing you have an SS/SC. What tyres do you use in the winter? I hope not the stock ones.

Finally, just how slippery does the road need to be in order for you to experience this? Does is have to just be wet? Greasy? Will it happen on packed snow? Or does it have to be glare ice?

Finally, is it just you in the car, or is there other stuff? Because left/right balance can have an effect as well.

 

Just a quick comment, there is a thread about Cobalts with rear drum brakes having adjustment issues resulting in a change of bias. Do you know whether you have drum brakes?