Cape Cod

I go over the same stretch coming home from work every day. There is a series of four manholes in this short stretch. Hitting them at dead even, straight, no increase or decrease of throttle, the car is absolutely fine when I go over them with the left wheels. Just an up and down. When I move the car over a bit, and the right wheels hit the bumps, I feel a definate "hop" to the side by the rear end. With each bump the car will jump over a bit in the rear. Only when I hit with the right wheels though, so wondering if there is a moment of air time with a drive wheel. If it isn't that, I'm thinking shipping spacers. I've had the car since new last June, and have only started to notice this since the weather got cold. Any thoughts would help.

WestSideBilly

2 factors here. First is you - you weigh something, and the majority of your weight is on the left wheels. Not a major difference, maybe an extra 60-80 lbs on the lefts vs the rights. This has a small effect on the compression and rebound of your suspension, possibly enough to create the difference you are noticing. Second is how you're hitting the bumps - just because the bumps are there in both scenarios, doesn't mean they affect the car the same. I'm a bit unsure of how far you're moving the car over in your statement (a bit = 6"? or = 58" - the width of the front track?), but unless you're hitting the same part of the bump with the same part of the tire, the car will react differently. A minor consideration with moving over is what the other wheels are doing, as well.

To answer your question, if you're driving in a straight line, both wheels should be seeing 50% of the power.

Wesmaster

A FWD could have a dominant axles because of the design (often one axles is shorter than the other due to how the transmission mounts on to the axles). But, yeah, the RWD S2000 should not have a dominant axle.

ultimate lurker

It isn't so much axle length Wes as it is torque moments. Any longitudianl drivetrain, RWD car will have a predominant axle (depending upon engine rotation and tranny setup). While I can't predict the dominant axle based on the S2K setup (because I don't know how the reduction gears in teh tranny work in terms of direction of rotation), I can tell you from experience that the passenger side tire gets the brunt of the work.

I say this becasue its the first tire to wear out on my car. Also, if you measure the strips left by a wheel spinning launch, note that the passenger side stripe probably starts first. Even with a mechanical LSD, there is a delay in lockup. The smaller the difference in starting points of your stripes, the better the LSD is (thanks to my friend Tom at C&T for that one).

UL

Cape Cod

So getting back to my experience, a slight hop over a bump with the right side could cause a split second bit of airtime, and the sidways lurch a result due to the shifting of dominance from right to left back to right in that split second? It's not all that terrible an experience, rear end hops over maybe an inch or two, but curious as to why it only does it when I hit the bumps with the right side.

98TypeR#21

This could also be predominantly an alignment issue. I had similar strange behaviour recently (granted I had worn rear tires), but after a slightly-performance-oriented alignment, it IS FANTASTIC NOW!

There's a recent thread with my numbers, but basically, the alignment TOTALLY fixed my strange handling problems.

FYI - it turns out that part of my problem may have been rear-camber that was not even between left and right, causing strange twitchy feeling over bumps and turns. Now it's exactly the way it should be!

Wesmaster

Hmm, I snapped my left axle first...then the other axle along with the diff. Not saying this means much but just interesting.

Duffer

Another consideration might be the "crown" in the road. Most roads are higher at the center-line than at the curbs to promote drainage. If your car is riding on the "slope" from the center-line to the curb., a momentary reduction of traction like you described could cause you to feel a slip down that slope.

I have the same problem on one stretch of road near my house that has a "washboard" section caused by cars braking for a turn just past this section. The road is straight, but has a fairly sever crown. When I go over this section with cold tires, my car feel like it's hopping to the right and it's more sever if I'm decelarating or braking. It's not so bad that it would cause a loss of control, just disconcerting if your not ready for it.

Wesmaster

Yeah, the crack/line between rows of laid concrete can be a pain with our soft S02's, along with the car's light weight...sometimes the wheels just want to follow the line...which doesn't always stay in your lane.

woodyandy,
You should also consider the fact that you might be driving with just you in the car. It's easier for the right-hand side to kick out due to the reduced weight on that side of the car.

twohoos

Has no one mentioned bump steer as another factor in this scenario?