Solution for wheel hop?

Hi,

Ever since I bought my 1999 Miata I have had a 'wheel hop' problem. Actually it is more correctly a slip and grip situation. The problem manifests itself in many ways. I have even descibed the symptoms to the dealer like 'it feels like the drive shalf is made out of a spring...imagine it winding up under load, then springing back'.

Of course dealerships and their techs can't think 'outside the box' and I have always gotten the 'I don't see a problem...it's to spec'. You don't know how frustrated I have become. There is just no way for a dealer tech to show independent problem solving or deductive reasoning.

Well I was driving today, shifting into second, and feeling the bouncing pull just after engagement, when I thought I may have discovered the a possible origin of the bounce, pulse, hop, etc. I remembered that a typical clutch disk usually has a set of integral springs. Could it be possible for the springs in the clutch disk to be so spongy? Could one of the springs be bad/broken, so that they no longer fully restrain the engaging and release of the engine's power?

Come to think of it, whenever I am slowly pulling into my driveway (an uphill incline), and I push in the clutch, I hear a clunking back and forth, like a spring wagging a part within the driveline.

Could the clutch springs be my elusive problem? If so, what you do... Would you wait untill the clutch is used up (starts to slip) and replace it then, Would you then choose to replace it with a stock clutch, Would you take it to a transmission place to have it inspected, Is inspection easy, or is it just as cost effective to replace the clutch at that time?

Once again, the dealership has proven itself useless in problem solving, so I can't count on them at all.

Thanks in advance,

BrianW

The good old slip/stick problem. The energy is stored in the shocks/springs, suspension bushings, sidewalls in the tires, and slack in the driveline. Every car will experience wheel hop under the right conditions ... some cars are more prone to it than others by their setup. I've had my car wheel hop, as my 240sx ... haven't experienced wheel hop in my parents Altima yet, but it will be possible. Pickup trucks with light rearends are the most prone to wheel hop.

Sorry man, but it's a normal part of life. The energy is stored up in many components of the car, every car can experience wheel hop, the Miata's light weight doesn't help either. As you said, it's a slip/grip problem, I remember studying this in my Dynamics course in college.

How many miles on the shocks?

I get wheel hop in the wet witht heKONIs set at 2/8, but not at 3/8....

- bill

The shocks are good. I've taken high speed video of the 'wheel hop'. The tires never leave the ground nor deform the sidewall. What the video did show was that the tire would roll along the ground, spin (relative to ground), re-grab and roll along the ground again. It's pretty amazing to watch the wheel turn fast, then stop, spin again, stop etc in very quick succession.

Something is storing up the engines power and releasing it like a spring. I was hoping that my thoughts that a broken spring on the clutch disk may now allow this type of unrestricted oscillating rotation. Does the clutch disk scenerio seem plausible? Has this happened to anyone?

Thanks for the help,

BrianW

Sounds like the normal functioning of a Torsen LSD. If your clutch were slipping, it would not be capable of spinning a tire at all.

Both tires spin at the same time then stop at the same time. So the torsen is acting normal, but it doesn't affect the slip-grip problem (in a negative way).

When I mention slip, I am referring to the tire slipping (peeling out). The springs on the pressure plate are strong and the clutch is holding strong but the springs on the clutch disk may be bad allowing the 'mush'.

For those that have replaced clutches before, the springs I refer to are the 4 or 5 coil compression springs that are mounted within the clutch disk itself. They allow the clutch disk to grip the flywheel and deflect during the engageement (to act like a clutch disk 'shock absorber' to minimize the intitial slip and prolong clutch life.

Pretty well all auto clutch disk now are made up of 3 integral sections (spline hub, springs, and friction disk). Clutch disks are not solid like brake rotors.

I hope I made sense to those that read the above.

Thanks,

Could it be a warped clutch plate? I think I have that problem right now, but I'm waiting for Spring to take it to the garage. Starting from a stop, the car sort of shakes or stutters while the clutch is on the way up and only gets worse if I try to give it more gas durring or before letting up the clutch. Someone could mistake this behavior for wheel hop.

For actual wheel hop, see Brian Dowling's RX-7 page on 'launching': http://www.rotarypowered.com/faqlaunching.html

Often, wheel hop disappears with the installation of a new set of tires. Just don't buy the same brand and model as what's giving you the hop. Borrow a pair of something else to see if it should work for you.

Although my SO-2s hop less, the only real cure is to launch around 3500 with just a dab of clutch slip.

I'm a bit surprized that the '99s still have that very annoying trait.

Yes, like I said, the tires (sidewall and tread actually), suspension bushings, bushings in the driveline (like the bushings that hold your tranny and engine in place), slack in the driveline, springs/shocks, etc. etc. etc. There are MANY components where the energy can be stored. Just because you don't see the flex in the sidewall (there WILL be some flex in the sidewall and tread) or see small changes in suspension movement doesn't mean it doesn't happen, it does. Every car will experience this under the right conditions, my Miata and my 240sx have experienced this slip/stick situation ... sometimes when dry, sometimes when wet, sometimes not.

It's normal.

It's also right where you want to be in a good launch, at the limit of