amartin

I've done some tests, and it looks like wheel hop happens REGARDLESS of how the vehicle is driven-- mearly the lack of traction causes the hop/bouncing in the suspention...

Don't believe me? Ok, first.. (traction control off)... launch hard on stick pavement.. hop-hop-hop... feels like crap and you're not hooking up-- but then, confusion sets it: I'm doing 30mph, but on a slick surface (wet/smooth).. got on it, and boom...Wheel hop.. but I was already moving-- the simply fact the tires broke loose caused this.

I'm wondering if stiffer rear shocks could help reduce this? Something has to fix this, its gotta be horrible on the drive train to shock it over and over when this occurs.

Anyone know of some 'fixes' or reduction to this? Obviously tire pressure isn't the kind of change I'm looking for-- more like a suspention mod.
I'm pondering differnt shocks and/or springs..


-- Aaorn

red_rx8_red_int

I've also tried several things but to no avail. I don't think its the lack of traction that causes wheel hop, I think its too much traction! Can someone with more experience settle this (I'm new to this)?

cgrx

BUMP

jerrymac

I think its a simple matter of 50/50 weight distribution and tires that do what their suppose to do, grab the road. I was downtown during a mist, stopped at a light on newly laid brick pavement (something downtown thought would look pretty at intersections). Small hit and the backwheels spun and a slight fishtail started (DCS OFF). Tires had nothing to grab.

GeorgeH

iTrader: (2)

I did a very nice burnout (at the request of a friend) on asphalt which was mildly damp (i.e., patches of dry & damp). No problems, no wheel hop. Not much forward motion, either.

On dry pavement, Miatas have wheel hop problems as well. I think we have to accept that Mazda sets their cars up to be great street/road racing/autocross cars, and they don't really care about how well they perform in a drag race. And I also think we should all be gratefull for that - I'd hate to see the RX-8's incredible ride/handling tradeoff compromised to gain a few 10ths of a second during a hard launch. It's not that kind of car. If you want to mod it, that's cool. But I like it the way it is.

My .02.

wakeech

i'm still not exactly sure what causes the hop, but it's certainly to do with the way the multi-link setup at the back responds to a hard launch.

would you rather have a happy rear end on launch, or have to put up with a leaf-sprung solid axle setup?? :p

6speed8

FWIW - live axel cars get wheel hop too. My 1969 GTO got it and my friend's 1968 Camaro used to get it. The GTO had coil springs and the Camaro had leaf springs. For the GTO the solution was a set of 'ladder bars' and the Camaro needed 'traction bars'. Both methods helped the wheel hop, but diminished the ride quality.

Charles R. Hill

iTrader: (7)

Wheel hop on the 8 is caused by the rear end preload from the factory. The only way to effectively reduce wheel hop is to have the four-wheel alignment readjusted for drag racing. Any decent frame/alignment shop can do this but, as stated above, the decision is whether or not you wish to sacrifice all around handling for mere straight-line acceleration. A solution that could cover both aspects would be to install the new Tanabe coil-over system. The Tanabe allows the end user to adjust the usual parameters along with the damping ratio. A soft 50/50 on the rear with a 90/10 on the front will enhance traction through compliance and weight transfer. You guys would fall over laughing at some of the "redneck" solutions that worked on the racetrack back when I was a dragracer. Most of it involved merely removing factory parts.

Charles

cgrx

Damn, I recently had some hop ~ I think my shift **** cracked my damn sunroof :D

oi812

Ok, wheel hop is normally something in the drivetrain loading up, then suddenly unloading. Remember from physics class that static (not spinning) friction is always higher than sliding (tire spinning) friction. Tire grip is highest at that instant right when it starts to spin or slip. Once the tire slips, the traction goes down and a bunch of driveline load suddenly goes away. If something in the system is flexible, it will deflect under the torque load, then suddenly try to "snap" back when the load goes away. The hop could be caused by anything the flexes or deforms excessively under the torque load (that is why "ladder bars" & "traction bars" helped on the old muscle cars).

For the RX8 it could be rear suspension link bushing compliance (the same compliance that gives us good cornering traction), as some others have mentioned above, but I have a different theory. Since there seems to be allot shifter motion (both vertical and lateral motion) during the RX8 wheel hop mode, I think it may have to do with the way the "powe plant frame" transmits load into the engine mounts. The RX8 has the softest engine mounts I've ever seen. Take the cover off the engine, and have someone slam the door shut and watch how much the engine moves side to side. I wonder if the hop has more to do with soft mounts for interior NVH (Noise, Vibration, Harshness) then it does the rear suspension?

red_rx8_red_int

That makes perfect sense. The forces "load" the car, and then when wheel spin starts, the car "unloads" causing the rear to jump 2-4 inches into the air. So several of the above posts are correct. My comments about the tires being too grippy are right, less grip means less load when wheel spin begins- so less unloading and less hop. Charles R. Hill's post about preload is also correct, lessen the preload and this may lessen the unload at wheel spin. Wakeech is also probably correct in attributing this to the multi-link suspension, it probably allows for a greater load before spin than a single link (??, leaf springs) suspension.

For me, I gladly accept the wheel hop in trade for the fantastic handling, but for those that fixate on drag times, what's the easiest way to reduce hop? Less grippy tires is easy, but it seems one would need a whole new suspension to fix the other factors. It seems that tire pressure can be adjusted as well, IIRC Judge Ito mentioned lowering the pressure. But doesn't that increase traction at the cost of tread wear?

oi812

Less traction will most likely reduce the hop, but it will also reduce acceleration. I don't care about 0-60 times, but I do like to spin the tires for fun, and it's not to fun with all the hop so I don't do it. I could go with crappy low grip tires, but above all I love to corner, so I don't want to give up any grip either. I'll just have to learn to spin the tires while turning, dosn't seem to hop then