wheel hopp

ERA 626 · #1 (**permalink**) 10-17-2003, 02:58 PM

Bob,
I was speaking with Al at Rieder Racing today (The guys who built my rear end "dana 44")
I am having a problem with wheel hopp.
He was saying about traction control?? How do I elimanate wheel hop? I tried stiffining the rear end and tighening the rebound damnping clickers but this did not resolve the problem, are there any after market traction control devices I can use? I have spoken with two other ERA owners and they are having similar problems.
I have BFG street T/A's they should just spin but they dont they hopp??

Mr.Fixit · #2 (**permalink**) 10-17-2003, 03:26 PM

wheel hop is often due to the deflection of rear end control arms and/or bushings. Geometry of the rear suspension is involved as well.

Hotfingrs · #3 (**permalink**) 10-17-2003, 03:29 PM

I've got the Dana 44 rear, and have absolutely no problem with wheel hop, as anyone at SF will attest...and also have never had a problem in any of my corvettes with wheel hop

bnewell · #4 (**permalink**) 10-17-2003, 03:52 PM

My SPF has "wheel hopped" in 1st gear before........but not all of the time. Since I am not a "motor-head" and have no technical knowledge of motors/transmissions whatsoever, I just decided to wait until I hit 2nd gear to get-on-it

Brian

decooney · #5 (**permalink**) 10-17-2003, 03:58 PM

Mike,
how much rear tire pressure are you running?

I stiffened mine a bit more, and will be raising the rear some more to see what changes. My Unique never wheel-hopped, same rear end too. The only difference is how Unique and ERA support the lower control arms differently. Unique is from the rear, in a triangle suport arrangement, and ERA is towards the front on the Jag rear.

ERA 626 · #6 (**permalink**) 10-17-2003, 04:36 PM

Mr. Fix it,
"Geometry of the rear suspension is involved as well."
What does this mean and how do I fix it?

Duane,
You said that you run 26lbs of pressure and that is what Doug at ERA reccomends, and you still have Wheel hopp.

Is this fixable or is it just the charicteristics of the era rear end?....

PatBuckley · #7 (**permalink**) 10-17-2003, 05:10 PM

I eliminated the wheel hop on my ERA by replacing the rubber track rod mounts with steel/steel mounts - I bought the pieces at Total Control, I think they were for the front suspension on a Mustang or something.

cobrakit66 · #8 (**permalink**) 10-17-2003, 05:11 PM

same thing happened to me , turned out to be weak coil over setup
ron

ERA 626 · #9 (**permalink**) 10-17-2003, 05:42 PM

Pat,
That sounds intresting. Can you send me a picture or explain more? I dont know what you are describing.

Ron,
Does this mean I should replace my spax with somthing else?

Bob Putnam · #10 (**permalink**) 10-18-2003, 06:54 AM

Wheel hop seems to be random so the solution for all cars seems to be elusive.

While I can't promise anything soon (very busy...), I have thought about adding a horizontal damper from the hub carrier to the rear chassis rail. This type of restraint is used on several late-model cars, both solid and independant, so the proper dampers are readily available. I would make the conversion bolt-on. This setup will not fit with under-car exhaust.

ERA 626 · #11 (**permalink**) 10-18-2003, 08:17 AM

Thanks, Bob
Would I have to weld brackets to the frame and carrier.
What kind of time frame are we talking about?
I know of at least 3 of us who want them right away

decooney · #12 (**permalink**) 10-18-2003, 10:14 AM

Mike,
- Yes, 26lbs.
- I have the solid control arm bushings now, I believe you do to with our serials so close together. No change. I don't believe this is the problem, and its not the final cure for my car.

...saw a quote on this on another side in regards to installing a rear-trailing arm configuration to eliminate wheel-hop,
quote:
"This allows for direct application of power from the differential to the wheels without the suspension alternately storing and discharging the force to wheels promoting wheel hop".

Bob Putnam,
1) Any chance of coming up with some sort of rear trailing arm configuration that would help to resolve this for good? I converted my last Unique to a rear trailing arm and center bar isolation setup. It was like a right and left triangle configuration, side by side. It completely changed how my car launched and came out of turns under throttle. No wheel hope and more stable after installed.

2) Or, what about a Watts Link type setup? Is that what you are working on in your previous pics? Does it really help the wheel hop situation? If so, how does it function to eliminate it? Thanks.

CJ428CJ · #13 (**permalink**) 10-19-2003, 02:52 PM

Mike,

I don't recall. Do you have the standard inboard brakes rearend or the optional outboard brake rearend? Have you done a four wheel alignment on the car yet? Is it possible that the rear wheels are not tracking "straight down the road?"

Chris

ERA 626 · #14 (**permalink**) 10-19-2003, 06:54 PM

standard inboard.

decooney · #15 (**permalink**) 10-20-2003, 12:43 AM

Bob P,
the more I look on the web, the more I'd like to talk with you about a Watts Link setup on Jag IRS.

Your ERA website makes note of a W/L setup that Contemporary Cobras used for a while... Any pics of that? I did hear back from George at AMP. Have you ever tried the AMP XK2003 WATTS linkage setup yet on an ERA 427? If so, how did it turn out?

Bob Putnam · #16 (**permalink**) 10-20-2003, 04:27 AM

The AMP setup is meant for a solidly-mounted differential, as is the leading arm design of the Unique design. Neither will work well (or at all) on the ERA subframe. The AMP design puts high stresses into the top bushings. The leading arms bind against the trailing arms and will simply not physically fit.

Give me some time to work on the details of my longitudinal damper design.

Chaplin · #17 (**permalink**) 10-20-2003, 07:33 AM

Mike-
Before doing suspension mods you might want to try a different set of rear tires. The main reason I did not put BFG TAs on the cobra is because of wheel hop. I had BFGs on another car and I found wheel hop to be excessive- never could figure out what it was- it was almost as if the rubber on the tires was too hard and they wanted to "skip" across the pavement. I put Dunlops on the cobra and so far I have been very happy with them. Now I will admit that I have not "gotten on it" yet because I am just trying to break everything in nice and easy, but so far so good, under moderate acceleration the car just seems to sit down and tracks straight as an arrow.

Just a thought . . .
Mike

rdorman · #18 (**permalink**) 10-20-2003, 07:38 AM

Has any one run their Unique with the triangulated setup and solid bushings in the lower control arm? Did the suspension freely go through its travel?
Thanks
Rick

ERA 626 · #19 (**permalink**) 10-20-2003, 07:39 AM

Chaplin,
My car tracks good too, under normal aceleration.
Let me know what happens when the tires spin... I am courious is it just my car or is this a problem with ERA's in general?

Chaplin · #20 (**permalink**) 10-20-2003, 07:43 AM

As soon as I'm man enough to spin the tires, I'll let you know

Rick-
Get back to work