Wheel hop when cornering

[athlon2k2]

Hey guys,

Hopefully this has a quick answer. I've had my '16 GT PP /w 3.73 for about 6 months and have about 2,500 miles on it. Just recently I noticed I get a lot of wheel hop when going around corners (right hand turns) even under fairly light acceleration. I am also losing traction under decent acceleration around wide turns (like left hand turns). Have I just worn these P-zeros down to where they won't hold on any more or is something else going on? The tires still seem to have a lot of meat on them.

Thanks.

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[robertwsimpson]

Could be the differential working. Mine feels funny in tight turns always... especially when the tires are cold.

It could just be wheel hop too... My car wheel hops like crazy under acceleration.

 

[BmacIL]

Hey guys,

Hopefully this has a quick answer. I've had my '16 GT PP /w 3.73 for about 6 months and have about 2,500 miles on it. Just recently I noticed I get a lot of wheel hop when going around corners (right hand turns) even under fairly light acceleration. I am also losing traction under decent acceleration around wide turns (like left hand turns). Have I just worn these P-zeros down to where they won't hold on any more or is something else going on? The tires still seem to have a lot of meat on them.

Thanks.

Two things will address that. 1. Stabilizing the IRS cradle/subframe. 2. Vertical links.

For 1, you have two options that are daily driver liveable:
A) BMR CB005 Cradle Lockout kit
B) Steeda Subframe Bushing Support System + IRS Subframe Braces

You could also do subframe bushing replacements, but those will provide noticeable and significant NVH.

For 2, you have a variety of options from BMR, Steeda, Boomba, UPR and a few others

The subframe is moving around significantly under cornering load and under power application. Stabilizing it and limiting its movement improves handling, wheel hop and even ride. The vertical links do have some deflection when applying power coming out of turns. They bend and spring back a little bit, and that's where some of what you're hearing/feeling is coming from.

 

[BMR Tech]

I have been battling these IRS shortfalls for 2+ years now.

What I will say is, I simply have not been able to cure some or all of these occurrences with only a few mods. I can cure wheel hop in a straight line - then get these odd skipping/tire shake on sharp turns under throttle....and I can cure the cornering tire shake, yet have straight line wheel-hop. In other words, I have not seen a magic few select parts that are a cure-all....and have only seen the best results with pretty much upgrading everything.

I can say this, I am of the opinion that the absolute best thing to do to the S550 IRS is to remove all of the deflection from the cradle mount, and all of the pivot point mounting locations.

My recommendation in order, for you specifically is: (similar to @BmacIL suggestion - but I will take it further)

1: CB005 Cradle Bushing Lockout Kit.
-This will remove the very sloppy deflection found on the S550 with the sloppy mounting of the IRS Subframe to the chassis. This should be everyon'es first step, EVERYONE'S - as you cannot troubleshoot and are limited on your performance increases without making the subframe (which controls the rear of the car) more rigidly mounted to the chassis.

2: BK055 LCA Bearing Kit
-Massive improvement, for any and everyone. The reason I have made this #2 is...you can overcome the poor performing stock Vertical Links by removing the fore, aft, lateral and vertical deflection of the control arm. The movement of the rear wheels in anything other than straight line situations, has alot to do with the geometry change - and that geometry change is most caused by the forward LCA bushing deflecting up to almost 1".

3: TCA045 Vertical Links
-This part is what the S550's IRS is named after. The "Integral Link IRS" (vertical links) - is a great design. The function of the Vertical Link is to control the knuckle movement in relation to the lower/main control arm. This is done by simply connecting the two, with the Vertical Link, to prevent excessive rotation of the knuckle. In other IRS systems without these vertical links present, the knuckle assembly tends to try and climb forward and snap back under load changes. The Vertical Links are an important part of the system, but I personally believe that upgrading them is a little over hyped and overrated. That said, in a handling application - they are definitely a MUST HAVE. They will help with your erratic knuckle movement you mentioned above.

4: FRPP M-5A460-M: Knuckle Toe Bearing Kit
-Have you ever wondered why Ford chose to put a RUBBER bushing on the toe link system? This still blows my mind. I cannot for the life of me agree with rubber being anywhere near the link that controls the toe alignment. Toe settings are one of the most important and overlooked alignment specs. Having erratic toe change during loaded accel, decel and cornering is NO GOOD. Like the CB005 I mentioned as #1...I also believe that everyone should swap this rubber bushing out for the FRPP Bearing. This will provide better tire wear characteristics, a more stable knuckle, better handling / braking / accel and more confidence behind the wheel.


The list above, is my absolute favorite first 4 products for tightening up and improving the performance of the S550's IRS System.

Hope that helps!

 

[athlon2k2]

Well it has been getting a little colder here, but 50 degrees still seems pretty warm to me. I kind of figured it was due to the IRS. It just seems strange that it just started happening or at least just now became noticeable. Perhaps the parts in the car are finally breaking in. Thanks for the feedback. Time to start modifying.

 

[BmacIL]

Well it has been getting a little colder here, but 50 degrees still seems pretty warm to me. I kind of figured it was due to the IRS. It just seems strange that it just started happening or at least just now became noticeable. Perhaps the parts in the car are finally breaking in. Thanks for the feedback. Time to start modifying.

You start to notice it more because of the reduced grip. The lower the grip from the tires, the more noticeable the wheel hop/IRS chatter will be, as the tire slides/spins and grabs, and slides/spins and grabs.

 

[VinnAY]

Well it has been getting a little colder here, but 50 degrees still seems pretty warm to me. I kind of figured it was due to the IRS. It just seems strange that it just started happening or at least just now became noticeable. Perhaps the parts in the car are finally breaking in. Thanks for the feedback. Time to start modifying.

The PZero on the PP are known to drop off significantly from 60 degrees.

 

[Rustang]

How hard is it to replace the LCA bearing? I looked everywhere but cannot find an install video to determine if it is something I could do myself. I have been debating my next mod and was thinking vertical links but if the LCA bearing is a better route I might go there. Just have CB005 and diff bushing supports. I am a straight line guy.

 

[BMR Tech]

http://www.bmrsuspension.com/siteart/install/BK055.pdf

It's not too bad. The hardest part is the R&R of the control arms.

 

[West TX GT]

How hard is it to replace the LCA bearing? I looked everywhere but cannot find an install video to determine if it is something I could do myself. I have been debating my next mod and was thinking vertical links but if the LCA bearing is a better route I might go there. Just have CB005 and diff bushing supports. I am a straight line guy.

It's not that bad if you have a press.


I have all of those except the vertical links. The skipping while accelerating out of turns is gone, but wheel hop under hard acceleration is still there. Hopefully the vertical links will help. I also have the BMR handling springs, I don't know if they are contributing to it or not since that are not geared toward straight line performance. I do think the stock PP Pirellis are a big factor.

 

[Seatown Stang]

I have been having the same issue and have replaced a number of parts in the IRS with no help while turning right. While turning left its not that bad but right is pretty aweful.

I have had a differential specialist shop take a look at the rear and they couldn't find anything wrong

Ive also installed these parts:
Steeda rear subframe brace
BMR vertical links
Steed IRS support bushings
Steeda differential bushings
Steeda IRS alignment sleeve

Personally its starting to drive me crazy and has me wanting to get a the new reface. Heres to hoping ford does something with the new reface to build on the IRS and make it more solid.

 

[BMR Tech]

I have been having the same issue and have replaced a number of parts in the IRS with no help while turning right. While turning left its not that bad but right is pretty aweful.

I have had a differential specialist shop take a look at the rear and they couldn't find anything wrong

Ive also installed these parts:
Steeda rear subframe brace
BMR vertical links
Steed IRS support bushings
Steeda differential bushings
Steeda IRS alignment sleeve

Personally its starting to drive me crazy and has me wanting to get a the new reface. Heres to hoping ford does something with the new reface to build on the IRS and make it more solid.

You may want to consider this. :cheers:

 

[Rustang]

Thanks they don't seem that bad. So based on what you guys are saying vertical links help wheelhop in a straight line while LCA bearing helps both but more so for hop when turning and may leave some in a straight line?

 

[BMR Tech]

Thanks they don't seem that bad. So based on what you guys are saying vertical links help wheelhop in a straight line while LCA bearing helps both but more so for hop when turning and may leave some in a straight line?

The answer is to do both upgrades.

I did not imply what you stated, but I did say that when upgrading the RLCA bearings it can help overcome the poor design/performance of the stock Vertical Links.

The issue with the stock LCA bushings is that it enables the entire lower control arm to move fore/aft under loads...which enables the toe link to push/pull the knuckle causing a twisting motion, which in turn throws the knuckle to control arm relationship off.

It is all a system. The best way to combat the erratic movements and geometry changes is to remove all of the deflection.

 

[BMR Tech]

Here is paused footage from an undercar GoPro that shows the fore movement with stock LCA Bushings. Notice the position of the wheel/tire in the fenders when under load, then not under load. It is even worse when racing the car on a drag strip or road course, or during heavy loaded spirited street driving.

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