Negative Roll System

Discussion in 'Classic Mustang Specific Tech' started by bort., Dec 6, 2003.


  1. bort.

    bort. New Member

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    Has anyone used the Global West Negative Roll System??? Want to know if it worth the money or would I get the same performance from urethane bushing. I have used the urethamne bushings on a different and love the handling.
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  2. 88 Fox GT

    88 Fox GT New Member

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    Do you have a link so we can see it?
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  3. bort.

    bort. New Member

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  4. Taylor

    Taylor Founding Member

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    I have their Tubular UCA, LCA, adjustable strut rods, front/rear springs, and Del-a-lum shackle kit.

    I did a lot of research on front suspension kits, and went with theirs. Check out this article. Their whole thing is about creating negative camber unlike the shelby drop which only reduces positive camber.

    Global West has also been in the business for a long time. I have no doubt I will be happy with this system.
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  5. 68GEETEE

    68GEETEE Member

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    urethane bushings are fine, but the negative roll system as I understand it is to accomodate a larger wheel and tire for the classic mustangs. If you are planning any kind of large wheel upgrade, 16" or larger, you have to have that system for the car to still handle properly. I dont have it cause I still have stock wheels.
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  6. bort.

    bort. New Member

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    Well that answered my question b/c planning on 17's...Now i have been reading some stuff about backspacers....What size would i need, i have a 69 Mach 1 w/a 351 or does it go by the rim, not to sure here
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  7. Taylor

    Taylor Founding Member

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    I would NOT spend that kind of money on Global West’s negative roll system just to accommodate bigger wheels. Sorry, it was not designed for that reason.

    You could do the Shelby drop for free in your case, and go with M+ suspension kit with polyurethane bushings.
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  8. DarkBuddha

    DarkBuddha Founding Member

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    This has been mentioned before on this forum, but it still is not correct. The function of GW's negative roll system isn't to accomodate larger diameter wheels, but rather to provide better handling by creating negative camber while turning, thus improving handling.

    It may however be true that if you get the negative roll system, you may indeed need to got with a larger diameter wheel to clear the upper control arm. I am running GW's negative wedge kit on my upper control arms and was able to run a 15" wheel with 4.5" of backspacing.

    BTW, I did notice a big improvement in handling (over and above the already installed urethane bushing upgrade) after installing the negative wedge kit. I had not previously lowered my control arms (Shelby drop), so I am not sure how much of an improvement over that it would be.

    In any case, if you've got questions about why/how the GW system works, definitely call GW directly and get some answers.

    Hope this helps... :shrug:
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  9. Randy'65

    Randy'65 Founding Member

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    I believe that's backwards. Most 16" wheels are 8" wide, and to make them fit in the wheelwell the backspacing is increased, pushing the inner edge of the rim inboard, closer to the upper arm. Interference between the upper arm and rim may occur when front suspesion is extended. Lowering the upper a-arm mounts changes the angle of the upper arm relative to the lower arm, allowing it to clear the rim. Therefore you need to lower the a-arm mounts to clear the rim. not increase the rim diameter to clear the lowered arm. I haven't really got a clear consensus on whether or not the shelby drop is enough to clear the a-arm, out of a 16" rims way, or if negative wedge drop is required. What width are your rims, Buddha?
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  10. planomustang

    planomustang Founding Member

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    I agree with darkBuddha. The NW kit is not designed to prevent interference between the UCA and the tire/rim.

    I have the GW Stage 4 kit, which includes all the parts in question. I also have Vintage 45 16X8's, with 4.5" back space. I had a small problem with the rim hitting the UCA. It was only on locked out steering, and I put some stops in to prevent it. No noticable loss of turning radius (even with the TCP R&P, but that is a different story I have already posted).

    As for how well the GW kit works, I still have not gotten to the track to find out. I like it so far. The look on passenger faces when I take right hand turns at 34-40 mph without slowing down seems to indicate that the system works pretty well ;)

    rk
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  11. bort.

    bort. New Member

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    How sharp are these turns???The all around aspect pf the car is important, I wanna go fast, stop great and handle like my Forumla 350 w/WS6. The first two I have covered, I'm just wondering about the handling b/c I know these old cars are pigs when it comes to that
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  12. DarkBuddha

    DarkBuddha Founding Member

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    Here we go again... the original statememt I was responding to was: "...but the negative roll system as I understand it is to accomodate a larger wheel and tire for the classic mustangs.", which I continue to believe is incorrect. As I said, the function on the negative roll system is to improve handling, not to accomodate larger (or wider) wheels as was mentioned. If a side benefit is that it helps to accomodate wider rims (especially those not available in variety of backspacings), all the better, but careful choosing of wheel diameter and backspacing may make that side benefit unimportant (and unnecessary).

    However, the reason I mentioned that a larger diameter wheel may be necessary is that the negative wedge kit places the UCA (at the ball joint) further from the lower (a wider distance), which may cause interference at the UCA ball joint mounting point with smaller diameter wheels (like 14" and 15" wheels with what would typically be correct backspacing for the application).

    In my case, I'm running a 15x7 rim with 4.5" backspacing. The clearance to the UCA at the ball joint is very close (less than 1/3 inch), but certainly if I upgraded to a 16" wheel this clearance concern would be eliminated. Prior to installing the negative wedge, I was running a 15x8 with 4.75" backspacing with lots of clearance, so I suspect I would have been ok running a 16x8 with 4.75" backspacing (though I definitely would have needed to roll the fenders for outer clearance).

    I hope this helps clarify... :shrug:
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  13. planomustang

    planomustang Founding Member

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    if you are asking me, I am talking about the typical surface street intersections here in Plano, where two 6-lane roads intersect at a 90 degree angle.

    rk
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  14. Randy'65

    Randy'65 Founding Member

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    Sorry, didn't mean to offend. I based my response to posts and articles I have read concerning this, as well as working out the mechanics of the front suspension to understand their reasonings. Made sense to me. I didn't have Fords engineering drawings to work out every last detail, nor have I personally installed the negative wedge kit or 16 X 8 rims on my Mustang. As I stated in my initial response, Interference between the upper arm and rim MAY occur when front suspesion is EXTENDED (fully). Perhaps you did not have interference problems with your 15 X 8 rims because your suspension did not fully extend, due to stiffer shocks/shorter springs, or perhaps you did not have a problem because your's is a '70, and what I've been basing my thoughts around is the 65/66 models, which seem to have more front end issues. Vintage Wheel Works, a purveyour of 16" rims for our cars does list on their website a need for shelby or global west UCA drop for '65/66 that they don't list for other years, don't know specifically if that is due to tire/fender interference or UCA/rim interference. Perhaps it's worth a call to the experts..
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  15. Randy'65

    Randy'65 Founding Member

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    DarkBuddha,

    One more thing, the issue I had was that you said that you may indeed need to got with a larger diameter wheel to clear the upper control arm. If anything, lowering the suspension mounts will create more room between the UCA and the rim. Sketch it up and see where everything goes.
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  16. planomustang

    planomustang Founding Member

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    Randy'65: I read the post by darkBuddha, and I don't think he was offended. I can't speak for darkBuddha, but I maybe I can explain some of the exasperation he showed.

    There are a few of mythical topics that wear me out. These topics are usually based on "posts and articles" that someone read. Here are some example post topics that show up regularly, but the claim is not generally true.

    1. A R&P will cause you to loose turning radius.

    2. A R&P will cause bump steer.

    3. Hydraulic roller-cams cannot rev past 6200 rpm.

    4. (This is a new one) The NW kit prevents UCA interference with the wheel.

    You can't believe everything that you read on the internet, especially if you don't read it carefully. One phenomenom that I have noticed is this. A long running thread is created, which contains lots of information, opinions, and experiences. A well meaning novice comes along a year later, then just half-ass reads the thread. The novice then makes a post that tries to condense the long thread into a few statements of fact. Next, somebody reads the novice's interpretation as the gospel truth.

    That leaves folks that know better to spending a lot of time trying to explain fact from fiction.

    Like I said, I don't speak for darkBuddha. Much of my exasperation comes from a long-time thread here on SN. Corpse was the original poster, but I don't blame him. Can you guess the thread ;)

    BTW, by "half-ass reads" I am not implying that Randy'65 or any other poster on this thread is a "half-ass". I was describing a general situation, not this one.

    Sorry for the rant,
    Randy
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  17. DarkBuddha

    DarkBuddha Founding Member

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    Oh no no no... I wasn't offended, or even really put-off at all. This discussion has happened before with no real decisive conclusion, and I only meant that we were probably starting that kind of thing again. I'm not a supporter of the other view, but I'm all for an open discussion. And if my tone seemed a bit short, it was because I was in tcb (taking care of business) mode, nothing more.

    I will readily admit that my only experience with the negative wedge/roll kit is on my own '70, so I typically talk from that perspective without really considering the context in which others are thinking of it. This is a problem, both mine and others. It is important to include details of the filter through which information is being sifted, and then, hopefully, ascertain the true essence and intent of that information. I do this when I parse info, but rarely when I'm passing it to others... I've got to work on that.

    With this in mind, your statements may be correct for earlier model cars. There are several known issues with running any 8" wide wheel on the front of early models, but I wouldn't presume to know much about the specifics.

    With regard to...
    In my previous post I mentioned that by adding the wedge to the upper ball joint mount, the distance between the upper control arm and the lower control arm is wider, which effectively moves the top of the upper control arm (at the ball joint higher. Consider: the distance between the ball joints is determined by the spindle (this does not change). Then the wedge is placed on top of the upper ball joint, between the ball joint and the upper control arm. This addition spaces the upper control arm up by approximately 3/4", as I recall. This additional 3/4" can place the upper control arm right at the edge of the rim, thus the reason a larger diameter wheel might be necessary. Does that make sense?

    Oh, wait, I think I have a pic...[​IMG]
    #17
  18. Randy'65

    Randy'65 Founding Member

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    Good pick. My impression has always been that using a rim with 4.75" backspacing would stuff the upper ball into the rim, creating the interference. Your pic obviously dispells this. Pics say a thousand words.

    Maybe someday I will get my stang put back together so I can research this stuff myself.
    #18
  19. mustangracer

    mustangracer Founding Member

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    Wait...everyone is right here.... :D

    The kit is NOT designed to allow for bigger rims and tires...it's a side effect.

    The change in camber curve with the shelby drop and GW kit ALLOWS a larger wheel and tire combo because it causes the top of the tire to tuck in on compression, thus keeping it from rubbing on the fender.

    For example, look at the way the tires sit at extension with a stock suspension, they kinda do /-\, and on full compression go the opposite \-/. The shelby drop reduces this tendency by lowering the arms, and the GW setup reduces it a bit more by also being a shorter arm, so the tires lean in at the top more on compression. This is what allows the larger wheels and tires. Ball joint interference is pretty much due to rim size and backspacing, with the stock stampings, sometimes the lip can be a little large and cause some interference.
    #19
  20. Randy'65

    Randy'65 Founding Member

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    That's what I had always heard. Is it possible that the spindles are different enough on 67-70 stangs from 65/66, that this is more of an issue with the 65/66's? :shrug: I'd love to be able to hold the two up side by side to compare. That might explain a lot.
    #20

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