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Summary table of swaybar options

20K views 80 replies 30 participants last post by  BradCTSV 
#1 ·
I originally put this over on the CTS forum, as I was trying to find out what the base and Sport CTS swaybar diameters were. I ended up getting the measurements myself from a couple of cars that were at Lindsay when I was there with my car. Still not positive on the CTS diameters - it would be interesting to check the parts database to see if there are different part numbers for front and rear on the base and Sport models. Just seems strange that they would "upgrade" by only 1mm, but that's what the vernier caliper said.

The Hotchkis and Addco bars are advertised in inch units, while the GMPP and Eibach bars are advertised in millimeters, so I converted them all to make them easier to compare.

. . . . . . . . . . . . . . . . . Diam. (in). . . Diam.(mm) . . . Construction . . Comments
Hotchkis CTS-V front . .. 1-1/4 . . . . .. 31.75 . . . . . . . tubular .. . . . . Sold as front/rear kit (2280)
Hotchkis CTS-V rear . . . 1 . . . . . . .. . 25.40 . . . . . . . ?

Hotchkis CTS front . . . . 1-3/16 . . . . . 30.16 . . . . . . . tubular .. . . . . Sold as front/rear kit (2279)
Hotchkis CTS rear . .. . . 13/16 . . . .. . 20.64 . . . . . . . ?

Addco CTS-V front . . .. 1-3/8 . . . . . . 33.66 . . . . . . . solid . . . . . . . 2290
Addco CTS-V rear . . . . 1 . . . . . . . . . 25.40 . . . . . . . solid . . . . . . . 2289

Addco CTS front . . . . . 1-1/8 . . . . . . 28.58 . . . . . . . solid . . . . . . . 2200
Addco CTS rear . . . .. . 7/8 . . . . . .. . 22.23 . . . . . . . solid . . . . . . . 2201

Eibach front . . . . . . . . 1.10 . . . . .. . 28.00 . . . . . . . tubular . . . . . Sold as front/rear kit (3878.320) or individually (3878.310 front, 3878.312 rear)
Eibach rear . . . .. . . . . 0.87 . . . . .. . 22.00 . . . . . . . tubular

GMPP front . . . . . . . . . 1.38 . . . . .. . 35.00 . . . . . . . hollow . . . . . . No longer available
GMPP rear . . . .. . . . . . 0.94 . . . . .. . 24.00 . . . . . . . solid

Stock CTS-V front . . . . 1.04 . . . . .. . 26.50 . . . . . . . tubular (?)
Stock CTS-V rear . . .. . 0.83 . . . . .. . 21.00 . . . . . . . solid (?)

Base CTS front . . . . . . 0.91 . . . . .. . 23.00 . . . . . . . tubular (?)
Base CTS rear . . . .. . . 0.63 . . . . .. . 16.00 . . . . . . . (?)

Sport CTS front . . .. . . 0.91 . . . . .. . 23.00 . . . . . . . tubular (?)
Sport CTS rear . . . . . . 0.63 . . . . .. . 16.00 . . . . . . . (?)
 
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#2 ·
I have the GMPP bars and the front one is a beast. It eats a set of links every year. Your data confirms why. Nice post.
 
#7 ·
Interesting. Did you talk to Addco directly? I noticed they're always listed with a significant shipping delay on summitracing.com, but I just figured that meant they were basically made to order (since there's not enough demand to keep them on the shelves).

I installed the Hotchkis bars a couple weeks ago, but may reinstall my stock front bar, as the handling balance isn't where I want it to be.
 
#8 ·
Time for the dumb question of the day.

Bit off topic, but just how does the swaybar work??? The reason I ask is because the end links are so flimsy. I had one come apart in my hands.
 
#10 ·
Since, the swaybar aka torsion bar is mounted to the suspension, the suspension is actually moving in the opposite direction as the chassis.
So, if the chassis dips down from a hard turn on one side of the vehicle, then the suspension is actually moving up and of course, the opposite occurs on the other side, when the chassis is moving up, the suspension is actually dropping down. The horizontal bar transmitts an opposing force to the other side, but because it is attached to vertical links, the links receive the brunt of the force being transmitted.
The bigger the bar, the more force transmitted, but the stiffer the ride.
From here, you get into understeer vs oversteer and how much force needs to be generated by way of front bar vs rear bar vs spring rate, vehicle weight, FWD or RWD. It's over my head.
 
#9 ·
Anyone have info about the Eibach sways.
I read somewhere that the Katech V had them.
Just wondering of anyone had some experience with em...
 
#12 ·
Resurrected this thread since I've been thinking about going back to a stock sway bar setup with my KWs. Interesting that the GMPP bars have a huge disparity in the front to rear diameter over the other options. About 46% larger in the front than back. Probably the most popular option is the Hotchkiss which is only a difference of 25%. The stockers are about 26%. The Addcos 32.5% and the Eibachs 27%.
Strange that you would think the GM bars would induce lot's of under steer since the front tires may saturate so much quicker (faster weight transfer) than the rears. Do the GM engineers know something we don't. I rode these GM bars for 2 years and really couldn't find anything unusual about them. Some low speed push but nothing much more than stock. I really liked them. Just strange that these bars have an entirely different balance front to rear than the others. Come to think of it the GMPP rear was adjustable and could be stiffened up. Just seems weird the GM racing guys went this route.
 
#26 ·
Resurrected this thread since I've been thinking about going back to a stock sway bar setup with my KWs. Interesting that the GMPP bars have a huge disparity in the front to rear diameter over the other options. About 46% larger in the front than back. Probably the most popular option is the Hotchkiss which is only a difference of 25%. The stockers are about 26%. The Addcos 32.5% and the Eibachs 27%. ...
Don't you have to take into account the fact that some of these are tubular and some are solid?

It would seem that what would be highly useful is if each manufacturer included a standardized measure of torsional strength, such as ft-lbs per degree of torsional deflection.
 
#14 ·
And the difference between your Hotchkiss rear and the stock front is less than 5% (plus your running and extra 1kg spring in the rear). A pretty sharp contrast to the GM setup of 46%. With the inboard rear springs, the wheel rate is lower than the front anyway so you probably would need to do something really radical to get the car to have terminal oversteer. If I had to guess, the KWs are a game changer. In any case, my sense is you just have to get out there and see what works much like you did. I'm going with the front stock bar first and maybe mess with the rear shock setting to see if that dials in things since I still get some low speed push.
 
#15 ·
I gotta say with the GM bars installed @ Summit, the instructor, on more than 1 occasion said the car felt planted and balanced.
Too bad this thread didn't pop up a few days earlier, I would have asked Andy Pilgrim the reasoning behind the sizing. His eyes did light up a little when I told him I had a set on my car. He said to just go buy an extra set of wheels and to put Hoosier A6's on...
 
#22 ·
Too bad this thread didn't pop up a few days earlier, I would have asked Andy Pilgrim the reasoning behind the sizing. His eyes did light up a little when I told him I had a set on my car. He said to just go buy an extra set of wheels and to put Hoosier A6's on...
When he drove my car at V Day 4 he said it pushed too much, and said that every car he'd driven with the Hotchkis sway bars was like that.

Funny thing is they ran the 3 and 4 way adjustable penske setup from Anze on the challenge cars though.
I would be absolutely stunned if the GMPP sway bars were used on the WC cars. AFAIK the GMPP sway bars (and diff cooler kit and trans cooler kit and rear control arms with stiffer bushings, etc) were made to support guys running the CTS-Vs in SCCA T2 competition. I would be willing to bet that the WC cars ran "standard" adjustable blade type anti-roll bars like every other dedicated race car.
 
#16 ·
Those bars are sweet. The GM guys have figured out the right set up for the FG2s. The rear bar has a stiffer mounting hole. Someday when your brave try that set up. I bet the car turns in even better.
 
#17 ·
Funny thing is they ran the 3 and 4 way adjustable penske setup from Anze on the challenge cars though. Wonder how that setup would work if it could fit...
 
#28 ·
Too bad we don't have the ability to swap all these on a single V1 then run it on a track and quantify the degree of understeer, neutral steer, or oversteer. That way, we could hold all the other variables constant.

I wonder if such results could be extended and used to predict behavior with other shock setups, other tires, other road surfaces, etc, etc. Hm-m ...

Yeah, I know, it's a pipedream.
 
#31 ·
We could just sell our cars, put the money together, and buy the challenge cars...I'll run the north east events, you guys divide up the rest of the regions...
 
#30 · (Edited)
AAIIC and crankedupforit: you guys are correct, the GMPP sways were probably designed for T2 guys. John B had them. Maybe Bobby Fischer too?
The world challenge cars definitely have the adjustable blade type with penske adjustables.
 
#32 ·
Lol. Good plan. I mean they're only $125k each right now. (I posted a link in the General section to the for sale thread for those haven't seen it). I'll take the rocky mountain events. ;)

Actually it would be nice to see what kind of design characteristics/parts could be adapted to our street cars.
 
#33 ·
Spoke to Dan over there, they are about 200k each. That price online is for 1 car plus some of the spares. I figure by the time we are all done with our cars it will be close to that amount in total...
 
#34 ·
Looks like Suspension Techniques has added front and rear bars for the 1st gen CTS-Vs. (Apparently they don't realize they'll also fit the non-V CTS, as their online catalog only calls up the V.) Rear is a solid 15/16" (23.8mm). Their catalog shows the front is 13/16" (20.6mm), which doesn't make any sense.

On a side note, I was surprised to find that this thread has been archived, and thus didn't show up when I used the site's search function - I had to use the google search bar to find it. I wonder if posting to it will pull it out of archive status?
 
#38 ·
thanks for the info.. great thread.. +1 for stickied status
 
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