Splined Sway Bar Info?

[ScotI]

I'm currently wrapping up a coil-over conversion for my '64 Chevy truck that has an assorted group of aftermarket parts that don't want to play well w/a traditional sway bar set-up. The mods consist of an aftermarket front cross-member (Porterbuilt) & narrowed a-arms (also PB). I have mocked-up multiple C10 bars as well as an f-body 1Le 36mm bar but only one lines up anywhere near close to the lower a-arm link mounts. My set-up = approx. 39.25"-39.375" wide @ the center of the outer link mounts on the arms. Others I've measured:

Belltech C10 'Sport' bar @ 1.375"od = 40.5"
Stock '00 S10 OE bar = ~41.5"
3rd GEN f-body 36mm bar = 43.75"
G-body Malibu OE bar = ~43.5"
Addco/Porterbuilt C10 bar = 44"

Of these units I played with, the Belltech bar is closest but still too wide. I can possibly get creative enough to get it to work @ the a-arm mounts but once you put the frame-pivot bushing housing on the bar & mount it to the bottom of the frame rails, it's the lowest hanging item on the truck & it's @ a very vulnerable spot. I have reached out to Porterbuilt to see if they have a narrower sway-bar that fits my dimensions but w/the mounting position @ the lowest portion of the frame being a concern, I sat back & wondered about alternative mounting of the bar. Moving the mounting location farther back w/the Belltech bar did help w/the mounting height (the frame starts to curve/rise in the area) but created other packaging issues. The shape of the bar is not ideal as-is which limits clearance as well so that's also a possible packaging issue (it may/may-not interfere w/my current minimal width front wheel/tire combo).

Ideally, I need to mount the bar within the frame rail vs. below it so I don't add a clearance concern to the bottom of the chassis which was purposely built to minimize clearance concerns.

This has me researching a Splined Sway bar as a solution. I've been doing basic Google searches for a few days & did find some info but where one source provides spec data, another doesn't (making it hard to determine what to get). Most I've found are race-car/rear set-ups. Welder Series has a DIY kit but it's not really a splined assembly nor do I feel it's adequately sized. Speedway has basically what I need (it's a 64-72 A-body spec kit) but it's too wide & they don't list narrower options in a similar configuration. I attached images of the Speedway/A-body set-up. A kit like this w/options for the main bar width is what I feel might work.

If you've been down this rabbit hole & know of a source/sources for splined sway (Torsion) bars, let me know.

[GEARBOXGARAGE]

I'm surprised that Porterbuilt didn't offer a sway bar as an add-on sale when you bought their kit. Seems like they would have offered the info that a standard C10 sized sway bar does not work with the setup they sold you.

Check out Speedway Engineering, they have virtually endless combinations of setups as you can buy the individual components to suite your needs. I'm sure if you calculated all of your dimensions and give them a rough estimate on vehicle weight, motion ratio of your front suspension and current spring rate, they could match up a bar rate for your intended application.

http://1speedway.com/index.php?route=product/category&path=76

[ScotI]

I'm surprised that Porterbuilt didn't offer a sway bar as an add-on sale when you bought their kit. Seems like they would have offered the info that a standard C10 sized sway bar does not work with the setup they sold you.

Check out Speedway Engineering, they have virtually endless combinations of setups as you can buy the individual components to suite your needs. I'm sure if you calculated all of your dimensions and give them a rough estimate on vehicle weight, motion ratio of your front suspension and current spring rate, they could match up a bar rate for your intended application.

http://1speedway.com/index.php?route=product/category&path=76

PB does offer sway bars. When I originally purchased this set-up, Addco was supplying the bars for him based off of his specs but there were continuous issues w/delays. His intent then was to try & start building them in-house so they have better control (I believe that's what he's now doing). The #5 bar on my list above is one of those Addco/PB bars & it definitely won't work as the end-link position is wider than all the others I tried/measured.

That being said, a fresh in-house bar built to length would solve my initial 'fit' concerns but still leaves the 'it's the lowest item on the chassis' concern. That's where a modular splined-bar would work better as I can position it on top/inside of the lower rail 'lip' raising it's centerline out of harms way.

I just browsed Speedways site again during my lunch & took additional notes but they don't list enough info on individual items to determine if their 'G-Comp Standard length bar @34" width' will interchange w/the A-body kits bar. They also now list an F-body 'kit' but no pics & not even similar info like the A-body kit.

I scratch my head & wonder how their web site content is modeled/approved.

[SSLance]

I know that my splined bar came from Speedway Engineering. It's housed in a tube mount that is welded to stands welded to the frame. The arms and links etc are all just pieced together as well, I think some came from Allstar.

The main thing I fought for space with was whether to go over the steering or under. Going under let me have a much shorter swing arm which increased my bar rate by a ton. The end links do hang down kind of low but they are right next to the inside of the tire and as of yet they haven't hit anything.

Start looking for the pieces you need instead of trying to find a kit and I think you'll be able to piece something together pretty easily.

[ScotI]

I know that my splined bar came from Speedway Engineering. It's housed in a tube mount that is welded to stands welded to the frame. The arms and links etc are all just pieced together as well, I think some came from Allstar.

The main thing I fought for space with was whether to go over the steering or under. Going under let me have a much shorter swing arm which increased my bar rate by a ton. The end links do hang down kind of low but they are right next to the inside of the tire and as of yet they haven't hit anything.

Start looking for the pieces you need instead of trying to find a kit and I think you'll be able to piece something together pretty easily.

Yes sir.... I printed off the bar spec tables from Speedway Engineering over the weekend to get an idea of a possible solution. The info will def come in handy as far as determining bar size. I have also been trying to figure out the under/over of steering linkage. I know the 'end-link' length plays a part on the bars reaction rate as does the 'arm' lengths. There isn't as much info on these parts & how to factor their numbers into the calcs when trying to match things to your combo.

I am starting out w/750# 10" springs/5" stroke shocks on the Ridetech coil-overs (sbc/700r4 combo) but don't have true scaled weights as the truck is still in the build assembly process.

[SSLance]

I wouldn't worry too much about end link length. I used to run extremely long end links to keep my swing arms above the tie rods with no issues. In fact, longer links will give more fudge room for the rod ends to not bind. The little itty bitty short ones I run now had to be just right to not bind anywhere in travel.

Length of swing arm is a big one though and was my motivation to run mine under the steering.

[ScotI]

I wouldn't worry too much about end link length. I used to run extremely long end links to keep my swing arms above the tie rods with no issues. In fact, longer links will give more fudge room for the rod ends to not bind. The little itty bitty short ones I run now had to be just right to not bind anywhere in travel.

Length of swing arm is a big one though and was my motivation to run mine under the steering.

I've measured to get an idea of arm length but that's just bending the tape measure & picking a possible C/L for the bar/mounts.

Good info to know on the links length. I wasn't thinking about the longer links helping from an alignment perspective.

[ScotI]

I know that my splined bar came from Speedway Engineering. It's housed in a tube mount that is welded to stands welded to the frame.

Some follow-up.... I sent an e-mail to Speedway Engineering for specific specs but haven't received a response yet.

While I'm waiting, was there a specific reason for your bar being housed in a tube arrangement? My guess is that the tubular 'housing' adds additional rigidity up front & g-body rails make accessing hardware more difficult.

My plan was the traditional mounting/pillow-block arrangement (with upgraded/billet mounting blocks) utilizing an existing x-members mounting points. This would allow using a standard 37.5"L bar & utilize 'straight' arms @ 8" length w/the links in a plumb position as well as 7" & 9" positions for tunability (this is what I currently have mocked-up).

[SSLance]

Because I decided to go under the tie rods with my swing arms, lowering the bar itself from the frame with the tube stands helped with the geometry of the end links. This along with the additional structural help is why we went this direction.

[David Pozzi]

Stay away from aluminum arms. A circle track magazine tested them and they have too much flex.

[ScotI]

Because I decided to go under the tie rods with my swing arms, lowering the bar itself from the frame with the tube stands helped with the geometry of the end links. This along with the additional structural help is why we went this direction.

Stay away from aluminum arms. A circle track magazine tested them and they have too much flex.

Thanks for that info Lance & mentioning that Mr. Pozzi. I've been looking @ the 1.25" x.750" steel arms. Didn't think the aluminum arms would be a 'good idea' street thing. My mock-up pieces using 1.25" tall 'arms' (yardstick sections) fit comfortably under the R&P's TRE's @ ride height.

I did speak w/a rep from Speedway Eng. yesterday & got the requested info on machined dimensions of the bars as well as some insight. For those curious... It seems their e-mail form of contact doesn't work so calling is best.

Is there a 'Blue Collar' calculation that can be done for the rate of the bar to help narrow a starting point on a modular set-up? My research yielded the info that Ridetech's C10 Strong-Arm 'MuscleBar' set-up utilizes a 1.5" OD x .250" wall tubular bar w/a listed rate of 1020#. I'm using that info as a comparison with the other bars I have (utilizing the Speedway bar-size to arm-length spread sheet for the rates):

Fixed Rate
OE GM standard bar 1.125" solid w/14" arms @ 264#
OE GM HD 1.25" solid w/14" arms @ 350#
Addco/PB 1.25" solid w/15" arms @ 330#
Bell Tech 1.375" solid w/14" arms @ 494#
RideTech/Musclebar 1.5" tubular @ 1020#


Adjustable Rate
Speedway Eng. 1.5" hollow w/14" arms @ 549#
Speedway Eng. 1.5" hollow w/8" arms @ 957#
Speedway Eng. 1.375" solid w/8" arms @ 864#
Speedway Eng. 1.25" solid w/8" arms @ 617#


The RideTech bar rate seems suspect based on the fact that all the other bars (which are OE or direct OE configuration replacements) have a measured arm length of approx. 14". Using the Speedway spread sheet for their hollow bar @ 14" arm length indicates the 549# and that's w/a .500" wall vs. RideTechs .250" wall. My 8" arm length is based off of relocating the sway bar closer to the a-arms which provides the additional ground clearance.

I feel comfortable w/my Speedway bar selections but wanted others insight before pulling the trigger.

[Beechy]

ScotI.......some more info is required to compare rates.

Ridetech quotes 1020 but their arm length might be 6".....entirely possible.
We need to know that arm length in order to compare.

Using this calculator......

https://swayaway.com/tech-room/torsion-bar-wheel-rate-calculator/

you can compare a 6" arm length to 12" arm for the same bar. Simple multiplication.....the short bar is double the rate of the long for the same diameter and same pillow block spacing.

Also if you shorten your BAR LENGTH (and locating pillow blocks closer) to get inside your chassis rails , you're gonna raise the rate massive. Warning....if your bar length is short relative to the amount of BEND in the arms to get out to your 39.3" then the amount of deflection in the ARMS reduces the bar rate and eventually fracture an arm at the pillow block area. Shortening the straight section of bar increases prolly by the square of change.....shorten 1" = 100# change.....shorten 2" = 400# change.

A HOLLOW BAR is only slightly lower in rate compared to a solid bar ..... how much? I don't know but maybe 5 or 10%. Gotta be on Internet somewhere.

My suggestion in this whole subject would be to calculate the wheel rate of a STOCK truck compared to your MODIFIED wheel rate then use the same percentage of factory bar to your desired bar. Don't OVERPOWER your spring/shock combo.
(ignoring sway bar....so just use the dimensions from inner lower pickup point to spring /shock mount, and inner point to tire contact dimension multiplied into spring rate)

[ScotI]

ScotI.......some more info is required to compare rates.

Ridetech quotes 1020 but their arm length might be 6".....entirely possible.
We need to know that arm length in order to compare.

Using this calculator......

https://swayaway.com/tech-room/torsion-bar-wheel-rate-calculator/

you can compare a 6" arm length to 12" arm for the same bar. Simple multiplication.....the short bar is double the rate of the long for the same diameter and same pillow block spacing.

Also if you shorten your BAR LENGTH (and locating pillow blocks closer) to get inside your chassis rails , you're gonna raise the rate massive. Warning....if your bar length is short relative to the amount of BEND in the arms to get out to your 39.3" then the amount of deflection in the ARMS reduces the bar rate and eventually fracture an arm at the pillow block area. Shortening the straight section of bar increases prolly by the square of change.....shorten 1" = 100# change.....shorten 2" = 400# change.

A HOLLOW BAR is only slightly lower in rate compared to a solid bar ..... how much? I don't know but maybe 5 or 10%. Gotta be on Internet somewhere.

My suggestion in this whole subject would be to calculate the wheel rate of a STOCK truck compared to your MODIFIED wheel rate then use the same percentage of factory bar to your desired bar. Don't OVERPOWER your spring/shock combo.
(ignoring sway bar....so just use the dimensions from inner lower pickup point to spring /shock mount, and inner point to tire contact dimension multiplied into spring rate)

Thanks for the feedback & insight.
I have the pivot point to shock/Lower BJ dimensions in my notebook @ work. I used those numbers when determining a starting spring rate for the C/O's & how I arrived @ the 750# springs. I'll follow up on that tomorrow.

All numbers posted were basing the arm length off of the current 1pc bars on hand. The Addco/PB is the only one that really has multiple bends; the others are pretty much just a 'U' bend ( I_____I ). I had to look @ an earlier version of the RideTech MuscleBar (under my dually) to verify it was similar in shape. The bar the listed 1020# spec was for could in fact be different in it's arm length since it is a more recent version (the bar under my dually is from 2014). These should all share an arm length that's fairly close since the C/L of the bars pivot point to end-link are the same.

As noted in my info, all of these C10 bars were wider than the modular set-up I'm considering which is part of the reason I'm searching for a replacement. The closest being the BellTech bar which is @ least 1" wider @ the base/arm).

With the 'standard' width (length) modular bar @ 37.5" plus the heim 'high-angle inserts', I should/would be @ the C/L of the upper link. I figure their straight arms will be used as-is after cutting to req'd length (they're 18"L) & holes drilled.

[ScotI]

Just to follow-up.... I purchased a 1.25" x 37.5"L x 48-spline bar w/the 1.25"x 18"x .750" 48-spline arms, 1.25" collars, & end-caps.
Plan is to trim the arms to a 10" length & drill 3 holes to allow for some tuning (@ 7", 8", & 9" from the bars center-line).

I appreciate the feedback that was given.