Do I need trailing arms on my custom IRS chassis?

[ironworks]

Are those spindles just for mock up or is that the final product?

[bret]

Originally Posted by garickman

Yes it was at the Dominator booth at Del Mar. And yes Leonard is an expert. I don't know the skill set of everyone on the forums, so when I have a few people tell me things might not work as well as they could it just makes me wonder.

Heard that. It's good to become educated...to get beyond blind faith, no matter who you're dealing with. I'm sure a conversation with Leonard will reveal why he thinks the trailing arms are un necessary.
Looks to be a great project!

[Bryce]

There are two questions to ask:

Is this a fully constrained system?
Is the setup strong enough?

The system is fully constrained as is. Some IRS setups use a ball joint top and bottom this allows for more adjsutments in the future. Toe, caster, camber. If you adjust the LCA to move forward then you will have more positive caster.

Without know material thickness and properties its hard to say if this is strong enough. I think that lower plate welded to a tube and bolted to the spindle needs some gussets. Also what car is that spindle from. That load path looks suspicious, is that the best place to attach the spindle?

[ironworks]

Originally Posted by garickman

The spindles are the final product so be gentle if you have some bad news. I have much respect for your business and the work you and your shop produce. I look forward to getting some input from you.

I just noticed why you may have asked about the spindles. If you are wondering about the right front spindle where the ball joint does not go in all the way, that side still needs to be machined with a different taper to accept the ball joint, the left spindle had been done already.

My concern was the current way the spindle is now being used is not how it was designed to be used by the spindle manufacturer. The spindle on the Heidts rear end is doing the same as what you have here. But the spindle design from Heidt's is much different then how this spindle from another application is being used. That lower mount on the spindle looks like it would put a lot of undue stress on the hub bolting area of the spindle. My guess is you would have been better off to just have used an upper and lower ball joint on the spindle like the spindle was designed and built for.

My other thought is that you should have more faith in your builder. If your willing to take some analysis opinion of your project from someone on the internet. The comment on "Toe Links" to me is someone who has no idea. They are called tie rod ends. They are used on a car with Balljoints like a vette or modern IRS. This rear suspension is similar to a jaguar, kugal, or heidt's. That is why I was asking about whether spindle was a final piece or just used for mock up to design or set up for a final product. I under stand this project is still under construction and lot sof this may change before whoever is in charge says it's complete. I'm guessing but this chassis must be going under something else besides your cop car, because you seem to be putting a lot of effort into a custom chassis for this project when lots of people make great parts to bolt on a chevelle that would accomplish the same thing for much less effort and money.

Thanks for the respect but I'm just a guy that uses common sense and smart friends to build what we can. I'm not trying to ruffle any feathers, You asked so I'm just sayin. Hopefully your builder has everything dialed.

[65_LS1_T56]

I'm assuming Ironworks was referencing me as "some guy on the internet" even though we all are just that...my post was:

Originally Posted by 65_LS1_T56

Also, most independent style rears would have a toe link too. Unless you are going for something like the Heidts system. .

Originally Posted by 509Chevelle

Greg, 65 LS1 T56 is correct about the toe link. Toe link bars are what will attach to the steering arm portion of your spindles. Which would be the equivalent of what the rack and pinion attached to on your front spindles. I've included a pic of an RS chassis with the toe link bar circled. Toe links or bars help with your cast when aligning the rear wheels and dealing with cast and camber.

He is also correct, it is called a toe link, not a "Tie Rod" in the rear.
a simple diagram of an independent rear, though different in design than the Jag style.


I do agree that Greg should just trust his chassis builder as well. The work looks great.

So thats it from someone on the internet who has no idea.

[214Chevy]

Originally Posted by ironworks

... The comment on "Toe Links" to me is someone who has no idea. They are called tie rod ends.

I've heard of them called "toe links" for years. And so do some of these other people too.

http://shop.britishracinggroup.com/G...H111GTRTLK.htm

http://nitronracing.wordpress.com/su...-toe-link-kit/

http://www.dinancars.com/shop/R280-0...Toe-Links.aspx

And last, but not least for the Corvette guys.......

http://www.google.com/imgres?imgurl=...ch&um=1&itbs=1

[ironworks]

Originally Posted by 65_LS1_T56

I'm assuming Ironworks was referencing me as "some guy on the internet" even though we all are just that.

Exactly, You might be the lead chassis designer for Chip Ganassi racing for all I know, No one has any ideas who is who, REALLY. All we have is screen name and a cool little picture. There are tons of guys who have been here for a while that we all find out are snakes in the grass years later. But my point is when you open up your project for the masses opinions, Your getting exactly what you asked for. The same idiots we share the road with, the same idiots who voted opposite as you, same people who do ugly things to certain cars that we like. There are tons of internet no it all's that have no idea about anything and once in a great while there might be a smart guy who gives you his opinion and all the know it all ponce on him. I did not mean any body in particular with my comment.

I really think these posts are a waste of time in the fact you cannot tell much from 3 pictures. And even if you could what is that going to prove when you go tell the guy doing the work what someone on the internet said. Pictures maybe worth a 1000 words but they give you no idea what is really going on during construction of a project, you have no idea what is what without really talking to the mastermind behind the project. Just like the saying goes you can't judge a book by it's cover, you also can't judge a project until it's complete.

I have never in my entire life heard the term toe links, So I guess I learned something new today. I wish you well on your project as I have heard you have had a rough go, but all I can say is you have to be on top of things or the same thing can happen again, don't trust anybodies work. Ask questions to be educated by the guy doing the work and keep asking until it all makes sense, if it does not make sense go ask some one smart who is willing to get involved. In a project car you connected to a guy for a long time with the quality of work they do. If you unknowingly pay for junk it will be with you until you cut it out and it will never be what it could have been. Picking a builder is like picking your wife, you better know exactly what your getting into. Because your going to be stuck for a long time with the person.

[bdahlg68]

System will work, and as a DD, I would suspect you'd be fine after the diff is braced. My only concern on the functionality of the system is the rocker arm system. I can't really tell you if the loading will be a problem for the spindle without a ton more info and some expensive software. But the short link from spindle to rocker arm is likely to do funny things with your spring rates. If this was considered by your builder, or if you are working in a narrow travel range, then don't worry. Again, probably fine for a DD. If it's meant for racing or running an absolute ton of torque through, then things are probably going to break regardless of how much planning the builder did or what IRS system you go with. It is a pretty sweet looking setup though and kudos to you and the builder.

[GregWeld]

Toe link - because it controls toe in (or out)



If you want to see what happens when the spindle - carrier - axle yoke is not well designed -- look at this thread.


https://lateral-g.net/forums/show...28681&page=133



FYI -- 1800# '32 Fiberglass roadster - 450hp 383 stroker (mild) - 5 speed... 10' burn out - 3rd time (10'r) this happened -- and this is the SECOND SET of these... Now THIRD set is beefier as shown here.

[Ron in SoCal]

Originally Posted by ironworks

....So I guess I learned something new today. I wish you well on your project as I have heard you have had a rough go, but all I can say is you have to be on top of things or the same thing can happen again, don't trust anybodies work. Ask questions to be educated by the guy doing the work and keep asking until it all makes sense, if it does not make sense go ask some one smart who is willing to get involved. In a project car you connected to a guy for a long time with the quality of work they do. If you unknowingly pay for junk it will be with you until you cut it out and it will never be what it could have been. Picking a builder is like picking your wife, you better know exactly what your getting into. Because your going to be stuck for a long time with the person.

I know at least one (or two) that will laugh at this, but these are words of wisdom in my book Roger. Your direct style is appreciated by many, even when it goes against the 'conventional' grain