1G tubular control arms

[PSI2HI]

The biggest question is, is the market willing to pay in upwards of $500 for a quality control arm like those pictured?

 

[dsm-onster]

Matt, have you seen the post/photo of the broken Polk arm?

Me? No. I'd like to.

 

[Ludachris]

The biggest question is, is the market willing to pay in upwards of $500 for a quality control arm like those pictured?

Definitely not as many people as in the Mustang market, that's for sure. It's not going to be a bulk item, which will help determine the pricing. I think these can be made and sold for about $350-400 in the DSM world.

These are meant for racing, and the people who are spending money on their cars in this market are the racers. And conversely, these are the only people that will really benefit from this mod anyway - and that's what I've been saying all along in this thread. There really is no sense in making a street car replacement.

The average DSMer won't buy these, just like the average DSMer won't buy 1600cc injectors, or a Driveshaft Shop aluminum driveshaft - how many DSMers will spend $750 on one of those to save 10 lbs of unsprung weight? And yet, many of us are glad that those parts are available. These new control arms could potentially save just as much unsprung weight and address a few major issues for the road racing crowd (like ball joint selection, brake cooling, replaceable solid bushings, etc).

 

[dsm-onster]

Well, unless you make the rear bushing adjustable. Lowering that joint 1-2 inches will cause the front tires to dig when launching. It will remove the brake anti-dive but will really help front wheel traction that AWD and FWD guys can benefit from. I did a similar mod to my FWD car and I could consistantly launch at a about 800rpms higher with street tires. I never really had an issue with the nose dropping when I was braking either. There's alot of pro-brake dive dialed in the rear.

RWD ls1-6 guys do this to their rear. I'd buy the part for the safety sake alone if it can do what my home suspension work did for me, since my mod can cause a little concern when you stop and think about what you're actually altering.

Making both joints adjustable will dial out the camber results of lowering the car too.

 

[Ludachris]

Well, unless you make the rear bushing adjustable. Lowering that joint 1-2 inches will cause the front tires to dig when launching. It will remove the brake anti-dive but will really help front wheel traction that AWD and FWD guys can benefit from. I did a similar mod to my FWD car and I could consistantly launch at a about 800rpms higher with street tires. I never really had an issue with the nose dropping when I was braking either. There's alot of pro-brake dive dialed in the rear.

RWD ls1-6 guys do this to their rear. I'd buy the part for the safety sake alone if it can do what my home suspension work did for me, since my mod can cause a little concern when you stop and think about what you're actually altering.

Making both joints adjustable will dial out the camber results of lowering the car too.

I guess you lost me on the launching - I still think this is more of a road race piece, but I guess that's me.

The rear joint is adjustable on the Mustang parts above. But the adjustable part of the design really isn't as important, since on a 1G, you'd want to adjust the camber with camber plates so as to not throw off the front and rear track. If anything, the real benefit is the solid bushings and the easy replacement of those bushings. And the biggest benefit is the opportunity to address the ball joint - making it so you can use an aftermarket ball joint that is taller in order to offset the negative effects of lowering the car - mainly bump steer.

 

[PSI2HI]

Definitely not as many people as in the Mustang market, that's for sure. It's not going to be a bulk item, which will help determine the pricing.

These are meant for racing, and the people who are spending money on their cars in this market are the racers. And conversely, these are the only people that will really benefit from this mod anyway - and that's what I've been saying all along in this thread. There really is no sense in making a street car replacement.

The average DSMer won't buy these, just like the average DSMer won't buy 1600cc injectors, or a Driveshaft Shop aluminum driveshaft - how many DSMers will spend $750 on one of those to save 10 lbs of unsprung weight? And yet, many of us are glad that those parts are available. These new control arms could potentially save just as much unsprung weight and address a few major issues for the road racing crowd (like ball joint selection, brake cooling, replaceable solid bushings, etc).

Yeah i hear ya. The reason i get into this is there is a lot of liability in manufacturing structural suspension components such as pictured. Therefore a lot of CAD/stresss analysis should realistically be put into the part before even thinking of realising it to market. The parts pictured on the first page definatly had neither put into them as the welding is very subpar and the bushing design is highly likely to shear off under load. I've done numerous chromoly suspension and steering components in the motocross industry thus i have some interest in such products.

 

[Ludachris]

Really liking BMR's rear pivot design. Mustangs also enjoy an extended ball joint that is a direct fit. For Mustangs.

Matt, have you seen the post/photo of the broken Polk arm?

Where did the Polk arm break exactly?

 

[dsm-onster]

I guess you lost me on the launching - I still think this is more of a road race piece, but I guess that's me.

Sorry. Look at the control arms as butterfly wings. We're dialing in anti-squat-- which usually this term applies to the rear under acceleration-- into the front suspension during acceleration. Here's an article touching on this. Click. Here's the camaro/f'bird anti-squat brackets and an brief explanation (RWD). Click. Here's another article discussing this in more detail focusing on FWD traction. Click. And here's a pic I drew to illustrate this. Click.

The same that applies to RWD applies to the front. This will push the front tires into the ground. Some will look at this and say that it will make the front lift, but having the suspension the other way causes the wheels to apply a force compressing the springs. As the stock suspension sits, once the springs match that force and cancel it, all the force goes to back to acceleration; which causes the force to be applied to the springs again. And over and over; and you see now why wheel hop actually occurs. If the wheels were inclined to dig instead of lift when a forward force is applied to the hub, then wheel hop would diminish and as the car lifts the wheels would go farther down to cancel out the height.

BTW, this really helps FWD and AWD cornering: more traction in the front when you gas it.

 

[underradar92]

Where did the Polk arm break exactly?

Me? No. I'd like to.

Post 13 shows the break. http://www.dsmtuners.com/forums/road-course-autocross/271341-last-race-season-last-race-eclipse.html

Here is my version of a cure for the break, along with an idea of what the Howe balljoint goes in. I know y'all can't actually see the balljoint stud due to the heat wrap but you do see how the body of the thing fits. You can also glimpse the tie rod mod in one shot.

The reinforcement is actually a ChroMo tube, welded all around and double plated. That should do the trick.

 

[InfiniteGSX]

I've been wanting to do this... but not too good at welding and I'm a perfectionist so I would never complete them the way I want cause they would never be perfect enough... but I always wanted Tubular Suspension thats fully adjustable... I had custom tubular suspension made for my old 87 Accord along time ago... I loved it... For longer races I could adjust anything to help me out. IT was great...

I wish I could get some stuff for the talon... Mainly the rear end... My camber is soo screwed in the rear... front is straight.... so its less of a problem then the rear is.

Also, it would be nice for a fully tubular rear end for wider tires/wheels. I'm on 8.5" wide wheels and they have a couple dings in them so I had to shave down the rear arm so they would stop rubbing. Car wouldn't move!

 

[underradar92]

Here is a possible rear camber cure: http://www.dsmtuners.com/forums/handling-tech/333399-3sx-rear-camber-arm.html

 

[dsm-onster]

Post 13 shows the break. http://www.dsmtuners.com/forums/road-course-autocross/271341-last-race-season-last-race-eclipse.html

Here is my version of a cure for the break, along with an idea of what the Howe balljoint goes in. I know y'all can't actually see the balljoint stud due to the heat wrap but you do see how the body of the thing fits. You can also glimpse the tie rod mod in one shot.

The reinforcement is actually a ChroMo tube, welded all around and double plated. That should do the trick.

Ah! so maybe the threaded rodstock wouldn't break AT the rear bushing. But you at least have you have to take into consideration the material for the lever arm between the front and rear bushings. I see. The rear bushing may see much more load than I would have thought too. Though the mustang rear bushing deams to be fine with a heavier car and the samy style as Paul's.

I'll add that Paul has a weld and two tubes at the point where that above control arm broke:

You must be logged in to view this image or video.

As soon as the other a-ar reduced to one tube, it broke right there:

Your mod to that other A-arm looks like it might hold up well. You can only test it and find out. Testing suspension prototypes is frightening .

 

[underradar92]

I've only heard of that one failure. Evidently, almost no-one else is road coursing these arms.

I've done a couple of track days before the reinforcement so I'm thinking that with the multiplication of strength in that area I'll be ok. Especially considering the similarity in the Mustang arm, which has just a simple gusset. Maybe the R.R. arm is visually different?

As for Paul's arms, I would still not skimp on over-engineering the rear triangle/bushing junction. A LOT of braking force goes through that area. It seems to me that it'd be easier to continue the tube right into the bushing and include a delrin or aluminium bushing for less overall cost than buying a urethane bushing, a bolt and then tapping that area after fabrication. And it'd be stronger/less liability. >No question<. That and the balljoint thing aside, I really like the arm design they are working on. I have voiced my opinion earlier on that aspect though.

 

[InfiniteGSX]

Do the mustang arms actually work for our car?

 

[Ludachris]

Do the mustang arms actually work for our car?

I wish I could find a Mustang owner so I can measure the stock arm. BMR never replied to my questions.

 

[underradar92]

No one has tried, to the best of my limited knowledge. A note in the Howe catalog mentions that the ball joint I'm using is compatible with Pinto spindles. Mustang-Pinto_Ford. I still wouldn't count on it.

Feel free to order a set for a trial fit. If the return policy is halfway cool, it may be worth it.

 

[Ludachris]

No one has tried, to the best of my limited knowledge. A note in the Howe catalog mentions that the ball joint I'm using is compatible with Pinto spindles. Mustang-Pinto_Ford. I still wouldn't count on it.

Feel free to order a set for a trial fit. If the return policy is halfway cool, it may be worth it.

The balljoint fitment is not even my concern. The arm can be modified to accept the balljoint we want it to with little work I'm sure. It's the connection points and the geometry that is key in my mind.

 

[VETTE_50_TH]

So, have you guys thought about when it comes time to lower your car off the lift, and you still have extreme negative camber? Or you may want a little toe in, and less camber. Have you guys thought about that at all with these lower A Arms?

I am trying to decide if i want to cut the arms a little, to "tuck" the wheel in better and run a little less camber.

James

 

[99gst_racer]

I wish I could find a Mustang owner so I can measure the stock arm. BMR never replied to my questions.

I probably have a few different sets of tubular Mustang control arms on the shelf here at work.

Which generation Mustang are they for and what measurements would you want?

 

[PSI2HI]

Ah! so maybe the threaded rodstock wouldn't break AT the rear bushing. But you at least have you have to take into consideration the material for the lever arm between the front and rear bushings. I see. The rear bushing may see much more load than I would have thought too. Though the mustang rear bushing deams to be fine with a heavier car and the samy style as Paul's.

I'll add that Paul has a weld and two tubes at the point where that above control arm broke:

You must be logged in to view this image or video.

As soon as the other a-ar reduced to one tube, it broke right there:

Your mod to that other A-arm looks like it might hold up well. You can only test it and find out. Testing suspension prototypes is frightening .

If these parts are chromoly and undersized wall thickness then the welding procedure could have created the problem which is what i suspect being it broke right outside a weld area.

 

[Ludachris]

So, have you guys thought about when it comes time to lower your car off the lift, and you still have extreme negative camber? Or you may want a little toe in, and less camber. Have you guys thought about that at all with these lower A Arms?

I am trying to decide if i want to cut the arms a little, to "tuck" the wheel in better and run a little less camber.

James

You can achieve both of those things with the RRE camber plates. I'd rather make these adjustments at the camber plate instead of at the control arm anyway.

 

[Ludachris]

I probably have a few different sets of tubular Mustang control arms on the shelf here at work.

Which generation Mustang are they for and what measurements would you want?

2005+ Mustang. Hell, maybe you could just take a piece of cardboard and trace the outline of the control arm and mark the location of the bolts (connection points). That's what I'd want to do.

Any chance you could send one of the arms out to me and I'd ship it back when I'm done?

 

[underradar92]

If these parts are chromoly and undersized wall thickness then the welding procedure could have created the problem which is what i suspect being it broke right outside a weld area.

I'm reluctant to point at the weld as an actual problem, as Polk has a good rep for race car fabrication.

The wall thickness of the tube in that spot is quite thin IIRC. That coupled with no gusseting, most likely due to this being primarily a lightweight dragracing design, are more likely the true cause. I doubt anyone else will be running these outside of the drag race community, and really, we are here to talk about other options.

 

[snowborder714]

2005+ Mustang. Hell, maybe you could just take a piece of cardboard and trace the outline of the control arm and mark the location of the bolts (connection points). That's what I'd want to do.

Any chance you could send one of the arms out to me and I'd ship it back when I'm done?

I could possibly get some measurements from a 2005 Mustang as my neighbor has one. Do you just want measurements of just the front control arms? I could take pictures and measurements. He most likely wouldn't let me take them off so I'd have to do the job just with the car in the air.

 

[InfiniteGSX]

Any chance you could send one of the arms out to me and I'd ship it back when I'm done?

+1 If you could actually do a trial fitments then you could get proper measurements. The only thing from the photos I see is the angle of where the ball joint is... Notice on ours the ball joint looks to be a straight line from the bushing/mount... the Mustang ones look to be a little off center.

Cause I don't think pulling out the ruler is going to really help. I'd love to pickup a set whenever some get made. I'd love to make my own but I don't have a welder worthy of molding pipes together. Just have a cheap 100 dollar welder for quick small jobs. Like my Strut Tower Bar.