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What: Replace the rear lower arm with a custom piece that is both lighter and stronger and longer. Hehe... Made out of aluminum. Easily made. Cheap.

Why: To increase the wheelbase. To move the rear wheels outwards. To allow you to put on wider wheels in back. To increase traction. To reduce body roll. To allow for increased grip during cornering.

Possible Problems: I see only one, the toe. Making the rear lower arm longer will point the rear wheels towards the inside front of the car (I think). There may be a way around this, but I'm not 100% sure yet.



See it, it's the part that connects from a rear lower tie bar mounting point to the rear lower arm. You can remove it (it has special torx bolts) and replace it with a custom piece. I think a nice solid piece of aluminum would do the job. It would have to be slightly thicker than the metal it replaces. Also including a little stiffener in the middle to reduce the chance of buckling might be a good idea... The stock piece is about 2.125" wide, 1/4" thick, and about 13" long. One possible replacement could come from McMaster.com (part number 89215K117). It's only $35.95 for a piece of 2024 aluminum that's 2.5" wide, 3/8" thick, and 3' long. That would surely be enough material to make two custom rear lower arms.

This is a DIY of sorts... Let me know if I'm missing anything.

1. Buy that piece of aluminum.
2. Jack up the car in back.
3. Put it on jack stands.
4. Take off the wheels.
5. Unbolt those bolts that you would unbolt when putting on a rear tie bar.
6. Take out that lower arm.
7. Unbolt those three torx bolts on each side.
8. Take off the stock lower arm.
9. Use it as a template to make the new lower arm.
10. Copy all holes.
11. Lengthen the new lower arm by a certain amount.
13. Transfer all hardware from the stock piece to the custom piece.
14. Install the new piece and make sure everything fits properly.
15. Modify whatever needs to be modified for the new piece to fit.
16. Check the toe after installing the new piece on one side.
17. You might be able to adjust the toe in back by tweaking part number 16 in the diagram. Labeled "BOLT, TRAILING ARM ADJUST"; Click Here!
18. If satisfied with everything take off the new piece and use it as a template to make the other side (they should be symmetrical).
19. If not symmetrical, then simply make the other side using the procedure from before.
20. Install both pieces and adjust the toe again.
21. Adjust the camber because it will be negative now.
22. You may need to roll the fender lip to fit your wheels on now (depending on how long you made the new pieces).
23. Put everything back together.
24. Take it for a test drive and make sure to drive over many bumps.
25. Check everything to make sure that nothing is damaged and that everything is working properly.
26. Re-check camber and toe again. Re-tighten the lug nuts. Done!

Things to consider:
- The new piece will be very strong in compression, but it might be weaker in bending. Buckling may occur. If after driving over many bumps nothing happens, then it's allright. Although material exhaustion could occur. Re-enforcing the piece with a little bar in the middle would prevent buckling. Welding on a piece is best, but bolting one on would work as well. Make sure to use short bolts with a large thread size and lock washers or LOCTITE.
- The thickness of the new piece will probably require you to shave the stock mounting thingies near the lower rear tie bar mounting locations. Just use some low grit sandpaper to do this until you shave off 1/16" from each side. Since stock piece was 1/4" thick and new piece is 1/8" thicker.
- The thickeness of the new piece may be enough to prevent buckling, so no further strengthening is necessary.
- The piece can be drilled out in the middle to enhance looks, but this will make buckling more likely. Again, it all depends on the strength of the stock piece vs. the new piece. I will be running a simulation to see what the forces are like with my father (a mechanical engineer) to see what I can get away with.

Anyway, what do you think? For less than $40 this would be a pretty k3wl modification IMO.

 
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My brother, although it's a great idea, I don't think I have to hash out with you the fact that the OE components are tested for structural integrity. I would hesitate to start slapping on major parts like that just to widen your wheelbase. There are just some components that you do not want to tinker with like that for safety reasons. Like no one makes their own coilovers or break pads...if it snaps, you're in for a lot more than 40.00 if you had to repair the whole thing should this experiment fail. You got lucky with your idle, but take something from that experience...Just my opinion, but I wouldn't do it.

 
Rep Power: 413

As much as the idea sounds good, I would agree with Twilight. Control arms take an amazing amount of abuse and you need to make sure that the new pieces will be as strong as the OE parts. You'll need some seriously strong box metal to handle the load. Not to be negative, but what is the true point of it? So it is adjustable? So you can put wider tires? Wider tires in the back on a Civic is a mute point since it is FWD. You'll gain no traction since the vehicle doesn't induce oversteer, it only induces understeer.... Good idea in theory, not so good idea in practice.... You have WAY too much time on your hands.... [IMG]i/expressions/laugh2.gif[/IMG][IMG]i/expressions/laugh2.gif[/IMG][IMG]i/expressions/laugh2.gif[/IMG][IMG]i/expressions/laugh2.gif[/IMG][IMG]i/expressions/laugh2.gif[/IMG][IMG]i/expressions/laugh2.gif[/IMG]

 
Rep Power: 418

Well, the point would be to have a slightly wider wheelbase in back. Also, running wider tires in back. My tires almost rub against the inner part of the wheel well. I had to set the camber in back to be a little less negative than what it was since my tires rubbed off some of the rubberized undercoating that's there. I fixed that since then and I set my camber slightly less negative. Plus for looks too since it would look pretty good when looking at it from the rear.

Anyway, me and my father did some calculations and it seems that the part I picked from McMaster.com would be exactly as strong as the OE part. If I choose one that's 1/2" thick, then it would be twice as strong (to buckling). We only have to worry about buckling since it can withstand over 43,000 pounds per square inch of compression. For a 2.5" x 0.375" part (the part I picked out), it could withstand 40312.5 pounds of compression before it failed. In the worst case scenario (cornering with a full load with a lateral acceleration og 2 G's) the compression force only gets up to about 10,000 pounds. The buckling force is actually better for the aluminum part since it's thicker (even the 3/8" thick one).

Anyway, it looks like I may be doing this. I just need to make sure that I can adjust the toe and that the wheels won't be touching the fender lip. Then again, I'll be rolling them up so that they don't interfere. That shouldn't be a problem. Then I can set up the back for more negative camber. [IMG]i/expressions/demon.gif[/IMG] Not only that, but I'll have a wider wheel base. All of this will make the back more stable under cornering, so I'll need to stiffen up the front to balance things out. Can't wait to get started! I just need to make sure that I can buy that kinda of a torx thingie to remove those stock bolts. That's about it though, the rest should be fairly easy to do.

 
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you should be able to find that torx bit at any good tool/hardware/auto store.

 
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that's a great idea. I'm just worried about the suspension. the angle or position might be too great if you widen the wheel base too much.

 
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You're such a nut dude...If you call my *** at 1am when your wheels start doing a "Days of Thunder" on the road, I aint answering [IMG]i/expressions/face-icon-small-tongue.gif[/IMG]

 
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This is one frickin' crazy idea! But it sounds like it will work.

 
Rep Power: 416

cant you just get wheel spacers? cause all your doing is making the tires stick out more right? or maybe use a different offset?

 
Rep Power: 418

Wheel spacers would work, but they have their disadvantages. They weaken the connection betwean the wheel and the hub. They also increase the rotating weight, so they slow you down. You wouldn't have to mess with the toe or camber though, so that's a plus. Different offset would work as well, but the rims I have are the ones I'm keeping. They don't happen to come in any other offsets for that tire size either.

 
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Are we nitpicking though? I mean, is there going to be such a significant loss in speed that it'll compromise your regular travels?

 
Rep Power: 418

Well okay, plus they're more expensive. [IMG]i/expressions/face-icon-small-tongue.gif[/IMG]

 
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Grey, you would have to find a longer upper control arm. Most of the camber kits barely(ingalls/SPC) give you 0 camber on there kits with lowered cars. That would be my only concern. Stucturally, I think the spacers are more stronger. They have been race proven and I have never heard on someone falling out of a race because of a broken spacer.

 
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See that's what I'm saying...and besides, I'd rather have a company to sue should the thing break under normal tolerances, rather than getting stuffed with a huge bill and no one to pay because of a custom job...see what I mean? It may be a cheap mod, but honestly...think about what you're saying...you want to fabricate an entire control arm just to get the tires bigger for cornering, and do it for 40 bucks? You don't autocross! lol waaay too much time on your hands...

 
Rep Power: 418

Yeah, I have my SPC. I can extend that slightly to give me what I want. I want more of a negative camber though (without touching the camber kit), so the longer lower control arm will do that for me. It's not like I'll increase the length by an inch! Not even an inch. I have to calculate how much I'll need. It'll probably hover around 3/8" or 1/2".

TwilightX: Thanks for the concern, but my father and I already calculated that the piece I will make will be more than sturdy enough for the job. Actually, it'll be much sturdier. You'll see... I'll make it, and it'll look cool, and you'll be like "Dayam!".

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Rep Power: 416

man its grey so i dont even doubt his ability. i just think its easier to use wheel spacers. i dunno maybe its cause i'm lazy and unskilled, but hey whatever works right

 
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What about the front? A wider rear is not going to do you good unless you do the front. Cheapest way for the front would be the spacers. You just have to make the front wheel wells deeper. I though about doing a wide bodykit. A friend of mine said he could get me a good price on some fiberglass. Custom mold it myself and paint it too. I'm going to help my friends dad rebuild a 69 Chevelle(engine, interior, and exterior). I scratched that idea when I got the idea to buy a junked 1.7 and rebuild it from the bottom up. That or save up for a better car. So many decisions.

 
Rep Power: 418

The front? I'm not sure, but I think the Type R lower control arms may be a bit longer. They're cast aluminum (or was that forged?). Anyway, those look sweet too! I might get them in the distant future...

 
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Want wide track? Buy a Pontiac. [IMG]i/expressions/laugh2.gif[/IMG][IMG]i/expressions/laugh2.gif[/IMG]

 
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for the front, wouldnt you have the angle the strut assembly more and also extend it(cause otherwise the car would be lowered)? also angling it more would require you to extend the steering arm.

 
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Yeah, the front wouldn't be easy to do. You'de have to extend the tie rods (or at least extend them to their full toe in range). Then you'de have to move the strut assembly out more. I guess those with the adjustable camber plastes would allow for a little of that. Then you would have to extend it even more when you lower the car though, so there are limits. The Type R front lower control arms have stiffer bushings in them too BTW. Kinda k3wl. I wonder how much they are? Oh yeah, plus the car would be lower when you do that. I guess that goes for the rear as well.

 
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And after doing the all the widening, your whole susupension setup will change. Your spring rates and dampening will be affected and there will be more stress on the tranny and essentially all the suspension parts. You do one thing to a car and you have to everything else. You gotta love it.

 
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True true true... I still want to do it though. [IMG]i/expressions/demon.gif[/IMG]

 
Rep Power: 418

I just bought the piece of aluminum that I mentioned. I will be doing this! I might look for the right size polyurethane bushing to use instead of the stock rubber bushing. We'll see though. Wish me luck!

 
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OK good luck.

 
Rep Power: 416

is this what your trying to make? lower control arm

 
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You got it!

 
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Yep. Mine will be for more than appearance though. They'll be a little longer than stock. Still haven't decided what length, but I have to do some calculation. Somewhere in the range of 1/4" to 3/4". See the ones on the right on that page? The silver ones... Those are the ones for our cars. The holes in the middle look kinda neat, but they weaken the bar substantially. I will instead have a stiffening bar in the middle to prevent buckling (which is the most likely way that the rear lower control arm will break). Still looking at the bushing design. Most likely it'll be out of polyurethane. We'll see though...