which is better for my daily driver.

i just bought umi sfc's and while im under bolting it to the lca bolts. i might as well replace with fresh bolts and replace my stock lca's.

so my question is for my daily driver not racing trans am. whats better bang for buck.

sphons square rear LCA
or umi tubular rear LCA????

 

whichever you want. It will not make any difference.

there is differences b/t the two, but for daily driving, you will not feel any difference. Even lower level racing, you wont feel or notice a difference between the two.

 

Hello, as 3rdgenmaro stated it is personal preference for a street car. We have several different styles of tubular from our poly/poly arms, a poly/rod end combo arms and our all out rod end moly arms. Here is a link to our site so you can see what BMR has to offer. If you have any questions please let me know.


http://www.bmrfabrication.com/F3.htm

 

Id personally never go poly/poly. poly doesn't have much give and you'll end up bending the mounts or brackets under heavy loads plus it will cause a lot of rear end bind since your full movement is limited

 

so then whats the purpose of all this stuff. im just tryin to improve my car any way i can.

im not racing this car but would like to think i can still have some fun with it and want it to be able to perform.

 

You'll want at least one end of each of the LCA's to have free movement of rotation. E.I rod end, johnny joint etc. etc. This will allow the rearend to move freely with out binding. Im sure it can get a bit confusing looking at these sites with all the options available just for the LCA's alone.

 

yes it is confusing.

if anyone wants to be a real nice guy and post a link to what exactly i would help my daily driver.

im tired of buying one thing then find out later oh i could of or should of bought this other darn thing.

anyways i appreciate the help guys i dont want anything special just a nice bolt in upgrade.

 

for a daily driver id go poly/ rod end or some other type of joint that allows free movement.

 

Like

http://www.umiperformance.com/catalo...roducts_id=105

http://www.umiperformance.com/catalo...roducts_id=351

 

buy the tubular. it will buy you a little clearance if you ever want to run a wide rim or a big tire.

 

thanks for the links. which end does the roto end connect to? or does it matter?

 

if its one poly end and one rod end, the rod end usually goes on the axle, and the poly on the body side

 

yup thats how it goes

 

Square and tubular can be the same thing. You mean square tube vs. round Tube

You want round tube......Why?.....

Because of weight. Even on a daily driver car that a little old lady from pasadena would drive, the lighter weight products help increase the ride ratio of sprung to unsprung weight. You want your unsprung weight to always be as light as possible. The lighter weight your wheels, tires, shocks, suspension componants, and articulating drivetrain componants are, the less they unsettle the chassis sprung weight when they are pushed upward ovr a bump in the road. less weight to stop articulation, the quicker it will slow and not unsettle the chassis as much as a heavier componant.

Dean

 

This is not true, for complete free movement you need a misalignment angle at both ends of the LCA, the 2 LCA frame mounting pints and the axle mounts connected with the LCAs always remain orientate in a parallelogram since no lengths can be changed, fixed length LCA, axle mount spacing & frame mount spacing. So, equal yet opposite angles exist at each end of the LCA. 1 johhny or spherical joint won't do, the other side will still deflect.


For a same diameter and wall thickness a square tube will be stiffer than round, however the round will have a significantly less cross sectional area (and weight), if you even out the cross section (larger diameter round tube) the difference will be less. So, if you choose a similar weight, you can up the diameter (and cross section) with the round piece and make it a lot stiffer/



D = OD, d = ID
____________
Area of round tube = PI/4 (D^2 - d^2)
Area of square tube = (D^2 -d^2)
Moment of inertia, round tube = (PI/64)*(D^4 - d^4)
Moment of inertia, square tube = (1/12)*(D^4 - d^4)

 

Poly on the front is 100% fine. If you mount a poly joint into the chassis and grab the rear of the arm moving it side to side (left to right, not up and down) it will wobble just a tad freely. It only needs to wobble enough for the rear of the arms to close gap about a 1/4" when the axle articulates up on one side and downb on the other. If the LCA chassis mounts are lets say 60" apart fixed, the axle mounts are also 60" apart fixed, but in articulation they dynamically close up to 1/4" in vertical geometry so each side needs to wobble 1/8" freely.......again, poly chassis mounts are fine. I had them. They just will bind in up and down movement if the mount bolts are torqued too high and/or not kept greased.

 

Right, but i was also counting in on the fact this is for his daily driver.
one poly end would dampen some of the Noise, vibration, and harshness Vs a rod end/rod end.

 

right guys this is for my daily driver. at first i thoguht i was gona spend 100 on lca's

now with the poly/rod end im lookin at 150ish.

this car never sees 100mph maybe once a yr. so i dont need racing specs. just a ncie upgrade to improve handleing and hopefully feel/noise

 

http://www.hotpart.com/shop/index.ph...ct_detail&p=42

These work well..They dont bind. I realy like them myself

 

I'm running rod/rod & 35-series 17" tires on my daily driver & honestly don't notice an increased ride stiffness/harness. I went for the offset bushings, to fit my 315s on, which most people won't need. So you could get standard bushings & come out a little cheaper.

http://www.umiperformance.com/catalo...roducts_id=107

If your car is lowered, you may want to look into LCA relocation brackets, if the LCA angle is off.

And look into getting an adjustable Panhard Bar, when the axle gets offset to the drivers side, after the lowering.

 

If this is a daily driver, why not through new rubber bushings into the stock lower control arms and just use new bolts and nuts when you re-instal everything. Then you'll only be spending ~$15.

Just my $.25

 

Hello
Thanks for suggesting UMI Performance! Like mentioned above we do offer 2 different versions of double adjustable LCA's. The standard is (2017) and the other is (2017OFF). But we also offer a single adjustable (2016) which offers a rod end and poly bushing to maintain a comfortable ride quality. If you have any other questions feel free to ask and I will be more than glad to help.
Thanks
Brad

 

If you are going to run rod ends on both sides, weight and strength should not be an issue if the two pieces are designed like they should be. The only load will be an axial load, since the rod ends will remove any bending loads in any direction. So the ideal area of steel for either round or square should be identical, removing any weight difference between the two. That said, all the square ones I've seen are much larger than need be, filling in the entire space between the LCA mounts. If you run poly on both ends, different issue since there will be bending loads.

 

Have you desided yet or are you still trying to read these posts lol

 

i havent decided yet. mostly because i dont wana buy something because on paper its better.

i wanna be able to feel the difference.

so still deciding.

i got one guy saying do poly/rods.

i got another guy saying use this tubular one with these patent pending flexing poly bushings on both ends.

only reason i'm interested is because i've replaced everything else and ill be under there installing SFC's and figure i can get 2 things done in 1 shot.

 

Hands down I will tell you the very best option in the world for LCA's.
There is nothing better.

First you buy this. Chrome moly tube is stonger and lighter than aluminum bar stock. It is the best material period. It is seamless normalized 4130N chrome moly and is TIG welded. They come with rod ends on both sides.
http://www.spohn.net/shop/1982-1992-...-Rod-Ends.html

THEN, you also buy on left and one right Del-Sphere bushings. Why? You are going to take off one left hand thread rod end off of one LCA above, and take of a right hand thread rodend off of THE OTHER LCA. You then place the LF Delsphere onto the one LCA with the LF rtodend removed, and so on. You now have tow arms each with one rodend, and one delsphere. each arm will still have a LF and RH threaded unit on each end. It does not matter that they will mount and each will adjust differetn rotational ways then the other arm assembly. One willl lengthen with left rotation, the other will lengthen with right rotation.
http://www.spohn.net/shop/1982-1992-...d-Threads.html
http://www.spohn.net/shop/1982-1992-...d-Threads.html

You now mount them with the heavier Delsphere end into the chassis and the lighter weight rodends ointothe axle side. The Delsphere ends will help isolate axle vibration ttransfer intot he chassis better than the rod end/rodend units would.

HERE'S THE KICKER!!!!! two years down the road, you now already have replacement spare rodends for each rear LCA accordingly when the rodends where.