After a ton of searching, I've came to the conclusion that Spohn can't make a K-member worth a darn, but no where have I found a consensus on who makes a good K-member for anything at all. Racecraft makes one for AX/RR, but 572_Rat had a nightmare with Racecraft that I don't wish to repeat. UMI's K-member has been vaporware for the last 5yrs. Everyone says BMR makes a good one, but no steering box brace mounts, no extra bracing for AX/RR, and no way to get solid mounts on the K-member makes it a no go. And AJE makes what looks to be a drag only K-member.

Therefore, the only guys I came up with were PA Racing. They make a CM K-member that can be beefed up for AX/RR and from what I've read from others on here, the only real grip was that the powdercoat is not that great and one guy had two issues with welding details on the tubes. I'm hoping that those out there who have a PA K-member can give feedback on it. The most recent review was from 07-08. It looks like a copy of the Racecraft one, according to people here there was a group that left Racecraft to form PA Racing, and its far cheaper than anyone else for the same thing.

Just for you Dean, I plan to offset the weight loss down low with all your recommended weight savings on top to balance things out.

Now for the A-arms. Again, it seems that Spohn has issues with them moving the wheels both with & without there K-member and I've also been reading that there are steering binding issues that happen with them. Again, it seems that PA Racing makes the best A-arms for the job. They have a stepped spring seat like Spohn, but are a fraction of the price.

Input & opinions welcome.

 

The aftermarket is forced to make their k members as basic as possible to attempt to avoid bad fitment issues. Now if everyone had the same car with the same motor, radiator, steering setup, on and on and on, then you would get something truly worthy. When I go the Tubular k member route I plan on adding my own touches.

 

I kinda figured steering box braces were going to be a DIY affair seeing as how no one else besides Spohn makes mounts for them. But there might be a glimmer of hope with the PA Racing one. There are some tabs that appear to be in the right locations for bolting straight up to the stock braces.

 

What's wrong with the stock arms and k member? You have a 2.73 open diff and drums and you want to "upgrade" your k member? You should try running on a track or ax first. It might change your priorities.

 

I have. Believe me, suspension & tires followed by brakes and drivetrain is the leading priority before other mods. I didn't ask this question because dropping money on cool tubular parts sounds awesome. I asked it because when I get to that point I want to know whats better and whats not.

I'm the kind of person that plans years in advance of what I want to do. Sure, priorities & things change, but its easier for me to do than get to that point and do things in a hurry.

 

When I get another car I plan on building my own Kmember out of retangular tube 3 x2 x 1/4wall. Simply because i plan on building an entire new front suspension geometry like I did on the Vetruck.

Dean

No, I am not sharing my ideas, its top secret. I have already said too much.

 

ur best bet is to take the ideas from all of the different companys make ALOT of measurments and plan out what u want from it and build ur own..

 

I ordered a PA Racing K member about a week and a half ago, it should be in my hands end of this week, I ordered CM with stock style spring perches, and plan to reuse factory a arms for now with upgrading in the future when money allows. I did my research as well and talked with others that have the same k member, and for the the most part everybody i spoke with was happy. When compared to others, UMI, BMR, SPOHN, etc. the PA racing unit was a quality part at a great price. I will repost in a week or so, let you know how it fits.

 

Knowing you it involves moving the engine behind the centerline of the front wheel spindles, most likely setup to handle coil overs, and will be a beefy item for possible accidents. I look forward to it like you Mumford Linkage.

 

What is wrong with the Spohn cross member?

 

Its notched to clear a steering linkage, it and/or there A-arms move your wheels back in the wheel wells, the engine set a couple inches lower, and there A-Arms cause steering issues from what I've read.

 

isnt 1/4" wall a little much Dean?

i think i know a bunch of what your planning, since you've slipped and said to much a few times. I do look forward seeing it (if you post pics), when/if it gets built.

 

Be sure to take plenty of pictures if you can

 

The 1/4 inch involves vital suspension mount points. I have boken shock mounts with single shear 1/4" and with double shear 1/8". I want to use 1/4" to feel safe if there is ever any inpact or major strain.

The Mumford link I posted was not my actual design, it was merely a rendering I put up here showing a little something close to what I actually would like to try- it is not the real design and certainly not to scale either. I have said this many times- I do not want any more of my ideas copied before I can try them first. On that note, I thought it was kindof funny the Reverse Watts came out not to long after I posted those images of that "mumford link" design I showed on here. I do not trust putting up any real designs I have.

I even have a design for the front end using a lightweight slidebar link in place of the strut- lets see what any manufacturer will run with on that idea being floated out there since I do not plan on doing that one.

 

DOH. How many times do I have to say it. The wheels do not get pushed back when both the K-member and A-arms are used.

Does the front wheel look off center to you?


The engine sits SEVERAL inches lower. Are you kidding. Several inches? My oil pan would be riding on the ground if the engine was several inches lower than stock. I went from stock K-member and poly motor mounts to Spohn k-member and stock rubber mounts and only dropped 1/2". The difference was attributed to the rubber mounts vs poly.

Look at the STB. Only 1/2" of clearance there. No way its "several inches" lower.

 

You're the first person I've heard say anything good about a Spohn K-member & A-Arm set. I read way too many reviews of people who have shelled out the $1k for both and they've all had a myriad of issues many of which I listed as they were the more common problems.

Either this forum is full of idiots, or you got lucky.

 

i like that picture!

i think he is confused with the hoop sitting a couple inches? lower than the stock k-member. I've never heard of the engine sitting lower. that would be a disaster, since the oil pans sit pretty low as it is.

 

Come on now you've been here long enough to know that most people on this forum rarely use their noggin and just repeat what they have heard.

I have heard of just the a-arms causing mis-alignment of the wheels, but I have not heard of a single person complain about the alignment when both are used.

As for the engine being lower, I suspect 86TA is correct and you are thinking of the lower hoop of the K-member. It is not actually lower than stock but looks it since the tube is physically smaller than stock. The hoop is just low enough to protect the oil pan from hitting the road. It is a good design. It also allows you to drop the pan without jacking the engine. The Spohn A-arms and K-member are actually one of the very few aftermarket parts I have purchased that fit correctly without modificaiton.

 

I agree. I have a Spohn crossmember and have no issues, that I know of. I know my camber is off, its -.7 degress passenger side and .7 degrees drivers side. I never did an alignment though before the crossmember to know if thats the issue. This is with the strut mounts in roughly the same place on each side.

I think he, or other people, are thinking of the hoop. It does sit lower, but I have never hit it on anything. Its nice though because if I had to take the oil pan out, I can without raising the motor or anything. There is tons of room to just take the pan out.

 

I wouldn't go so far as saying someone took your Mumford link idea and reworked it for a Reverse Watts. The designs for both are over 100yrs old and the Reverse Watts was in use in Austrailia for a quite a while. Could be someone got the idea from somewhere else and made it work on our cars. Timing could easliy be a coincidence.

Good point. Nobody has distinguished the A-Arms from the K-member before. I was skeptical of the engine being lower (yes, I know the hoop sets lower and makes maintenance easy hence one of the reasons I want it), but pictures lacking and tons of supposedly first hand reviews can lead one to believe it albeit with a large does of skepticism.

 

Let me know if you need any other pictures. I have lots.

 

You really think I thought I came up with the Link Ideas? Give me a break.

"Could be someone got the idea from somewhere else and made it work on our cars".= Yeah, ya think? That would be the part I am talking about them copying me. Check my post and you will see a striking resemblence to my crossbar mount idea. Thats why I did not post my real idea and did this Mumford in reverse also.

 

James Watts invented the Watts Linkage in 1784. The Mumford replaces the bellcrank to allow Watts motion at the ends while eliminating lateral movement. The earliest reference I found for a Mumford link was around the early 1900's. Yes you didn't invent them or come up with the ideas on your own, but I guarantee you're aren't the first and only person to have thought about applying either to a thirdgen in the last 30yrs. The reverse Watts was in use in Austrailia for the Supercar series by about the late 90's at the earliest as far as I can tell.

Also, I have looked at your link and there is nothing in your Mumford link that resembles the cross-brace of the Fays2 Reverse Watts link. I highly doubt that someone was able to take your sketch & VERY vague post about a Mumford and go: Hey, lets screw this Dean guy in the butt and make a ton of money off of stupid people. Now, if you had posted in detail a Mumford link and then a year later someone rolls out a 3rd gen Mumford, I'd buy what you're selling. I don't see why you think you were ripped off. The two function radically different and bear no resemblence at all. Theres a ton of history and real world application for a reverse watts working against you in this case. I guarantee that someone thought of making and was developing a Reverse Watts for a thirdgen long before you posted about your Mumford.

I know that you have a ton of great ideas, but don't whine when someone else comes up with something that you think bears resemblance to what you were thinking of. If you have a ton of great ideas and want to make money with them, open your own shop and go into business and show Spohn, UMI, BMR, PA Racing how its done. Don't whine about having your ideas "ripped off": patent it, make it, and test it.

Personally, I think you're very paranoid of being ripped off. Just my opinion, but the world's not out to get you or steal you designs.

 

Post up pics of the under side & install if you got them.

 

I have a few pics of the underside of mine as well and tomorrow I'll take a pic of the front wheel from the side. I have stock A-arms on the Spohn crossmember.

 

Back to the topic- USe the stock kmember unless you have grood fabricating skills to build your own with understandings of chassis dynamics.

Edit= additional info I would like to say= Anyome keeps there car s like I do and can trust one of these tubular kmembers on their car after 15 years of hard use then-hey, go buy one. I don;t trust them. I have had tubular parts break on me. I have broken a tubular a=arm that darn near killed me, I have seen many ripped and torn tubing in NASCAR to know what it does in 2nd and thrid impacts if the clips where not cut off after good hits and replaced. Tubing fails on multiple impacts- tale that to the bank. You can keep those flismsy aftermarket Kmembers that do nothing but look nice and empty your pocketbook like Pablo has posted (Im stealing his words so I want to give him credit) I like bulkyness where bulkyness is needed. I just hit the Kmembe ron one of myt cars last night in a rock slide.

 

Vetruck, you write a lot of long inciteful posts and I'll admit to not fully reading all of them.

But for reference the Watts and Mumford links that have been mentioned in this post I have never even heard of before. As long as you more experienced guys keep fighting, us 'youngens' get correct and debated information and get new topics to research.

First I bought a book about turbocharging now I need one about racing suspension, thanks alot.

 

Why don't we keep this topic on track.

 

In this picture you can see the crossbar of the k-member. It is probably 3"-4" off the ground.

 

Are those the upper spring seats/adjusters for Ground Control Weight Jacks?

 

yes they are

 

AWESOME!!! I've been wondering how they fit aftermarket K-members.

 

The outside diameter of the weight jack is bigger than the inside diameter of the k-member so there is some slop. So I took some heater hose, put a slit in it, and slid it over the weight jack. As a result if fit very tight now. As you can see in the picture, it is held upside down without falling. It also effectively acts a spring isolator.