Bolt in race trailing arms, R&D Options

[BMXerror]

Hey all. I've been with the club for a bit, but I'm new to the Paddock. I would like to do some racing, hopefully by next year sometime (money is the limiting factor of course). Anyway's, my brother who does various forms of fabrication and I are designing a set of trailing arms with adjustability for toe-in and camber built in. After shortly browsing the Paddock, I found that people are doing this for their own cars already, but nobody seems to sell them.
To the point, my brother and I were thinking of prototyping with my car, and then producing them for sale once we get the product all sorted out. Before we invest in that, however, I want to know if this is something that people would be interested in. We have to know that there's a market, if only a small one, for these before we start producing them.
Our idea was to have something that can just be bolted up in the stock mounting points for simplicity. They'd be made from watercut and boxed flatbar, and they'd probably be drilled and dimple-died for lightweight and strength. As previously stated, they'd have full camber and toe adjustment built in, but would probably be set to factory spec by us for simplicity's sake. We'd have them powdercoated as well.
That's the basic idea, but we also have a couple question on what people would want. For example, what brakes do most racers like to use. Should we bracket it for SC calipers, turbo calipers, 964 calipers, or should we just leave it stock and leave any conversion to the customer. Also, what stub axles do most racers use? This is actually a subject that I don't know much about. I don't know what model year 911s are the same or if ANY are compatable with the 914. This of course affect which CVs you can run and what bearing carriers we'll have to use, so I would like to get the racer's input on this.
I know that this post is rather irregular. Maybe there's a demand for something like this, and maybe not. I won't be cheap, of course, because of all the labor involved, but our goal is to make it as simple for the customer as possible. It should be just a bolt up job. This is why I'd like to get your input and see what brakes and stub axles you prefer, so that we can make it as easy as possible on the customer and, well, sell more to be honest. Any input on whether this is a good or bad idea AND WHY is also appreciated, so please speak up. I hope to hear from you.
Mark D.

[J P Stein]

That's a fine idea, but.....
A properly done trailing arm...with good (read pricey)
bushings ain't gonna be cheep. 914 owners are (for the most part)
CSOBs and won't spend money on something like that. I fear your sales would be disappointing (Iz'at tactful or whut?) (IMG:style_emoticons/default/biggrin.gif)

[Aaron Cox]

post a rough sketch of what you are thinking of making if you could...

and some racers are limited to stock trailing arms by class rules....

stub axles and hubs should use the same 914 bearing... so you can still use 911 hubs and stubs.... or 944's etc... they all use the same bearing ID... so i would design it around teh 914 bearing...

BTW - how heavy? etc...

[Jeroen]

(IMG:style_emoticons/default/popcorn[1].gif)

[BMXerror]

That's a fine idea, but.....
A properly done trailing arm...with good (read pricey)
bushings ain't gonna be cheep. 914 owners are (for the most part)
CSOBs and won't spend money on something like that. I fear your sales would be disappointing (Iz'at tactful or whut?) (IMG:style_emoticons/default/biggrin.gif)

Your cander is appreciated. Like I said, I want to hear any constructive criticism that you may have. All that will do is save us trouble in the long run. My bro is the fabricator here, so I'll leave the scetching to him. I gave him a link to this thread, so he can read your responses for himself. If he stetches up what he wants to do, I'll post it. However, I will say that from what he described, it sounds somewhat similar to the arms on the blue and green Sheridan car, at least as far as the toe adjustment goes. Like I say, I'm not really in charge of the design. I really helping him more with the Porsche research for compatability perposes.
As far as weight goes, we haven't gotten that far yet. We're still in the planning stages. We need to get a stock set of arms (I'm using the ones under my car) to help figure out what we need as far as strength. We will want to build them strong enough for heavy use on a car with a big heavy six in it. So the weight is yet to be determined. We'll get back to you on that when we start prototyping.
Thanks all. Keep the comments coming. Jeroen, enjoy your popcorn.
Mark D.

[URY914]

This is not going to be a simple project.
Good luck, I got plenty of popcorn too. (IMG:style_emoticons/default/popcorn[1].gif)

[nebreitling]

multiple sanctioning bodies and classes mean multiple rules. i don't think it's realistic that one design is going to satisfy everyone's needs.

[Trekkor]

I'm having some trailing arms fabbed this winter. How can you tell if they are bent or not before you start working on them?
( fabbing stock ones )


KT

[Brad Roberts]

And.. what do you mean by "fabbing" Trek?

I just noticed last night in the VW mags that they sell a bearing carrier and cover plate for making control arms.

I think it would have been a little easier to start with something "fresh" than do what Kevin did with the stock.

I have thought about this for years.. then I realized how many good stock arms were out there and how I never really had one fail or bend on me unless I caused it.


B

[BMXerror]

multiple sanctioning bodies and classes mean multiple rules. i don't think it's realistic that one design is going to satisfy everyone's needs.

True. Still, I think the rules in most cases would either state whether you need to run stock trailing arms or not, so it's not like we'd have to make a zillion different versions. They'd either buy a set or not. Still, I do agree that that does lower our market.
No Ury, this is not going to be a simple project. we're still in the planning stages, so it'll be a while.
Brad, it's not really about preventing failure, as they don't really fail all that often. It's more about being able to dial in the rear suspension under all kinds of racing conditions, ride heights, and bent up frames. This has been developed significantly for the front suspension on the 914, but hardly at all for the rear. We just thought we'd take a whack at it.
We're still working on solving that problem, trekkor. We will try to get the best factory arms we can find and as much info on what demensions they should be before we make our jigs. Any further microspopic imperfections will be tuned out when you set up your suspension. However, we'll keep it on the microscopic level.
Mark D.

[brant]

The stock arms are adjustable for toe and camber already.
are you trying to increase the range of adjustability?

many of the custom arms you see race cars run, are done because they have raised or modified the pick up points and then do need to make changes to their camber due to other extremes

I'm not sure that there would be any benefit to buying an aftermarket arm that was bolted into the stock location.

I agree that you could design/build something with a greater range of negative camber, but I can already get -2.8 in my stock suspension points and don't need much more than that.

regarding the rules on wether or wether not something like this would be legal in racing. My opinion is that it largely comes down to "stock-ish" versus modified racing groups. what would partially work against you is that the higher level of racers are fabricating really custom one off items for their particular application.

and that the market for off the shelf custom arms would be largely the lower level of racing fan and those just getting into the sport. Those folks are on average going to run in the stock classes.

not trying to be negative.
but I would be surprised if there was a market for more than a dozen of these. Maybe ask Chris at CFR how many custom suspension-point cars he has done?

brant

[914forme]

Trek

All the arms I have seen bend do it in a way you would know for sure. (IMG:style_emoticons/default/biggrin.gif)

I suppose you could tweak them in a way that could not tell, but I doubt it. Once they reach the point where the twist it is kinda like denting a pop can, they go fast.

[Brad Roberts]

I have raised the suspension points in 3 cars now. It is a lot of work!!

I have one more I'm going to do..


B

[race914]

I'm having some trailing arms fabbed this winter.

[race914]

From the "Vellios" thread in The Garage

(IMG:http://www.ebarrettinc.com/images/trailingarm.jpg)

Vellios trailing arm setup for drum emergency brake, vented rotors, 911 caliper, etc.

[Mueller]

From the "Vellios" thread in The Garage

(IMG:http://www.ebarrettinc.com/images/trailingarm.jpg)

Vellios trailing arm setup for drum emergency brake, vented rotors, 911 caliper, etc.

why is it so hard to list prices??


those trailing arms still offer no "other" alignment settings, just slightly wider wheel bearings and a 3.5" spacing caliper mount..and the drum brake option which is a no brainer....

[ChrisFoley]

I have raised the suspension points in 3 cars now. It is a lot of work!!

I have one more I'm going to do..


B

It's not that bad with my kit Brad!
I can set you up for 2" or 3" raised pickups.

I think the market for custom arms would be mostly with V8 conversion guys. If it was really well done and not too much $$$$$$, you might sell a few to racers.

I'm getting set up to offer light weight stiffening and static camber alterations to stock trailing arms.

[ChrisFoley]

...
but I would be surprised if there was a market for more than a dozen of these. Maybe ask Chris at CFR how many custom suspension-point cars he has done?

brant

I've done 3 or 4 in house and sold half a dozen kits so far. (in 2+ years)

[Aaron Cox]

I'm having some trailing arms fabbed this winter.

(IMG:style_emoticons/default/chairfall.gif)

beat me to it (IMG:style_emoticons/default/chairfall.gif)

[Andyrew]

I havent heard many v8 guys twisting trailing arms.. I havent yet.. but with my 10.5in slicks im sure I will..

Andrew