VD Toelink Turnbuckles

[Lyngengr]

While I would think most people know about the VD toelink turnbuckles, I thought posting something might lead to some solutions.

These parts are made from some type of steel, exactly what I don't know. However, fatigue failures in the threads are common, typically with the rear links, and when this happens, you are a passenger. Last weekend, this happened to a competitor of mine in the braking zone for T7 at Sonoma, and he ended up into the wall. I know other drivers have had this happen as well, with similar results. All over a $50 part. Personally, I had one break when I was putting the rear suspension back on the car (see picture).

Does anyone have a better part than what we get from the usual suppliers? If someone knows what material these are made from, I could definitely look at the fatigue life and switch to a different material with the same tensile strength but much higher endurance limit.

[Lotus7]

You don't want a "better part", you want to replace the entire rear upper A-arm design with the piece that R-sport sells. Its a seperate toe link with a rod end at each end that doesn't have to be pre-loaded into position, then fatigue stressed every time the wheel moves up and down.
Yeah, its a few bucks, but costs WAY WAY less than the cost of repairing a car thats had instantaneous toe-out at 100mph.

(edit: photo coming asap when I find it; Paul's website is down, I'm helping with this as best we can)

[TimH]

Yeah, its a few bucks, but costs WAY WAY less than the cost of repairing a car thats had instantaneous toe-out at 100mph.

Not to mention the cost of repairing the body passively riding in that missile. That was the cause of a fatality at the Road America Kink a few years ago.

[Lotus7]

this is what you need to buy from Paul, contact me if you cant reach him, we're neighbors.

[Lotus7]

Not to mention the cost of repairing the body passively riding in that missile. That was the cause of a fatality at the Road America Kink a few years ago.

... and Kevin's (thankfully not fatal) car-destroying accident at Lime Rock back in April

[BeerBudgetRacing]

Star Mazda ones look more stout.
Maybe adapt them..

http://starracecars.com/index.php?op...product_id=644

What do FEs use?

[Rick Kirchner]

The Star Mazda ones look like the right way to design one of those. The originals look like an outtake from "Engineer to Win" on why parts break

[DaveW]

While I would think most people know about the VD toelink turnbuckles, I thought posting something might lead to some solutions.

These parts are made from some type of steel, exactly what I don't know. However, fatigue failures in the threads are common, typically with the rear links, and when this happens, you are a passenger. Last weekend, this happened to a competitor of mine in the braking zone for T7 at Sonoma, and he ended up into the wall. I know other drivers have had this happen as well, with similar results. All over a $50 part. Personally, I had one break when I was putting the rear suspension back on the car (see picture).

Does anyone have a better part than what we get from the usual suppliers? If someone knows what material these are made from, I could definitely look at the fatigue life and switch to a different material with the same tensile strength but much higher endurance limit.

That piece is designed to fail. No stress relief at the end of the threads (major stress concentration) is a recipe for disaster even if there was not a bending load thrown in.

[pkr]

Ok... A few people contacted me about this , our website is down (Ugh!) so here is what we have available....
***** just got the website back on line: www.rsport.us ****
We offer Revised Upper rear wishbones that use a floating toe link, rod ends on both inboard legs, and a fish mouthed spherical bearing housing on the outboard end.
This revised configuration eliminates the preload that occurs when the toe turnbuckle is not perfectly aligned with the rear steering arm on the stock 'Z' configuration VD wishbone.
When this condition exists (and it usually does) the turnbuckle and rod end, being threaded parts, are under preload and apt to break.
If you have been running a VD a few years you may have witnessed the rear toe turnbuckle break – if not your own, someone else’s.
The other failure prone area is the cast bearing housing plates.
If the spherical bearings pressed into these plates are too tight, it will create stresses trying to flex the plate and eventually lead to the plate cracking and breaking.
The wishbones are USA .049” wall 4130 streamline tubing.
The toe link is USA 4130 round tubing.
Both are finished with a weapons grade durable black coating that is chemical resistant.
The toe links come with a numbered band to help with quick toe setting adjustment.
You can use your existing reducer bushings and If you chose to use them, the VD rod ends (3/8" shank – 5/16"bore) are the same size .

We also offer a solution for the rear upright camber block.
This Revised rear upright Top Block & Steering Arm includes several beneficial features:
It eliminates the spacer plate between the upright and the block.
It incorporates an extra 20mm dowel that indexes in the center of the stock VD upright.
This provides extra shear strength as the stock dowels are small and located close to the edge of the upright casting.
They will often ‘egg-out’ the pockets or break through the casting wall.
This is common if you use the curbs while driving or crash that corner of the car .
The block has a window that allows you to change brake discs or drive pins without removing the block from the upright.
The Block is also designed with a much larger camber shim surface area for increased clamp load.
The Revised rear steering arm has a matching camber shim configuration for a more ridged assembly.
We supply wider surface area camber shims for these parts (photo lower right shows the difference from stock).
The Rear Steering Arm also has Inner walls for strength and a window that allows easier access to the camber bolts.

Hope this answers a few questions.
Paul........ text/voice: 412-721-2664 email: paul@rsport.us

[Lyngengr]

Ok... A few people contacted me about this , our website is down (Ugh!) so here is what we have available....
We offer Revised Upper rear wishbones that use a floating toe link, rod ends on both inboard legs, and a fish mouthed
spherical bearing housing on the outboard end.
This revised configuration eliminates the preload that occurs when the toe turnbuckle is not perfectly aligned with the rear steering arm on the stock 'Z' configuration VD wishbone.
When this condition exists (and it usually does) the turnbuckle and rod end, being threaded parts, are under preload and apt to break.
If you have been running a VD a few years you may have witnessed the rear toe turnbuckle break – if not your own, someone else’s.

Paul, this is a much better solution than the stock configuration, which, as you point out, puts a bending load on the turnbuckle. I was hoping there would be people on this forum who would have some good ideas, but this is way better than I was hoping for. I'll get in touch with you by email.

[pkr]

BTW, Just got our website back on line if you want more info on the revised rear VD stuff: www.rsport.us

[pkr]

If you are attending the Run Offs at VIR;
You can see the revised Rsport parts at the 'Pelfrey' FF Canopy in the paddock.
Ask for 'Ian', He will be working with Tim Minor in FC.

[Messenger Racing]

I want to inspect them and will look Ian up. Thanks!

Jay

[problemchild]

Paul's parts are awesome and I would encourage those buying new to go that way. For those on tighter budgets, I got pretty good at tweeking the original style A-Arm (N-Arm) to insure reasonable alignment for the toe-adjuster. Being aware of the problem is the first step, and learning to use some wooden blocks and a big bar are the 2nd step. If you don't crack or kink it, the loads under normal use can certainly handle the tweeks of fractions or a few degrees.

Certainly a good fabricator could convert the N-arm to an A-arm with ears for a toe adjuster, at reasonable cost as well. Lots of options to manage this issue once you are aware of it.

[douglap1]

Recently, I became a concerned that my RF01 toe-links had never been changed, so I bought some new ones from Primus to hopefully avoid fatigue failure. From the photo below, they have obviously changed the design to a radiused change in diameter from the previous conical diameter reduction shown on the right. However, I'm not sure this is a big improvement, as there is still the stress concentration at the end of the threads where the original poster's turnbuckle had failed:





Now I'm thinking about what is the best permanent solution. I like separate toe link A- Arm design that RSsport sells as discussed previously in this thread, but it looks like that will require staking new Grumman bearings in the A-arms and running new brake lines inside the A-Arm tubes.

Then there is this shim adjustable toe device that Velocity Haus sells:

https://velocityhaus.com/collections...-assembly-rear

This shim adjustable unit looks like it would also solve the stress concentration problem of the existing turnbuckle, while using the original A-arms.

Anyone have any experience with these options, or words of wisdom?

Thanks,

Paul

[Mike B]

I don't think the RSport arms are available anymore but I could be wrong. We just did what Greg suggested and converted our own. I got some 4130 tube and some weld in tube ends from Meziere to make the toe links and had SendCutSend make the plates that welded to the a-arm. Very easy, cheap, and no reason to stake bearings or run brake lines. No more stressed turnbuckles.

[Lyngengr]

Recently, I became a concerned that my RF01 toe-links had never been changed, so I bought some new ones from Primus to hopefully avoid fatigue failure.

Anyone have any experience with these options, or words of wisdom?

Fast Forward makes these turnbuckles out of better material and properly heat treated.

Change the rear turnbuckles every two seasons. Move the older rear ones to the front, keep the old fronts for spares.

[douglap1]

Thanks for the suggestions guys.

I'd still like to hear from anyone that is using the shim adjustable toe links before I move ahead.

Anyone...anyone?

[chrisw52]

Thanks for the suggestions guys.

I'd still like to hear from anyone that is using the shim adjustable toe links before I move ahead.

Anyone...anyone?

I have used the shim adjustable toe links. Great for setting up the car and getting the setup accurate to sub millimeter precision. I. like it because you can accurately change the settings during a test session with precision. The shim kits do not solve the problem of the stress on turnbuckle (or shim stack in this case).