"Real" pin-drives vs. Trigo adapter pin-drives

[excelguru]

A question or two for you guys... I wanna have pin-drive wheels on my Cobra. Just a personal preference. As I understand it, I have 2 ways to do this:

1. "True" pin-drive wheels which require special hubs (very expensive).

2. Trigo pin-drive wheels that use a 5-lug hub with an adapter (much less expensive).

The problem is, I want my wheels to have the proper "deep" look. You know, the depth from the outside of the rim to the spokes (is this what you call "offset?). If I understand the Trigo's design correctly, this depth would have to be slightly less to accomodate the adapter and still maintain the proper track.

So if I'm wanting to maintain the correct "depth" AND the correct track AND use the Trigos to save a bunch of money, do I have to have the half-shafts shortened? If I choose to leave the half-shafts alone, is the difference in "depth" very noticable?

I know it's a picky thing, but I'm only gonna build one of these in my life (that's what I keep telling Elizabeth anyway) so I want it to be juuuuuust right.

Keith

[Bob Putnam]

I can't say about other cars' wheels, but on an ERA the wheels look exactly the same. Park takes a little extra material off the wheel's mounting surface to compensate for the thickness of the adapter. The adapter is also a little bit shorter so that it doesn't extend past the outside of the wheel/wing nut too much.

The primary disadvantages to the 5-pins are about 3 lbs extra at each wheel and the added complication and possible failure of the adapter.

[Bud Man]

The Cobra Restorers Ltd. catalogue lists both pin drives and the adapter wheels. Their literature states that the bolt-ons add 3/4" to the track. Don't know if they mean each wheel or the entire rear end!

Bud

[RACER X #99]

Keith,
I installed the trigo's with adapters on my older Contemporary.
I had to shorten the lower control arms and had new half shafts made. If you are starting out new you probably should to go for the original pin drive set up. It probably won't cost much more.
X

BTW I spend a lot of time on the track and I use 5 lug bolt ons for that use. The wheels are much cheaper plus I carry 4 spares with me. this could be very expensive if I had to have 12 trigo wheels.

[John 550]

Keith , one nice thing with the trigo's is, I think if you take off the addaptor , you have a typical five lug set up .

[Rick Parker]

The trigo adapters have a 3/8" base with the threaded portion machined from one piece of metal. It will without any other modifications increase the track 3/4" of an inch overall but as mentioned above can be allowed for by machining from the back of the wheel.
I used Trigos blank (undrilled) adapters and mated them to PS Engineerings FIA wheels on a narrowed 9" all to keep the wheels and tires under the car to achieve the proper "LOOK" that we all strive for. The pad that is on the back of the FIA wheel will only allow a 6 pin fitament (no 5 lug) and I was concerned that the original 1/2" diameter drive pins with 3/8" threaded portion were questionable (unfounded at this late date). When ordering new axles I hade them drilled for 6-1/2" studs (stronger) on a 4 1/4" circle and when mated with the properly machined adapters and 6-3/4" barrell nuts that hold on the adapters themselves make for a great bulletproof combination, Far stronger than the original cars and providing for a larger surface area to actually drive the wheels themselves. When I was in the design and planning stages of this and speaking with Phil at PS Engineering he had not previously done this combo but it has worked out perfectly.
The Halibrand style wheel WILL allow for a 5 pin fittament because of the larger mounting pad on the back and their spoke design. That is specifically why they are so popular in this application. The Trigo adapter is very similar to an original car except the oeverall diameter of the adapters themselves are intended to match up to the diameter of the axle flange on a typical live axle and after fitting they can be reduced in diameter if desired. Lynn Park who owns Trigo is well versed on any type of wheel fitting desired on a Cobra he usually answers the phone himself.

[427orFIAisOK4me]

Rick;
You seem to understand this discussion well, while on the other hand I do not. Could you shed some light for those like me still in the dark..

> If you have “stock” Trigo bolt-on adapters can you still mount original six-pin drive wheels? If not why?


Thanks, and I’ll take my answer off the air.

[Rick Parker]

The problem that is unappearant to the novice is that the pin drives on the original cars both 289 FIA/427 was a 6 pin on a 4 1/4" bolt circle. The pins themselves have a 3/8" diameter threaded portion that provides the locating and clamping forces to hold the center Spud or hat to the drive flange. The drive portion of the pin is 1/2" and inserts into the wheel itself. The Trigo adapter attempts to minimize required macine work by utilizing the existing studs in the axle flange (normally 1/2") and bolt circle 4 1/2" (Ford). The barrel nuts are 3/4" diameter cylindrical about 1 1/4" long with a tapered face on one end and internal wrenching hex on the other. They screw onto the studs in much the same design clamp the threaded hat to the axle flange and combine with the studs to form the drive pins that are 3/4" diameter in this conversion. In my application I had to change to 6 studs/pins as the 5 stud/pin pattern could not be made to fit on the back of the FIA style wheels that were part of my project. The mounting pad on the back of the wheels have a scalloped unusually shaped pad which will not allow for a 5 pin pattern without reducing the bolt circle diameter significantly (weaker). I could have used the original 3/8"-1/2 drive pins (relocate hole centers) but I was concerned (overly??) about the power being driven through the 3/8" threaded portion of the original studs, it goes against everything I read about fasteners and mounting them in shear. I considered having special drive pins made (longer threaded with a shoulder area) but at $500+ for 26 (2 spares) I considered against it. What I have is consideably stronger and capable of handling more horsepower and abuse than the original design and has (6) - 1/2" studs in shear with the power driven through pressed in studs bearing on the splined area insted of the power being driven through 6 - 3/8" (threaded area) pins. If these pins break you will lose a wheel. I'm sure that the 5 pin fitament is plenty strong given the fact that most domestic vehicles including 1/2 ton pickups until recently utilized only 5 studs to mount their wheels.

Hope this helps!!!

Rick

[mr bruce]

Rick, what kind of front spindles are you using?

[Rick Parker]

I'm using Mustang II front spindles completly redesigned & ploted front suspension, narrowed MGB steering rack, coil over Alden shocks (revalved), Carrera springs, with rod end at all pivot points allowing for complete adjustablity. We have checked the travel and have less than .015 bump steer through the entire
travel. Should be quite nice when finished, it's been a long time
planning and waiting but isn't that what we all do when we build one of these?

Rick

[Dominik]

keith,

i used them both on two of the same cars.

Correct is that the 5-pin TRIGO wheel is a little heavier than the 6-pin, but the adapter for the front axle (Jaguar) is a lot heavier than the adapter for the 5-pin.

If you are going to use a Jaguar axle. I do not know how the other axles are adapted.
But one i know for sure: as soon as you adapt a 5-pin drive to a 6-pin you need enough material thickness to bolt on the adapter because 5 bolts will always interfere with 6 bolts.

It is different for the rear because a new part comes with the set, that is why it is so expensice.

Plus: for the six pin version you have to mount the wheel bearings in the adapters.
I case you have already refreshened your existing parts you are going backwards.

You will need about 5.5" from the front fender to the wheel mounting flange to fit the (correct looking) 7.5" wheels and about 8" for the 9.5" wheel in the rear.
With 225/60/ tires front and 275/60/15 rear.
Just to put you in the ballpark.

There is almost no difference for these dimensions either for 5-pin or 6-pin.

Meaning: once you cut the axles to fit 5-pin adapters 6-pin may be used later as well.

Cosidering the huge engine torque applied to either, I see no problem with the 6-pins or 5-pins.

The 5/6-pins bolts are not exactly stressed in shear. Looking at 3 bolts that hold a flexplate from an automatic trans I always wonder why the did not shear off. The same with the 4 bolts for the drive shaft.
Somehow the friction of the mounted surfaces increase as RPM increases holding the parts together like welded. (Not really sure about that theorie).

But I would use 5-pins not only for cost reasons or that Lynn is a nice guy.

Dominik