Trigo adapter drive pins

my427cobra · #1 (**permalink**) 08-13-2006, 08:23 AM

I am finally installing my Sunburst wheels on my car using special hub adapters Trigo made for me. The drive pins are a thou or two less than 3/4" and the drive pin holes in the wheels are exactly 3/4". The drive pins test fit in the wheel smoothly (although snuggly), but the fit/clearance is so tight that pulling them out is like pulling a stubborn cork out of a wine bottle. The suction is so strong I can barely pull them out.
I have bolted the hubs on using the drive pins and alignment ring, but the pins are so tight in the wheel as I start to put the wheel on, I'm afraid I will not get the wheel off, even with a liberal dose of antisiezeon the pins.
What should the pin OD to wheel hole ID clearance be?
Would a 25/32" wheel hole be too sloppy?
Any input would be appreciated.
Thanks
Greg

strictlypersonl · #2 (**permalink**) 08-13-2006, 10:19 AM

That's too much clearance.

The problem is that the hub pin pattern probably doesn't exactly match the wheel pattern due to machining tolerance in both. We ended up Blueing the wheel holes and subtly hand-finishing with a die grinder. Before you do, mark the hub and wheel so they can go together the same way every time.

my427cobra · #3 (**permalink**) 08-13-2006, 12:15 PM

Thanks stricktlypersonal. If 25/32 is too much clearance, would one size smaller, 49/64 work?
I guess I'm wondering what a proper clearance wouls be.
Greg

Rick Parker · #4 (**permalink**) 08-13-2006, 01:15 PM

Greg: When the .750 diameter 6 pin on a 4.25 bolt circle was done on my PSE FIA wheels a few years ago with the Trigo adapters, 49/64 was the drill bit that was used to drill the holes in the wheels. Like it or not when you go to slip the wheels on there has to be a small amount of clearance to allow all of the pins to slip into the holes at the same time. This application is not a true precision fit situation. Here is a picture of the hub with pins installed. The 1/64 (+-.015) tolerance on a non solid 26 inch diameter tire will never be felt.

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LMH · #5 (**permalink**) 08-13-2006, 01:54 PM

I had a similar problem and found that the center threaded hole in the drive pins weren't exactly centered. I had to clean up the pins on a friends lathe, which helped a lot. I use anti-sieze on them too.
Larry

Lindy · #6 (**permalink**) 08-13-2006, 03:23 PM

Anti-seize worked very well for me. I used a small amount on each of the drive pins, as well as a very small amount around the radiuses of the mating holes in the wheels.

my427cobra · #7 (**permalink**) 08-14-2006, 08:50 AM

Thanks all for your advice. I think I'll go Rick Parker's way and drill/ream the wheel holes out to 49/64". Thanks Rick.
Seems this achieves the same clearance result as turning each of the drive pins down.
By the way Rick, what is the disc brake set-up on your rear end in the pic you posted?
Greg

Rick Parker · #8 (**permalink**) 08-14-2006, 10:25 AM

It is from 88 Tbird Turbo coupe. I changed the calipers to the front of the rotor and put them in oposite sides of the car. I also had to do some fabricating on the part that the E brake cables attach to. That was a little creative. The outer cable does not anchor on the caliper housing but rather on a bracket on the axle housing. It works fine. Be sure you get to holes reamed concentrically. You may want to have a reamer, or drill bit ground to size with a step to guide it so they all end up "On center", I would caution against just using a ordinary 49/64 drill bit to enlarge the existing holes.

my427cobra · #9 (**permalink**) 08-14-2006, 12:45 PM

Thanks Rick. good advice.
Greg