Pin drives or 5 stud/brake options - any opinions?

[Guest]

15 inch tyres are limited in UK. To get correct speed rating there is nothing out there that is available. Hence why 17 inch is becoming popular with new builders. With 17 inch it is easy to get through our SVA test. Some people use 15 inch lesser speed rated tyres. Practically as you do not cruise in excess of 130 mph for 2 hours or more you will be ok. But in breach of the law as technically you could drive a 40 in excess of 130 mph for 2 hours (I wish!. Some people use good old fashioned cross plies which are not speed rated. However there is debate over road legality and hence insurance cover. If you are not going on the road then run historic style race tyres. Goodyear or Dunlop do some great stuff which is popular here.
Malcolm

 

[Paul Thompson 'Hooligan']

Hi all,
I have posted some pictures below of pin drive hubs that Frank Catt of Wealden Engineering has developed for the GTD-40.

For further details contact Frank on: [email protected]

regards

Paul Thompson

 

WOW, I bet they will set you back a few pounds, er um Euros to get those.

 

WOW, I bet they will set you back a few pounds, er um Euros to get those.

 

[Frank Catt]

The peg drive hubs and spindles shown in the above photos were originally developed as a one off for Robin Batts yellow peril" GTD. Robin has always wanted to continue development of his car to be as close as realistically possible to the originals, and had wanted for some time to go the peg drive route. We both agreed that the Bolt-On type adaptor was just not acceptable, particularly on safety grounds considering the type of use the car was to get on the tracks, and so we started the design of hubs to replicate the originals. We started by borrowing a set of AC Cobra pin drive hubs (this is were Fords started as well)and also detailing from an original 40. It was designed to use the original race bearings, making the job harder as these do not have built in preload, and the prototype units were installed and used on track 2 seasons ago. I have refined the design a bit since then, and now two cars are successfully racing with these units, together with AP Racing brakes and PS Engineering wheels (15" halibrands)All dimensions are basically same as original cars with the exception that I do not machine in the wire wheel splines as these are not used anyway. Any further info. please call Frank Catt

 

[Guest]

Malcolm M,

"Some pick up points are suicidal to touch on a GTD eg the trailing links to chassis points but others are open to improvement."

so what problems arise if you change these pickup points. I ask because on the chassis I designed and am building I moved them outboard, but didn't change the heights.

I'm asking about the long rear trailing links front mount point. I moved them to where the links are parallel to the longitudal direction.

I'm guessing here but are you saying it changes things like the anti squat? I've already checked the camber gain and bump steer and their ok.

 

[Guest]

The way I was initially thinking in my posting was if you lower the position of the links the car became very tail happy (loose). Why I don't know but that was the consensus of opinion and everyone who did quickly changed back. Sometimes after fitting new rear body work! You haven't done this so all good there.

However you have moved the points out to parallel. This doesn't seem right to me either. Please bear inmind I am not an expertin suspension but lets think it through. As the rear wheel rises and fall it does so in an arc around the longitudinal centre line of the car. Therefore if your trailing links are parallel in the at rest position both in bump and droop you will be stretching them. Rubber bushes may absorb this, nylon blocks may split and heim joints may fail! Or it will increase the rear wheel toe in giving you rear wheel steering. YOU DON'T WANT THAT! All cars I have seen with trainling links as part of the rear suspension are angled out as yours sounds like they were initially. This would overcome the stretching effect I think you may suffer. If the original position wasn't to your liking maybe you should look at a compromise? I can't tell you what to do but it could be worth re-examining for your own satisfaction that you are happy with what you have done.

An aside but relevent bit of info. I saw the new GTD factory chassis last year. They had moved these pick up points but I am jiggered if I can rememberd which way they moved them, in or out. Certainly I don't remember them as parallel. Maybe Brian has a photo he can look at and say what they did?

Malcolm

 

Julian, I have produced my chassis with 5 stud and knock on pin drive. I dont use adaptors. My front spindle is 40% larger than most and uses a knock on hub with taper roller bearings. It was designed to retro fit GTD cars. On the rear i use a one piece drive hub which is internally splined to accept the drive spindle through the bearing carrier. Also designed to fit he GTD. My one piece rear hub can carry a variety of brakes and i have used PBR, Willwood, Alcon and AP Racing. Depending on whether you require a parking/handbrake, there are good rear calipers available. I'll be happy to advise you further. My chassis is available though currently three month waiting list. My front and rear hubs could be made to fit others, though how much work is required is another question.
All the best

Mark Sibley
MDA

 

[Julian West]

Mark,

Thanks for our reply. Does your retro-fit GTD pin drive kit include uprights & are they aluminium or steel?

Regards,

 

Julian, because most of my upgrade work was with GTD's It was designed to retro fit the older models. I am not so sure about the later CAV chassis desgn, havent seen one. I have made the front carrier from steel profiles, tig welded, jig positioned. CNC machined, and a large quality spindle is inserted. This runs taper roller bearings in my knock on pin hub. The whole item is 1.5 kgs heavier than a standard GTD spindle. You can carry a variety of brake off the uprite. The rears were also design to fit into GTD rear carriers. Minimalizing the work to change. They mate up to the rear drive spindle coming through the bearing carrier. Effectively it replaces the ford wheel flange entirely. I am trying to upload pictures, but bear with me, i havent dont it before. My items will fit older chassis, though without seeing later ones, i cant say for sure. But we can make anything fit,right?
Regards Mark

 

Hopefully, Fingers X there should be pictures!

 

Ok, Ok, I fluffed it! 2nd go.

 

Sorry, gonna have to trash my computer! I'll up load them from disc its easier! get to it a little later guys.
Mark

 

[Ron Earp]

MDA, the pictures that appear on this site are linked to the actual image that is elsewhere. This site does not allow you to load pictures up. I noticed your attempt has a link to you local hard drive, c:\XXXXXXXXXXX - this will not work. Search the forum and there is some fellow that has posted a nice description of how to post the pictures. Best regards,

Ron

 

Ron, Thanks, I would have trashed my computer before I found the right way to do it! Cheers. I understand now its hyperlinked to other areas. I can do that, Well maybe, errr. I look for that link, then do it right, I have two thousand photo's GT40, Development projects, racing, Parts, etc etc. The need to get my website changed is more prevelant now. I would put links with all relevant GT40 Parts and Features. Thanks again.
Regards
Mark