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rossnzwpi 17th November 2017 19:17

Cromodora CD 1 specifications
 
3 Attachment(s)
What is the spec of original Cromodora CD1 Ferrari Dino wheels? I have a set and measured them years ago but can't remember. This from the Ferrarichat website suggests their offset is 4 inches (approx 100mm)! But this is nuts and based on physical measurements John Corbani took 12 years ago. He is referring to the distance fro the edge of the wheel to the mounting face of the wheel but isn't offset the distance from the centreline of the wheel to the mounting face?:
https://www.ferrarichat.com/forum/th...offsets.69024/
https://www.ferrarichat.com/forum/at...l2-jpg.197550/

a quick look at the diagrams in the Ferrari 246 workshop manual and a CD1 blueprint in an Italian magazine article suggests that the offset isn't zero and is more like minus 14mm to minus 11 (or the 3/4" Corbani suggested) :

Attachment 4768

Attachment 4769

Attachment 4770

I know Dehavilland suggested they would sell zero offset "CD1" replicas in 15x7" but the photo they show of a wheel on their Facebook page doesn't look that much like a CD1!

thecarbuilder246 18th November 2017 08:49

chassis
 
Hi ross

I was told the cromadora wheels as fitted to the dino were a 0mm offset and I have based everything around this. Now I know the deon used an 8mm offset and I assume this was to bring the wheels slightly inwards so I'm assuming this would be minus - offset? I guess some net searching would either correct me or put me straight!
Now I have a set of reproduction cromadora's in the attic so will measure these later today. (guess should have measured earlier!!).
The first dino 206 bodyshell was built to fit on a lotus europa chassis I beleive-thread elsewhere on here-and may have been stretched to fit. Jhclassic' Jon Hurst then saw an opportunity in the market the came up with a chassis to fit the body shell.This is where I think the track has grown. Fitting the chassis to the body and not the other way round.

ian

thecarbuilder246 18th November 2017 17:29

chassis
 
3 Attachment(s)
Hi all

I've measured my cromadora wheels and they have a 5mm off set.See photos.
The mounting face of the wheel is 5mm off the centre of the wheel towards the outer face meaning the wheel track becomes smaller.
I now know this is a plus + offset as it states it on the wheel box-doh!!:redface:

ian

thecarbuilder246 18th November 2017 17:49

Quote:

Originally Posted by thecarbuilder246 (Post 91906)
Hi all

I've measured my cromadora wheels and they have a 5mm off set.See photos.
The mounting face of the wheel is 5mm off the centre of the wheel towards the outer face meaning the wheel track becomes smaller.
I now know this is a plus + offset as it states it on the wheel box-doh!!:redface:

ian

If you take a look at the first photo you will see from the mounting face to the outside face of the wheel the measurement is 107mm. The wheel overall is 204mm. So centre of wheel is half this size 102mm minus the 107mm gives us a size of plus 5mm.

ian

rossnzwpi 18th November 2017 17:49

The wheels look fantastic Ian! Where'd you get them and did you have the PCD & bore custom drilled for your hubs? Dinos were originally 5x108 PCD too but the centre bore was about 58-59mm if I recall correctly. Are your hubs Ford?
cheers
Ross (in NZ)

thecarbuilder246 18th November 2017 18:05

chassis
 
Hi ross

The wheels came from superformance around 3/4 years ago and at that time were £545 a set plus vat. They have gone up recently as new owners have taken over and I think they are nearer £800 plus vat now. PLus vat at that time had been reduced temporarily to 15%. It's 20% here now.
The bore is the standard bore they came with and I need to machine new spacers up to fit the wheels to the new hubs. At the moment the spacers are for the lancia beta/fiat 124 hubs.

ian

thecarbuilder246 18th November 2017 18:25

chassis
 
4 Attachment(s)
hi ross

couple more photo's for you.
first is the re machined hubs and brembo dis'c
second is the newly made brake carrier
third fitted to hub with wilwood caliper
fourth is when I trail fitted the cromadora.

ian

rossnzwpi 18th November 2017 20:07

That's looking amazing Ian. So what hubs and discs have you used? What machining did the hubs need?

scimjim 18th November 2017 20:57

Quote:

Originally Posted by rossnzwpi (Post 91878)
What is the spec of original Cromodora CD1 Ferrari Dino wheels? I have a set and measured them years ago but can't remember. This from the Ferrarichat website suggests their offset is 4 inches (approx 100mm)! But this is nuts and based on physical measurements John Corbani took 12 years ago. He is referring to the distance fro the edge of the wheel to the mounting face of the wheel but isn't offset the distance from the centreline of the wheel to the mounting face?

The 4” is backspace - hub mounting face to rim. Offset as you say is hub mounting face to wheel centreline.

rossnzwpi 18th November 2017 23:15

original offset - 14x6.5 Cromodora CD1
 
5 Attachment(s)
Well, my curiosity is piqued now so I measured one of my original Dino wheels - as fitted new on a 1971 Dino 246:
it is 193mm wide ( centre line therefore @ 96.5mm)
mounting face of the wheel is 114mm deep
offset is therefore 17.5mm
(as measured with my daughter's plastic ruler, LOL)

Attachment 4780

Attachment 4781

Attachment 4782

Attachment 4783

Attachment 4786
I should add that the distance from the mark on the ruler ( 196mm ) to the base of the ruler sitting on the wheel mounting face is 114mm
cheers
Ross

thecarbuilder246 19th November 2017 14:05

chassis
 
5 Attachment(s)
Hi Ross

I had some steel spacers cnc machined up to press fit on to the fiat 124 hubs from the back. The back face was machined parallel to the front face. The outside diameter was untouched and used for accuracy.
With the spacers pressed on to the fiat hubs new 5x108 holes were bored and new studs pressed in from the back. The steel spacers were also machined on there outside diameter for the new brembo disc's. The spacers sit approximately 0.25mm down from the hub face again using this original face for accuracy when bolting the wheels up.The action of the wheels being bolted on eliminates any chance of anything coming loose!!
To mount the brakes I first tried to use the original fiat caliper mount and machined an aluminium adaptor to mount my wilwood calipers onto but it was to baulky and also clashed with the steering arm on full lock.So I designed my own based around the fiat ones had them laser cut and I welded them up.
The original fiat hubs had a taper on the wheel mount boss so this was squared up so I could turn up my spacers.

thecarbuilder246 19th November 2017 14:16

chassis
 
5 Attachment(s)
Hi Ross

The rears were done in a similar way but are bolted from the front as there was not enough room to fit them from the back.
Again cnc machined up but this time the were surface ground from the machine face for accuracy. As I couldn't press these on I've used the hub nut to hold them on and again used the wheel bolts. The brakes have been mounted using an adaptor mounted to the original brake mounts.
I'm not happy with the handbrake assembly so I'm looking at removing this and using a pair of brembo units.

thecarbuilder246 19th November 2017 14:22

chassis
 
5 Attachment(s)
hi ross

the rear brakes were a pain as I've tried to incorporate the hand brake.
I've made new mounts and I've had to reshape the strut brackets and also weld the bolt in to become a captive thread to prevent it clashing with the cable mount,but I've managed to get it all in.
Will look at brembo handbrake calipers though.

thecarbuilder246 19th November 2017 15:11

chassis
 
Hi

Forgot to add-my wheels are larger than the standard 14 inch on the 246 dino
at 16 inch as I wanted a larger choice of tyre. And these wheels are usually supplied by superformance to be used in conjunction with the 246 big brake upgrade kit. This may be the reason behind the different offset.

ian

rossnzwpi 19th November 2017 18:05

Wow, impressive engineering! Thanks for explaining Ian.

thecarbuilder246 19th November 2017 23:16

chassis
 
Quote:

Originally Posted by rossnzwpi (Post 91962)
Wow, impressive engineering! Thanks for explaining Ian.

It took 2 years!! And I was lucky enough to have two spare front hubs to practice on as well.

ian

rossnzwpi 20th November 2017 00:02

Spares - always useful. I was about to pick up a couple of MX5 spindles & hubs to see if the Alfa 166 rear hub could be adapted to them - since it is perfect for my cromodora cd1s.

thecarbuilder246 20th November 2017 11:53

chassis
 
hi ross

I think I read somewhere where someone used a pair of toyota mr2 rear handbrake calipers and swapped the hub and bearings for alfa hubs when they fitted an alfa v6 engine and box to a deon-but can't remember where!

ian

rossnzwpi 27th December 2017 02:11

Hi Ian, going back to the comments about using a rear macpherson strut-type suspension (or a front macpherson - used in the rear of your chassis). I just watched a couple of videos that helped me understand some stuff: Agent 47 racing's video explains that lack of camber control is one area where macpherson is not as good as double wishbone. The strut acts essentially as a sliding joint and the camber doesn't change much. The big angle on front macpherson struts is to do with scrub radius - and this is not an issue on the rear.

https://www.youtube.com/watch?v=ftf3KYHTOYU

/Drive have a series of videos explaining geometry. In episode 1 he notes that lopping 2.5" off a strut has a big effect on geometry and will be "pretty messed up".

https://www.youtube.com/watch?v=x0oi9SHJPvg

Camber control for grip, stability and braking is one thing but the other, as Ozijim points out in his post, is keeping the roll centre under control - if it changes drastically the car could get suddenly out of balance.
cheers
Ross

thecarbuilder246 27th December 2017 12:31

chassis
 
Hi Ross

I've watched endless videos like these. My idea is to keep the front suspension pivot /mount points the same as the deon just reducing the centre chassis distance by the required amount. The deon uses a mini rack with extensions screwed on to the steering arms which are used to eliminate bump steer. I can screw these further onto the threaded steering arms to keep the set up the same.I intend to use a billet upright designed around the fiat 124 upright so kingpin/inclination and camber will be the same as the deon.
It's at the rear where I was looking into using a strut,mainly to give me more room in the engine bay.
I've a spare v6 engine that I'm mating to a toyota mr2 turbo box too and this will be my starting point. Just got to get my adaptor plate machined up and the start with an engine bay.If I can work it with double wishbones I will but my problem here is the engine and box will be 25mm wider overall than the deon v6 set up with the chassis reducing by 40mm (I think) so a 65mm reduction of space overall.

ian


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