Tyres for Pre 82 FF - ACB9's or ACB10's

As I will be competing in my 1978 Dulon again this year I would be interested in your opinions re tyres. As a pre 82 car I belive I can run either Avon ACB9's or ACB10's. The 9's are slightly taller but the car was designed to use this size of tyre.Therefore I think the suspension would be better suited to this tyre.
Comments please?

Andy,
ACB9 it is for you. The following is 'lifted' from an email from Steve Burns
2004 technical regulations will be as per the Ford Motor Co. regs so any new
'Zetec' chassis will have to fully comply with the FF1600 regs.

Regarding tyres, having taken advice from Avon, Ford and a number of team
managers and chassis builders it is intended that Pre '82 cars will use ACB9
or Dunlop (as most of them use these already) and Post '81 cars will run
ACB10. I hope that this clarifies the situation and allows everybody to
continue using what they already have.
I suggest you seek guidance from one of the old hands, as I believe your car will need resetting up, probably ratio changes as well
diz

When I changed mine quite a few years ago (the other way - to ACB 10's) it was mainly ride height and ratio's. Andy - I think I have the old ratio details somewhere, pm me if you need them and I'll see if I can find.

Hi

Some ratios can be found on http://www.classicformula.se/dreveu.html

You can also find a "complete" 2004 Historic FF calendar

http://www.classicformula.se/datum.html

Henrik

I believe that a question has been fired into Steve Burns to clarify the position relating to the ACB9 / 10 issue.

This regulation contradicts the 2004 URS Classic Formula Ford 1600 regulations, which state you can use either.

Many of the Pre-82 cars come from this championship and it would potentially put some drivers off competing. I have run my car on ACB10 since there introduction, and in back to back testing there is little or no difference, its more down to personal preference and driving style, except for the rain when the ACB 9 are better.

I can see no good reason why the Pre-82 cars should not be free to choose. I will be turning up with ACB10 whatever! If Steve is on line do you have any comment? I believe Steve Pearce has been in touch with you.

aczak,
Many of the 1970's FF cars built and exported to the US had different factory settings to run on US tyres which if I am correct where at the time a lower profile, similar to the ACB10, (but a slick).

The original Royale RP26 handbook refers to alternative suspension geometry for US cars, in the main differing space arrangements on wishbones etc. On my car I use the US Spec spacing.

Apart from that I to can confirm that the only changes I made from Dunlop’s to ACB10 was ride height and ratios, as far as camber is concerned I just followed Avon / Dunlop guidelines.

Hope this helps but as previous post I would hope that when all settles down we will not need to change! Over to you Steve!!

Tyre regulations for the BRSCC Formula Ford Championship were written in consultation with Ford and Avon Tyres.

We were advised to include the following, which is now written into the 2004 regs;

Pre '82 - ACB9 or Dunlop
Post '81 - ACB10

I understand that both are eligible for the Classic FF1600 championship, but the BRSCC do not run that championship and so have no influence on the regulations.

Steve, the CFF regs have not changed this year they still say 'any Avon or Dunlop FF1600 tyre' so allow ACB9's or 10's. By making your regs ACB9 only, you are making things awkward for anyone with older cars who's on ACB10's at the moment. I've got no problem if Dunlops are left off the list, as any Dunlops left are probably over 10 years old by now!
Also, any older cars doing regional FF (SOM, NW, etc) will also be on ACB10's at the moment - so easiest thing would be to allow both types for older cars (Pre 82)
This may seem petty but easier to sort out now, than in a post race scrutineering bay?

Please send me a PM if you need to discuss this further.

Steve, the CFF regs have not changed this year they still say 'any Avon or Dunlop FF1600 tyre' so allow ACB9's or 10's. By making your regs ACB9 only, you are making things awkward for anyone with older cars who's on ACB10's at the moment. I've got no problem if Dunlops are left off the list, as any Dunlops left are probably over 10 years old by now!
Also, any older cars doing regional FF (SOM, NW, etc) will be on ACB10's at the moment - so easiest thing would be to allow both types for older cars (Pre 82)
This may seem petty but easier to sort out now, than in a post race scrutineering bay?

Please send me a PM if you need to discuss this further.

Having had the chance to test 2 almost identical 1974 crossles today, one on ACB10 one on ACB9 , (in the dry) go for the ACB9 ,lasts longer more grip when cold and is very even ie the car slids all 4 wheels - no awfull understeer as with the 10's.
We should really try 9's for everyone , the benefits ;- cheaper, last longer, safer and most cars designed to run on this profile .

Thanks for all your replies you have been most helpful. I will put 9's on the car, and reset the ride heights, toe ins and cambers. See you out soon.

Andreas, Pop down to Three Sisters on Saturday - if you can. You can cheer on MikeM and swift. Maybe even have a play if you are lucky.

I've got some wheels & tyres off a Titan mk6 which R no use to a Ray95.

Does anyone have a set of reasonable used ACB9s for sale. Needed for testing historic FF till I can afford a new set. David Bain