Section : General

4-pot callipers binding on 5j wheels

Posted By : Chris Gould, 24-May-2005, 03:46pm

• 4-pot callipers binding on 5j wheels

  Posted By : Neil Nasralla, 24-May-2005, 04:39pm

  Hi Chris, I fitted some 6J Revolutions to my Spitfire 1500and they fit a treat and to my mind look the business. I do not have anything other than a standard brake setup so cannot comment about whether they would fit easily. I do know that the 5.5J Revolutions have a smaller backspace and that is why I decided against going for them as I knew that they would foul the wheelarches. Tim Bancroft can tell you all about this as he has them on his GT6. You would have thought that 6J Revolutions would be similar but they have a larger backspace so they do not foul either front or back.
  
  My point here is that it is not the width of the wheel that will be important to you it will be the backspace which is the distance between the inner rim of the wheel and the mating-to-the-hub surface of the wheel. You can find some information here http://www.triumphspitfire.com/tires.html about Spitfire/GT6 wheels and their backspaces and here http://www.triumphspitfire.com/wheels.html.
  
  Some backspace information about Revolution wheels can be found here http://www.tyresave.co.uk/revorace.html (I have no interest in them other than they are really nice IMO). You need wheels with a smaller backspace so the inner rim sits further out from the callipers/suspension/discs (etc) which your current wheels are fouling. Your other option is to use spacers although you do not want to use thick spacers as they can put stress on bearings and the studs. If you go for more than 3mm then I think you will need longer studs which are available from Jigsaw amongst others.
  
  I bought my Revolutions from Avonbar Racing http://www.speedgenie.co.uk/avonbar/ and got the 4 wheels with Dunlop SP30 tyres (seem reasonably good to me and have favourable reviews) balanced (weights on the rear) and delivered to my door for £477 including VAT. I thought that was a good deal although I had to wait 3-4 weeks as they came straight from the manufacturers (who incidentally charge more).
  
  You have 2 number of options.
  
  1. Use some spacers to move your current wheels out and deal with any issues with the wheels fouling the wheelarches if necessary. Risk of stressing studs and bearings?
  2. Purchase some nice new/secondhand wheels with an appropriate backspace lower than the backspace of your current 5J wheels.
  
  I hope some of this makes sense.
  
  Regards and good luck
  
  Neil

  • 4-pot callipers binding on 5j wheels

    Posted By : Chris Gould, 24-May-2005, 05:28pm

    Hi Neil,
    
    Thanks for the links, I've seen the spitfire magazine link for wheels, but didn't realise they had the backspace measurements for some of them. I think it'll be more a problem with the profile of the backspace, but I've always been tempted to fit cosmic mk2s for that period/sporty look so I'll check the measurements against the standard and scout around, whilst talking to work's machine-shop about spacers - though the wheel-arch factor is a problem. I don't want to butcher a mint mk3 bonnet.
    
    Those revolutions do look pretty sweet in black and chrome. Good value for tyres, wheels and carriage too; and the wait wouldn't be too much of a hassle since the body should be going on this weekend - at least another month of rebuilding left b4 driving!
    
    Many thanks, always handy to get other peoples perspective.
    
    Cheers,
    
    Chris

    • 4-pot callipers binding on 5j wheels

      Posted By : John Davies, 24-May-2005, 08:37pm

      Chris,
      Try spacers. Yes, extra strain on the bearings and depending on how wide a spacer you need, longer studs nay be required. The longest available are by Ford - 2 1/4". They install with a little work to the fronts, but more work is needed at the back - see my article on the TTN - http://www.totallytriumph.net/dcforum/DCForumID57/... .
      
      John

      • 4-pot callipers binding on 5j wheels

        Posted By : Chris Gould, 25-May-2005, 03:07pm

        Thanks John,
        
        Neat trick with the rear brake-plate! I've noticed that Jigsaw racing has 67mm high-tensile wheel studs that use the original wheel nuts (unlike those by john wolfe). Only thing I'm worried about when using the spacers is the lack of a 'lip' which the wheel sits around on the hub - it must increase the strain on the studs quite dramatically. To machine such a lip onto the spacer would require a substantial thickness of spacer, hence problems with wheelarches and MOTs. I want to keep the car as original looking as possible, and I really hate flared wheelarches!
        
        Looks like I'll be doing a lot of measurement and trial&error this weekend!
        
        Many thanks,
        
        Chris