Dick Axtell
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| posted on 24/7/13 at 03:05 PM |
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Re: Self-centring & Tyre press
Have searched thru the various threads on this, and am now confused. There seems to be some variance in views on tyre pressures needed to procuce
IVA-satisfactory self-centring effect.
Possibly some differing views depending on whether Sierra or Cortina hubs are used. I have used Cortina uprights, with upper wishbones giving what
seems to be approx 3 deg castor. Had the car front end fully tracked, camber angles adjusted and toe-in set at Procomp. Matt and Ivan did a great job,
and offered useful advice; big thanks to them.
So, the question is - what tyre pressure should I set for the fronts? One view suggested low pressure e.g. 16 psi, another view reckoned it should be
40 psi, just for the (re-) test.
Your suggestions please.
Work-in-Progress: Changed to Zetec + T9. Still trying!!
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daveb666
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| posted on 24/7/13 at 03:10 PM |
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I increased my tyre pressure from 28psi to 35psi for the IVA and noticed an improvement (all be it not that significant) and mine passed OK;
that said - could have been fine on the normal pressures.
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theprisioner
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| posted on 24/7/13 at 03:15 PM |
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I was wondering the same thing prior to IVA and I was told (by someone on this forum) they recommended 8psi at the front to get a J15 thru (because
Bently do that). On the day I forgot to lower them and it passed anyway. The self centring on my car is barely perceptible only if the camber is in my
favour. My pre-prepared excuse was "that all the bits are new and a bit sticky".
http://sylvabuild.blogspot.com/
http://austin7special.blogspot.co.uk/
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big_wasa
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| posted on 24/7/13 at 03:22 PM |
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The best way is to get a new set of top wishbones with the full and designed 7 deg.
Replacing the rubber bush on the steering column with the bearing mod also helps no end.
[Edited on 24/7/13 by big_wasa]
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nick205
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| posted on 24/7/13 at 03:38 PM |
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Good tip on the steering bushes, the more free running they are the better for self-centering and general feel.
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907
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| posted on 24/7/13 at 04:21 PM |
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quote:
Originally posted by big_wasa
The best way is to get a new set of top wishbones with the full and designed 7 deg.
Replacing the rubber bush on the steering column with the bearing mod also helps no end.
[Edited on 24/7/13 by big_wasa]
Every now and then someone posts a reply that's spot on, 100% common sense.
It's a shame they are not more frequent.
Paul G
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panichat
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| posted on 24/7/13 at 04:27 PM |
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What worked for me...
- check the free movement of the steering rack - if the damper is too tight it can make it too stiff to center well (particularly if you only have 3
degrees of castor). You can add another shim very easily.
Dave
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Dick Axtell
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| posted on 24/7/13 at 07:28 PM |
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quote:
Originally posted by big_wasa
Replacing the rubber bush on the steering column with the bearing mod also helps no end.
What bearing mod? Please can you point me to the right thread?
Found it!! See here - http://www.locostbuilders.co.uk/viewthread.php?tid=183202
And thanks to everyone else for their feedback. Wishbone mod for the future; re-test next Mon. Lack of self-centring is the remaining critical
issue.
[Edited on 25/7/13 by Dick Axtell]
Work-in-Progress: Changed to Zetec + T9. Still trying!!
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