Tyre Geometry advice for 19 inch alloys by Trebor


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Trebor
My 19 inch alloys have started to scuff on the outside of all 4 wheels so i took it for 4 wheel laser alignment earlier only to find out when it was on the ramp that the insides are also starting to do the same.

I have a few issues/questions as a result:

1) They are non oem wheels and tyres so i was told that the settings for toe in/ out may need to be different than the standard 0 degrees - does anyone know if that is true, and if so how i could find out ?

2) Is it worth just making sure that the wheels are properly set up using the
oem settings given that i have larger wheels on or would i be wasting my money ?

3) I was also told that none of the wheels can be adjusted for camber, just toe in/out - is that also true ?

3) In the end i didnt have them done whilst i do a bit more research, and i phoned Wheels in Motion from Buckingamshire who are specialists and they told me that if the tryres are wearing on both sides it points first of all to under inflated tyres and that i should try putting 4psi more in each tyre, it is a problem with non oem wheels of a different size as you cant refer to the manual to get the correct pressure. I have 235 35 19 tyres and have been using 32 psi in each tyre but will now try 36psi and see how it goes.

The fitter at the 1st place i went to never mentioned tyre pressures as a possible cause yet it seems an obvious one to try first.

If there are any wheel/ tyre experts out there i would appreciate your input
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Posted 23 Jul 2010, 18:03 #1 

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TyphoonTT
Would have to say tyre pressures myself, although 36psi seems pretty high. :confused:

You'll have to stop taking turns flat out! :mrgreen:

Posted 23 Jul 2010, 21:56 #2 

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Trebor
i am past all that now Ben and a fairly sedate driver although when i get on the M54 each night from work the junction slip road is almost a spiral and i wondered if it might be that but got to be worth trying the tyre pressures, see you at the nano
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Planning is an unnatural process, much better to just get on with things, that way failure comes as a complete surprise instead of being preceeded by a period of worry and doubt

Posted 23 Jul 2010, 22:40 #3 

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Bernard
I can't see that a geometry error is going to manifest itself as wear on both edges. Low tyre pressure is the classic cause as everyone says. I wouldn't say 36psi is very high really.
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Posted 23 Jul 2010, 22:57 #4 

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JohnDotCom
Different make of tyres and specifications come with some strange recommendations for PSI
XL tyres at that size only meet their index when combined with a higher pressure.
Recommended looking at 2.9+ Bar!
John

"My lovely car now sold onto a very happy new owner.
I still love this marque and I will still be around, preferred selling to breaking, as a great runner and performer"

Posted 24 Jul 2010, 15:54 #5 

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Jürgen
Trebor wrote:I have 235 35 19 tyres and have been using 32 psi in each tyre but will now try 36psi and see how it goes.

32 psi seem a bit low to me, Rob. That will most probably be the reason for the extensive wear at both sides. Therefore I would go for 36 or even 38 psi.

BTW I'm using ~37 psi (2.6 bar) on standard 195/65 R 15 tires and I feel comfortable with it.
Jürgen

75ZT Community & Midlands Nano Meets & 75 & ZT Enthusiasts

Posted 24 Jul 2010, 17:59 #6 


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