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Track Width Increase With 7.5 Disc Conversion

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#1 Alanf


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Posted 03 December 2019 - 07:50 PM

Hi All

Iam sure this has covered before but I have fitted a 7.5 inch disc conversion to a 76  850 and the track is much wider than the drums, I just want to know by how much I need to widen the track.

Thanks Alan

#2 nicklouse


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Posted 03 December 2019 - 07:52 PM

I don’t get your question you have already widened it by fitting the disc set up.


add the disc drums to the rear and you will be sorted.

#3 Alanf


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Posted 03 December 2019 - 08:06 PM

sorry nicklouse yep thats the question will the drums with built on spacers even it up or do I need a spacer ring of a certain width

Thanks Alan

#4 Stevie W

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Posted 03 December 2019 - 08:36 PM

Hi Alan,


As Nicklouse has stated, if you use the spacered drums on the rear, that'll bring the rear track width out to match the front Cooper "S" disc set-up.


Cheers, Steve. 

#5 unburntfuelinthemorning


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Posted 03 December 2019 - 09:56 PM

Is it necessary to being the rear track out to match the front?  The Mini has an understeering tendency anyway so maybe it'll make the handling more neutral?

Edited by unburntfuelinthemorning, 03 December 2019 - 09:56 PM.

#6 Cooperman


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Posted 04 December 2019 - 11:25 AM

To maintain the correct geometry the track should also be widened on the rear as well by fitting the spacered drums.

As standard the rear track is 2" narrower than the front, so you don't want the rear to be 4" narrower.

It is normal to fit the correct wheels when fitting 7.5" discs. The datum offset with what used to be called the Cooper 'S' wheel allows for the wider track and re-sets the tyre centre bak in the correct position to maintain the geometry as designed originally.

#7 whistler


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Posted 04 December 2019 - 12:13 PM

Don't forget to change the rear studs for the longer variety with the spacered drums.

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