craigdiver
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| posted on 18/2/18 at 08:56 AM |
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tyre size
my wheels are from a ford focus and have 195/60R15 tyres fitted. This seems an uncommon size when searching for tyres and is limited for choice. Will
it make much difference for road use if I fit 65 profile (apart from theoretically raising the car 5mm)? (195/65/15 Pirelli P6 £37.58, Toyo Proxes CF2
£34.61). Going down a size to 195/55/15 would enable me to fit very sporty looking Nankang Sportnex NS-2R, however, not wanting to go much lower as my
sump (at present) has only 75mm clearance :-0
If it ain't broken, fix it anyway (just because).
Building - BMW powered Haynes Roadster/442E hybrid.
Volvo C30 T5 Polestar
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cliftyhanger
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| posted on 18/2/18 at 11:11 AM |
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Have a think about gearing. The tyres youmention change the gearing by about 3%, one bigger, one smaller. and about 20mm difference, one will lower
the car 10mm, the other raise it 10mm.
195/65 15 is a common tyre size and cheap, used on loads of passenger cars. But you may be better going to 195/50 15 and sorting the sump.....
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craigdiver
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| posted on 18/2/18 at 11:48 AM |
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quote:
Originally posted by cliftyhanger
Have a think about gearing. The tyres youmention change the gearing by about 3%, one bigger, one smaller. and about 20mm difference, one will lower
the car 10mm, the other raise it 10mm.
195/65 15 is a common tyre size and cheap, used on loads of passenger cars. But you may be better going to 195/50 15 and sorting the sump.....
Great advice, thank you. Gearing not really a consideration as running gear was out of a 5 series BMW and that had 18” wheels so am expecting improved
acceleration and lower top end.
sump is a project for post-IVA so might put the 195/65 15 on as cheap as chips then move to 50 profile when sump reworked (or M3 engine fitted).
If it ain't broken, fix it anyway (just because).
Building - BMW powered Haynes Roadster/442E hybrid.
Volvo C30 T5 Polestar
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overdriver
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| posted on 18/2/18 at 05:59 PM |
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...... or, rim width permitting, try going the 205/50/15 route where there is a good selection of rubber. In theory this would reduce your ride height
by approx. 14.5mm. Many of us live with a sump/bellhousing clearance of less than '3 fingers' - i.e. <60mm.
Michael.
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SuperV8
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| posted on 19/2/18 at 12:26 PM |
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quote:
Originally posted by craigdiver
my wheels are from a ford focus and have 195/60R15 tyres fitted. This seems an uncommon size when searching for tyres and is limited for choice. Will
it make much difference for road use if I fit 65 profile (apart from theoretically raising the car 5mm)? (195/65/15 Pirelli P6 £37.58, Toyo Proxes CF2
£34.61). Going down a size to 195/55/15 would enable me to fit very sporty looking Nankang Sportnex NS-2R, however, not wanting to go much lower as my
sump (at present) has only 75mm clearance :-0
Going from a 60 profile to a 65 does not add 5mm to the radius of the tyre!
The 60 number is the height of the side wall as a percentage of the tyre width,
so for a 195/60 - the 60 is 60% of 195mm, so 117mm height.
A 195/65 would be 126.8 so a difference in theoretical radius of 9.75mm
Tyre pressure is obviously also important in determining the ride height.
Tom.
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craigdiver
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| posted on 19/2/18 at 05:27 PM |
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quote:
Originally posted by SuperV8
quote:
Originally posted by craigdiver
my wheels are from a ford focus and have 195/60R15 tyres fitted. This seems an uncommon size when searching for tyres and is limited for choice. Will
it make much difference for road use if I fit 65 profile (apart from theoretically raising the car 5mm)? (195/65/15 Pirelli P6 £37.58, Toyo Proxes CF2
£34.61). Going down a size to 195/55/15 would enable me to fit very sporty looking Nankang Sportnex NS-2R, however, not wanting to go much lower as my
sump (at present) has only 75mm clearance :-0
Going from a 60 profile to a 65 does not add 5mm to the radius of the tyre!
The 60 number is the height of the side wall as a percentage of the tyre width,
so for a 195/60 - the 60 is 60% of 195mm, so 117mm height.
A 195/65 would be 126.8 so a difference in theoretical radius of 9.75mm
Tyre pressure is obviously also important in determining the ride height.
Tom.
everyday is a school day!, would have put money on the 60 being 60mm tyre wall.
Thanks :-)
If it ain't broken, fix it anyway (just because).
Building - BMW powered Haynes Roadster/442E hybrid.
Volvo C30 T5 Polestar
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SuperV8
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| posted on 20/2/18 at 12:21 PM |
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quote:
Originally posted by craigdiver
quote:
Originally posted by SuperV8
quote:
Originally posted by craigdiver
my wheels are from a ford focus and have 195/60R15 tyres fitted. This seems an uncommon size when searching for tyres and is limited for choice. Will
it make much difference for road use if I fit 65 profile (apart from theoretically raising the car 5mm)? (195/65/15 Pirelli P6 £37.58, Toyo Proxes CF2
£34.61). Going down a size to 195/55/15 would enable me to fit very sporty looking Nankang Sportnex NS-2R, however, not wanting to go much lower as my
sump (at present) has only 75mm clearance :-0
Going from a 60 profile to a 65 does not add 5mm to the radius of the tyre!
The 60 number is the height of the side wall as a percentage of the tyre width,
so for a 195/60 - the 60 is 60% of 195mm, so 117mm height.
A 195/65 would be 126.8 so a difference in theoretical radius of 9.75mm
Tyre pressure is obviously also important in determining the ride height.
Tom.
everyday is a school day!, would have put money on the 60 being 60mm tyre wall.
Thanks :-)
That would make a lot more sense haha.
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loggyboy
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| posted on 20/2/18 at 12:52 PM |
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https://tiresize.com/tyre-size-calculator/
Mistral Motorsport
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