Technical is the 15'' rim size ok still?

[nakedpotato]

Hi,
I have Grande Punto , with 185/65/R15 tires, 15'' rim.
I want to buy rims only, 15'' , that are 6,5J and 4x100. but have 195/50/R15 tires.
if I take out those tires, and use my size, is everything still going to be ok?
the other tyre size confuses me.

 

[Juggers2k]

Ignoring for a second whether the width of the tyres is correct for the wheels, and whether there's space for 195's (I don't know), you have an immediate problem that you're changing the overall size of your wheels by a fair whack (-7.25%).

As you're reducing the profile of the tyre a lot without increasing the width of the tyre by much (or increasing the size of the rim), you're effectively dropping the diameter of the wheel + tyre by 45mm:
http://www.etyres.co.uk/tyre-size-calculator
http://www.kouki.co.uk/utilities/visual-tyre-size-calculator
That equates to a 15cm difference in distance per wheel revolution.

So your speedo's gonna be an extra 7.25% out (and it's going to look like it's fitted with tiny wheels!)

Edit -
For reference, that tyre width and profile combination would work better on a 17" rim, where it only makes a 0.9% difference!
If you want to stick with 15's and for for 195 width, you shouldn't really go below a 60 profile.

 

[nakedpotato]

but the rims I currently have are 15'' 6,5J 4x100. (with 185/65/R15 tires)
and the rims that I want to buy are the same size (15'' 6,5J 4x100) (but with different tires 195/50/R15) )
if I take out those tires and use mine (185/65/R15) , I think it will be ok,
I don't know is it possible to use different tyre sizes on a same rim, as it is the case here.
on a same rim size, I'm using one size, and the ones I want to buy are different size :S
don't know how that tyre size fitted that rim size at first place ..

 

[the rake]

Keeping your tyres on the new rim won't change anything at all.

You can get many a different size tyres to fit any rim,

I'm currently running 195/45R16 on a 9J rim when they'd be better suited to a 6,5J

Yours would be fine as the rims are identically sized.

 

[nakedpotato]

thank you, I thought that a specific tire size has to mach specific rim size

 

[Caravadossi]

thank you, I thought that a specific tire size has to mach specific rim size

You are correct - or more correctly a specific tyre size will have a specific optimum rim size from within a range of `approved’ rims.

See: Bridgestone Pattern Digest, p17
http://www.bridgestone.co.uk/English/Global/FILES/BridgestoneDatabook.pdf

222205Z