Why 195/50/15

[Cotty]

I have 7/15" wheels which have 205/55/15 tyres.

I have just bought a set of 7/15"Hartge rims with 195/50/15 tyres on them. and have just seen another set of 7/15"'s in the for sale section with 195/55/15's on them.

Why do people put a smaller tyre on the 7/15 rim if it can take a 205 and wouldnt the 50 sidewall height throw off the speedo

[Pilsbury]

According to http://www.miata.net/garage/tirecalc.html 195/50 15's would throw the speedo out by 5%, meaning it would overread 60mph when you were doing 57mph

[orangecurry]

I have 7/15" wheels which have 205/55/15 tyres.

I have just bought a set of 7/15"Hartge rims with 195/50/15 tyres on them. and have just seen another set of 7/15"'s in the for sale section with 195/55/15's on them.

Why do people put a smaller tyre on the 7/15 rim if it can take a 205 and wouldnt the 50 sidewall height throw off the speedo

cos they are cheaper
yes

[Cotty]

According to http://www.miata.net/garage/tirecalc.html 195/50 15's would throw the speedo out by 5%, meaning it would overread 60mph when you were doing 57mph

thats what i thought, I just cant understand why someone would do it