> Staigiai reikia pakeist, kaip ieskoti dydziu? Dabar 225/45/R19. Su paskutine 
> dalimi viskas aisku. Kaip suprantu pirma ir antra dalis daugmaz gali 
> keistis, bet kokios protingos ribos? 

Tik siaip smalsu, kas blogai su 225/45/R19? 
Alternatyvos is tech. puses ar kokias finansiniais sumetimais?

Trumpai - 7,0" - Min 195, Ideal 205 or 215, Max 225 
 
215/45/R19 -1,3% 
205*/45R19 -2.6 %
205*/50R19 +0.4 %
195*/50R19 -1.0 %

* - Qashqai nedeklaruoja tokiu siauru padangu kaip zjbs net su R16..
https://www.wheel-size.com/size/nissan/qashqai/2015/

Pvz.: https://www.wheel-size.com/calc/?wheel1=225-45-19X7ET40&wheel2=205-50-19X7ET40

******************

Ilga versija:

Koks ratlankio plotis? .. pagal ji gaunasi pora dydziu (plocio) OK .. ir pora ant ribos
http://www.tyresizecalculator.com/charts/tire-width-for-a-wheel-rim-size-chart
Tipo 8,0" 225 gali keist i 235 .. jei 7,5" - 225 gali keist i 215 

https://www.wheel-size.com/calc/

 Plus Sizing  - 19 " minus zero

225/45R19 x 7,5"

235/40R19 x 8 = -2.1 % << geriau ant 8", nes 7,5" ribinis
235/45R19 x 8 = +1.4 %

 Minus Sizing - 19 " minus zero

215/45R19 x 7.5 = -1.3 %

O kad Nissan Qashqai 2015, tai:
https://www.wheel-size.com/size/nissan/qashqai/2015/

215/45R19 7Jx19 ET40 5x114.3  
225/45ZR19 92W 7Jx19 ET40 5x114.3 

Pagal kalkuliatorius 215 plotis geriau dera prie 7,0" ratlankio
7,0" - Min 195, Ideal 205 or 215, Max 225 

https://www.wheel-size.com/calc/?wheel1=225-45-19X7ET40&wheel2=215-45-19X7ET40 

Overall Diameter  685 mm vs 676 mm -1.3%

**************

Tokie skaiciavimai sako, kad nx ir dar karta nx .. 
geriau det, tai ka gamintojas numate, nes treciakart nx.