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Replacement tire size question

HeatonJL

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#1
2013 Sedan, Titanium

I have the stock 195/50-16 tires on the car. I was thinking of putting on 205/45-16. Can I do that on the same rims, or would I need to replace those? I was thinking because it's only 1cm width difference that it should be ok, but I want to check before doing it.
 
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Handy Andy

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2018 Ford Fiesta SE HB
#2
Hmmm...Back in the day...they used to use 5.5" (inch) rim width. But with the 2013 I think they have been using the 6" (inch) width - so the WIDTH would be ok.

More IDEAL width would be a 6 - 1/2 in or 6.5in width rim.

It's the Offset or the "JJ" Or double J - how far the Rim "sticks out" or "goes in" - the spokes of the wheel in relation to the center line of the width axis

Not enough offset - the Tire could be ruined by either rubbing the inside or outside part of the wheel well.

So you'll need to know just how much the WIDTH the new tread may have as impact on the WIDTH of the rim itself. OEM RIMs provides a margin of safety to prevent issues, but changing width can make the RIM width an even more important issue. So if you keep the OEM Rims - 1cm is not much to worry about - it appears you did some home work as far as PERIMETER of the tire (Circumference - distance traveled per rotation).

However, hear me out...

Width from centerline of turn (the pivot point and how far-off the off-axis rotation distance offset to maintain steer angle entry and exit) the new tire size would have, it doesn't appear as an issue but the level of performance you get from the steering geometry will be affected and you may find that the car will now "fight" you as you turn.

This can make the tire rim edges wear prematurely - think of it like a differential - the outer part of the tire will scrub "ahead" (Outer portion of tire - like the outer wheel - has to turn faster so it attempts to gain speed thru distance traveled) while the inside part of the tire will tend to want to scrub "behind" generating a type of friction the tire itself will wear upon. It's why they chose the OEM size, to reduce the effects of this scrubbing yet provide the grip the tire needs in order to handle the vehicle in a turn. You often times hear it referenced in Understeer and Oversteer - this isn't the only cause of this effect, but it adds to the level of geometry you have, as references, to figure out when you go up or down in tire size.

You should be ok, but the advances in Tire tread may make the sizing issue moot, for a simple change in tread pattern will change performance. That can make a big difference.
 
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