Tyre size question

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astrafan
Posts: 33
Joined: Fri Nov 03, 2017 8:06 pm

Tyre size question

Post by astrafan » Sat May 23, 2020 3:59 pm

I have the 18 inch wheels on my Astra and have always put on tyres size 225/40/18 as standard, but is there a limit to how large you can increase the sidewall by before they stop fitting? I was wanting to have more protection against the dreadful potholes around where I live.
Also will this alter the comfort/handling and my fuel economy?
Thanks

Pompeydave
Posts: 607
Joined: Sun May 21, 2017 2:42 pm
Astra Model: Astra Sri nav VX-line 1.6t
Astra Colour: Silver

Re: Tyre size question

Post by Pompeydave » Sat May 23, 2020 4:14 pm

I'm a member of the 'seat' owners club as previously had a Leon and they seem to be against swopping and changing tyre sizes around. Handling , comfort , true speedo will all change when messing with tyre sizes.Thats not to say it can't be done as many on the site have (similar reasons to yourself - potholes) changed to slightly higher sidewall for better comfort.
Check out a tyre and will it fit website before you start spending the £££.

astrafan
Posts: 33
Joined: Fri Nov 03, 2017 8:06 pm

Re: Tyre size question

Post by astrafan » Sat May 23, 2020 4:23 pm

Thanks for your advice Pompey, do you have the same tyres on yours? A tyre fitter once recommended I go for a larger sidewall and said that theoretically there was no limit to how big a sidewall could be, but I’m not sure how true that is?

Pompeydave
Posts: 607
Joined: Sun May 21, 2017 2:42 pm
Astra Model: Astra Sri nav VX-line 1.6t
Astra Colour: Silver

Re: Tyre size question

Post by Pompeydave » Sat May 23, 2020 4:39 pm

I assume you mean by sidewall the profile ie 40 ? I certainly wouldn't go much larger than 45 'if' it is poss .
Go too big and fouling of the arches would come into play let alone steering etc. Yes mines 225/40/18 on the vx-line.
Pressures around 33-34 .
Winter gone I went down a huge pothole that was covered by floods and the Astra stood up well to it .

astrafan
Posts: 33
Joined: Fri Nov 03, 2017 8:06 pm

Re: Tyre size question

Post by astrafan » Sat May 23, 2020 5:41 pm

Sorry yes I meant the profile (40). Sounds like I should reconsider changing the size if It’ll Impact on handling characteristics etc. Are your arches different to my SRi arches?

Pompeydave
Posts: 607
Joined: Sun May 21, 2017 2:42 pm
Astra Model: Astra Sri nav VX-line 1.6t
Astra Colour: Silver

Re: Tyre size question

Post by Pompeydave » Sun May 24, 2020 12:06 am

Same arches on the vx-line , 18" alloys as standard. Have you checked tyre pressures ?
Also tyre choice is important when it comes to comfort.

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