Locovolataic
New Member
Gonna start by saying I'm a complete beginner when it comes to wheels and tyres, so please do correct me as I honestly find this whole topic a bit mad!
So, I believe a T5 with OEM wheels has a rolling diameter of 27". I was reading somewhere that if you change your wheels and / or tyres, then try to stay within 3% of this number to avoid messing up the vehicles speedo and possibly safety systems.
My 2008 T5 currently has the 17" Davenport alloys and some budget 215/60R17 tyres. I've been mathing and this gives me a rolling diameter of 27.2".
However, I want to put on some 235/65R17 tyres which would bump my rolling diameter up to 29" which is outside this 3% range.
So a few questions:
So, I believe a T5 with OEM wheels has a rolling diameter of 27". I was reading somewhere that if you change your wheels and / or tyres, then try to stay within 3% of this number to avoid messing up the vehicles speedo and possibly safety systems.
My 2008 T5 currently has the 17" Davenport alloys and some budget 215/60R17 tyres. I've been mathing and this gives me a rolling diameter of 27.2".
However, I want to put on some 235/65R17 tyres which would bump my rolling diameter up to 29" which is outside this 3% range.
So a few questions:
- What are going to be the effects of changing to a tyre by this much? Other than the speedo (which I can live with), will any other systems be affected? Bearing in mind this is a 2008 van, I'm not sure what "systems" it has to start with.
- Based on the above is there anything I can do to "fix" anything that is affected?
- I had a friend recently who's Transporter failed its MOT due to alloys, I thinkg they were 20". I've been meaning to ask him more about it, but haven't seen him yet. Just wondering if an increase like this would cause an MOT fail?
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