R46Yam Posted June 18, 2020 Share Posted June 18, 2020 Good evening all, I'm new to Audi and new to the forum so firstly hello to all. I find myself here, hopefully like many other members before me looking for advice and guidance. I have an '08 Q7 3.0TDI which when bought already had 22" wheels fitted, I'm considering changing these for 21" wheels. After looking in to this I'm stumped and trying to work out best tyre size for correct wheel rim width and offset. It isn't helped because I've read somewhere that the 9.5J rim currently fitted may be considered too small for the 285 tyre fitted. The ET of the current wheel is 48. I'd really appreciate it if someone could point me in the right direction for a 21" wheel rim width and offset suitable for the correct tyre that keeps my speedo as true as possible. Apologies if this post is in the wrong area. Many Thanks in advance Quote Link to comment Share on other sites More sharing options...
Magnet Posted June 19, 2020 Share Posted June 19, 2020 Hello Glyn, Re tyres sizes, it’s a maths thing where you work out the increased tyre profile you will need to ensure outside diameter the smaller wheels (and greater rubber) matches as close as possible, the OD current set up. Kind regards, Gareth. Quote Link to comment Share on other sites More sharing options...
R46Yam Posted June 19, 2020 Author Share Posted June 19, 2020 I understand the tyre sizing as in finding the correct rolling diameter. My query relates to whether the existing setup is correct according to the original spec. I would also appreciate finding out the original rim width for cars fitted with the 21" rim. Quote Link to comment Share on other sites More sharing options...
Obasa Posted June 19, 2020 Share Posted June 19, 2020 Hello and welcome. 😀 I am wondering why you want to drop down from 22" to 21"? Quote Link to comment Share on other sites More sharing options...
Magnet Posted June 19, 2020 Share Posted June 19, 2020 Thanks Glyn. Perhaps stating the current tyre sizes in a simple comprehensive form may assist others to respond whether theirs are the same as yours. Quote Link to comment Share on other sites More sharing options...
R46Yam Posted June 19, 2020 Author Share Posted June 19, 2020 5 hours ago, Obasa said: Hello and welcome. 😀 I am wondering why you want to drop down from 22" to 21"? Biggest thing for me is that the current 22" rims are only 9.5J with a 285/35 tyre. I've read somewhere that this size tyre is too wide for that rim. If I go for a wider rim 10j x 22, it'll be a big cost plus the new 22" tyres every 3-6 months. If I go for 21" inch rims I'd get a 10j which will take 295/35 tyres, these are cheaper to replace. It unsettle me to think the 9.5J are too narrow for that tyre, I bought the car to carry my family. I'd rather invest in a correct width 21" rim than lay out even more for a new set of 22's. Quote Link to comment Share on other sites More sharing options...
R46Yam Posted June 19, 2020 Author Share Posted June 19, 2020 (edited) On 6/19/2020 at 5:29 PM, Magnet said: Thanks Glyn. Perhaps stating the current tyre sizes in a simple comprehensive form may assist others to respond whether theirs are the same as yours. I have an '08 Q7 3.0TDI which when bought already had 22" wheels fitted, I'm considering changing these for 21" wheels. After looking in to this I'm stumped and trying to work out best tyre size for correct wheel rim width and offset. It isn't helped because I've read somewhere that the 9.5J rim currently fitted may be considered too small for the 285 tyre fitted. The ET of the current wheel is 48. I'd really appreciate it if someone could point me in the right direction for a 21" wheel rim width and offset suitable for the correct tyre that keeps my speedo as true as possible. Tyres have a 35 profile Edited June 21, 2020 by Trevor Moderator edited post to maintain flow of thread Quote Link to comment Share on other sites More sharing options...
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