Omega Owners Forum

Omega Help Area => Omega General Help => Topic started by: DC on 25 February 2008, 21:54:56

Title: tyres/wheels - at the risk of being crusified
Post by: DC on 25 February 2008, 21:54:56: Hi everyone!
My Omega is on its winter rims/tyres right now, but am not sure if my summer set will manage to last me whole season once I put them on (FYI, 225/55 Michelin Primacy HP on AEZ Paron 16 inch rims). I have a chance to get cheaply a set of 17inch Stilauto Ghiblis with almost new Dunlop SP9000s in size 245/45,but have not seen anyone on the forum actually using this size. It seems like everyone on 17inch rims has 235/45, so my question is shall I consider them or not? It would also be nice if any resident expert could write a word or two on the topic of ET. The rims I just mentioned come from Vectra, dont know which one.

Thanks
Title: Re: tyres/wheels - at the risk of being crusified
Post by: markey mark on 25 February 2008, 22:20:37: they will be fine matey only 10mm wider could make your speedo slighty high !! :y
Title: Re: tyres/wheels - at the risk of being crusified
Post by: Kevin Wood on 26 February 2008, 11:59:18: The Offset might be more of a problem though. :-/

Do you know what offset they are against what you currently have?

Kevin
Title: Re: tyres/wheels - at the risk of being crusified
Post by: The Doctor on 26 February 2008, 19:41:23: Quote
they will be fine matey only 10mm wider could make your speedo slighty high !! :y

Bigger diameter wheels will make the speedo read a tad low, and your actual speed will be a little higher.
Title: Re: tyres/wheels - at the risk of being crusified
Post by: hotel21 on 26 February 2008, 19:45:17: Lots of wheel/tyre info here (http://www.carbibles.com/tyre_bible_pg2.html) including a replacement tyre size calculator which gives your percentage error......
Title: Re: tyres/wheels - at the risk of being crusified
Post by: DC on 26 February 2008, 21:43:55: thanks everyone for the answers. I have had a look at various sites before posting and found that 225/55R16 and 245/45R17 are practicly the same diameter. I am more worried about the ET (offset). All I know is that 17inch rims are from a Vectra but the question is which one. The current Vectra uses rims with offset of something like 42. My 16inch rims are either 35 or 38mm (cant remeber), both of them being OK on Omega, but I am wandering how big offset can I have on 17inch rims and still be on safe side. Will offset affect wheel geometry in any way? Also, does anyone know what was recomended offset for Vectra I?
Title: Re: tyres/wheels - at the risk of being crusified
Post by: Tricky on 27 February 2008, 01:42:35: I wouldn't want to go any lower than et38. You run the risk of being very close to the coil springs after this. Go the lowest offset you can. I'm working on some et13's at the mo...:D
Title: Re: tyres/wheels - at the risk of being crusified
Post by: Minispud on 28 February 2008, 22:12:46: Vauxhall's front wheel drive cars are all 49mm offset, if I remember right, that is if Vauxhall has not change it ::)