Wrong offset - how serious?

From reading the posts here, I think I now understand wheel/tyre sizes, offsets etc - my thanks to the forum regulars :biggrin: However, I have a problem: when I bought my wheels, I was more ignorant, and I trusted the retailer to get it right. I will try not to go into (too much) unecessary detail - my car is a 95 Civic Coupe (EJ2) which came with 175/70-R13s, and I wanted to fit some 15" rims with 195/50-R15 tyres. I found a wheel/tyre package that I liked the look of, was cheap enough, and came with brand name tyres instead of the usual questionable quality rubber.

I knew the wheels were wider than stock, and it turned out that they were 7" compared to 5". When I fitted them to my car, they kinda stuck out quite a lot, which I thought was OK at first, but I soon decided it looked a bit wrong. The wheels stuck out about as much as the tops of the wheel arches (hence questionably legal). Anyway, according to the posts I have read on this forum (mainly those of CivicSiRacer) 7" should be fine on the Civic, but the offset should be 42mm for this size (at least for a 6th gen Civic, but I suspect this also applies to the 5th gen???). So, I checked my wheels, and they had a 35mm offset :uhoh:

Now, I don't have any problems with the look of the these wheels, other than thinking they should be tucked under the arches more, but what I really want to know is the severity of this offset error (35mm compared to 42mm)...

- Would this totally screw up handling?
- Would this put a serious strain on wheel bearings/suspension/etc?
- Was the retailer wrong to supply these wheels with a 35mm offset?

I only used the car a couple of times before deciding to take the new wheels off (I just didn't want to drive on them if they were wrong). From the two short journeys I made, I can't really comment on the handling, other than to say it was different, and I may have noticed some kick through the steering on tight turns (but can't really remember).

Thanks in anticipation!

Here is a wheel offset calculator:

http://toy4two.home.mindspring.com/offset.html

The offset of the wheels should be stamped into the back of one of the spokes.
The offset changes as the wheel gets wider also. If you can get a copy of April 2004 Grassroots Motorsports Magazine they have an article about offsets, scrub radius and steering axis inclination. The article starts on page 167.

Yes the retailer was wrong in ordering you that offset. Goes to show you should never trust anyone with car mods. Everyone is an idiot.

For a 15x7" wheel you need a 42-44mm offset with 205/50x15" tires. Your 195/50x15" tires are ok, but a 7" wide rim should be using a 205 width tire.

Thanks guys, I will get on to the retarded retailer (but won't be holding my breath).

@THEOLDMAN:

Thanks for the link. The Grassroots article sounds interesting, but I think it's just too much trouble to get hold of here in the UK.

@CivicSiRacer

Thanks for confirming my suspicions, although I had no idea the tyre size was also sub-optimal. So is there a general rule that tyre width should be about 1" wider than wheel width? (In which case the 195 section tyres would be good for 6.5" wide rims, which is what I should have bought in the first place).

There is a range.

Like my OEM Si wheels (15x6") come with 195/55x15". See the list below the middle is the more appropriate tire width. Where the others will fit the rim.

5.5" rims: 175 185 195
6" rims: 185 195 205
6.5" rims: 195 205 215
7" rims: 205 215 225