Wrong offset - how serious?

[mattday]

From reading the posts here, I think I now understand wheel/tyre sizes, offsets etc - my thanks to the forum regulars 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

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!

[THEOLDMAN]

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.

[CivicSiRacer]

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.

[mattday]

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).

[CivicSiRacer]

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