[semiretired]

My "E" currently has rim & offset of 6.5 x 15 ET 48
I bought a set of Lorinser RS1 8 x 17 ET 38 with 7mm spacers.

I put one of the Lorinsers on the mighty "E" today and the tire sticks out a few too many millimeters from the edge of the front fender.

So now I'm looking at new tires, but what size will fit in just flush with the fender?
Is there a website that has a self help calculator for such a thing?
Am I at the mercy of the tire dealer to tell me what tire he has in stock that will fit?

 

[ettienne]

I found this link somewhere (in the roadster forum, I think) Alloy Wheels Direct Ltd | Fitting Chart Index
Its a chart telling you what size wheels may fit your car, or what type of mods needs be done to make them fit.

I assume you found an offset calculator by now. Googling for rim offset calculator brings up tons.

Curiously enough this link states that an 8" ET30 rim should fit the W124 without any modifications. Not sure why you are running into issues here.

Have you resolved this in the mean time? How did you manage?

Remember that the offset is measured from the center of the rim towards the outside. If your car needs a 48mm offset on a 6.5" wide rim, then when fitting an 8" rim it means that the rim is 1.5" wider in total, i.e. 38mm, i.e. 19mm from the center towards the outside and 19mm from the center towards the inside of the rim.

Measuring the distance from the mounting surface to either edge of the wheel as follow: 6.5" rim = 162.5mm wide. Center at 81.25mm from either edge. 81.25 + 48 = 129.25mm from center to inside. 81.25 - 48 = 33.25mm from center towards outside.

Similarly the 8" rim measures 138mm from center towards inside and 62mm from center towards outside. Add to that the 7mm spacer and the measurements become 131mm and 69mm. So the outside moved closer to the fender by 35.75mm.