problem with offset on alloys

[classicsl]

Before i go any further i admit that this problem is all of my making for not doing enough research. bought some lovely used lorinser deep dish alloys fitted with yokohama tyres for my 107 sl. Replacing 205/65/15 with 205/55/17 so knew were correct size and seller (from ebay but auction ended so purhcased privately) from a guy who had previously had them on a 107. went to fit today and real problemn with offset, it seems the new wheels have an offset of 11, whereas the original 15 hole 15 inch wheels are 25. The new ones catch on the brake caliper when fitted on and will not rotate freely as a result. is it right that spacers can be used to rectify this or am i better off selling the wheels on and cutting my losses?

any advice would be much appreciated

thanks

tim

 

[talbir]

Firstly, it is impossible for anyone to evaluate this without knowing the width of the wheels - offsets mean NOTHING without taking into account the width of the wheel.

Secondly, the lower the ET number, the further the wheel centre will be from the hub. Offset is the distance from the centre line to the hub centre on the wheel. So an ET of 25 means that the hub mating plate on the wheel is exactly 25 mm behind the centre line of the wheel. Imagine a cross-section of the wheel and draw a line from the centre point down, i.e. if wheel is 8 inches wide, then draw a line down at 4 inches. Then exactly 25mm to the right (if the wheel is facing to the right), will be the centre hub of the wheel.

So an offset of 11 will mean the centre piece of the wheel sits FURTHER away from the hub, than a wheel which has ET 25 - IF and ONLY IF the wheels are the same width. A second condition is the shape of the centre piece - some wheels have centre pieces which curve away outwards, some have flat centre pieces (i.e. BBS RS wheels). IT is these wheels which can give caliper clearance problems.

I am guessing the Lorinser wheels you have are 8 inch width. ET 11 with 8 inch wide wheels is a perfect fitment for the 107SL BUT it depends on the design of the centre piece of the wheel. I am guessing the cnetre piece is flat if it rubbing the caliper.

The wheels that AMG designed in the 80's for the 107 SL were 8 inch with ET 11. On those the centre peice curve outwards.

I am guessing it is only the fronts which are rubbing as the fronts have big calipers. How much is it catching ? If it works with a minimal spacer, i.e. 3 or 5mm then fine. If still not, then don't bother. If you plan to run bigger than 5mm spacers in the front you need to find hubcentric spacers that are approved for front usage (crucial for insurance purposes as insurance will invalidate policy if spacers are not approved for front usage). Also, if running 8 inch wheels with ET 11, then a spacer of 10mm wll give you a net offset of ET 1 , in which case the wheels will stick out further than the wheel arch. A possible MOT failure.

Also, try fitting the wheel to the other side of the car. Does the same thing happen ? If it works on the other side, then you may have a faulty stub axle on the side that is rubbing on rotation.

Need to know width of wheels and whether it rubs on the rears and on both sided of the car at the front. If it is just touching, then a minimal spacer will do the trick.


talbir

 

[talbir]

From the width of tyres, 205, it would seem they are 7 inch wide ?

Never heard of 7 inch Lorinsers for the R107 though.

 

[classicsl]

hi talbir and thanks for the reply.

i have only tried the front offside wheel and as the tyres on them are directional i didnt see the point in trying it on the other side. although the rim doesnt seem to be catching to hard on the caliper when you push it on, when the bolts are tightened the wheel will not rotate at all, i would not want to use anymore than a 5mm spacer for safety. I will try and take some photos tomorrow. The inside of the wheel does curve away, but it seems the extreme outside of this is catching as the hub is some distance from the inside edge.

not very technically informed so apologies for my lack of knowledge on the basics of offset and thanks for explanation

 

[Myros]

spacers

I can recommend the Eibach spacers if you do go for that option. Search for them on the internet, or through the tuning accessory retailers. Not cheap, but beautifully made and just the job.

 

[Myros]

Bolts

I forgot, you'll also need to source longer wheel bolts. The merc standard alloy bolts don't grab much thread anyway, so you need to be looking at bolts that are longer by however thick your spacers are.
I got some from Performance Alloys in Northern Ireland.
They cost about the same as bolts from MB anyway.
You're looking at 17mm head, radius seat, 40mm long(plus spacer thickness) 12.5mm diameter, 1.5mm thread pitch.

Good luck

 

[classicsl]

thanks myros. These wheels are turning into a bit of a pain but i hope will be worth it. i have managed to get hold of a set of 50mm bolts and some nice matching locking ones. Got the car booked into a wheel specialist to see if they can find a suitable spacer and managed to find a company online who ususally only supplies to trade but has agreed to provide hubcentric spacers at trade price.

 

[Myros]

spacers

I got my Eibachs, with all the certificates and TUV tests you need, from performanceparts ( I'll find them if you like) in Scotland. They cost £130 ish for four ( I got 15mm ones), but there was two-week lead-in. If yours are cheaper, go ahead, if not, get searching the interweb.
Be careful with the longer bolts, as you might need to grind a bit off to clear the backplate/brake mechanisms. Some inferential measuring is required. Just rememeber that if you tighten the bolts up and they foul, each full turn you have to back them off is 1.5mm to grind off.