Technical Wheel Arch Rub - More to it than meets the eye

[Pete145]

Hi all,

This became a bit of a sub-thread in a previous thread relating to an oil change issue that I had last week.

I have 12" alloy wheels on the car, replicas of the original Abarth wheels, but this is causing an issue of tyre rub on the very front of the left hand wheel arch (when I'm turn right).

You can visibly see that the clearance between the tyre and the front of the wing's arch is very tight at that point (not enough to put a finger in-between them).

Before modifying body work the advice so far has been to check the alignment/camber/toe in etc, and also consider changing the tyres to a smaller size (at the moment they're 145/70xR12, maybe drop down to a 60).

There's a tyre place near to where I live that has a classic 500 on the forecourt most days. It belongs to the owner, so I drove mine in today for him to take a look.

We've managed to discount toe-in and alignment, but on further inspection we noticed that I'm also getting rub on the BACK of the wheel arch on the right hand side.

So, if we pause to consider that for a moment:

1 - Rub on the FRONT of the left hand wing.
2 - Rub on the BACK of the inside of the right hand arch.

You don't have to be Einstein to figure out that the wheels are sitting at an angle on the springs. The left front wheel is too far forward and the right front wheel is too far back. Once you get your head around that you can actually see it quite clearly when you look at the position of the wheels within their respective arches.

Any ideas on how to fix that? It's certainly beyond my grease monkey capabilities, and the Fiat 500 owner at the tyre place suggested that even they don't have the equipment to fix this.

Thoughts?

 

[Franko500]

Hmmm, my first idea would be to place vehicle on flat ground, pump tyres up to correct pressures, turn steering to straight position and roll car back and forth to get f/wheels pointing in forward direction.
Then measure from wheel centres front to rear on both sides.
This will give you an indication what is wrong & by how much.
You could slacken the clamps off which hold the spring in place to see if there is any adjustment. But chances are you have worn joints/bushes.
There is a rubber that holds the spring in place, these could be worn, check for play ie.try pushing the spring back & forth to see if it moves easy.
Or you may have movement in the top or bottom joints. You only need 0.5mm play in 2 joints and you have an issue!
Worst ways is the vehicle could have had a shunt or if it has had major replacement panels ie sills & floors then the lower cross member could have moved. you can check this by measuring each side from the studs to a bolt that holds the rear arms in place.
But my money is probably worn bushes. Change them all and then you know everything is good. Then remeasure.

Hope this helps

 

[fiat500]

Pete, I wouldn't jump to conclusions about the relationship between the two instances of rubbing. These cars mostly seem to have had a lot of replacement panels over the years and with the vagaries of panel quality and of the people who replace them, it's quite possible that the careful use of panel beating hammers could give the right clearance. This is dependent on tyre wear and handling being OK. I would have thought there are places out there that could accurately check all your suspension angles against spec.
I would certainly look closely at all the bushes as Sean says; add kingpins to that.
The front spring may not be standard and I have always wondered how some owners are able to reverse the main leaf and remove some. Maybe yours has that situation too?

 

[Pete145]

OK, I took this to a local classic car body specialist who claimed to know the 500 pretty well.

He had the car for a day or so to assess it and concluded that there are no mechanical issues with the car, other than the fact that the wheels and tyres that are fitted to the car are really too big for the arches.

Given that he's managed to grind a little away on the inside of the right arch (it was catching on a seem) and also peel the front of the left arch over a little more to give it about 10mm more space.

In short, this has seemingly fixed it and I now have enough clearance.