wheel on auxiliary belt tensioner V6

[cc]

The auxiliary belt adjustable tensioner (ie the spring loaded component that maintains belt tension) on my 2002 156 is probably the original part. The wheel has a wide groove about 0.1mm worn into it by the belt and has some noise.
A friend thought it had another year left in it but am going to update it (have replaced the the 2 other wheels).

The spring loading part is still quite strong/powerful. Am thinking of not replacing the whole component, just the wheel. Its diameter is 80mm which is the same diameter as the fixed tensioner wheel next to the alternator. Th wheel is approx  1/3 the price of a complete tensioner.

Interestingly the engine has about 3 hours on it since replacing the t/belt, t/belt tensioner and the aux belt as discussed above. The aux belt is showing some signs of rubbing on its side walls.