Citroen XM Forum

Hopefully the combination of messing around with things will work, there is nothing left to fiddle with.
This latest belt has a kind of felt texture to it though.

Photo to follow.

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Solid belt to the left, then Gates, then the Dunlop one Will put the link up for.
IMG_3495 by Deanxm, on Flickr

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The outer two look as if they will have a lot more contact with the V-sides.

Ironically, solid belts don't grip as well as toothed ones, but do have a greater contact area. That Dunlop one appears to be best of both worlds, heavy duty and toothed.

In comparisonm the Gates one looks puny. I've just fitted a Gates one to my car...I thought it looked a bit more meaty than that one, though. I'll get hte p/n tomorrow. It's raining now.

Daft thought, but is there any scope for getting more wrap-around on the pump pulley - with a longer belt and an idler?
I'm not familiar with the belt layout.
And, is it definitely the pump pulley that is slipping/wearing the belt, and not the other one?

A strobe light would confirm exactly what's slipping and what's not. Bit of disco gear (variable frequency)?

It's a really simple belt run and at idle you can see which pulley is slipping. In my experience it's the pump pulley that slips as due to applying the roational drive, the drive pulley grips the belt, but then causes slackness at the pump, so the belt then slips.

Yes solid belts do transmit less max torque but are supposed to be better at surviving slip.
The gates in the middle is a 6208MC It was the original belt that started slipping but was too long and i ran out of travel on the pump tensioner bracket.

The solid Challenge belt has the most taper, the New Dunlop has very little taper, the Gates is about half way between the two, the Dunlop is very square in its cross section profile.
The Dunlop also sits very high in the pulley, this will work to give a better leverage over the pump pulley and greater contact area, the pump pulley being the smaller one is where the slip occurs, it offers the lower friction of the two pulleys.

Fingers crossed

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I know this is obvious, but if the belt taper (side angle) doesn't match the pulley angle, grip will be limited and the belt will wear rapidly, and slacken as it does so. Belt length, width and thickness is only 3/4 of the story, at most. Time to measure the pulley angle?

I feel a real heel suggesting this, but it's basic stuff.

What are the two pulley outer diameters, Dean?

Quite right, Chris, i prefer the element of chance though

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As said, the pulley taper will be important, however, in my experience, having the belt sitting right on the outer circumferance of the pulley is the best mthod of ensuring long term reliability with very slow wear.

I'm sure that once the pelt wears and drops below the outer circumferance of the pulley, the angle of v is irrelevant, as the belt has already worn to whatever angle the pulley is.