VW accessory belt size question

[ChrisTyas]

Hi,
VW belt sizes detailed in ETKA etc (e.g. 12.5mm x 950mm), is the belt length detailed (950mm in this case) the inner length or the outer length?
Thanks,
Chris.

[TwinTurbo]

I have been through 10 belts trying to solve a conundrum on a custom install.. And never worked out the sizing question... for me 5mm length difference would make all the difference of breing able to fit the belt and the alternator then hiiting the steerign column. 

But 950 Inner vs 950 Outer in the Flat Four install is going to amount to very little. the amount of adjustment in the alternator is vastly greater than that very little. 

Have you not got a belt on with markings already? 

 

[ZsZ]

They are La (outer perimeter) sizes

Probably does not matter on long petrol belts, but the diffedence is PITA on the short two belt diesel ones

[ChrisTyas]

Being honest, this question (whilst relevant for my T25 and everything else VAG) is for the Golf - I have an '89 mk2 GTI with factory air conditioning which has power steering belt (crank, water pump, power steering pump), main belt (crank, water pump, A/C compressor) and alternator belt (A/C compressor, alternator).
I have no confidence that the belts it had on when I bought it (ten years ago) were original or correct length, I always try to go back to OE/ETKA but 1. belt lengths in ETKA are difficult to discern especially for a rare model and 2. the 12.5 x 950 main it seems to indicate is incredibly tight (almost impossible to get on) with adjustment at minimum on A/C compressor.
The question is because some belt suppliers sell them quoting inner length and some outer length (and some in inches..).
I want to work out appropriate sizes for the main and alternator that leave have them close to the minimum adjustment when new but don't need a crowbar to get on the pulleys..
Chris.

[ChrisTyas]

I have been through 10 belts trying to solve a conundrum on a custom install.. And never worked out the sizing question... for me 5mm length difference would make all the difference of breing able to fit the belt and the alternator then hiiting the steerign column. 

But 950 Inner vs 950 Outer in the Flat Four install is going to amount to very little. the amount of adjustment in the alternator is vastly greater than that very little. 

Have you not got a belt on with markings already? 

950mm inner circumference is 302.4mm inner diameter and 1012.85mm outer circumference (allowing 10mm for belt height)
950mm outer circumference is 282.4mm inner diameter and 887.15mm inner circumference (allowing 10mm for belt height)
or:
Inner        Outer          Diameter
950          1012.85       302.4
887.15      950             282.4

As you say, on the WBX wouldn't make any difference but makes quite a difference on the Golf and the main belt adjustment alters the alternator adjustment as they're compounded.

Chris.

 

[Aidan]

Etos says 068 260 849 G 12.5 x 947LA is the v belt for air con 1989 Golf

13x950 seems to be what everyone sells now instead

[ZsZ]

Unfortunately part cross-references are really bad