So further to this I ordered a pair of Optibelt super xe-power pro XPB 1320 belts. I chose the toothed ones as the alternator pulley is quite small diameter.

Anyhow after a few hours running the teeth are flying off. I have checked the tension which could have been on the tight side, but not excessive enough. on close inspection it appears that the taper on the pulleys is different to the belts the belts taper in more sharply than the pulley so that the surface in contact with the pulley is only the top of the side of the belt.

Looking again at the optibelt website the XPB profile is the only one that is 16mm wide at the top and 13mm high. The other profile codes are for 13mm wide and 10mm. 

I also measured the depth of the pulley which is 15mm so the 13mm high XPB does not bottom out. 
I will call Optibelt tomorrow and see what they say.

Maybe I should not have gone for the toothed belts!

Any thoughts out there re toothed verses normal wedge belt and taper on pulleys?

38 degree taper comes to mind as standard but I am not sure.

Nick

Amelia back in Fiskardo Greece

AML 54-019

On 5 Jul 2019, at 08:11, ngtnewington Newington via Groups.Io <ngtnewington@...> wrote:

Hi Oliver,

I had a look at the Optibelt website  and it certainly looks very promising. I will buy a couple of pairs and we can put it to the test.

Nick

SY Amelia anchored Corfu

AML 54-019

On 4 Jul 2019, at 12:50, Oliver Henrichsen, SV Vela Nautica <oliver.henrichsen@...> wrote:

Hello,

I got same setup. 

Its mandatory to get bets matching the small pully belt disk size and that are possible to get tighten over the back.

Some lawnmower belts do that. 

I got now some OPTIBELT SUPER XE-POWER PRO M=S XPB 1320

No experiance for now, need to relaunch in few days after this refit. 

Oliver

Vela Nautica 54#39

Portugal

On Thu, Jul 4, 2019, 10:20 ngtnewington Newington via Groups.Io <ngtnewington=aol.com@groups.io> wrote:

I have a 175A 24v alternator on my 54. With twin pulley v belts.
It is the set up with the alternator to port and separate from the 12v alternator and raw water pump  belt. I know some 54’s are set up with the alternator to starboard and run off the same belt as the 12v and pump belt. Not my Amelia.
I am disappointed with the life I am getting from a matched pair, only about 100 hours. I tried to get the green stripe quality in the UK and was sold some blue belt.
The pulley grooves are for 15mm or maybe 16mm,  so that they do not bottom out. That is, so the sides of the belt grip the pulley. Which is what I used.
I have now put a pair of belts that the previous owner bought which are 13mm, but a matched pair (so it is bottoming out) as an experiment, to see how they perform.
Does anyone with my twin belt set up, recommend any particular brand and size/specs?
It would be nice to find a brand that does not shed dust and that lasts for 300 hours or more!

Nick
Amelia Corfu area
AML 54-019