Measuring a flay hyvo type belt how?

[lynall]

I am after a spare belt for the my engine, its the flat hyvo type style, no problems at all with the current one, but I would like a spare.
I have measured the outside of the belt and come up with 2315mm but dont know if they are measured internally or what, all the belt sites I have looked at come up with 2235 and 2330, so I really need to know if either one of these is correct?
I have managed to suss its a K section belt with 6 grooves so 6PK

 

[RichardS]

If it's measured like a V-belt look for Li = internal length, La = external length or Lw = nominal length = somewhere between Li and La depending on belt profile.

One or more of these measures will be quoted in the belt suppliers specification so you at least know what you're looking for. As can might surmise, I learned the hard way that a 925mm belt is the same as a 990mm belt depending upon who manufactures it!

Richard

 

[lynall]

Richard thanks for that, its a volvo penta belt with only a vp part no on it, now being a mech I know vp dont make belts so with some effort I can source one for better price and post it up as there does seem to be very little info on some of the parts.
The bit Im struggling with is the outside of the belt wone be the length I need , flat belts are normally size as for example 6pk2315, meaning 6 ribs, k section 3.56 mm centres, but its the length Im struggling with.

 

[Plevier]

It's the effective length which is about 15mm more than the ID (2*pi*groove depth of 2.5mm) for a pk.
Yes I fell into this trap recently.
On that length belt 15mm is within adjusdtmrnt range isn't it?
My belt is only 755mm (from memory) D1-30

Never heard of hyvo - to me it's a poly vee.

Edit - pk section is 4.6mm thick so I reckon you need about 2300-2305. Doesn't seem to be a standard.

 

[cryan]

When it comes to belts I usually refer people to Brammer.
www.brammer.co.uk Their belt catalogue has measurements and conversion details.