Defining a V belt

[Theo]

Theodora has a triple drive belt from the gearbox to the prop shaft.  I have jsut replaced it with the spares that I keep on the boat and now need to buy a new set.  Trouble is there is no legible code on either the old set or the new set.  So what do I ask for?

 

I would imagine that I would cut oneof the old belts so that I can measure its length accurately and measure the width of the pulley groove.  Will that be enough information to give to the supplier?

 

They are a bit of a sweat to replace.  What do you think of the PowerTwist belts? Being able to "break" the belt would save my having to unbolt one of the Plummer blocks.

 

N

 

 

[Tracy D'arth]

1 hour ago, Theo said:

Theodora has a triple drive belt from the gearbox to the prop shaft.  I have jsut replaced it with the spares that I keep on the boat and now need to buy a new set.  Trouble is there is no legible code on either the old set or the new set.  So what do I ask for?

 

I would imagine that I would cut oneof the old belts so that I can measure its length accurately and measure the width of the pulley groove.  Will that be enough information to give to the supplier?

 

They are a bit of a sweat to replace.  What do you think of the PowerTwist belts? Being able to "break" the belt would save my having to unbolt one of the Plummer blocks.

 

N

 

 

No need to cut one. Measure the outside with a piece of string.  And the width.  The belt store will be able to work out the size.

[David Mack]

Plenty of belt supplier sites online to help work out what belt you need e.g. https://bearingtech.co.uk/pages/belt-identifier

(Other sites are available).

[BEngo]

Just take one of the old set into somewhere like a local branch of Eriks ( was Fenners)  or a bearing supplier and they will have a widget for measuring them.  Then order a set of three.   Ordering a set means they should match the belts so they are all in the middle of the tolerances. Ask for good ones, like Gates, or Continental.

 

Mind you ,  modern manufacturing is such that any old three the same nominal size will probably be close enough.

 

N

[adrianh]

Unless things have changed link belts are not really suitable for a multi belt drive.

My experience of them industrially was a 'quick fix' then having to remove links frequently as the belts stretched.

On a multi belt drive belt wear and tension is critical to share the drive load equally between the 3 belts, this would be very difficult to achieve.

I would expect a very short and troublesome life with this type of belt.

If you are buying a set of 3 belts you need to ask the supplier for a matched set so that technically the all have the same circumference, if not you can get 1 or 2 that will run loose and slap about.

Cutting a belt and then measuring is the best you can do but you have to take of an allowance for stretch due to usage.

Old style belts generally went up in 1 inch increments, ie might be marked B40 or C40 for instance. The top width of the grooves on the pulley usually define the belt type.

Lastly avoid cheap makes

[Theo]

Thanks all.  Lots of useful advice there.

 

N

[matty40s]

5 hours ago, Theo said:

 

I would imagine that I would cut 

They are a bit of a sweat to replace.  What do you think of the PowerTwist belts

These are basically a get you home, nylon tights kind of replacement Nick, we have these on our dock pumps, but it takes seconds to remove a link when they stretch too much, and seconds to add a link to replace a broken one...not something you would want on a boat...on a river....

We use simplybearings for almost all our belts nowadays, you need internal and external lengths if poss, and width...of original belt, it may be different to what is left on your boat!

[Theo]

Thanks, Matty.  Are Simply bearings local to you or online?

 

Nick