Mower Belt Buyer's Guide
It is not always straight forward to work out which mower belt is right for your mower. In this guide, we will look at some of the key factors that you need to be aware of, in order to help you to find the right belt for your mower and application.
V-Belts are typically measured in 1" increments, however manufacturers measure their belts differently. Some manufacturers measure on the external circumference whilst other manufacturers measure their belts on the internal circumference. This does not make it fun or easy for the consumer who may not be aware of this factor.
Some manufacturers note how their belts are measured by offering this information after the belt size. For example, 'Li' notes that the belt is measured by 'Length Inside', whilst 'La' notes the belt to be measured by "Length Outside". Please note though that many manufacturers do not give you this information at all and quite a bit of research is needed if you do not have a belt measurer on hand. So going by a size noted on your V-belt may not always give you the information that you require in order to accurately purchase a new belt. Another aspect to be aware of is the type of belt that you need.
Mowers use a combination of both Standard V-belts and Power-rated Kevlar® V-belts. You will absolutely need to know the type of belt that you are trying to replace.
Most mower decks require a power-rated Kevlar® V-belt because of the environment it must endure. Power-rated Kevlar® V-belts are able to turn back on themselves where standard V-belts are not. Some deck belts are quite fine with a standard belt eg. Some Greenfield and Victa mowers.
Kevlar® V-belts, also known as power-rated and Aramid V-belts are both wrapped and corded in order to strengthen them. They come in a variety of colours including blue, green and black. A black Kevlar® V-belt typically lacks the luster that a standard black V-belt has, so you can tell them apart if you know what to look for.
Kevlar® V-belts can cost around 3 times the price of a standard V-belt, but you will more than likely get more than that out of them. You can run a Kelvar® V-Belt in place of a standard V-belt but needless to say, if you run a standard V-belt in an environment that requires a Kevlar® application, it is likely to last between 2 hours and 1 week, tops. It is simply the incorrect belt for that application.
Most mowers use standard V-belts as a drive, transmission or primary belt, but there are many mowers that still require a Kevlar® application. It is vital to know what type of belt your mower needs for the application you are using it for. Some Manufacturers note their Kevlar® V-belts with a 'K' in their sizing eg A103K. Unfortunately, not all Manufactuers offer this detail. So consumers need to be aware.
Another aspect to be aware of is profile. The most common profiles are "A" and "B" section. There are numerous V-belt profiles, but these are the main ones. Some mowers require an "M" section V-belt which are also known as a "Z" section V-belt. As you can see by the image below, the profile relates to the sizing and angle of the V-belt.
A section: (mm) 12.5 or (inches) 1/2"
B section: (mm) 15.8 or (inches) 5/8"
M section: (mm) 10 or (inches) 3/8"
The most accurate way to ensure you get the correct size and type of belt is by obtaining your manufacturers part#, otherwise known as the OEM# (Original Equipment Manufacturers) number. This will ensure that your belt is accurately cross-referenced. IF, like most of us, you no longer have your Operators Manual, manufacturers have generally uploaded them online.
Sometimes, Make/Model/Year and deck size will also prove fruitful, however it is not as accurate as having the OEM# as there can still be variants. Please note that using ONLY your model# will NOT accurately lead you to the correct belt you are after. This is because there are varying deck sizes relating to the same model#. Some mowers like MTDs can have over 20 varying possibilities and you absolutely need to have further information in order to pinpoint the belt you require.
If you are unable to locate your manufacturer's part# or any other vital information as noted above all is not lost. Your next best thing to do is take your old belt into your local Bearing shop to be measured and matched. Moving forward, you will know exactly what to purchase next time. If you don't have your old belt, obtain a piece of string and wind it around your pulley/s in order to obtain the length and also take this to your bearing shop. Please note that the latter will still not give you the type of belt you need, so there still could be some inaccuracies. Doing this through your local Bearing shop will save you the back and forth postage costs in order to accuartely acquire what you need. Moving forward you will know what to purchase online.