Washing your motorcycle is one of those tasks that you either love or hate. I fall in the latter category, yet I understand the importance of keeping my motorcycle clean to prevent corrosion and damage in the long run. So when I wash my bike, I do it because I have to and because I care for my bike.
I often use dish washing liquid to wash by motorcycle and many riders have asked whether this is safe for the bike. I didn’t consider it, but being paranoid by nature, I did some digging to find out. Here’s what I’ve found.
It is safe to wash your motorcycle with dish soap as long as you rinse off the dish washing liquid afterward. The salts in dish soap dissolve oil and grease but are not corrosive like sea salt. Washing your bike often with dish soap may require you to re-wax the paint to prevent damage.
There are many differing opinions online about using dish soap to wash a motorcycle and it is often not based on fact. There is, however, no hard evidence to suggest that dishwashing liquid can harm your bike. Here’s why.
Is it safe to use dish soap to wash my motorcycle?
When washing your motorcycle, especially after a ride in the dirt or mud, it is always a good idea to wash off the dirt as soon as possible to prevent spots forming on the metal and plastics. Dirt can also collect in certain areas which can cause rust to form over time. Spraying down your bike with water is definitely better than nothing, but many types of dirt required the use of soap.
In general, there are two types of dirt – water-soluble dirt like dust or soil; and grease, oil, or tar based dirt. To remove this dust and dry dirt you can often get away with just water or a very gentle soap. But if your motorcycle has fallen victim to something stickier, like dead bugs, tar splatters or oil, you will have to use some type of soap to dissolve the grime. Dish soap seems like an obvious solution, as it has been designed to cut through grease and oil. Dish soap is also usually readily available in most respectable homes.
The concern that most riders has with dish soap is that it contains salts that can cause or aggravate corrosion. John Milbank, Consumer Editor at Bennett’s Bike did some proper research and found that the salts in dish soap are not the corrosive type you get in table salt (sodium chloride). Instead, these salts area active ingredients (ionic surfactants) that degreases metals by dissolving in water and in grease or oil.
You can watch the whole video below, but in short, these salts trap oil in little bags of water with a film that doesn’t break and then washes it away.
John did some test with electrolysis to find out whether dish soap will cause rust. His findings suggest that normal tap water is more corrosive than a 10% dish soap solution.
John consulted Professor Bob Eden, who has a masters and doctorate in corrosive science and engineering no less, who explained that it is the chlorides in road and table salt that is corrosive. Dish soap, as Prof Eden explains, does not contain chlorides otherwise it would leave dull deposits on your glasses and plates. The chlorides in salt when combined with water can break down the protective oxide layer that forms on the surface of some metals and can speed up the corrosion process.
Dry your bike properly to prevent rust
Now that we know dish soap is safe to use, let’s chat about a bigger concern. Evidence suggests that the tap water you use to rinse your motorcycle after a wash may be a far bigger contributor to causing rust. The best way to reduce the risk of this happening is to properly dry your motorcycle directly after each wash.
Using an air blower of some type, like a leaf or snow blower, is probably the easiest and quickest way to do this. You can also opt for a specialized drying towel or natural chamois and gently wipe away all excess water. You may be tempted to just get on your bike and ride it until it is dry (it surely is the most fun way), but this may not be as effective and may leave droplet marks on the metal and plastics.
I do, however, always start my bike after a wash just to make sure that I blow out any water in the exhaust to reduce the chances of exacerbating rusting inside the pipe. Letting the bike idle for a few minutes also lets heat from the engine evaporate excess water that collected in hard to reach places.
Will dish soap remove the wax from my motorcycle’s paint?
If you repeatedly wash your bike with dish soap, especially if you combine it with some elbow grease, the dish soap will eventually strip your bike’s wax and protective sealant.
Dish soap is after all a grease cutter designed to dissolve grease and oil from last night’s sticky ribs and chicken wings. The protective layer of wax on your bike is also grease-based, which means that when you use dish soap to wash your bike you will also remove this protective layer in the process.
Without this protective layer of wax, the paint of your motorcycle will be exposed and vulnerable. This is particularly problematic when you think about the harmful effects that dead bug splatters, tar, and tree sap can have on exposed paint. Wax also protects your bike’s paint and plastics from harmful UV rays which can dull a bike that basks in the sun all day.
If you are thinking: “Ah, there’s the catch… I knew dish soap was bad!” just remember, even soaps that are recommended for washing bikes specifically may have the same effect on your bike’s wax job. Any car or bike soap will remove the wax over time as those products were also designed to dissolve grease and oil.
Luckily there is an easy solution to remedy this. You can, and should, simply re-wax or re-seal your bike after each wash regardless of the soap that you use. This will prolong the life of your bike’s paint job and protect it from the sun and normal wear and tear in the long run.
So is it safe to use dish soap to wash your bike? Yes. Yes, it is. By all means buy expensive bike soap if you like, but if you don’t have any at hand, dish soap will do a better job than water alone. So don’t get fooled by marketing messages and have a closer look at the ingredients in the soap you use first.
Now go wash that bike!