Oil squirting from somewhere on bike during ride

Question

I have a hybrid-style bike (Dawes Discovery 301) with a Shimano Alivio/Deore gearset.

After a recent ride I noticed that the light-coloured t-shirt I was wearing had been speckled with oil around the stomach area (and nowhere else). I later gave the bike a thorough clean, making especially sure that there were no traces of oil around the handlebars, headset and front derailleur.

However, on the next ride the same thing happened again, although to a slightly lesser extent. After cleaning the bike a couple more times the issue still occurs, so the oil appears to be squirting up from somewhere, but I don't know where.

I've had this bike a couple of years but hadn't noticed this issue before as I usually always wear a dark-coloured top when going for a ride. After inspecting the black jacket I often wear, I can see that it does have some oil stains speckled around the same area that my t-shirt was stained. So this has probably been happening for some time and I just hadn't noticed it before...

Does anyone know what might be happening here and how I can stop it?

Answer 1

The most common places where there is a chance of liquid oil getting out in bicycles are: suspension fork, rear damper, and hydraulic brakes.

The bike you mention, however, does not have suspension, but does have hydraulic brakes. Could that be brakes? Have you noticed any change in braking action recently?

Another possibility is that the contamination is actually coming from the road you ride. If your bike does not have a front fender, the road moisture and dust will be thrown by the rotating front wheel upwards towards your body.

In my opinion, it is much more likely that what you see is the result of riding (even slightly) dirty or dusty roads without a full front fender.

Answer 2

The key is to identify the source of the oil.

Some Dawes Discovery 301s have V brakes and others have hydraulic. If you have hydraulic brakes it's possible the oil could be coming from your brakes but it's unlikely to have been happening over the length of time described without noticing a reduction in braking power.

It's difficult to say with accuracy based on the description but there are two places most likely to splatter oil.

1. The chain
   An overly oily chain can splatter oil. I can't think of a time when I've seen an oily chain splatter onto the rider's stomach so this seems unlikely. Apply lube sparingly and wipe down your chain with a rag to prevent splatter.
2. The road
   Oil is used to treat roads and oil is dripped by cars onto the road and can be picked up by the front tire and splattered on the rider's stomach. Oil picked up by the rear tire can be splattered on the rider's back.
   The times I've ridden through oil the main area of splatter on the bike was the bottom of the down tube and the back of the seat tube.

If the oil is from the road the only way to keep the oil off of you is to avoid those sections of road. Every rider should be road aware - pay attention to what you are riding on so that they can avoid road hazards and pick the best path for the tires. It takes some practice to be able to safely shift your attention around your environment to watch all the things you need to keep track of.

An oily road is not only messy it's also dangerous for bicyclists. Oil can be very slippery.