Ok i know that sounds obvious, but apparently it’s not that obvious to me.
Obviously there is friction when they repeatedly wipe across your windscreen, and in some cases you see them get tattered and what not. Fair enough.
But in the majority of cases in my experience there is no obvious damage, not even any noticeable wear and it’s certainly not like they have run out of rubber or anything. So why do they stop wiping the windscreen effectively?
Also, i’ve only been driving a few years and never had a brand new car so tell me, how long do wipers normally last?
Yes, windscreen wipers wear out. The constantly changing temperatures, pollution, and UV radiation from the sun causes the rubbery stuff to get inflexible. The wipers don’t work as well when that happens. Round here, a set of blades will last around two years, but your mileage may vary.
Here’s another thing to consider: Your wipers may be fine; your windshield may be coated with wax. If you take your car through the automatic car wash, a film will build up on your windshield that will reduce the effectiveness of your wipers. You need to thoroughly clean the window with some regular window cleaner and paper towels to remove that wax film. I have to do this all the time, as I frequently run the car through the car wash.
I’ve changed a few sets of perfectly good wipers before someone told me that little gem.
Ironically, windshield wipers last for a shorter time in dry climates. Although we’ve had a wet winter, it normally only rains (consistantly) around August. I usually have to replace my blades at the start of every “maybesoon” (You know, like monsoon, but maybe it’ll come, maybe it won’t), due to dryrot throughought the year, for the reasons Squink pointed out.
When I lived in Minnesota and Michigan, the main cause of deterioration was operating them when they were partially stuck to the windshield ice, leaving bits behind.
If they are natural rubber, then ozone also takes a huge toll, in addition to the environmental factors mentioned above.
Frequent use may actually lengthen the service life. There are plasticizers in the rubber that deplete from the surface causing the rubber to get hard and crack. Regular flexing helps re-distribute plasticizers from within.
Two more things. Dirt wears them out; your car gets dirty, and when it rains, you’re dragging the blade through a slurry of powdered rock.
Reverse your blades once a month. This is from a friend who worked at a leading maker of wipers. The blades take on a “set” while parked on your windshield, and it makes the blades wear out faster. Flip them over to bend them the other way.
Thanks for the replies folks. I tried cleaning both the wipers and the windscreen just in case but apparently they had just reached the end of their service life.
Replaced the blades at the weekend, oh man, silent running - bliss! The last ones had gotten so noisy i forgot what it was supposed to be like.