The only gripe I have with my Yeti is the dirty spray from the wheels that is sucked up onto the rear window in wet weather.

 

When it's raining I have to keep the rear wiper on intermittent all the time.

 

I am considering fitting longer rear mud flaps - has anyone found these reduce the filth that gets on the rear?

 

Has anyone found any other answer to the problem?

 

Do all the flat backed cars suffer the same - if not, why not?

 

Norry

Fabia MK2 is the same, I think its all flat backed cars. I drove my dads Fabia back to Dorset last night and when raining I had the rear wiper on the whole time otherwise there was no visibility through the back. From memory I don't think mudflaps on the back will make much difference, the water gets sucked up by the vortex that forms behind the car due to its shape.

I think Llanygraham found some mudflaps so you could PM him and ask for the details.

you could also treat the rear screen with one of the rain x type products to help prevent the water collecting on the glass too.

I use Rainex which does a great job of keeping the glass like new and reduces the porosity of the glass as well.

It is a fundamental aerodynamic issue with flat-backed cars. Mud flaps may ease the issue but won't solve it. I count myself thankful that there is an intermittent setting for the rear wipe, and I don't mind driving with it set like that in wet conditions.

My Audi A1 suffers the same, to a lesser extent... it is quite stubby-backed too. My previous Volvo V50 and Mercedes B class were the same. Conversely, my RX-8 window stayed bone dry in even the worse spray.

I doubt the mudflaps will make any difference.

 

I don't find the spray on the Yeti's rear screen too bad. My dashcam has a separate rear-facing lens fitted in the rear window, and I found with my Focus I was always wiping the rear screen to get a decent image when it was wet, I'm not having to do so as often on the Yeti.

 

Rain-X is definitely worth a try though, I've used a similar product ("CarLack 68") and it's very good at repelling water. 

It's a fundamental outcome of a KAMM tail design that is designed for a sharp cut off of aero drag.

The after market accessory sellers have had a field day with this subject over the years. I've lost count of the "spoilers" that have been produced to "improve" the airflow and their claims of improved rear visibility, fuel consumption, reduced tyre wear, reduced noise etc.

Unless you have the facilities of a Formula One racing team wind tunnel I doubt any improvement to any of the aforementioned claims could be achieved.

One thing you can be sure of is that your wallet is likely reduce in value.

 

Fred

It's a fundamental outcome of a KAMM tail design that is designed for a sharp cut off of aero drag.

 

Is a vertical tailgate on a what is basically a square box body - which is basically what the Yeti is - really a "Kamm tail"?  If it is then practically every bus, truck and van in the UK has a Kamm tail!  I thought a Kamm tail should be a streamlined shape that is truncated ie the cross-sectional area should start to reduce before the bluff rear end is reached.  Something like the old Citroën GS & CX, for example.

 

A lot of the other small SUVs now on the market do have something approximating to a Kamm tail, because the roof line drops towards the rear before the tailgate eg the Kia Sportage and the Evoque.  That shape has practical disadvantages IMO, such as reduced roof height for rear seat passengers, reduced boot loading height and poorer rearward visibility out of the smaller rear window.

 

Trek are now using the Kamm tail idea in their triathlon bikes: http://www.granprixbicycles.com.au/reviews/Review%20Sheets/speed-concept.html

When it's raining I have to keep the rear wiper on intermittent all the time.

 

 

OMG. How DO you cope?

My modified mud flaps do reduce the spray, but not stop it totaly.

 Have a look here http://www.briskoda.net/forums/topic/311368-longer-mud-flaps/

Is a vertical tailgate on a what is basically a square box body - which is basically what the Yeti is - really a "Kamm tail"?  If it is then practically every bus, truck and van in the UK has a Kamm tail!  I thought a Kamm tail should be a streamlined shape that is truncated ie the cross-sectional area should start to reduce before the bluff rear end is reached.  Something like the old Citroën GS & CX, for example.

 

A lot of the other small SUVs now on the market do have something approximating to a Kamm tail, because the roof line drops towards the rear before the tailgate eg the Kia Sportage and the Evoque.  That shape has practical disadvantages IMO, such as reduced roof height for rear seat passengers, reduced boot loading height and poorer rearward visibility out of the smaller rear window.

It's never going to have a rear axle aero lift problem at speed, that's for sure but there is a kick-up at the rear of the roof line to break the airflow and marginally reduce drag.

Yeti never had an Audi TT problem that's for sure.

 

My MINI's abrupt rear end is pretty terrible in the wet or the snow. So is the LR Discovery3. Wouldn't expect any better from a Yeti. That's we have the wipers.

It's a fundamental outcome of a KAMM tail design that is designed for a sharp cut off of aero drag.

 

Erm the Yeti's rear is as far from a KAMM tail as you could possibly get...  look no further than the Audi A2 or the Toyota Prius to see a real KAMM which tapers town substantially to end in a spoiler.

http://en.wikipedia.org/wiki/Kammback

So I have had a KAMM tailed A2 without a rear wiper and have found the Yeti not that much worse to be honest. More muck yes, but same amount of water. Which will land there every time you stop. So unsure how the RX-8 mentioned above had a bone dry rear window unless you never ever stopped whilst it was raining?! 

Well, of course it got wet by falling rain, but the heated rear elements would clear this quickly once on the move.

Well, of course it got wet by falling rain, but the heated rear elements would clear this quickly once on the move.

I would strongly advise using Rainex .....the element will help welding the dirt to the screen if it's allowed to dry out dirty....only usefull for misting and ice IMO.

Rainwater is essentially clean and pure, and no spray got on the window, so it stayed pretty clean all the time. Anyway, I got rid of that car 8 years ago!

every time I read the thread title, my brain has a picture of rear windows being installed by spraying them out of an aerosol can! 

every time I read the thread title, my brain has a picture of rear windows being installed by spraying them out of an aerosol can! 

 

Likewise here!!!  And those spray-on-mud things spring to mind as well!

On my FL 1.2 SE the rear wiper wipes on intermittent when the front wipers are on - I think there is an option in the menus somewhere. On single speed it seems to flick the rear about every 23 front wipes; on double speed every 14 front wipes or so. I don't find it annoying, it doesn't go dry and means I don't have to keep flicking the rear wiper.

I tried a spoiler I made from plywood and polystyrene,

no real result as it was big  because I could only clamp

it to the roof bars. You could see washer water on the

back screen being pushed down by the airflow at a rate

of knots. However in the words of the Lioness ..............

"get that mess off my car" the prototype was hidden in

the garage for another day.

Rainwater is essentially clean and pure, and no spray got on the window, so it stayed pretty clean all the time. Anyway, I got rid of that car 8 years ago!

Not if it's come via the Sahara!

 

Fred

I find the rear wiper is fine for keeping good vision - the bigger issue for me is the dirt and grime that gets onto the tailgate release catch.

On my FL 1.2 SE the rear wiper wipes on intermittent when the front wipers are on - I think there is an option in the menus somewhere.

 

Nope, it's standard behaviour, as documented in the owner's manual* (page 57 of the current edition) and cannot be changed via the maxidot:

 

If the lever is in position 2 or 3...the rear window is wiped every 30 or 10 seconds if the vehicle's speed exceeds 5 km/h.

 

It might be possible to change it using VCDS.

 

* I sometimes wonder why Skoda bother producing this document.  It would be a lot less effort for them just to hand the keys over and tell people to figure out how to operate the new vehicle that they've just spent thousands of pounds on by themselves.  That seems to be what the majority of owners do anyway...  <curmudgeon mode off> <winking smiley>

Edited 17 May, 201412 yr by ejstubbs

In this post from 2011 Polypenko fitted a roof spoiler but never clarified how much it helped the rear window stay clear.

 

http://www.briskoda.net/forums/topic/199875-yeti-roof-spoiler-fender-flares-dashboard/?hl=spoiler#entry2487670

 

tom