Well, I figured I better post this one over on safe ground where I will only get kidded a bit (unless this turns into a testy thread). I posted a couple of pictures of a damaged derailleur over on the BM forum. My old eyes aren't too good so I hadn't noticed how grungy the pulleys were until I looked at the high res photos -- whew, not pretty. So, to the subject question - is it reasonable to blow the crap out/off with a power washer or do I need to use a hand brush if I want to get this nice ultegra device lookin good? (The arrow is pointing to a problem area. It is the rest I need to clean.)

I don't know about the power washer, might be a little much. However I bought one of those pump up weed sprayers ( so I knew it was clean), filled it with hot water and added a little soap. Pump, pump, pump. Worked wonders. Didn't knock any paint off in case that's what you are trying to do.

As a general rule, power washing is not advised anywhere around bearings or seams where water may be forced into areas that cause damage. Rusty bearings, tubes, etc. You could use a brush and soap solution to clean it with much less chance of damage.

I tend to agree. I would not use any high pressure to wash any part of the bike. I would also not use a stiff brush near seals but will on gears & chains. In this case some degreaser and a tooth brush would be my first thought (but don't put the tooth brush back in the bathroom )

From what I can tell, recent Ultegra top pulleys are OK for pressure washing, assuming you're about to tear it apart and clean and lube the bushing afterwards. Lower pulley might have a sealed bearing. Do not pressure wash it unless you're about to replace the lower wheel and/or bearing unit. Probably best to keep the pressure washer away from the RD in general.

The only bike parts I pressure wash are chains.

I concur with the other posters.

Bikes and pressure washers are a bad mix.

I've had success using a brush designed for scrubbing vegetables and some kind of solvent that mixes with water. I do this in my basement at the double tubs.
Drinking beer and listening to the "Stones" helps too.

Thanks everybody. Simple Green and a softish brush it is.

No.

Power washer? Not only no, but hell no.

I would take the chain off and clean it, take the derailleur off and spay it with Simple Green or something similar and clean it with a rag and a toothbrush. After everything is clean and dry, lube all the moving parts with oil. Short cut method would be to wet a rag with Simple Green and rub the grunge off.

Power washers are OK- providing you don't go near any bearings. Off road and we sometimes collect mud that by the time you have got home- has set like concrete. We are on a clay area and only two ways to get the bud off. Leave the bike for a week and then chip the Clay off by hand when it has gone dry- Or Power wash. Ordinary hose takes a long time and still doesn't reach the inaccessable stuff that has to be brushed out.

My feeling is that anything to make the job easier- and a Power washer definitely does that. The bike still has to be cleaned and re-lubed though but that should be done after every ride in the mud.

It's not very nice to the trails to ride them when they're that muddy. I suppose it's alright if you were just riding on that dirt road the bike's standing on in the pics, however.

Different aspects over here- I have gone into it before but Cycles are allowed on Bridleways and white paths. White paths are open to ANY vehicle including cars and motorbikes. Cycles don't use them in winter due to the 3ft of mud and don't use them in summer due to the ruts or the worry of 4x4's coming down the hill or round the corner out of controll.

Bridleways are what they sound like. Horse trails. Many of these are old rights of way or cart tracks. They are used all year round by horses (Not many Carts nowadays) and they are continually muddy in winter. They are only legal for horses- Peds and cycles with priority in that order. Most of the damage to the trail is done by horses. The path is then widened by Ramblers not wanting to get their "NEW" boots dirty and the bikes take the line of the horses unless it is too deep in mud to get traction.

And in Friston forest we do have dedicated Cycle trails. Used all year round and they grade from easy to "Help". I can assure you that a flint covered clay based 15% hill that has no traction due to mud in winter and the flints and scree in summer takes a bit of effort and skill. Especially as this is a drovers trail for cattle around the hills.

Different aspects of trail use and conservation- but I can assure you that Cycles do less damage to the trails- If any- in comparison to hundreds of ramblers- plenty of horses and the Sheep- cows and herds of Shetland ponies that are used to control scrub on the hills. And if you want to see real damage to a trail- Look at a footpath over the hills or through the woods after the Winter meets of the Rambling association. They are dedicated footpaths where cvycles and horses are not allowed.

And attachment is of a couple of our "Worst" bits of the trail in winter- showing how it recovers in summer. The first is of the Drovers trail that is "Difficult in Winter. The Tandem is on a White trail in spring. You can see how deep the mud is by the position of the rear wheel. And the 3rd is of one of the Cycle trails and the bike is just launching from a dropoff.

It's sometimes hard to avoid all bearings with a power washer, particularly hubs and bottom brackets. It's also easy to overwhelm the seals and put water where it shouldn't be. That water washes out the grease and you now have wet metal on wet metal, soon as it dries you have rust. Conventional hubs and bottom brackets can be packed with boat trailer bearing grease which is much more water resistant. The problem is cartridge hubs and bottom brackets that are sealed units, the seal to keep you from getting into it to repair it is often a lot better then the seal against water. The companies making these units do not use water resistant grease.

Is the job easier with the 3 minutes it takes to get the mud off plus the 2 hours to repack all the bearings, or the hour to take the mud off with a good stiff brush and a bucket of water?

I find the ramblers statement hard to believe, but I've been on plenty of heavily used bridal paths before and know what you mean about that one. In your pics, I'd say the third one is one that I'd not want to ride in the muck, as it could just possibly be made to be much narrower and nicer in the summer if it was avoided in the mucky months.

One more tip if you don't mind : avoid water bottle use on heavily trafficked equestrian, pack animal and livestock trails. There are prophylactics for water bottles, but hydration bladders are really the way to go.

Oh, and once upon a time, I'd get my bike that muddy on logging roads and ATV trails out on the coast range and never used a pressure washer on it. Hose and brush worked fantastically.

for dirt and mud, simple green and garden hose has worked well. CX, MTB, Road = all same
for grease, a degreaser spray (like wd40) followed by simple green and garden hose - clean

of course, "clean" is relative. My clean could be someone else's dirty!
I know a couple guys whose bikes are immaculate. If my chain and cogset are silver, i'm happy

oops, just realized this is 50+ area. Well, this works well for us younger folks.

I live on the South Downs and it is famed as a National Park. Plenty of visitors and plenty of cycle tyres and hob nail boots get onto those trails. The ramblers society have plenty of members nationwide and they organise trips to walk certain parts of trails. Imagine 60 to 100 sets of boots walking one footpath 6ft wide on a wet day-- Even worse is imagine the same number walking a muddy Bridlepath in one day. They would not keep to the designated 10ft wide path as it is muddy so before long- the path is 20ft wide. History lesson This has been going on since the middle ages- 14th century- on these established trails as No roads other than hard packed soil and you have to get your horse and cart to market in the next town. Historical problem that solves itself every year when spring and summer arrive.

And on water bottles- Never seen them on your bikes but over here MTB bottles have a cap to cover the spout. But camelbacks are the way to go. For health and for ease of use.

And on the power hose- I do use it but rarely. I am lazy but we have a wonderfull product over here called Rain and plenty of it. Normally the mud is washed off the bikes on the way home. That is not a poor picture- it is rain blurring the Pic. Mud does not stay on bikes when it is this wet.

I'm sure the trails were pretty nasty with ox cart traffic back in the day. I suppose the hikers and bikers in the area want to keep 'em as close to 14th century conditions as possible. Oh well.

Simple Green or a made-for-the-job Citrus based cleaner. They make specific brush sets for this purpose, they also make specific tools for cleaning chains, while the chain remains on the bike

This power washing isn't where I have to wear some sort of power meter in the shower, is it?

OK, I promise to do better on the maintenance. Simple Green and a small brush does make a tremendous difference - in appearance, if not performance. Here it is cleaned up a bit. I guess I will never know what caused the tab to split inward -- the scratches are undoubtedly from my vice grip:

FWI: I find the selection of cleaning brushes at the grocery store (kitchen section) and hardware store to have an interesting mix of shapes and sizes at reasonable prices.