So I'm thinking about finally making the plunge and switching from old mountain bike clipped pedals to clipless. Anyway, should I go with full on clipless like SPD M520's or the two sided pedals with the platform on one side? If I put them on myself, I'm going to need a pedal wrench too, right?

Being a noobie to clipless, I love the M520s. Easy to clip in and out but still solid with the retention just one click shy of as loose as possible. I installed them myself with no pedal wrench. I think it's 14mm, but any standard wrench will do, you don't even need to get them that tight, they will tighten as you pedal. Just be careful not to cross thread them, grease the threads and remember that the left pedal threads backwards.

A pedal wrench is 15 mm. If your pedals are tight, you will need a wrench that is strong enough to do the job and allows you to develop enough leverage... Regular mechanics tools like adjustable wrenches and regular wrenches are often too wide (thick) to fit. A 15mm cone wrench will fit but is easily bent out of shape if the pedal is tight.

Make sure you are turning the pedal axle in the correct direction to take the pedal off. When facing the bike, put the wrench on the pedal axle and turn it towards the back of the bike. This rule works on both the left and right side of the bike.

I use the pedals that are clipless SPD on one side and regular platform on the other. I seldom use the platform side, but it is nice to have when I'm not wearing my cycling shoes.

Look at the pedal when you buy it some have an allen wrench fitting on the axle. You can tighten them with an allen wrench instead of pedal wrench. a few of shimano spd pedals don't have flats for the pedal wrench like the M770 or M970.

I have the PDm324's on my "touring" bike. I like 'em a lot. I got them to ride either way but have never ridden just platforms (at least that I remember)
There is no problem with weighting so I dont have to fidget with them to find the clips. Highly recommended.

50/50 pedals are nice if you find that you'd like to ride in regular shoes or sandals and have a wider platform which can greatly increase foot comfort if you wear a softer cycling shoe.

You don't have to gorrilla the pedal on but they need to be tight (and they will self tighten).... the reason a pedal wrench is long as you sometimes need immense leverage to get frozen pedals off a bike.

Make sure you grease the pedal threads and I am in the habit of taking my pedals off whenever I do any tune up and will re-grease the threads... they are never hard to remove when you do this.

What kind of grease do you use for things like this? I'm looking for a general purpose one I can use on pedals, seat post, bolts, etc.

Aaron - bearing grease works on more things than just bearings.

You can use anti seize compounds but they cost a lot more.

If all you have is motor oil, use that and remember whenever you grease / lube threads it will enable you to torque them down with more force so be careful when you do this to small fittings.

I noticed that Nashbar has a new Rodeo 2 pedal that has SPD on one side and a semi-platform on the other - the original Rodeo had a plain cage on the non-SPD side.

Oh my gosh, M520's are no longer two sided?

I have the Nashbar SOHO's on my SS and I like them too... I've actually used the platform on them too. Don't know much about the Rodeo (except that I think it is more or less the same as the PD-M324's) but the SOHO's are great.

They were when I bought them from my LBS last week.

Also, I haven't done this for bikes, but in general if your normal wrench isn't long enough to get good leverage, a piece of pipe over the wrench works nicely.

Aha I knew what you were getting at.

sorry, I meant pedals that had two different things (one on each side - platform on one and clipless on the other). My bad. I know m520s have the same thing on both side.

.....

I have a bike with SPD X platform. If they ever fail, I will get SPD X SPD (just to be clear). I almost never ride without cycling shoes, and the few short trips I've made on the other bike with full SPD wearing street shoes hasn't been a problem.

I have the SPD/Platform pedals on my commuter and love them. My work commute is so short it isn't worth changing shoes, but when I do a longer ride, the clipless are great. On my new-to-road bike, I'll be putting just clipless because I don't think I'll be using it for my commute or errands or anything other than going to long rides. It depends on what you do with your bike and how much.

with the spd x platform pedals (I like that designation to tell them apart) how much of the time do they flip on you? With my current pedals, the cages are heavy enough that at least 2/3 of the time they flip over when I'm stopped and it's a pain in traffic to pedal on the opposite side through the intersection and then try to flip it over so I can put my foot back in the cage with cars all around me (basically have to work up to a decent speed so I can coast for a little bit to do that while not slowing down enough to piss off the cars behind me if I've taken the lane and do it without looking down to see what side I have up to look out for potholes/pedestrians jumping out into traffic).

What about a caged clip-in clipless pedal (I think that's the term) like SPD M424? Would that fit my needs better? I could clip in or not on either side without having to feel for the right side. Given that I commute (and do all my riding) on an old lbs mongoose hard tail mountain bike with slicks, drops, fenders, and a rack that weighs an absolute ton, the fact that those pedals are heavier doesn't bother me. Are those as good of quality? I just see the clipless x clipless or clipless x platform recommended but never these. Is there a reason?

Depends on your shoes. I had to return a pair of similar pedals because the tread on my MTB shoes hit the platform preventing the shoes from clipping in.

Good to know. May I ask what kind of shoes you have?

I am assuming that you mean something similar to these

Forte pedals

I don't think that I would like toe clips on the bottom when I am using the spds, it leaves the clips too close to the ground for cornering and may snag on something causing a crash.

I have the forte brand and feel that they are harder to find the attachment point than a standard pair of spd pedals.

Thanks for the note about the forte pedals. I'd looked at those as a cheaper option. In my last post, I was actually referring to these, which have a resin area around the clipless part that allow you to use regular shoes on either side as it just pushes the clipless mechanism down or something.