Every few months a newbie asks what to use for pedals. Then several of us make suggestions, the Shimano M324 and A530 pedals are usually some of the recommended ones. I have been using M324 pedals for years for touring, bought a pair of A530 about a year ago and have used them enough that I felt I could provide a good comparison. So, I thought I would list my comments on how the two differ.

Both pedals take SPD cleats on one side, platform for plain shoes on the other side. For touring I like to use SPD shoes, but when I am in the campsite or out sightseeing, I often switch to hiking shoes or trail running shoes. And if I am off-road on some really tricky terrain where I might have to put a foot down on the ground really fast, I do not like to be clipped in. Thus, I like a pedal that works with both.

In the first photo below, the M324 are on the left, the A530 are on the right. Cleats are not shown.



Weight. The scale in the photos below is set for grams. Thus the M324 are 525 grams (18.5 oz), the A530 are 383 grams (13.5 oz). Thus, the M324 are 5 oz heavier than the A530. I weighed them without the cleats.



SPD. Both come with one set of cleats. Shimano makes a couple different styles of SPD cleats. I am not going to comment on that because I do not really know the difference between them. It has something to do with how they release.

Cost. The A530 usually cost a bit more than the M324. I listed the links below to REI website. But the prices vary greatly, so if you are shopping for a pair, you might want to do some research. As an example, I paid less than half of what REI charges for my A530 pedals, but I got them from Europe and I had a big enough order so that I had free shipping.
Shimano M324 SPD Pedals - REI.com
Shimano A530 SPD Sport Road Pedals - REI.com

Installation. Both use the typical 15mm pedal wrench for installation or a 6mm Allen wrench. The REI website link above says the A530 uses an 8mm Allen wrench, but my pedals take 6mm. Maybe there are different versions?

Platforms. Besides weight, this is where I find the big difference between them.

• M324. I like the M324 better when I am wearing hiking boots or hiking shoes. The M324 pedals have a chromed steel U shaped part that your shoes sit on, that concentrates the foot pressure more on that part of your shoe, my hiking boots and hiking shoes that have deep lugs seem to grip that steel part of the M324 better than they grip the A530 surface.
• A530. But, I prefer the A530 when I use soft sole shoes like sneakers or deck shoes because the A530 pedals have a much larger surface area on top to spread the weight out on, you can see in the first photo above that the A530 is physically longer from front to back.

Repair. I have never opened my pedals up. But the limited research I have done indicates that the relatively inexpensive tool TL-PD40 is used to open up the A530, but the more expensive tool TL-PD33 is needed for the M324. There are some good you tube videos on pedal rebuilding so I won't try to explain something that I have not actually done.

Other considerations. The M324 can be fitted with toe clips, I think it unlikely that anyone would want to do that, but if you did then the A530 is not for you. My M324 pedals have a lot of rust on them, that is partly because I use them in winter so they are exposed to road salt, but they also have a lot more steel than the A530. And if looks is important to you, the A530 is listed on some websites as being available in black.

Exploded diagrams:
http://www.shimano.com/media/techdoc...9830608609.pdf
http://www.shimano.com/media/techdoc...9830820605.pdf

Summary. Which is better? It depends. There will be trips where I use the A530 and other trips where I use the M324. I have had the A530 on one of my bikes for most of the summer, but I will be switching to the M324 when it gets colder because when it gets into the 20s (F) or colder, I prefer hiking shoes or hiking boots instead of cycling shoes and I like the M324 pedals better with hiking boots. If I am more concerned about weight, the A530 wins. The cost is close enough that it really is not an important factor. And, if you are concerned about rebuilding them, the cost of the special tools to rebuild them becomes a factor, the A530 uses a much lower cost tool. So, if you are shopping, I hope the above information was helpful.

Shimano also makes a T780 pedal that also offers a SPD side and a platform side, but I have never used it so I am hesitant to comment on it here. Here is a link to it at REI. If you are shopping, you may want to look at it too.
Shimano PD-T780 Pedals - REI.com