I’ve recently moved to SPD-SL on the grounds that using my MTB SPD cleats was hilarious to pretty much everyone I was racing against. I’m not sure how I’m going to conclude this post yet but it will probably be along the lines that everyone else is right. But with a few caveats!
Firstly the cleat is the bit that you screw onto your shoe. The cleat then fits into the pedal. Sorted, now you know. This fixing mechanism allows better power transfer to the pedal and some say allows better power transfer from being able to pull as well as push when pedaling.
The cleat/pedal combo will usually allow the cleat/shoe to float…ie to wiggle a bit in the same horizontal position. This restricts knee injury but probably results in limited power loss for some people.
Anyway whichever you use they are probably the same regarding the amount of power they transfer to the bike. So why bother agonising about which ones to use? Well of course we are talking duathlon/triathlon here so you have to get off the bike (ie disengage the cleat/pedal mechanism) and then run on the cleat/shoe combo. Neither of which are ideal sporting activities.
1. Straps: ie use NO CLEAT. Well you lose power by going down this route. But you get on and off the bike a little easier. Running in T1 and T2 is a doddle!
2. The triangular Look or SPD-SL systems: Firstly whichever system you choose don’t try and mix and match, it’ll end in tears. These systems are broadly the same. The SPD-SL has a bigger footprint than the Look and in theory should allow a better ‘feel’ and/or better transfer of power to the bike. But they are pretty similar in reality. However this bigger footprint should give a power and feel advantage over the basic MTB SPD type systems. However it is quite tricky running in the Look/Cleats in T1 and T2. The rubber bits on the end of the SPD-SL and it’s slightly larger shape might help a little. Because there are 3 points of contact these shoes allow finer adjustments toe-in and toe-out.
3. SPD. I think you can actually run better in these in T1 and T2 than the SPD/Look alternative. Because the point of contact to the ground is small the foot pivots better over it. However on the bike the story is different where the more conventional road shoe works better, ahem, on the road. Also if T1/T2 is on tarmac then the SPDs are slippery and a bit dangerous, especially in the wet. Whereas on mats and grass they are fine. You can’t adjust toe-in with these and if your anatomy and/or style needs that then this is a no goer.
4. SPD damages my new oak floor! SPD-SL’s lovely rubber pads don’t damage my floors!
5. Getting the darned cleats to engage in the pedal. My experience with look and SPD-SL is great. They go in like a dream. SPD are much harder to engage IMHO.
Summary: Use Look/SPD-SL type systems. The latter is probably a bit better on the ‘feel’. However, and here is the promised caveat, the MTB SPD is actually not worth dismissing out of hand if you have a neutral pedaling position and if your envisaged T1 and T2 ground surfaces are soft/spongy. If you consider other systems then see how popular they are, if they are not popular it will be for a reason.