djdelarosa25

I'm planning on buying a pair of cheap SPD-SL pedals to replace the worn-out PD-R540 that my father gave me. These two are on the lowest-end of Shimano's range.

PD-R550
PD-RS500

The R550 is Tiagra-grade and seems to be of an older design whereas the RS500 is non-series but is seemingly based on the current generation of higher-end pedals (looks very similar to the PD-R7000 in fact). The R550 has a larger metal wear plate but the newer, higher-end pedals from Shimano seem to have ditched that so I guess it's not really more durable? I don't even think I can get replacement ones where I'm from if they ever wear out. The R550 costs 15 USD more than the RS500 here in my country and I have to order it online since my LBS only has the RS500 in stock. What do you think, should I just go with the cheaper one? Is there even any noticeable difference between the two?

Iride01 

The guts.... spindles, bearings and stuff are the same parts. The cleat retaining bolts and washers are different. Obviously there are some very minor differences in the pedal body.

https://si.shimano.com/api/publish/s...RS500-4555.pdf
https://si.shimano.com/api/publish/s...-R550-3555.pdf

The R550 claims a wider tension adjustment. But compared to what I don't know.
The RS500 claims easy to step in, easy to step out. And optimized for beginners.

https://bike.shimano.com/en-EU/produ...0/PD-R550.html
https://bike.shimano.com/en-EU/produ.../PD-RS500.html

djdelarosa25

Wow, thank you for this. Seems like they use pretty much the same internal assembly. Those different parts are from the cleats not from the pedals themselves. And looking at the copyright date, the RS500 is only 2 years old whereas the R550 is almost 8. I guess I'll go with the RS500 then. I wonder when Shimano will release the R560

eduskator

The RS500s are 50$ cheaper than the R550s according to my LBSs. It is a significant price difference.

The RS500 seem to be Shimano's entry level SPD-SL pedals whilst the R550 are a slight upgrade.