- Preparing for my first power meter purchase. I have one All Road custom bike (with mechanical Shimano Ultegra) upon which I swap wheelsets a few times a year for road and gravel as well as swapping SPD-SL to SPD pedals. Because (a) I have signficant L/R muscular imbalance, and I understand most of the so-called dual crank and spindle meters only read the left side, and (b) I’m strongly considering shortening the crank length (more below) (otherwise I guess I’d go with the Favero Assioma and swap the pedal bodies), I’ve settled on a spider based system. It rather looks like the Magene PES P505 is popular for achieving the best price-performance ratio … any feedback, and/or other recommendations?
- I’ve been learning that reducing knee pain is a big part of the trend towards shortening cracks. Is this the case for others? Anyone have an experience where shortening cranks made the knee pain worse, or caused other problems?
- For context, I have separately torn the ACL in both knees decades ago, but only the left one gives me trouble today (for now) after I had a meniscus procedure a few years ago … and it has developed into quite a lot of pain [[in related news, I’m 53
]]. The muscular imbalance is severe (I’ve had a DEXA scan that showed 0.6 kg more muscle on the R leg compared to the L). Therefore, if I do end up purchasing the P505 or other spider-based meter, I’m strongly considering shortening the 175 mm cranks I’ve ridden all my life to probably 170 mm. I’m a 5’11” / 195 lbs dude in Vancouver.
I can’t answer all of your questions, but I have a few thoughts.
For your number 1 question: I ride with lots of folks who use the Favero pedals and love them. They are reasonably priced, have good company support if ever there’s a problem, and they’re accurate as well. Highly recommended. I’m sure the other ones (Magene) are fine as well but I have no experience with them.
For your question 2: The research I’ve read does make the case that a shorter crank arm can help with reducing knee pain. Your present cranks (175mm) are very long- and I’m sure the move to 170mm would help.
For question number 3: Why do you have a muscular imbalance? It would seem to me that this imbalance is contributing to the pain in the knees. The stronger leg is most likely compensating for the weaker one. This puts an undue stress on the stronger leg, not to mention that it also probably interferes with a smooth pedalling motion. I’d recommend you see a good sports therapist and get an exercise program (moderate weights and stretching) to reduce the leg strength imbalance. I’d also check out Yoga. I’ve had amazing results in terms of both flexibility and strength with a daily 20 minutes of yoga
Finally go for whatever power meter system you like, DO shorten the cranks, and aim to reduce the leg imbalance. I’m sure all of these things will go a long way to contribute to pain free cycling. Good luck.
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I had knee pain for years that cleared up when I switched to shorter cranks (165mm from 172.5mm - I’m 5ft9). I think since it opened my hip angle just enough. But I know it doesn’t work for everyone.
If you’re going to mess with your cranks though - isn’t that an argument for, not against, a pedal based power meter? Pedals are also great when you go on holiday and rent a bike / want power on your old inaccurate turbo trainer / decide to upgrade your bike etc.
My road bike shipped with 172.5mm Ultegra cranks with a 4iiii pm but I was keen for 165mm cranks. The Magene PES P505 (P515 now) was a logical swap. It was cheap, and allowed me to continue using my Shimano chainrings - so no compromises in shifting performance.
It’s been very reliable - no issues after 16 000kms. The graphics are a bit over the top but aside from that it’s difficult not to recommend it.
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Just fyi, 4iiii is one province to the east of you and they can factory install dual-sided on smaller cranks. I know they do 160, not sure if they go down to 155. Might be a clearance issue when you get that short, depending on your frame.
I’m a similar vintage to you. Went to 160mm and all sorts of issues went away. Mine were mainly hip/hamstring though.