simon.r
Person
- Location
- Nottingham
A bit of background - about 32 years ago I was knocked off my motorbike. After several months in hospital, 4 operations and months of physiotherapy I was discharged with my left leg 15mm shorter than my right and unable to bend my left knee beyond 90 degrees.
Since then my knee has gradually become more painful (the last time I had it x-rayed I was told I had severe arthritis and the knee of a 90 year old!) and I've found it increasingly difficult to get over the top dead centre of the pedal revolution.
I started cycling about 20 years ago and until a few months ago I'd always managed to get by, but it's only occurred to me recently how many minor adaptations I'd had to make over the years to remain relatively pain free:
- left cleat set as far back as possible
- layback seatpost and saddle as far back as possible
- saddle set at a height that was a little too low for my right leg and a little too high for my left leg
- a Brooks saddle which over time had conformed to my differing leg lengths slightly and was noticeably 'sunken' on the left side
- 165mm cranks (I'm faitrly tall and convention is that I should use 175mm cranks)
Despite all these modifications cycling was becoming increasingly painful, to the point where I was seriously wondering whether I'd be able to continue. I started to seriously research my options - here are the results:
1 - use a shorter crank on the left. Through a process of trial and error I found that a crank 150mm long was just about ok, but I had to go to 140mm (ideally even less) to have minimal pain in my knee. The main problem with this solution is that it feels very odd not being able to fully extend my leg at the bottom of the pedal stroke and the whole set up just feels very unbalanced.
2 - use a pair of crank shorteners, with the left being 15mm shorter than the right. Similar to the above, this worked, but the 2 problems were still there, albeit that I could extend my leg slightly more. I also had to raise my saddle significantly, which had the knock on effect of having to raise my bars. Given that I already ride a large frame, this did look a bit like I was riding a circus bike!
3 - use a pendulum crank (http://www.getcycling.org.uk/details.php?id=460). The design of this means that it can be mounted to accommodate the 15mm difference in leg length, I can fully extend my leg at the bottom of the pedal stroke and it in effect makes the crank as short as you want it to be in the top dead centre position. The negative is the fact that it places my left foot about 25mm further away from the bike. This has resulted in minor muscle pain just above my left knee, although I'm fairly convinced that this is just a case of getting used to the altered position - it's already becoming less noticeable.
I've now used the pendulum crank for about 500 miles (including a 65 mile ride yesterday) and I'm incredibly happy to be able to say that my cycling has become almost pain free for the first time in years.
I'd like to offer a massive thank you to @mickle for sorting me out with the pendulum crank. I'll be calling and ordering at least one more in the near future!
I'm now starting the process of 'unmodifying' my bikes, one step at a time. Cleats, saddle and cranks are all being normalised and I'm pleased to report that's all going well so far.
Since then my knee has gradually become more painful (the last time I had it x-rayed I was told I had severe arthritis and the knee of a 90 year old!) and I've found it increasingly difficult to get over the top dead centre of the pedal revolution.
I started cycling about 20 years ago and until a few months ago I'd always managed to get by, but it's only occurred to me recently how many minor adaptations I'd had to make over the years to remain relatively pain free:
- left cleat set as far back as possible
- layback seatpost and saddle as far back as possible
- saddle set at a height that was a little too low for my right leg and a little too high for my left leg
- a Brooks saddle which over time had conformed to my differing leg lengths slightly and was noticeably 'sunken' on the left side
- 165mm cranks (I'm faitrly tall and convention is that I should use 175mm cranks)
Despite all these modifications cycling was becoming increasingly painful, to the point where I was seriously wondering whether I'd be able to continue. I started to seriously research my options - here are the results:
1 - use a shorter crank on the left. Through a process of trial and error I found that a crank 150mm long was just about ok, but I had to go to 140mm (ideally even less) to have minimal pain in my knee. The main problem with this solution is that it feels very odd not being able to fully extend my leg at the bottom of the pedal stroke and the whole set up just feels very unbalanced.
2 - use a pair of crank shorteners, with the left being 15mm shorter than the right. Similar to the above, this worked, but the 2 problems were still there, albeit that I could extend my leg slightly more. I also had to raise my saddle significantly, which had the knock on effect of having to raise my bars. Given that I already ride a large frame, this did look a bit like I was riding a circus bike!
3 - use a pendulum crank (http://www.getcycling.org.uk/details.php?id=460). The design of this means that it can be mounted to accommodate the 15mm difference in leg length, I can fully extend my leg at the bottom of the pedal stroke and it in effect makes the crank as short as you want it to be in the top dead centre position. The negative is the fact that it places my left foot about 25mm further away from the bike. This has resulted in minor muscle pain just above my left knee, although I'm fairly convinced that this is just a case of getting used to the altered position - it's already becoming less noticeable.
I've now used the pendulum crank for about 500 miles (including a 65 mile ride yesterday) and I'm incredibly happy to be able to say that my cycling has become almost pain free for the first time in years.
I'd like to offer a massive thank you to @mickle for sorting me out with the pendulum crank. I'll be calling and ordering at least one more in the near future!
I'm now starting the process of 'unmodifying' my bikes, one step at a time. Cleats, saddle and cranks are all being normalised and I'm pleased to report that's all going well so far.
Last edited:
but the quest to ride lighter as my 6 pack slipped below my belt meant ditching it. 
