# Dodgy knee, short cranks, pendulum cranks, pain and relief!



## simon.r (20 Sep 2014)

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.


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## mickle (20 Sep 2014)

Nuf respect rude bwoi.


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## TheCyclingRooster (9 Aug 2015)

simon.r said:


> 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.
> 
> ...




Hi Simon. Did you get fixed up with short cranks ? I have had total left knee replacement in November 2007 and grade 4 arthritis in my right knee and pending replacement at any time in the next couple of years.

The Bianchi Via Nirone 7 Alu Carbon in my Avatar and my Benotto Modelo 850 both have short cranks and Stronglight triple chainrings.

If you still need fixing-up then please reply to this post and if the forum has a PM system - PM me.


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## simon.r (10 Aug 2015)

TheCyclingRooster said:


> Hi Simon. Did you get fixed up with short cranks ? I have had total left knee replacement in November 2007 and grade 4 arthritis in my right knee and pending replacement at any time in the next couple of years.
> 
> The Bianchi Via Nirone 7 Alu Carbon in my Avatar and my Benotto Modelo 850 both have short cranks and Stronglight triple chainrings.
> 
> If you still need fixing-up then please reply to this post and if the forum has a PM system - PM me.



@TheCyclingRooster I'm very happy with the pendulum crank (link in my post above). I now have a number of the mounting brackets and two of the cranks so I'm not swapping them between bikes constantly. A year and a few thousand miles on I've adjusted to the pendulum crank and have no pain in my dodgy knee. I appreciate that your needs may be different, but for me I'm very pleased to say that this solution works.

(Just one comment for anyone else stumbling across this thread - the pendulum crank mounting bracket needs the crank to be vertically straight at the point it's mounted so the pedal is at 90 degrees. For me that has meant using a small wedge at the top or bottom of the mount on some cranks).


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## TheCyclingRooster (10 Aug 2015)

Hi again Simon. Thank you for your reply. 
Rather than post far to much info until I knew the thread was still active - I refrained.

Whilst I totally accept that the needs of the many are many and varied - my particular cycling continuity issue is made a little more difficult by the fact that I stand at 4'10" in my bare feet and have a rather short inside leg measurement of 23".

After several months of research and numerous phone calls I settled for the SJS (Thorn) 140mm products - indeed crank sets with five -arm spider. I actually have three complete crank-sets and all at 140mm so as to avoid the need for constant swapping,changing and adjusting.
This was also on the basis that I would have a wide choice of chain-rings from both Stronglight and Shimano.

Another consideration which resulted in the SJS cranks being chosen was the fact that I use the same Marcel Berthet Lyotard Platform Pedals with short reach toe-clips and straps on all of my bikes and only ever ride Selle Italia saddles.
The pedals can quickly be changed on any of the bikes and I can be riding clipless in minutes - possibly with a tiny adjustment to the seat height depending upon which shoes are used.

There is absolutely no power loss through the albeit shorter fixed length cranks and at 70yrs young next month that is an important consideration/need.
Despite my short stature I ride a 50cm Bianchi Via Nirone 7 Alu Carbon and a 52cm Benotto Modelo 850 with a third in the throws of being built - a 51cm Steve Goff frame-set.
The Steve Goff is now ready for wheels and bar-tape with all of the associated drive-train bits ready to fit.

I had also built and rode a brand new Fuji Track Frame on Fixed Wheel but the knees could no-longer cope with the continual rotation albeit I was riding an but that was later sold. The Fuji was built with a very quick change into a Flat-bar Road Hybrid as an option. It saddened me to let it go but a house move and a massive down-sizing left me with little choice.


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## Oatesy1 (21 Apr 2016)

Hi Simon, I know this is quite an old thread but yours is the only online feedback I can find relating to the Pendulum crank, which I'm considering for myself. I was hoping to get in touch with you to get some more information based on your experience. 

I have quite advanced osteoarthritis in both knees & struggle to bend either knee > 90 degrees. I'm not sure if it is feasible to use two Pendulum cranks or whether the pedalling effort required would be too much.
Cheers, Linda


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## mickle (21 Apr 2016)

You can try them and if you don't like them you can send them back (excluding the cost of postage).


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## TheCyclingRooster (21 Apr 2016)

Oatesy1 said:


> Hi Simon, I know this is quite an old thread but yours is the only online feedback I can find relating to the Pendulum crank, which I'm considering for myself. I was hoping to get in touch with you to get some more information based on your experience.
> 
> I have quite advanced osteoarthritis in both knees & struggle to bend either knee > 90 degrees. I'm not sure if it is feasible to use two Pendulum cranks or whether the pedalling effort required would be too much.
> Cheers, Linda



Hi Linda. Please forgive me for butting in here but I can probably help you a little further with this one. I considered pendulum cranks before opting for a fixed length shorter than normal crank from SJS Cycles.
The reasoning behind my choice was the potential for wear on the joint in the crank structure and the fact that a fixed length crank is always a positive connection.
The business of 'knee-bend' is largely down to to your stature and your general build and in particular you inside leg length/measurement from the ball of your foot to your 'Sit Bones'.
The fore/aft position of your saddle also has baring on whether your knee is comfortable with the action or not.
After locating the 140mm cranks from SJS Cycles I discovered that there were shorter ones also available but I cannot recall whether they were from SJS or Spar Cycles.
Just for the record - I am 4'10" tall and have a 23" inside leg measurement - I ride both a 50cm Bianchi Via Nirone7 Alu Carbon and a 52cm Benotto.
I find the Bianchi a more comfortable and manageable steed because of the stand-over height and the fact that is a slight dropped cross-bar model.

Which area of the country do you live-in ? You are listed as Perth is that still correct ?


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## Ajax Bay (21 Apr 2016)

@TheCyclingRooster I am intrigued to know how, with a 23" inside leg measurement (58cm) you are able to ride a 50cm or even a 52cm frame (c-c?), even with 140mm cranks. Do tell? Really useful thread for those of us pessimistically expecting knees to get worse than they are already.


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## TheCyclingRooster (21 Apr 2016)

Ajax Bay said:


> @TheCyclingRooster I am intrigued to know how, with a 23" inside leg measurement (58cm) you are able to ride a 50cm or even a 52cm frame (c-c?), even with 140mm cranks. Do tell? Really useful thread for those of us pessimistically expecting knees to get worse than they are already.



Hi Ajax Bay. Rest assured that I do ride both of the Italian bikes that I have shown in the images above and the Fuji track frame and many many others over the last few years - the largest being a brand new 2010 53cm Claud Butler Levante Flat-bar Hybrid.
The seat position on each and every one of my bikes is 750cm from the top down to the pedal spindle position.for the ball of my foot.
Before I had the Total Left Knee replacement I could ride standard 170mm cranks albeit with the seat correspondingly lower and on a 20.5" (52cm frame).
What I cannot do and have never been able to do is touch the floor whilst sat on the saddle albeit kerb-edges do come in very very handy at times.

I used to carry a brick on a piece of string  but the quest to ride lighter as my 6 pack slipped below my belt meant ditching it. 

You will doubtless have realised that I am not an 'Arse in the air head on the bars projectile' at 70 yrs young my back would not cope with the contortion.


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## Ajax Bay (21 Apr 2016)

TheCyclingRooster said:


> every one of my bikes is 750cm from the top down to the pedal spindle position


Now you're just boasting


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## TheCyclingRooster (21 Apr 2016)

Ajax Bay said:


> Now you're just boasting



Hi Ajax Bay. I wish to simply blame the grey cells after a serious fall from the bike when not focusing on the kerb-edge  - yes you are correct - but not a boast - only 75mm.


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## Ajax Bay (21 Apr 2016)

I'm sure your grey cells are fine, but now you've gone all minimalist! 


TheCyclingRooster said:


> only 75mm.


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## TheCyclingRooster (21 Apr 2016)

Ajax Bay said:


> I'm sure your grey cells are fine, but now you've gone all minimalist!



Hi Ajax Bay. 750mm or 75cm and 29.5" is all the same - take your pick. It all adds up to the same thing - I'm a 'short-arse' 70 yr old 68kgs rider.


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## simon.r (21 Apr 2016)

Oatesy1 said:


> Hi Simon, I know this is quite an old thread but yours is the only online feedback I can find relating to the Pendulum crank, which I'm considering for myself. I was hoping to get in touch with you to get some more information based on your experience.
> 
> I have quite advanced osteoarthritis in both knees & struggle to bend either knee > 90 degrees. I'm not sure if it is feasible to use two Pendulum cranks or whether the pedalling effort required would be too much.
> Cheers, Linda



@Oatesy1 I've been using the pendulum crank for approaching 2 years now and have nothing but good to say about it.

I still have a virtually pain free knee - in fact, if I have more than about a week off the bike my knee pain gets much worse, which I assume is due to it 'seizing up' through lack of movement. The 'minor muscle pain' I mentioned in my original post disappeared after a few weeks, so I'm putting that down to the initial slight change of position.

I can't see any reason why you couldn't use 2 pendulum cranks. You can still push down on the pedals as you would normally. Pulling up (if you use clipless pedals) there's a sort of 'dead spot' where your effort is moving the pendulum crank and not the actual crank, but that's not a real problem, it just makes you slightly less efficient. As I say, not a problem in the real world.

I'd take up @mickle 's offer if I was you (he works at the shop that sells them), you have little to lose by trying them.

I'm pleased you found this thread and hope it helps. PM me if you want to, but not sure I can add much to what I've posted here.

Hope they work out for you if you do decide to try them. Let us know!

Simon


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## simon.r (21 Apr 2016)

A couple of photos to demonstrate.

At the bottom of the pedal stroke (i.e. Leg fully extended), pedal in normal position:







At the top of the pedal stroke (i.e. Leg bend would be > 90 degrees without this), the crank is, in effect, about 70mm long (this is adjustable), meaning leg bend is well under 90 degrees):






There are 3 pedal mounting holes in the pendulum as supplied, I've shortened mine after deciding I only needed the one position.


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## Oatesy1 (22 Apr 2016)

mickle said:


> You can try them and if you don't like them you can send them back (excluding the cost of postage).



Hi Mickle, thanks for your kind offer. Please can you pm me with price + delivery cost to Australia. 
Cheers :-)


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## Oatesy1 (22 Apr 2016)

TheCyclingRooster said:


> Hi Linda. Please forgive me for butting in here but I can probably help you a little further with this one. I considered pendulum cranks before opting for a fixed length shorter than normal crank from SJS Cycles.
> The reasoning behind my choice was the potential for wear on the joint in the crank structure and the fact that a fixed length crank is always a positive connection.
> The business of 'knee-bend' is largely down to to your stature and your general build and in particular you inside leg length/measurement from the ball of your foot to your 'Sit Bones'.
> The fore/aft position of your saddle also has baring on whether your knee is comfortable with the action or not.
> ...



@cyclingrooster. Thanks for the input. I'm afraid my knee bend is very much affected by the osteoarthritis in both knees & much reduced. I think I need such a short crank that I wouldn't make much progress! The pendulum crank appears to allow much more power output than a smaller crank. Hence my interest in them. Although I could be wrong. It's a costly investment & one which might not work at all for me, which is why I'm doing some careful research. 
Yes, I currently live near Perth, Australia.


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## Oatesy1 (22 Apr 2016)

simon.r said:


> @Oatesy1 I've been using the pendulum crank for approaching 2 years now and have nothing but good to say about it.
> 
> I still have a virtually pain free knee - in fact, if I have more than about a week off the bike my knee pain gets much worse, which I assume is due to it 'seizing up' through lack of movement. The 'minor muscle pain' I mentioned in my original post disappeared after a few weeks, so I'm putting that down to the initial slight change of position.
> 
> ...



Simon, thanks so much. I really wasn't expecting any response, let alone such a quick one. The information & photos are very helpful. Are you saying that the maximum length of the Pendulum crank is 70mm or is that what you currently have it set at? I'm trying to work out whether it will shorten the cranks enough for me, as well as the knee problems I'm also quite short. Maybe @mickle can answer this. I will hopefully be able to take him up on his offer.
Thanks again, Linda


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## simon.r (22 Apr 2016)

Oatesy1 said:


> Simon, thanks so much. I really wasn't expecting any response, let alone such a quick one. The information & photos are very helpful. Are you saying that the maximum length of the Pendulum crank is 70mm or is that what you currently have it set at? I'm trying to work out whether it will shorten the cranks enough for me, as well as the knee problems I'm also quite short. Maybe @mickle can answer this. I will hopefully be able to take him up on his offer.
> Thanks again, Linda



You can alter the effective length of the crank to suit the amount you can bend your knee. In my photo the effective crank length is about 70mm, meaning I don't have to bend my knee much at all. You could make it more or less. Bear in mind that a normal crank is about 170mm long, so that's a huge difference.


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## Gail70 (30 Jan 2019)

I've just purchase the hase pendulum crank an have to say I'm impressed. Finally found a solution after 18yrs after an op leaving my kneecap to high leaving me with limited bend.


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## TheCyclingRooster (30 Jan 2019)

My use of permanently shorter cranks give a higher cadence- faster spinning.
Generally speaking the use of 140mm cranks is the equivalent of a two tooth increase in chainring size.
Since my very much earlier post with images I have sold my Bianchi Via Nirone 7 Alu Carbon and my Benotto is stripped and on E'bay and Gumtree. 
The Steve Goff is now fully built and on 10spd Campagnolo Centaur and I have also built a Bianchi Via Nirone 7 Alu Carbon as a Flat-bar Road Hybrid which is also on 10spd Campagnolo but this time I have chosen Veloce.

Both bikes are also equipped with my 140mm cranks and Stronglight triple chain-rings.


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## simon.r (8 Sep 2020)

Update!

I have recently discovered that unicycle cranks come in very short lengths and are available to fit square taper and ISIS* bottom brackets. This means that the clamp part of the Hase system isn’t required - the ‘pendulum’ part can be attached to the pedal hole on the short crank.

This reduces the Q factor and feels more natural. It also does away with the problem of getting the pedal absolutely square. As a side benefit I guess it also reduces the weight a bit.

*ISIS seems fairly common on E-Bikes, as pictured.


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## TheCyclingRooster (8 Sep 2020)

Way back on the 5th November 2007 I had my Left Knee totally replaced and corrective surgery performed at Liverpool Broadgreen Hospital and it left me with the inability to ride regular 170mm cranks because I could not acheive any better than a 92* bend and therefore could not perform a full circulatory action with my 'new knee'.
I worked out on my drawing board that changing crank arms to 140mm would cure the problem.
I had considered the other options as described in the post by simon.r but the Thorn 140mm cranks were the less fussy option.

I was already riding Stronglight 5 arm triple rings so with the help of Thorn cranks (SJS Cycles) the issue was satisfactorily overcome.
I had ridden Marcel Berthet Lyotard Platform Pedals.
Sadly I have parted with my last two bikes both built up from the naked frames and both running Campagnolo 10spd cassettes as per the two attached images in my previous post of the 30th January 2019.
Extreme arthritic pain in my right shoulder and elbow has put paid to my cycling just before my upcoming 75th birthday.


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## Godzilla (19 Oct 2021)

simon.r said:


> Update!
> 
> I have recently discovered that unicycle cranks come in very short lengths and are available to fit square taper and ISIS* bottom brackets. This means that the clamp part of the Hase system isn’t required - the ‘pendulum’ part can be attached to the pedal hole on the short crank.
> 
> ...


I've been looking for THIS solution, and didn't even know it. THX.


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