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

[simon.r]

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.

 

[Oatesy1]

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 :-)

 

[Oatesy1]

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 ?

@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.

 

[Oatesy1]

@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

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

 

[simon.r]

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.

 

[Gail70]

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.

 

[TheCyclingRooster]

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.

 

[simon.r]

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.

 

[TheCyclingRooster]

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.

 

[Godzilla]

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