Search Results for CRANKARM SHORTENERS
Yes, I am talking about the crankarm shorteners again. They arrived in the mail today and I installed them on my wife’s recumbent bike I have set up on my indoor trainer out on the enclosed patio. I tried them out and WOW … what a difference! I really like them. I can position my feet normally on the pedals and pedal quite comfortably. My new freshly installed man made knee joints are loving them. There is only one problem. It is just too darn cold out there even inside the enclosed patio. At least I didn’t have that nasty wind to contend with. And this is jut the start of winter. C’mon April! I chose to install them on my wife’s bike instead of my trike … for now that is … as I don’t intend to try riding my trike outdoors in this miserable weather. Anyway, I just wanted to post a quick note about the crankarm shorteners. They really work great and I highly recommend them. BTW, wouldn’t you just know it? The very same place I bought my crankarm shorteners from is now selling them for over $7 less than I paid for them. The price I paid was the lowest I could find at the time. Oh well, it is truly the story of my life. 🙂
HERE is an article I wrote previously about crankarm length.
Here is a video which explains the need and benefit of shorter crankarms.
Short cranks are popular with many recumbent trike riders because they help you spin faster and also decrease the pressure on your knees. In general, for any given rider, the shorter the cranks are, the easier it becomes to spin a rapid cadence. HERE is the late Sheldon Brown’s article on the subject. And HERE is a short article about short cranksets and knee pain. And HERE is yet another article by Mike Burrows. And HERE is an article on how to determine (calculate) the crankarm length you need.
As far as I am concerned I think every pedal powered bike/trike should come equipped with crankarms which offer multiple positions for the pedals such as shown in the picture below. Then riders of all size can choose what is best for them. That just makes sense to me!
Shortening crankarms can be accomplished by replacing the crankarms or by using adapter plates with predrilled and tapped holes such as shown below. No matter which you choose none of it is inexpensive.
I personally really like the idea of the multiple hole add ons like I have pictured above and below. They offer all those positions. They space out the pedals a bit further widthwise. They are easy to install. And I would imagine that they are a less expensive way to go. However, from what few I have found online the cost is a whole lot more than I thought they would be … like within $25 of the cost of a new crankset. It is reported that these don’t stay tight and often times don’t fit the crankarms correctly.
Note: (1.5 years later after first writing this article) For what it is worth I now have a set of Ride2 crankarm shorteners (see further below) and have not had any problems at all with them.
IMPORTANT UPDATE: One of my crank arm shorteners fell off onto the ground as I was riding along. The 1/4 “-28 that attaches it to the crank arm sheared off. In the process of trying to get the parts needed to repair is I found out that the Ride2 product I bought is for children and not for adults. There is absolutely no mention of this on many websites selling these. They make one for adults so be aware of this and don’t order the black Ride2 shorteners for adult use.
HERE is their product for adults:
As you can see it is silver color.
Here is a video which explains the need and benefit of shorter crankarms.
There are various manufacturers of these crankarm shorteners and each is different from the other.
Adjustable crankarms are also available.
Yet another option some people go with is drilling and tapping new holes in the existing crankarms. So long as the crankarms are made in such a way that this can be done and the person doing this knows what they are doing this is by far the cheapest option. All that is involved is the labor to accomplish it. Definitely this must be done right or one would ruin an expensive set of crankarms. Ideally this should be done in a machine shop where accuracy in spacing and alignment be more ensured. Also the hole should be flat faced by milling the surface. Doing all this by hand would be more difficult to get it straight and accurate although it could be done. I have contemplated doing this to my crankarms. This should only be done on aluminum crankarms.
This person will professionally shorten crankarms. It is not inexpensive to have it done, but it is cheaper than buying an all new crankset. The two pictures above are examples of his workmanship.
Just a note here for those who ride tandem trikes: “Any tandem team needs to come to terms with the cadence issue. With practice and patience, most couples can work this out on a standard tandem. Some teams, particularly those who are not well-matched in leg length or pedaling style may benefit from use of different length cranks for the captain and stoker.” … from Sheldon Brown’s article.
Also from Sheldon’s article he states: “For reasons that are not completely clear, many recumbent riders benefit from shorter-than-usual cranks. Some people who have no knee problems on upright bikes find that their knees pain them when they ride a recumbent. Shorter cranks can often alleviate this, though it isn’t clear that the long cranks per se are the cause of the problem.
One theory is that the knee pain results from pushing harder, “lugging” in a too-high gear. With an upright bike, if you push very hard you are lifted up from the saddle, so you know you are doing so. With a recumbent, where you are braced against the back of the seat, it may not be so easy to judge how hard you are pedaling, so you may just over strain your knees by pushing too high a gear without realizing it.”
HERE is an article with information on what length of crankarms we should use based on our height. It only goes down to 5 foot 5 inches and up to 6 foot. HERE is another one with a chart showing inseam and corresponding crankarm length.
I used the calculator found HERE to determine the crankarm length I should use. Of course, it is only as good (accurate) as the measurements are you put into it. According to the results shown in the image below I should use about 135 mm crankarms. My trike came with 165 mm crankarms.
Note: The thing I have noticed about these various charts and calculators as they all come up with considerably different results. For myself I have found crankarm lengths ranging from 130 mm to 160 mm. That is a considerable difference and seems rather absurd to me. I guess this is why this subject matter is so controversial. Anyway, I am fully convinced that shorter people need shorter crankarms as do those who have knee joint issues.
One of the statements made on one the websites follows: “I think the main thing that this suggests is that the TA chart, which at first glance seems so radical in suggesting either very long or very short cranks, is in fact on the conservative side, and that short people especially might consider getting even shorter cranks than those recommended by the chart.” I tend to agree with this. I have found I do much better with shorter cranks than what some recommend for my inseam. I prefer the 130 mm crankarm length over the 155 mm length some show for me. I am short and have gotten shorter as I have aged. I have always had a short inseam. I have lost 1.75 inches in overall height thus far in my elderly years.
HERE are YouTube videos on the subject of short crankarms.
One thing to keep in mind, nearly everything written about this subject was written concerning bicycles and not tadpole trikes. I am no expert so I can’t say much about this. I can only speak from my own experience. As a short person who has had knee joint issues the shorter crankarms have been a God-send. My only regret is I didn’t switch to them many years earlier.
When it comes to short crankarms these are the options that I am aware of. Shorter crankarms just might be your ticket to help you …
ENJOY THE RIDE!
P.S.- (Dec. 2016 … 1.5 years later) I have purchased and am now using the Ride2 crankarm shorteners and really like them. Right now I have them mounted on my wife’s 2 wheel recumbent bike which is set up on an indoor trainer out on the enclosed patio. It is winter here where I live and too cold and too much snow to attempt riding my tadpole trike. I will install them on my trike when better weather comes along and I can go out riding it. I have also just undergone the surgical procedures for knee joint replacement on both knees so these crankarm shorteners really are helping during my rehab therapy. Right now I have the pedals in the next to the shortest holes which is about 106 mm I think. I expect to move them out further as time goes along. The various holes shorten the crankarms by 24, 41, 59 and 76 mm. So with 165 mm crankarms these adapter plates provide 141, 124, 106 and 89 mm settings. As you can see there is no 135 mm option. The closest I have is the 141 which is likely to be what I end up using in due time as I fully regain my range of motion.
Well, I dood it! 2 weeks and 5 days after my 2nd knee joint replacement surgery I rode my tadpole trike on the trail today. I wasn’t exactly burning up the asphalt, but it was good to be out riding. I had to pedal with my heels on the pedals as it was too painful to place my feet normally. I just hope I don’t go thru another session of several days of muscle soreness after riding today. I only rode about 2 1/2 miles and I spent most of it picking up tree limbs and tossing them off of the trail as we had rain and high wind last night which brought a lot of them down.
I wish I could ride my trike into the hospital and to the outpatient rehab room to show the staff there my therapy machine. Everybody is amazed at how well and fast I am progressing. I was walking without a walker one week after surgery. After the staples were taken out of the incision (10 days post surgery) they had me on the recumbent exercise bike and I was able to pedal it normally immediately. With the first knee joint replacement surgery on the other leg I had to take about 6 minutes of rotating the crankset back and forth before I was able to pedal it clear around in full revolution. So things seem to be going better with this 2nd surgery than the first one and everybody thought the first one went pretty well. I give thanks and acknowledgement to the fast healing power of God. I know I have a lot of people around the world who are praying for me. I thank each and every one of them.
Nope, I am not exactly burning up the pavement so I doubt if you smell anything like burning rubber. But hey, this “bionic triker” is working on …
KEEPING ON TRIKIN’
and I am hopeful that eventually I can come close
setting my tires on fire riding on that asphalt 🙂
(that might be a pipe dream for someone nearly 70 years old)
update: I did not have any soreness after riding so that is good. I sure wish I had the crankarm shorteners so I can change the pedal position. The crankarms on the stationary recumbent exercise bike in rehab has the crankarms set at their shortest setting and I can pedal it fine. I did so today and got up to 100 rpm a couple of times which BTW was about 80 watts of power being used by my body. Most of the time though I pedaled at about 50 rpm. I really enjoy riding the recumbent bike, but they won’t let me ride it very long as they want to get onto the medieval torture they get paid for. 🙂
It may not be a tadpole trike, but it is a recumbent and for now I am using it as part of my “rehab” after total knee joint replacement. It is said that pedaling is one of the very best things one can do for recovering from total knee joint replacement. However, just getting on and off of it is a bit challenging … getting my leg up and over the frame … more so than pedaling it. I am managing it though. Once I have myself straddling the frame I am “in like Flint”. That being said, in order to pedal I need to place my heel of my foot on the pedal so that I am moving my knee thru a smaller circle. I am slowly inching my foot backwards on the pedal as I spend time pedaling, but I only have to move it a short distance before I start “feeling” the discomfort it brings on.
The recumbent stationary bike in the rehab facility where I go is set up with the crank arms quite short and I can spin them easily … even at 100 rpm cadence. I usually only ride my tadpole trike at about 60 rpm. I really need the crankarm shorteners, but alas, my wife says no as she doesn’t want me to spend the money right now. So I am improvising by placing my heel on the pedal. Of course, when I get the other knee joint replaced in two weeks without the crankarm shorteners I will have to place both heels on the pedals. BTW, one might think that pedaling with one foot properly placed with the ball of the foot on the pedal while the other foot has the heel on the pedal would be awkward and weird, but actually it is not a problem at all. It feels rather normal and natural to me. Of course, I would much prefer to pedal with both of my feet positioned normally.
Hmmm, maybe I can sell something to get the money to buy the crankarm shorteners. They would be the “cat’s meow”. (For those who don’t understand that term here is a definition/explanation: “The cat’s meow” is an expression referring to something that is considered outstanding.”) I am not a fan of pedaling with my heels, but a guy’s gotta do what a guy’s gotta do.
Yep, you are looking at the cat’s meow!
While others … KEEP ON TRIKIN’ … I just want to … KEEP ON PEDALIN’ … until I can join you. 🙂
10/28/2016 Update: I have been able to slowly work at sliding my foot back on the pedal and continue to pedal until I was able to place my foot the same as my other foot. However, every time I get on the bike I have to start all over with my heel on the pedal. At least this progress is encouraging even if it doesn’t last at this point in time. BTW, I am now able to get on and off of the bike much easier that I could at first.
Cadence … when talking about bicycling is by definition: “the pedaling rate … the number of revolutions of the crank per minute.” I suspect that there will be those who don’t agree with what I will be saying here. That’s ok. To each his own as they say.
Typically most people pedal somewhere between 60 and 80 rpm. Does cadence matter? I say yes, it matters a lot. Ideally one should pedal as fast as they are comfortable with and can maintain without over stressing themselves. That being said I would add that it also is not good to pedal too fast even if you are capable of it. One needs to strive for a reasonable cadence. 60 to 80 rpm is ideal in my opinion. It is not good to pedal slowly while pushing hard on the pedals. It is far healthier to spin faster not exerting a lot of pressure on the pedals even if you are a brute capable of such. It is not only hard on your body, but it is hard on some of the components of your trike. In fact, you can quite literally do serious damage to your trike by pushing too hard on the pedals. We need to strive for a sensible compromise between how fast we pedal and how hard we push on the pedals. Most of our trikes come with quite a selection of gears. As one changes gears they should select the gear ratio which will keep them pedaling at the same cadence continually. Pedaling at a higher cadence provides more of a cardiovascular workout. Pedaling at a slow cadence pushing hard on the pedals can damage your knees.
I personally usually pedal at a cadence of about 60 rpm. I have found just recently that I can reach 120 rpm … something which I didn’t think I could do at my age. This was while using short crankarms. I am sure I could not do it with long crankarms like my trike came with. I would do good to pedal it at 100 rpm.
This cadence thing all gets into the matter of how your trike is setup. The length of the crankarms play a major role in what you are capable of when it comes to how fast you can pedal. Shorter people need shorter crankarms for optimal performance and doing right for one’s self. Too long of crankarms will prevent or at least hinder one’s ability to pedal at a proper cadence. Typically most bicycles and tadpole trikes come with fairly long crankarms. They are fine for taller people, but for those who are on the short side or have knee joint issues shorter crankarms are needed.
I have written previous articles about crankarm shorteners. I recently started using them and really like them. I wish I would have got them many years ago. Actually I wish manufacturers would simply install crank arms which either adjust or have multiple tapped holes in them so the buyer can position the pedals wherever they need them.
Some people are not capable of pedaling at a higher cadence. If that is true of you then all I know to say is do the best you are able to do. Most of us, however, are capable of pedaling at what is considered a proper cadence (60-80 rpm) and we should strive to do so as we will benefit from it. Learning to use the gears our trikes have so we maintain a constant cadence is essential.
Our trikes need to be set up properly with the boom adjusted to the correct length. Our leg extension needs to be about 85 % and our feet should be placed on the pedals so that the balls of the feet are making contact. We should not be using our toes or instep on the pedals.
Some computers have cadence sensing built into them. They require a pickup magnet and sending unit quite similar to that which is used for the speed. It, of course, is mounted on the crankset in order to measure the cadence. I have never had one myself. I have a pretty good idea of how fast or slow I am pedaling without having one. Cadence counters are good though. Since I have never had one I have simply used my watch and counted my rpms various times over the years. I have gotten to know my cadence thusly.
I personally believe that one can ride longer spinning at 50 or 60 rpm than they can at a higher cadence. And I think our bodies will thank us if we keep our cadence down to 60 or 70 rpm. When we spin faster we start using considerable more oxygen which is not good for our muscles over an extended ride. Muscle fatigue can occur if we spin too fast for an extended time. Blood flow increases with higher rpm so pedaling at 60 – 80 rpm is better than 30- 40 rpm as some people do.
Well, that is my take on this subject and you can take it or leave it. Spinning vs. mashing is healthier for us and for our trikes. Use those gears and maintain a proper cadence. It will help you to …
KEEP ON TRIKIN’