Mixing Crank Lengths for Leg discrepancy



bulaboy

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Jan 5, 2006
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CAMPYBOB said:
Where were you racing...back east or out west? I used to RR at Mid-Ohio and Nelson's Ledges.


I had polio when i was 2-1/2 years old. One leg is 1/2" shorter. I'm running a 172.5 crank and set the seat up to go with my shorter leg. For 34 seasons on a bike it's worked out fine for me. Good luck!
Same question to you Bob. Is your short leg weaker than the other? If so have you tried to build it up? Will it maintain strength?
 

CAMPYBOB

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Sep 12, 2005
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bulaboy said:
Same question to you Bob. Is your short leg weaker than the other? If so have you tried to build it up? Will it maintain strength?
Polio (infantile paralysis) is a disease that is kind of like getting the flu...you 'have' it, then it's gone. It's a virus.

Polio kills the nerves that control the motors of the body, the muscles. Simply put, the affects of polio are muscles that cannot be made to contract by the motor nerves that control them.

My polio centered in my right leg, below the knee primarily. From age three to age sixteen i went thru seven major and several minor operations. Some of these involved up to three months in a cast. This resulted in my right foot being two shoe sizes shorter (and yet wider..go figure) due to be restricted in those casts during much of my growth years. Rather like the Japanese binding of female feet to keep them dainty...heheh!

Needless to say that even after decades of racing and training there is a noticeable 'horsepower' difference between my legs. This gets much more pronounced as the time length of the effort grows. You know how racers can be seen on camera to be losing their form on the bike? This effect starts in my right leg. Then (maybe alienator does the same?) I find myself compensating with the stronger leg to make up for the loss of efficiency in the weak leg.

Still, it's great just coming across the line in the chase group or with the pack. It's a good feeling to give a max effort no matter the result.

Right now I'm 53 years old and staring post-polio syndrome right in the eye. This syndrome is the rapid loss of strength and control of limbs/muscles of polio (man, i hate the terms 'victims' and 'survivors')...those that had polio. It occurs in middle to late stages of life and the weird thing is that most affects those that trained to overcome their weaknesses.

Uh oh...not a good prognosis for a guy that raced and trained since I was eighteen!

No worries! Folks like alienator, bulaboy and I get back up from the road and keep on keepin' on.

I raced in the Para-olympic road race am proud to say I got my ass handed to me by the great time trial champion, Alan Kingsberry. Prior to the Para games, Alan was on a U.S. record pace in the nats time trial when he was struck, broadside, by a cement truck! His Tibia/Fibia on one leg has a 2" side-to-side offset, is shorter and yet he still managed to throttle it wide open to beat the best the world could throw at him.
 

alienator

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Jun 10, 2004
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bulaboy said:
Well if you're gonna wipe out you might as well do it with style. It's a credit to you that you were able to overcome the injuries as well as you have. After I touched down following my crash I lifted my head to check out the damage and my left foot was standing next to my knee like a boot. Is the strength in the shorter leg less than in the other? I find that my short leg just won't maintain the strength. I can devote months to bringing the strength up but as soon as I stop strength training the leg just shrinks back down again. The longer leg will always do more work than the short one and it is quite strong. If I had 2 legs like the good one I'd be an animal on the bike.

Any weakness in my leg is not a result of the tib-fib mangling, but instead a result of crashing and breaking my hip on that side almost two years ago. The surgeon who fixed the busticated hip had to do a lot of damage to my thigh to get to the bone for the fixin'. He said the downside to busting yer hip when you're young is that a lot more muscle has to be cut than if you bust yer hip when yer old.

At any rate, after a lot of PT, I don't notice, now, any real difference between my two legs.
 

danielhaden

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Jan 17, 2006
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Before you try such a large difference in crankarm length, do try a pedal shim. This will work out much more comfortably.

My left leg is short, so I just put a spacer into the bottom bracket to bring the left crankarm closer to the bike. This little 2.5mm spacer ring helped me a lot! However, if it is the other leg, I'm sure that an "adjustable cups" bottom bracket is up to the same job.
Some of my other bikes have a compact crankarm on one side, with a non-compact on the other.
Also possible is mountain on one side and road on the other. There's a lot of difference there. Even though the arms are the same length, this uses up at least 1/4" of the too-long leg. The short leg side has the crank that nearly touches the frame.

The crankarms are the same length, so there's no troubles with saddle positioning or over-working the injured leg by a shorter crankarm that unfortunately removes its leverage. That's not for me.

Pedal shim will work just as well and you can use this in addition to "tread offset" of having the short leg use a crankarm that's much closer to the bike frame than the other side.

Only after these adjustments should you start to consider different length crankarms.
In my opinion, a shorter crankarm on an injured leg will make yet more injury by working the short leg much harder than the long leg.
 

irishunder23

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Feb 12, 2007
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Hey guys,
Well its been a while since I started this chat and in the mean time I decided to place 8 Lemond Wedges stacked together underneath my left cleat and i have to say it has helped alot! virtually no back pain now which is a major improvment. Still need some tweaking to be pain free as maybe after 2-3 hours my back will anoy me but its little and does not affect my riding to much,
I will keep in touch will any further improvements noticed,
Irish Under23
 

9.8mps2

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Feb 9, 2006
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Outstanding. So you are shimmed only, with equal crankarms ? A lot of you guy's have some ballsey stories and have suffered to overcome much.
Aliens line caught my eye as a lifelong m/c rider .
"Right after the highside, I was alright " - Yeah ! then I hit the fekkin ground !
good on you lads.
 

bigpedaler

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Feb 10, 2007
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barndoor said:
As a US Chiropractor and cyclist I have a few thoughts. After so many surgeries and trauma, I would check with a chiro who can determine actual leg length difference from a functional difference. By this I mean your pelvis could be off by 5-10 mm. This would cause the legs to lengthen or shorten depending on which side is out of whack. Spinal adjustments to the lumbar spine and pelvis could stabilize the functional part of the leg length difference. Then the"actual 30mm" short leg may be more or less.

After treatment a more accurate set up on the biike could be done
was seeing a chiro a few years ago, and they tried to tell me the same thing -- my left leg is about an inch shorter (btw, i have no pedaling issues), they tried to say it was the pelvic imbalance. i first found out about my leg almost a decade earlier, in the army -- one boot heel wore faster than the other. but the idea that the pelvis shortens the leg is ludicrous. NO ONE is 100% biomechanically perfect, we all have some sort of imbalance, some are bigger than others; but you don't have enough power of persuasion to convince me that the spine is the source of it all, as presented by the chiro community. i used to play football, part of which involved placekicking (i kick w/ left foot), and there is no doubt in my mind that this, during my growing years, is the source of the imbalance i have.

i don't have a definitive answer about the efficacy of the 165/175 crank question, although it sounds like it would work; there are experts out there who can answer it. it may cost a bit, but the OP's dedication to riding sounsds like he believes it would be worth the investment.

btw, the chiro treatments (6 months long) did NOTHING for my imbalance.
 

alienator

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Jun 10, 2004
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9.8mps2 said:
Aliens line caught my eye as a lifelong m/c rider .
"Right after the highside, I was alright " - Yeah ! then I hit the fekkin ground !
good on you lads.

I really wuz alright after hitting the ground, and oddly enough, it felt kinda cool sliding down the track at some stupid speed on my back...kinda surreal. The whole "motocycle landing on leg and then proceeding to jump and down it a few times" did suck.

Yer right, though: highsides generally don't turn out well, whether your two wheels are powered by legs or by 110 octane Sunoco.