Harry and all,
I would suspect that Richard might want to stay with the same make of crank that he uses now for the following reasons:
1) It is always easier to evaluate the effect(s) of fit changes by changing only one variable at a time. Changing the crank length at the same time as one changes the Q factor (crank width/pedal spacing from center) adds up to two major independent variables at once, which makes analysis of the results difficult.
2) Maintaining the same crank brand and model facilitates using the same chain rings and gearing. This makes life more economical and it further simplifies analysis: changing gearing at the same time one changes crank length = confusion as to results .
3) Aesthetics. Some of us just naturally prefer the look of Campi NR over SR (or vice-versa) or cannot abide Dura-Ace before or after a certain date. Others cannot live without Stronglight 93s. Cranks with the same "look and feel" keep us happy. Keeping the aesthetics the same will further reduce the potential introduction of outside factors ("This BMX crank set looks different") or analysis skewed by "looks."
There is much more to consider, but others have already covered a good number of points.
Regards,
Jon Spangler looking forward to catching up on my sleep after the TDF finale in Alameda, CA USA
On Jul 25, 2010, at 5:59 PM, Harry Travis wrote:
> Speedplay founder/engineer makes much of the company's expertise in custom fitting. They even distribute, to qualified folk, an extensive kit of wedges and extensions etc. for that customization.
>
> There's a lot to be said for not falling though, whether while becoming familiar with a new cleat system, or when a temporary pedestrian walking on polished floor. Be aware to accessory covers for walking, and even rubber bumpers for better walking grip, now available for some Look -style cleats.
>
> Yes, 165mm cranks from classic brands are harder to find; but the BMX crowd has established a firm demand for cranks down to 155mm length. They are available, inexpensive, and may even use on-topic bottom brackets. Bullseye was the name, but the same crank is now sold with a different label. BMX, yes, but you won't have to buy the purple anodized models.
>
> Harry Travis
> Pine Barrens of NJ
> USA
>
> On Sun, Jul 25, 2010 at 12:30 AM, Jon Spangler <jonswriter@att.net> wrote:
> Ted and Charles,
>
> Your posts about rehab and the many details of bike fitting offer a wealth of information.
>
> Charles, your comments on the many factors affecting one's rehab and recovery are excellent.
> There are SO many details to consider, all of them related....
>
> Ted's detailed descriptions of modifying cleats and bike parts to obtain a good fit remind me of my own
> less-sophisticated mechanical customization efforts.
>
> 1) I used long 5mm x 0.8 screws and nylon spacers between the pedal and the toeclip to functionally lengthen my
> (off-topic plastic) toe clips to accommodate work boots and running shoes and place the ball of my mismatched feet
> over the pedal axle.
>
> I used rubberized midsole material from my local shoe repair shop to add stack height to the (off-topic Look)
> cleats on one shoe to deal with a leg length issue, plus a whole package of the cleat wedges to position my surgically-
> reconstructed right foot.
>
> I may need to make a pilgrimage to visit Ted in southern California and learn more about the techniques I'll need to
> achieve the results I still seek...
>
> Jon Spangler
> who is encouraged in Alameda, CA USA
>
> Message: 12
> Date: Sat, 24 Jul 2010 21:09:57 -0700
> From: "Ted Ernst" <ternst1@cox.net>
> Subject: Re: [CR] Old Age vrs Crank Lengths
> To: <Classicrendezvous@bikelist.org>
> Message-ID: <C6FC9B0AC1724565B6B6913F43ED1140@D8XCLL51>
> Content-Type: text/plain; format=flowed; charset="iso-8859-1";
> reply-type=response
>
> All the individual experiences have put the hammer right on the nail!
> Everyone's problem and solution(s) is different and yet many are similar in
> origen.
> First when I do fitting with a rider who has had an accident, operation, has
> a congenital problem, any other a/o part or all of the above, I ask what
> they perceive a their limits are and where does it hurt or restrict
> activity.
> First I start with the foot position on the pedal and any ankle movement
> difficulty and work to resolve that.
> Too little foot on pedal and toes could get numb and not get best leg
> muscle leverage and efficiency.
> Too much foot into pedal gets into arch so that the "inner" center foot
> tends to "bend" on pedal and power loss results in more knee pressure and
> loss of efficiency.
> I would set foot position first and if you ride with clips and straps, if
> you have to, cut the toe clip in half and get it welded up to proper length.
> Then I go to leg length and set saddle height to good position for the
> longer leg.
> I've had good luck taking pedals and widening the plates to make up for the
> leg length discrepancy. Good welding can work miracles!
> Widest I've done is 3/4".
> By making the plates wider ala TA interchangeble plates, way ahead of it's
> time, you keep the leverage the same while allowing the short leg the same
> rotation and power without twisting back/spine too much on pedal revolution.
> Rotation and ankle float is an individual thing and do what's comfortable
> and works for you.
> I broke my femur head in a spill in '82 and has 4 pins in it to make it
> happy again. The foot slants out a few degrees after the set so that it took
> about a year to get my foot angle on my cleat to eliminate my knee pain.
> Because my fooy is angled out a little it made my hips a little off when I
> sat on saddle. I moved my saddle a few degrees over to straightn out my hips
> and I found that i could pedal straighter and easier on both knees and hips
> so that my inner thigh presure was eqal on saddle and I didn't get thigh
> soreness on one side of my inner leg by my groin. Paradise regained!
> Seems you can go about half the difference easily and body is able to adapt,
> but I like to go no more than 5mm diff.
> Then you can raise heel somewhat on stroke to compensate and not have too
> much difference in muscle stretch and efficiency.
> If you set saddle for short leg, then longer leg gets jammed and knee
> overloads losing much strength, and then hip get pushed up instead of pulled
> down by short leg giving back the same unbalanced stress.
> For years I rode 165 cranks on track bike, we started racing on fixed gears
> for all races from 1/4 mi to 50 mi.and then we got road bikes with 170's and
> we could go back and forth w/o any noticeable stride.
> I tried 172.5 but after over 20 years on 165/70 the 2.5's seemed to make me
> ride "squares" but then that was my "feel". Went back to 170.
> Remenber if you go down in crank length your leverage diminishes so that you
> may have to gear down a cog or you push too hard with higher ratios on
> shorter cranks overloading your knees.
> Your circle on longer cranks is much greater diameter and the resulting knee
> crunch is not always tolerable, so use crank and gear ratios accordingly to
> balance equation.
> I often use the tapered wedges Big Meat or the LeMond fit kit stuff to
> balance foot out so that your natural angle of downward push feels equal
> pressure on pedal.
> I also have taken nylon, plastic, delrin type material, cut to cleat
> outline, drilled holes/slots in plate and gotten longer screws , and
> attached the spacer in between the cleat and shoe to make up leg length diff
> when too many of the 1mm wedges were not practical.. One guy with over an 1"
> diff on leg length went to orthpedic guy and had a 3/4 inch piece of wood
> made for his cleat spacer and had this fat cleat on one foot, but voila
> foot/leg/back problemos - GONE!.
> Once the foot and leg reach differences are worked with then at similar time
> the seat for and aft plus height are brought into place and then the
> clockwise rotation moves to the bar and stem set up.
> It's a logical sequence, and the computers aren't bad to get close enuf for
> regular riding.
> If you have difficulties in setting up a special need, then all those Robert
> Hall suit averages are out the window and it takes a little "extra"
> knowledge and experience to fulfill a rider's need so that they can maximize
> their pleasure and get the exercise and fun they deserve.
> Positions are tricky at best and riders that aren't quite symmetric present
> a real chalenge for the fitting person.
> We all vary so much and we are so unique that the only rule that's constant
> is there's not a general rule thats constant in bike fitting.
> Down in the drops, it's the lowdown from
> Ted Ernst
> Palos Verdes Estates
> CA USA
>
> <snip>
>
>
> ----- Original Message -----
> From: "verktyg" <verktyg@aol.com>
> To: <Classicrendezvous@bikelist.org>
> Sent: Friday, July 23, 2010 10:57 AM
> Subject: Re: [CR] Old Age vrs Crank Lengths
>
>
> Dick,
>
> I had a total hip replacement back in 2003. I went through 2 months of
> physical therapy plus several more months of range of motion exercises
> to get back to "normal". Knees are far more complicated and recovery can
> take longer.
>
> I used to ride 170mm cranks on my road bikes and 180mm on my off road
> bike. My road cadence was 90, off road it was mostly mashing.
>
> Some folks claim to have the "Princess and the Pea" gift and can tell
> the difference between 170mm and 172.5mm cranks. Right now most of my
> bikes have 170mm cranks but a few have 175mm - I can't tell the difference.
>
> After the hip surgery, my right leg is 3/4" shorter than my left plus my
> right foot is canted out about 10? more than before. I've also had
> chronic tendinitis in my knees and bone spurs under my knee caps which
> have worn grooves in the cartilage.
>
> I use a pedal extender on my right pedal plus I ride with toe clips and
> straps but no cleats. This allows me to move my feet around at will much
> more than I could do with clipless pedals.
>
>
> The angle of my feet in the pedals has a major effect on knee comfort.
> My feet are wide, 10 1/2 EEE so I use wide MTB pedals. The toeclips are
> mounted all the way to the outside of the pedals. I ride with my toes
> pointed outward and that's had a positive effect on the tendinitis.
>
> You mentioned range of motion issues. I don't know that a 5mm (less than
> a 1/4") change is going to make that much difference for you.
>
> You might want to try riding with just a toe clip on the affected side
> and let your foot "float". You may even need a pedal extender for that side.
>
> It can take months of exercising to get your range of motion back.
>
> Good luck,
>
> Chas. Colerich
> Oakland, CA USA
>
>
> Jon Spangler
> Writer/editor
> Linda Hudson Writing
> TEL 510-864-2144
> CEL 510-846-5356
> JonSwriter@att.net
> http://www.linkedin.com/
> http://www.twitter.com/
>
>
>
>
>
> _______________________________________________
>
>
>
> --
> Harry Travis
Jon Spangler
Writer/editor
Linda Hudson Writing
TEL 510-864-2144
CEL 510-846-5356
JonSwriter@att.net
http://www.linkedin.com/
http://www.twitter.com/