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), 340 mm / 170 mm = 2.0. For a given set of chainrings and rear cogset, the bikes top gear is higher. We are focusing on the highest and lowest gear that you want for your geography and fitness. But am wondering what does that do as far as how high would I have to raise my seat, which way would that make my seat move, forward or backward, and how much lower would the handlebars be relative to my new seating position? I recently had a Retul bike fit with 172.5mm cranks. Does crank length affect saddle height? So if I go to a 165 to a 172.5mm crank length, it will be easier to pedal? This often causes a crash. Unfortunately, the handwriting is on the wall for all inch-based measurement systems. I m concerned that I might be too tall above the bars and have too much weight on my hands. The video below includes a discussion of this, explaining that power is determined by torque and cadence; although longer cranks do cause an increase in torque for the same force on the pedals they also tend to cause a decrease in cadence due to the larger pedaling circle. My take? You need a browser with JavaScript. or 170 (because Im on mtb). Webjack senior footballer; umaine graduate board. The chart below shows your gearing for 170, 165, and 160mm lengths. I notice that many of the people who express satisfaction with the change to shorter cranks also like to mention that they are getting older. 120mm / 2 = 60mm (half axle length) 60mm - 17mm = 43mm So I have a 43mm chainline from my rear hub. When I said Im looking for 165mm for my hardtail, people say 165 are not used much except for some women for mtb.. Its not so much that MTBs have longer cranks, its more that often all MTB sizes come with the same 175mm cranks; the bigger sizes still dont get 180+ as would be appropriate if the goal was merely to have them longer for everyone. Now you guess which crank length gives me no knee pain? Bikepacking & Ultra-Distance Cycling Advice, Crank length and comfort for long-distance cyclists, Avoiding Bike Crashes & What To Do If You Crash, Gear Ratios for Bikepacking & Ultra-Distance Cycling, Transcontinental Race results: Scratch rate, finish time & distance per day, Lieblingsblogs Folge 86 - Coffee & Chainrings, CRANKARM LENGTH & CLIENT FEEDBACK - Bike Test Reviews, https://www.suginoltd.co.jp/us/products/accessory/images/chainring-message.gif, Focus on Fit: Cycling and Hip Mobility and Alignment - Focus Physical Therapy, http://www.andel.com.tw/products.php?cid=32, Shimano 212-speed Dura Ace & Ultegra groups launched Ride Far, | , Scientific Opinion on Different Crank Lengths, Further Considerations for Ultra-Distance Cyclists. Its also easier to breath when the my knees dont hit my ribs . 170 to 175 doesnt sound like much but you need to add the 5mm at the bottom of the stroke with the 5mm at the top off the stroke. On the other hand, there doesn't seem to be any deleterious effect from shorter cranks. A 47/34 chainring combination? Kona is known for the possibility of huge tailwinds after hitting the turnaround at Hawi. 340 mm / 170 mm = 2.0. Thanks to David Richardson for the photo. Calculated by the Diameter of the Wheel times the Gear Ratio. Last Updated: Ive always used 172.5mm cranks (172cm tall and 82cm inseam) and have never had any significant, lasting knee or hip issues (a crash caused hip pain for a few weeks, and the knee issues have usually been the result of fore aft position being incorrect.) The lowest gear on most mountain bikes is around 22-26 inches. For reasons that are not completely clear, many recumbent riders benefit from shorter-than-usual cranks. WebThe Ratio of distance the end of the crank arm travels to the distance the wheel travels by taking into account the length of the crank arm. If your saddle height is less than 65cm you will definitely need cranks shorter than 165 (to open the min knee and hip angles). Since a short crank results in a higher gain ratio, this setup would ask the the weaker leg to push harder than the stronger one. TA Cyclotouriste, Lambert: bolts between outer chainwheel and others. In the case of doubles, measure to the halfway point between the two rings. Yes-and-no. If you find that you have serious cadence incompatibility, start by installing 175 mm cranks for the rider who wants a faster cadence. I call this a "gain ratio" (with thanks to Osman Isvan for suggesting this term.) Stronglight 80, 99, 100, SR Apex (Obsolete). There are many possible causes of this, but crank length should certainly be a very important consideration for such riders. On Sheldon Brown's gear calculator, there is the option of choosing the crank arm length. Ay, there's the rub! Its all about how long ones legs are. my Adventure Cyclist article about gain ratios. Yes, if you go to longer cranks without changing any of the other variables, you will have more "leverage", which is another way of saying you'll have a lower effective gearbut on a multi-speed bike, you can change gears at will! Or it is totally wrong idea ? My road race bike has 172.5 cranks, my cyclocross bike 170, my track race bike had 165 crank and my 29er MTb 175. Do you use the same gears on all bikes, regardless of crank length and wheel size? nc state baseball 2021 schedule. I then discovered how many ultra-distance cyclists have found that shorter cranks helped them to avoid or were a solution to certain joint problems. Some also have holes at 96mm for inner chainring. Rollout. 73 for oversized ISO/British. Gear Inches. I also agree with you about the long-distance bikes. When I was in my fourties, a friend gifted me his barely used Dura-Ace 172.5mm crankset. This gives a gain ratio of 5.8. Table of bolt-circle diameters 4-bolt, even spacing 4-bolt, uneven spacing 5-bolt 6- and 3-bolt More cribsheets: Click here! Manage Settings Fichtel & Sachs, Sachs and SRAM are the same series of hubs, shown together. His articles are worth your time to read, and are a large part of what got me personally interested in bicycles. But make sure that the problem isn't just that, Crank-extractor threads of a cotterless crank may be damaged. Now the mtb has 175mm cranks and things seem better although the road bike is still on 177.5mm. 170mm cranks, which most cycle manufacturers fit as standard to most bicycles, are unsuitable for anyone shorter than the Most bicycle chainrings have holes spaced around a bolt circle to attach them to the crank,. Many cranks by the major brands like Shimano, SRAM, and FSA are officially listed as also being available in 165mm, but that length can be difficult to find for sale after-market. Calculate How to Use the Crank Length Calculator 1) Measure your inseam (barefoot from the ground to the top of your crotch) How to Measure Inseam for the crank length calculator 2) For any distance bike riding like road, gravel, touring, XC MTB, etc the calculator should give you an exact length. I loved having the 55 for downhills and tailwind. Table of bolt-circle diameters 4-bolt, even spacing 4-bolt, uneven spacing 5-bolt 6- and 3-bolt More cribsheets: Click here! Youre almost on top of the rear axle and there is simply no place further back to go. Its not perfect; changes in cassette size have a larger overall impact on gearing. For double road cranks and single speed cranks this is straightforward, but for triple cranks there are two current measurement methods: Further, the confusion that your table is attempting to help solve is the same confusion that we tried to address in the ISIS Drive standard. The term was coined by Grant Petersen during his time at Bridgestone Bicycles. Ferrer-Roca and coleagues published research on the effect of crank length in the Journal of Sports Science in 2017. Feel free to print it out, but please don't reproduce it without proper credit and linkage. Shimano cartridge bottom brackets are typically coded with a model designation and two numbers: shell width and length. The highest gear on road racing bikes is usually around 108-110 inches. 1395w-3a(b)) is amended (1) in paragraph (1) (A) in subparagraph (A), by inserting after "or 106 percent" the following: "(or, for a multiple source drug (other than autologous cellular immunotherapy) furnished on or after So it is a no brainer that at 67 years old and 171.5 cm (I have shrunk from 174cm) I need to drop from 172.5mm cranks to 165mm, Happy to do so but I have no idea how this will affect the set up of other components (including cleat position). 6C iron fore plane. In some instances, deliberately setting the saddle slightly askew might also help. Thanks for writing this article for us. All of these systems share a common inadequacy: none of them takes crank length into account! A broken crank. Rotors 3D+ and Flow cranks should be available in lengths from 155 or 160mm up to 180mm [update, Feb. 2018: the new Rotor Aldhu 3D+ crankset is available in 150-175mm lengths), and Vision Trimax cranks in 155-175mm. I think I will end up going with the shorter cranks. Does the angle of the extension (deviation from perpendicular) change relative to the seat tube when the crank is rotated? Some crank length changes require odd chainring sizes, such as 37, 40, and 41-tooth sizes. We and our partners use cookies to Store and/or access information on a device. For other factors to consider when choosing gears, see the Gear Ratios for Bikepacking & Ultra-Distance Cycling page. There is certainly no blanket rule or advice that works for everyone. I also feel I get less fatiqued as the smaller circle and bend of the knee is more natural for me. To keep the saddle to bar drop constant, you would then need to raise your bars by 7.5mm, which could be done by moving spacers, flipping the stem to have a positive instead of negative angle (although that will probably cause a much bigger change, so at the same time youll probably want to lower it) or buy a stem with a different angle. Very odd that I am taller than average, and everyones frame in my size is labeled large or extra large, yet I get the best fit and a big performance boost with the smallest of the standard crank sizes. The proper crank arm length is typically dependent on the riders height and inseam. 68 rabbeting spokes. 24 mm spindle, spacer to use 6805 bearings with 25mm I.D.. Bottom bracket shell must be faced so cups are parallel. Very old Campagnolo standard (pre '67) (Obsolete), Standard Road double and triple (outer 2); Sturmey-Archer FCS, Stronglight 93, 101, 103, 104, 105 (Obsolete), Old Campagnolo Gran Sport touring, Victory, Triomphe, Campagnolo CT inner/middle/outer with one bolt at larger diameter behind crank, FSA K-Force ABS: uneven pattern, 4 bolt with extra bolt behind crank. Webcrank arm length calculator sheldon brown hypersensitivity vasculitis after covid vaccine urban sucking. Tighten the tool onto the crank. The first number given is for holes either side of the crank. If this helps, but not enough, get 165 mm cranks for the rider who has trouble pedaling fast. and the rough area where the crank finally gave way. So, why do cranks offered on mens bikes only vary between 170 mm and 175 mm, a 3% difference, and on womens bikes between 165 mm and 172.5 mm, a 4.5% difference? A mountain bike with 26 inch wheels (13 inch radius) and 6 3/4" cranks: Remember, the "radius ratio" only has to be figured out once for a given bike, because it is the same in all gears. (Check that it doesn't wobble as the pedal is threaded in.). --> All the calculators above suggest far longer cranks for my inseam, so Ill continue with what I have for now and work on my hip mobility, but if any issues arise Ill just bite the bullet and go to 175 cranks. Cobb do 145, 155, 165. Weight Double this, subtract it from the over-lock-nut dimension of the hub (or the frame spacing , which should be the same), then divide the result in half, and you have the rear chainline. The "Q" stands for "quack", a reference to the wide stance and In many cases, it makes more sense to upgrade to an inexpensive modern cartridge bottom bracket. There is no need for the plane to be aligned carefully perpendicular to the centerline of the frame, because you need only calculate the difference between measurements. To view the purposes they believe they have legitimate interest for, or to object to this data processing use the vendor list link below. 1 comment share save hide report 100% Upvoted Log in or sign up to leave a comment Log InSign Up Sort by: best level 1 Some triathletes and time trialers are now using shorter cranks so that they can more comfortably have their bars at a lower, more aerodynamic position without their knees coming up too high or their hips compressing too much. I did not want this to be true because it was a fairly expensive change, but switching back and forth on the fit bike made the improvement too obvious and too dramatic to ignore. TA Criterium bolts between outer chainwheel and others. Because the seat tube isnt vertical, the vertical drop from saddle to bars will increase by slightly less than the amount you raised the saddle by, but hopefully you can change your stem position or angle to compensate. Campagnolo Super Record, Record, Chorus 2015- inner. The Ratio of distance the end of the crank arm travels to the distance the wheel travels by taking into account the length of the crank arm. I have a Shimano ultegra crankset. Thus, if you know the chainline is 48.5 mm with a 113 mm ISIS Drive spindle length, then you automatically know that if you use a 118 mm ISIS Drive spindle length your chainline will increase by 2.5 mm (each crank moves outward 2.5 mm, for a total of 5 mm). Garrett Smith, Truvativ International. However, many people find it hard to notice the difference if changing their crank length by only 2.5 mm. What can Daniel do? You can calculate gain ratios, gear inches or meters development with my, A road bike with 170 mm cranks: (The usual generic diameter value for road wheels is 680 mm, so the radius would be 340 mm. The 2 bikes are very different in frame geometry and frame size though. I think it affects the "gain ratio" value which is Sheldon's way of interpreting the effective leverage at the pedal by using a ratio between crank arm and wheel radius and using that value instead of just the wheel radius like gear-inches does. For multiple calculations, you should close each set of results in turn, not hide them. We and our partners use data for Personalised ads and content, ad and content measurement, audience insights and product development. The method used by Lennard Zinn suggests using far longer cranks than most other sources recommend. how much is murr from impractical jokers worth; fanatics cowboys jersey; what kinds of news are most important to you Several studies have examined the effect of crank length on power output. Lets pretend that both your road and triathlon bikes currently have 170mm cranks, 53/39 chainrings, and 11-23 cassettes. When trying different crank lengths, keep in mind that shorter cranks encourage a higher pedaling cadence (because people tend to keep their tangential foot speed constant rather than their rotational foot speed). --> Instructions have been moved to a separate page. The term was coined by Grant Petersen during his time at Bridgestone Bicycles. This system is a bit more cumbersome than the gear inch system, for two reasons. SRAM XX1 11-speed, Cannondale, Specialized Stout. If there are three spacings, the last and smallest is for holes opposite the crank. Using Browns gear calculator, I got as close as possible to the baseline 170mm 53/39 numbers by manipulating the chainring sizes. if(typeof ez_ad_units != 'undefined'){ez_ad_units.push([[468,60],'sheldonbrown_com-large-mobile-banner-1','ezslot_3',827,'0','0'])};__ez_fad_position('div-gpt-ad-sheldonbrown_com-large-mobile-banner-1-0'); If you do a calculation, get a result, then bring this window to the front, subsequent "results" windows from subsequent calculations may be hidden behind this window. All of the racer guys at the shop told me that I needed 172.5s, but I had no problem keeping up on the hills or anyplace else for that matter. One theory is that the knee pain results from pushing harder, "lugging" in a too-high gear. Crank lengths: TA cranks, 155 and 170mm; between them, a 4-inch Webcrank arm length calculator sheldon brown. Using Browns gear calculator, I got as close as possible to the baseline 170mm 53/39 numbers by manipulating the chainring sizes. We and our partners use cookies to Store and/or access information on a device. Why not? Im a avid mountain biker. If your saddle height is less than 65cm you will definitely need cranks shorter than 165 (to open the min knee and hip angles). (The radius ratio)2.0 X 53 / 19 = 5.58This number is a pure ratio; the units cancel out. Zinn cranks are great, but cost significantly more. My very best friend, a cyclist, Chiropractor and Acupuncturist is 5 5 1/2 tall. Bottom brackets come in different sizes, according to the nationality of the frame. The problem is, the industry settled long ago upon the right length crank for a given size of bike for example, try finding a size 56cm without 172.5mm cranks attached. I found that it made my knees hurt every time I rode it. Some define short as 170mm, while others dont call it short unless its 150mm or below. On Sheldon Brown's gear calculator, there is the option of choosing the crank arm length. 6C iron fore plane. Oxygen demand could loosely be tied to the amount of fuel being burnt and therefore making better use of this resource. Total height has nothing to do with what length crank is appropriate for a given individual. Gear Inches. http://www.andel.com.tw/products.php?cid=32 . Thank you for collecting all these helpful information. Overall, cranks must be the poorest-fitting part of a bicycle, but this is rarely discussed and bike shops rarely suggest changing it even when doing a full bike fitting. Diameter matches, but thread pitch does not. There seems to be a lot of internet people in my size bracket who all seem to be happy moving down to 165mm and very few happy moving the other way. anodization of rims. Most bends of cranks are obvious, and the crank will have a scrape where it hit the ground, but if not, there is a way to test, avoiding the need for precise setup or measurement. For small changes in crank length, gearing is minimally affected, but anyone considering a big change (> 5mm) should take a few minutes to run a gear calculation using the tool linked above. Prone to problems due to the right-threaded fixed cup, which tends to unscrew itself in use. However, ultra-distance cyclists are not very concerned with how much power they can possibly generate and instead focus on optimizing comfort and avoiding over-use injuries, so how might it affect those criteria? Im building an entirely new bike specifically for riding far. The BCD when holes are evenly spaced is: They present the same formulas as I do above. Garrett Smith Then come back to this page to find out which common brands and models use the bolt pattern that you have identified.The templates also slet you quickly determine a chairing's tooth count. just like KOPS, its not exact science, but it was derived from Squating mechanics. Most of the research on the topic shows basically no change in power over a broad range of crank length, so it should be comfort and injury avoidance that primarily determines your choice. 1.701, 1/sin 36, times the spacing between adjacent holes, Any help out there? The 54 is doable, as several manufacturers make this choice. Most people would consider a 10 mm difference in saddle height to be significant and noticeable, so the same should be true about crank length 5 mm is already quite a lot. This gives a proper 47.5 mm chainline and lower Q-factor. Her inseam is 78 cm and she has just changed her crank arms from 170 to 165 mm and reports an An example of data being processed may be a unique identifier stored in a cookie. The selection of cassettes is up to date as of February 2018 for Shimano, SRAM, SunRace and recent Campagnolo models. But physics says that the longer the lever arm, the more you're moving but the less force you're putting in. Webdwayne johnson rock foundation contact. I used to occationally have knee problems, quite painful at times, with 170 and 172,5mm cranks. My wife is over 70 and Im over 60. The most common lengths are 170, 172.5 and 175 mm, but it is possible to find cranks between 165 and 180 mm in the market. Note that this results in the middle chainwheel's being to the right of the chainline for the middle rear sprocket. The largest frame size is therefore about 25% larger than the smallest for each gender, and if we look at distributions of peoples heights then these sizes should cover at least 95% of both males and females. document.write(document.lastModified) There might have been other reasons, but I felt this helped as soon as I got the new cranks. 170 to 175 doesnt sound like much but you need to add the 5mm at the bottom of the stroke with the 5mm at the top off the stroke. Im 183.5 cms, and was using 175mm cranks on a road bike before my knee op. Calculatrice des Braquets de Sheldon Brown. And the big component makers should bring back 165 and 167.5mm road cranks at every price level. Proportionally, 200-210 cranks are equal to 165-175 cranks when a 32 vs 38 inseam is compared. Kept telling myself that I would adapt. Also, the resulting value is a less-convenient number to work with, a single digit plus two decimals. speed. one sprocket unless you choose a stock cassette. 172.5 to 165 mm should make a noticeable difference and I would say its worth it, but Im surprised that your bike came with a 172.5 if you are small enough for the guidelines to suggest 160mm cranks. In this case, hes likely stuck choosing between a smaller 39-tooth chainring or staying with his existing 42. I am female of average height (1.77 metres) but have an inseam of 86cms, which is LONG! Having got used to the increased comfort, I could never go back to using the longer cranks for the long-distance cycling that I love to do. In countries that use metric measurements, the usual system is "development" in meters. What effect does this have in the available calculations (i.e., gears or speed)? nike air force 1 '07 light bone/white. Im not even that short, about 175cm with 79-80cm inseam. To find out whats right for you, youll might need to start experimenting, but the formulas might at least give you a better starting point than the simple whatever crank length came on my bike technique. I've seen the sizing of cranks increase over these past years on road bikes when before it was rare to see anything bigger then 172.5's. So if I go to a 165 to a 172.5mm crank length, it will be easier to pedal? (Chainring already mounted in desired position on crank.) Lot# 3 - Trustworthy 14-inch iron jack p. Lot# 4 - Scarce OHIO TOOL 18-inch iron s. ABSENTEE ONLINE BIDS CLOSE BEFORE LIVE AUCTION AND ARE BID AGAINST LIVE AUCTION. WebOnline Gear Calculator or with your slide rule An Example: A road bike with 170 mm cranks: (The usual generic diameter value for road wheels is 680 mm, so the radius would be 340 mm.) For someone from 5.5 5 10, a 175mm usually works well and taller folks may want to consider 175mm+ cranks. I replaced Cinelli criterium bars with cow horn type, and now find I need to reduce the reach forward stem with adapter for steel frame and an adjustable stem to get bars 50mm higher, and 50mm back from where they used to be. Bolts not interchangeable with others. This is a partial catalog. Shorter cranks can often alleviate this, though it isn't clear that the length of the cranks itself is the cause of the problem. The Obree and Machine formulas place me on a 165-167.5mm. They can sometimes be found from smaller manufacturers, but none of the biggest component manufacturers make them. I had a pair of TA 150 cranks that used to be on my kids' Cinelli BMX bike, so I've put these on the Trek. nike air force 1 '07 light bone/white. Hallelujah! Thanks for sharing your experience, Art. TA Professional (10 mm holes), many old Euro steel cranks. I have got the x rays back and they confirm chronic FAI, the I standing for (hip) impingement. Lot# 1 - Siegley No. The design is a real benefit to riders who have a splay-footed (toes-out) pedaling style, avoiding interference between the rider's heels/ankles and the crank. TA Spcialites is well-known for offering a wide range of crank lengths, with the Vega and Carmina models available in 155-185mm lengths. Webcharles schwab 401k login; adidas gazelle women's black. When I first get on the bike after riding with longer cranks, it feels a bit funny at first, but within a very short distance it's just fine. Measurement using a ruler The table below on this page gives the dimensions hat you need to measure using a ruler. Put simply, a set of 55/42 chainrings on a 165mm crank is a huge gear. Since Im on Shimano (ultegra), the shortest I can get appears to be 165mm. The knee pain would die down after about 6 weeks but has come back twice after overdoing it a bit in group rides. It could be worth a shop's doing this test if it does a lot of repair work, You need to make a tool. I used Sheldon Brown's gear inch calculator, and the length of the cranks made no difference in the gear inches. This is the distance that the bicycle moves with each revolution of the pedals. In any case, I have to shift gears more often, drive smaller gears and cant just push over small hills or climbs like before. Webcrank arm length calculator sheldon brown. People shorter than the range that these cranks are suitable for have far more bend in their knees at the top of the pedal stroke than is ideal and those who are taller have far less of a bend in their knees. Some of our partners may process your data as a part of their legitimate business interest without asking for consent. Webcharles schwab 401k login; adidas gazelle women's black. In addition to the lines for recommended crank lengths, the graph above also includes typical height distributions for males and females. Id switched to 180mm cranks about 18 months previously with no issues including 9 hour races. This is close to the chainline of the outer ring of a typical MTB triple. Thanks for the great info. For the purpose of this graph, Ive assumed that inseam = 0.475 * height, but this wont be true for everyone, so its better to measure your inseam and use the formulas. Coming back to cycling and Audax events in my fifties, I found all bikes offered to me in 172.5 or 175 mm. WebOnline Gear Calculator or with your slide rule An Example: A road bike with 170 mm cranks: (The usual generic diameter value for road wheels is 680 mm, so the radius would be 340 mm.) You sometimes see 56cm I'm running a 45/17, which gives a gain ratio of 5.9, just a bit higher. But physics says that the longer the lever arm, the more you're moving but the less force you're putting in. The ordinate axis units (for height) are listed as mm; I think they should be cm. The simplest system in common use is the "gear inch" system. This is what comes stock on most tandems. Patrick T. I developed knee pain on one side after a long mtb bikepacking race. cranks (most Japanese models) may bottom out if installed on ISO spindles. While there is general agreement about the angle, there is no such agreement about the actual width cut off. WebPhone: 3144977884. are adjusted to nearest whole degree of angle between bolt holes, Im preparing for tour divide. Calculatrice des Braquets de Sheldon Brown. Press J to jump to the feed. The hip joint is optimized for walking, and in normal walking the footsteps are pretty much in line, with little or no "tread.". FSA Afterburner, Comet, K-Korce, SLK MTB ABS. A cotterless crank may be loose on the bottom-bracket spindle. I would certainly recommend experimenting with it, but I also wouldnt want to change many things too close to your big event without having the chance to properly test them. If the mountain bike has 175's and the road bike 170's, the gear on the mountain bike is really about 3% lower! 170mm cranks, which most cycle manufacturers fit as standard to most bicycles, are unsuitable for anyone shorter than the Please consider donating a few dollars towards our costs. These two characteristics of ultracyclists (extensive use of aerobars and possibly a slightly lower saddle height) suggest that ultra-cyclists should certainly experiment with using shorter cranks than would be recommended by the universal formulas above. Youre considering a change to short cranks on the tri bike, and would like to maintain the same gearing. Im 61 and frames my size come with 175mm cranks. If your saddle height is less than 65cm you will definitely need cranks shorter than 165 (to open the min knee and hip angles). The small one will overlay the large one in a browser which supports tabs. I used Sheldon Brown's gear inch calculator, and the length of the cranks made no difference in the gear inches. Cranks that are too short are not dangerous, however. In his book Bicycle Design, Mike Burrows warned against using cranks that are too long to avoid knee problems and Sheldon Brown has written about crank length and how riding with cranks that were too long for him caused knee pain. In the case of ISIS Drive, the standard spindle lengths are symmetric and vary in multiples of 5 mm. My very best friend, a cyclist, Chiropractor and Acupuncturist is 5 5 1/2 tall. for everybody, i also tried these tables you get a crank arm at X length. Garrett Smith, Truvativ International. This brings up one question, for me. There are some specific characteristics of long-distance and ultra-cycling that suggests that cranks lengths shorter than suggested by the above equations could be more appropriate.