Crank length for height. Primož Roglič is aboard 172.

Crank length for height That includes the rod length, one half the stroke length and the pin height. ” 175mm? 180? Custom length specially made? What actually makes these the Apr 25, 2022 · Of course you'd have to raise the saddle with shorter cranks. ) Please Note: Only an estimate of your ideal crank length for height in proportion to leg length is given by the crank length calculator. 5 does not track with body size but stays flat for a wider range of bike frame sizes. BMX Racing Schedule with localised times; BMX Racing Medal Tally Since 2008; BMX Racing medals since Beijing 2008. Generally, most bikes are fitted with a 170-175mm crank, but the range can stretch from 140-190mm. May 9, 2012 · But for the record I would be more concerned about running too long a crank (i. Feb 9, 2022 · Crank Length It’s surprisingly common to see people with their saddles much too low because they’re using cranks that are much too long. 5mm and I’m thinking upgrading to a shorter crankset. Graeme Obree, the Scottish former hour record holder, proposed a formula of 0. Publish Date: January 8, 2023 Updated: November 25, 2024 May 16, 2020 · 2. The moral of the story is specifics matter and Go way shorter lots of benefits for shorter cranks despite height. You cannot talk about this without context for the type of bike and era. A crank length calculator takes these factors into account and recommends the ideal crank length for the rider. If your height is 5’5” – 6 feet you are likely spinning 172. What Is The Crank Length. The same goes for Davide Ballerini (5’9″; 1. Crank Length Recommendations. 95 * height “Machine” method: crank length = 1. Nov 16, 2021 · Also, shortening crank length by 10 mm should ideally be paired with raising the saddle height by 10 mm so the leg extension with the pedal at the bottom of the circle is the same. 5mm has so little to do with this that its probably not worth talking about. Femur length in inches should be the same as crank length in cm (alternately, femur length in cm divided by 2. A few studies have attempted to find the ideal crank length and decide if rider inseam or height is the determining factor, but the results have been confusing and contradictory. The ideal crank length for a modern full suspension vs hardtail vs ridgid mtb vary, moreso when comparing bikes built in previous era. Use charts, apps, and formulas tailored for mountain bikes, Shimano, and 5DEV. Mountain: crank length = inseam * 0. 5 mm cranks. 2 cm. Sep 17, 2022 · What is the Optimal Crank Length? In a study conducted in 2002 tested the affects of crank length on maximum cycling power. Using special adjustable crankarms, subjects rode with Apr 18, 2024 · When choosing a bicycle crank length, it’s important to consider the crank length comparison and the pros and cons of different options. Although many cyclists begin with the standard length that came with their bike, various riders require varying lengths for best performance. Last week, I installed a set of R7000 165mm cranks to replace the original 172. Nov 26, 2021 · Where does evaluation of crank length take place? Before the practical/on bike part of a bike fit two things need to happen: evaluation of the bike; Measure up the key elements, seat height, saddle fore/aft, reach, stem length, stem angle, and of course includes crank length. 5mm to compensate for the shorter crank length with the leg extended, the increased distance from the saddle to the top of the crank arm when at the 12 0clock position will be 5mm. Choosing Crank Length. Should I choose a crank length from the acceptable range provided? The acceptable range provided by the calculator offers flexibility in choosing a crank length that suits Because the crank length is a part of your bike fit, the best length depends on your height, body proportions, and joints. Select the appropriate crank length of your trainer: Match the crank length of your road bike. D. 021; Limitations. Seat height was set to match each Short Cranksets Selector Guide What crank length is right for me? Several years ago, we began promoting the use of a shorter length crank arm for all bike riders. Crank length. Typically, the modo adopted by the industry is this: Choosing the right crank arm length is crucial for optimizing your cycling. On the track someone 6'6" may actually want 160 mm crank length to improve turnover rate. The Orca has 172. The longer the cranks the lower the saddle, the shorter the cranks the higher the saddle. May 1, 2001 · The crank length to leg length and crank length to tibia length ratios accounted for 20. 5 length cranks, the Diverge has 175. If you are 170cm tall, you should use “165mm or 167. bicyclerichmond. com/Free eBook for road cyclists: https://www. uk/Support the channel, check out my streetwear brand here - https://wearethewildones. Washington would be absolutely devastating. If we think of things in terms of saddle height : crank length, lets compare a triathlete (athlete #1) who has a saddle height of 860 with 172. 95 x rider height, divided by 10. 5% of their height or less. 2. Optimal crankset length. This measurement represents Nov 29, 2024 · Here, you’ll find the key factors for choosing the ideal crank length: 1. 217 + height * 0. One early study (1976) experimented with different proportions of crotch height and concluded that ~20% was the most suitable. 022; BMX: crank length = inseam * 0. My saddle height is a little lower than average due to an ISM saddle and trying to mitigatingmitigate knee pain and both bikes have got identical saddle height when measured from the bottom bracket. This study is an outlier re: optimal crank length – probably due to the upright cycling position. 10 to 2. While many bit fitters agree that crank length should be proportional to body size, there are numerous methods for determining ideal crank length and many cases in which a rider’s Dec 30, 2022 · 4: Swap Crank Length: Switching crank length, reinstalling pedals, adjusting seat height, inputting new crank length into cycling computer and power pedal calibration took approximately 5 minutes. By inputting this value into the calculator and clicking "Calculate," the estimated crank length would be: According to their findings, the optimal crank length is “20% of leg length or 41% of tibia length. Author: Matt Appleman. Adaptive Training Get the right workout, every time with training that adapts to you. Jun 15, 2019 · Crank length change of 2. Oct 16, 2020 · My crank length at the moment is 172. 172. Jan 9, 2023 · There is a lot of information, misinformation, outright ridiculous claims, etc. 54 equals crank length yields the same result) This is based around the idea that the upper leg is the major lever when applying force to the pedals and that the lower leg is the connecting rod and plays little part. I've been running 172. I have, by the way, had the experience setting up a bike for someone 5'2", changing to 152 mm cranks to avoid toe overlap, and finding that in fact she greatly preferred the pedaling feel with more height-appropriate crank length, independent of the toe overlap issue. (Remember that you shouldn’t go above the allotted length, but you can if you like. Some brands are reserving the once-standard 172. Jan 4, 2024 · Here are the factors that you should consider while finding your saddle height: 1. Height is 166cm and inseam 76cm, age is 56. But in 2024, we are starting to see a change in the bike industry. Check appleman cranks (exspensive) but they explain alot in detail about crank length. Aug 28, 2024 · Crank arm length is an important factor in the relationship between a cyclist and their bike. If you go with longer crankarms of 172. Seat height – distance along that line (in cm) It will spit out a suggested crank length rounded to the nearest 2. 5. The Local Overnighters Project is a unified effort to document and map one-night bikepacking routes all over the world—by locals, in their own backyards. Use your height or inseam to determine the crank length (Crank Length Options). 5 mm cranks despite being roughly the same height as Pogačar. e. 175mm cranks could be too long, too short, or just right! Sep 25, 2023 · Does crank length affect saddle height? Yes, crank length affects saddle height. The Lemond formula (which is really the Guimard formula) of 0. 5mm”, if you are 180cm tall, you should use “175mm or 177. 5mm. I feel like most people should reduce their crank length by 5, 10 or more. It provides upper and lower boundaries for crank length. Set your crank length to one of four positions. Pedal stroke and knee health Sep 24, 2024 · Crank lengths and rider height. Biomechanics Perspective Using your inseam length and knowing the desired knee angle, we can calculate your Leg Stack Height. camnicholls. Armed with this information, cyclists can confidently select the appropriate crank length when purchasing a new bike or upgrading components. The article has the recommend crank size for inseams from 70 to 93cm. Sep 13, 2020 · A quick summary (though I do suggest you read their article) is that inseam length and crank length are correlated. Feb 3, 2011 · 4. There is something to be said for trying to focus on running a hair lower saddle height and keeping the heels lower. The crank arm lengths found on stock bikes stem from the normal distribution curve of riders’ heights and assume their leg length (or arm length) are proportional to their height. For your height of 5'7", most bikes have traditionally come with a 170mm crank. 95 × your height • ‘Machine’ method: crank length = 1. Other Available Crank Arm Sizes Pedal strike in relation BB Height and Crank Length have a been a concern since the 1980s. Type of riding, 3. 25 × inseam + 65 • Lennard Zinn method (upper end): crank length = 2. 5mm cranks. So it causes discomfort and they wobble around. Crank Length. com. Myth #3: The Small Difference In Crank Lengths Makes Changing Pointless: One of the other common comments we hear is that the change in crank length is so small that it doesn’t really make a difference, so why change? This is a half-truth. May 12, 2023 · The crank arm lengths found on stock bikes stem from the normal distribution curve of riders’ heights and assume their leg length (or arm length) are proportional to their height. We were met with strong resistance initially but as a few of the pioneer riders tried them and realized the results, they started to gain popularity. 5mms, and if your talk and long – clip into some 175’s and see how they feel, work, etc. May 9, 2024 · Anne Haug’s crank length (top) is 155mm, while Jan Frodeno (bottom) opts for 170 mm. Your leg stack height is the simplified measurement of your leg at the bottom of the pedal stroke. Oct 1, 2023 · The optimal crank length for a biker depends on several factors, such as the rider’s height, inseam length, riding style, and the type of biking they will do. Jan 15, 2024 · Also, that the ankle position shifted from dorsifexed position to plantarflexed as crank length increased. Graeme Obree Method: This method calculates crank length as (height × 0. IMHO, I seriously doubt it'd cause joint problems on your left side. I also used to drill out my shoes to get the cleats far enough back. 16 × inseam • Lennard Zinn method (lower end): crank length = 2. My inseam is 30 inches (762mm) and by the formula I found on the internet by GCN, I should have a 160mm crank length. The researchers determined that out of a selection of crank lengths including 120, 145, 170, 195, and 220mm cranks, two were the most optimal. 16 * inseam Oct 23, 2024 · Crank length does not affect gear ratios. It's crazy to think how little crank lengths (5mm or about 3 percent) vary for 90 percent of riders, when these riders vary so much in height and limb length (about 6 inches or 10 percent). In a study 4 that looked at the effects of crank length on power, a set of cyclists rode a predetermined test set where they sprinted on crank arms that varied in length from 120mm to 220mm. , 160mm crank on a 6'6" person) due to potential hip flexibility issues. Martin’s Revolutionary Study. 1% of the variability in maximum power, respectively. Try to ride a different length as well for comparison, and don’t make up your mind Parents usually ask for cranks that are much too long for their children. Are 175mm Cranks Too Long? It depends on your leg length. I guess I’m concerned about wearing out my knees as a few days after riding they seem to hurt a little more than they used to. Martin and Spirduso [ 8 ] divided 710 feasible pedal places into 16 groups for modeling and simulation and found that knee joint forces were smaller near saddle Oct 31, 2023 · A shoe with a thicker sole or a pedal with more height will effectively increase the distance between the foot and the crank, impacting saddle height. Jim Martin, Ph. No saddle height calculator was gonna get my number right. These formulas provide an excellent starting point. 5's, but don't want to spend the money. The longer the cranks, the lower the saddle; the shorter the cranks, the higher the saddle. For instance, im about an inch taller than you and raced on 175's for 20 years. This upper angle is controlled by the length of the crank and is something that I am quite sensitive to. – Nov 4, 2022 · For BMX and downhill, you can subtract up to 10mm. Calculate: The calculator will provide the optimal crank length based on your height. That's because they’re on a massive crank length and it closes the hip up at the top. C. This will effectively make your saddle too "low" relative to the lowest pedal postion on the left crankarm. uk/c Feb 23, 2023 · By Length (days) Overnighters & S24O; Weekend Routes (2-4) Week-long Routes (5-10) Odyssey Routes (11-30) "Freakouts" (31+) Local Overnighters. Hello, I've recently changed my crank length from 175mm down to 172. Raise your saddle by about the same amount. 020; Track: crank length = inseam * 0. 5m”, if you are 175cm tall, you should use “170mm or 172. I think this means I need to slightly change my fit, at least by increasing the seat height by 2. See full list on bikedynamics. Mar 24, 2019 · Crank length sets the floor and ceiling of saddle height, but there's a decent range of adjustment in between, and the shorter the cranks the more range you have to play with. Someone with an inseam of 28” (71cm) should run 150mm cranks while someone like me with a 90cm (35. Oct 22, 2015 · The fact that this chart has a non-diagonal line for the crank length vs height only for the "industry standard" specs but not for any scientifically based fitment strategy. However, if we took the ratio of his saddle height:crank length and applied it to a smaller athlete such as Rachel Joyce or Mirinda Carfrae (both have a saddle heights around 670mm and ride 165mm crank lengths), they would need to move down to approximately 135mm crank length to maintain Jan’s ratio. Individual preferences and riding conditions may necessitate adjustments to Jan 5, 2025 · Lennard Zinn Method: This method recommends a crank length range based on (inseam × 2. Rider’s leg movement range. Measure by inseam for precise adjustments. 95 x height) or Machine Head Software (inseam x 1. 75 m), Jonas Vingegaard (5’9″; 1. Fred’s result is a saddle height of 77. While we don’t expect to have all the answers we did create an easy to use sizing chart tool for this exact reason. I’ll give you my take on it: I’m 6’6” tall, have a 35 inch inseam, and ride 190mm cranks and while I’m getting older and slower, I was pretty fast and strong in the day. Calculating your Foot Stack Height is found using foot length, cleat position, and pedaling style (pedaling dynamics). The simplified formula for estimating crank length based on height is as follows: \[ CL = H \times 0. Example Input Values: Total Height: 70 inches; Crank Length: Leave this field blank to calculate it. 75 m), as well as the much taller Mathieu van der Poel (6’0″; 1. 883. You need a baseline of where you started. Jan 10, 2024 · Crank length, does it even matter?For as long as I can remember, most road bikes have had cranks between 170 and 175mm long. Aug 3, 2020 · What is the crank length? Crank length is the length from the centre of the bottom bracket to the centre of the pedal axle. My knee would be higher at the top when using longer crank arms, and I'm not sure I'd like that when in the drops. 220 + height * 0. Equipment choices. (Photo: Brad Kaminski/Triathlete) Many consumers assume that their crankset arms come in one length—the size installed on the bike when they purchased it, typically in conjunction with the bike’s frame size. Length Height; 165 mm: Up to 5’6” / 168 cm: 170 mm: 5’6”-5’9” / 168-176 cm: 5mm won’t be noticeable. The wrong saddle height/setbck up Mt. 16). 5 at the risk of f'ing up your biomechanics. Let me explain what I mean by these: For a concise explanation and table chart, skip to section: “5. However, manufacturers produce crank arms Apr 26, 2021 · For example, setting an appropriate crank length [5–7], pedaling cadence , and the pedal condition [9, 10] (pedal height and pedal position) affects the outcomes of rehabilitation. As a bike fitter We have designed calculators to help you choose your frame size, tyre pressure, handlebar width, dropper travel, crank length, and saddle height. Opens up the hip angle, smooths out the pedal stroke, easier on the joints, no real effect on speed or power. – 2. The formula to calculate crank length is straightforward: Jan 5, 2022 · In the past, the crank length was considered to be “your height / 10”, but recently, many people seem to be using “(your height / 10) - (2. 5 inch) inseam, should run cranks no longer than 173mm. Book a bike fit with James here: https://www. Here's an explanation of how it works and what the results mean: What is Crank Length? Crank length refers to the distance from the center of the pedal spindle to the center of the bottom bracket axle. Crank arm (“pedal”) length Jul 21, 2024 · Interestingly, crank arm length tends to vary despite rider height differences. com/fr Mar 21, 2003 · So, if you consider yourself short (<5’8”) or have a shorter inseam, then start out with a shorter (170 mm) crank length, if are of medium height, go for the 172. ” Luke Craddock of Synergy Performance adds: "Crank length is a very hot topic within cycling currently. The average power was recorded, and it showed that output power varied by only 1. about crank length. What is a Bike Seat Height? Bike seat height refers to the distance between the bottom bracket (where the pedal cranks are attached to the bike) and the top of the seat. 25 + 65). This block dimension from the center line of the main bore dictates the final stack length for the crank, rod, and piston assembly. Sep 19, 2023 · To take the saddle height part of a crank length change once more; as a general rule of thumb, you change the saddle -> BB center measurement by the same amount that the crank length has changed (10mm shorter cranks = 10mm higher saddle relative to the BB center, with a tiny adjustment for relative setback if you wish). uk Feb 9, 2022 · Does Crank Length Affect Saddle Height? Yes, crank length affects saddle height. Consult a qualified bike fitter if you are unsure. If you have bikes with different crank lengths, adjust the saddle height for each bike. Oct 3, 2024 · Advances in bike fitting technologies and increased awareness of biomechanical efficiencies have led to more personalized recommendations for crank length. 883 x crotch to floor? Mar 17, 2024 · It has never had any validity whatsoever as an absolute predictor of optimal final height. 5 cranks to another triathlete (athlete #2) with a saddle height of 670 with 165 cranks. Check the crank settings in the Tacx Training app (Customizing the Trainer Settings from the App). Does that mean that if crank length is increased or decreased, seat height as measured from bottom bracket centre doesn’t change? Apparently so. So, if you're reducing the left crank arm, you'll have to keep the same saddle height becuase you're not changing the right crank arm. Crank Length: The most common way to measure saddle height is from the centre of the bottom bracket to the top of the saddle. 5mm, and 175mm. Steps 1-4 were repeated 3 times each session. Primož Roglič is aboard 172. A longer crank can provide more power, but may also cause more strain on the knees. Jun 1, 2023 · Suffice to say: I think about crank length a lot. Rod length and pin height can can be juggled according to the application, but the final dimension is always fixed by the block height. 5mm”. So, where is the crank length mentioned in 0. 5mm or 175mm, there are more likely to be fit problems. About Neill Stanbury: https://neillsbikefit. The most commonly available crank lengths are 165, 170, 172. au/About the RCA: https://roadcyclingacademy. There are a lot of reasons for this, including: It doesn't account for crank length; Pedals and shoes have different amounts of offset; Humans have different amounts of joint mobility; Saddles flex different amounts Sep 3, 2024 · Find the ideal crank length for your bike with our bike crank length calculator. There is a common myth that longer cranks increase pedaling efficiency or power, however, this has been proven false in a number of studies (you can see an interesting study by Paul R Barratt here ). 25 * inseam + 65; Lennard Zinn method, upper end: crank length = 2. Short vs long cranks? The debate has raged for years, but what actually are the advantages of going long, or short? In this video Alex and Conor go to the ex Dec 6, 2008 · 5'7" height, 31"-ish leg length, and 170mm crank arms. Let's consider an example to illustrate how the Bike Crank Length Calculator works: Suppose a cyclist has an inseam measurement of 32 inches. O. Saddle height is normally set to achieve a suitable knee extension at the bottom of the pedal stroke, but the knee angle at the top of the pedal stroke is almost never measured. Jan 6, 2024 · Use A Crank Arm Length Formula Based On Height or Inseam. After u. 6 foot can easily use 150,155, 160. There are lots of recommendations and formulas for how to determine a cyclist’s “ideal” crank length, all of which are slightly different, but most lead to similar Feb 7, 2017 · Formulas for computing crank length (in mm) from height, inseam measurement (in cm), and femur height (in cm, measured from the floor to the top of the femur bone) include: Graeme Obree method: crank length = 0. Top online Crank length can have an important effect on a rider’s biomechanics; a poor-fitting crank can negatively impact performance and result in injury to the rider. Common lengths include 165mm, 170mm, 172. Apr 30, 2020 · Crank length should be proportional to leg length, just as saddle height and handlebar reach are proportional to other body dimensions. Please note that this calculator provides an estimate and should be used as a guideline. 180mm cranks produced the highest power. This crank length calculator uses multiple formulas to recommend your crank length: • Graeme Obree method: crank length = 0. Over 6 feet and the length “standards start to vary. Discover the optimal crank length for cycling efficiency and comfort, tailored to individual rider needs. Height and leg length, 2. Apr 17, 2017 · while it may seem like leg length should determine crank length, it doesn't appear that this holds, so an optimal crank length for two people that have the same inseam may in fact be different For example, an individual requires a higher saddle height relative to the center of the crank when using the 145 mm crank length compared to a 175 mm crank length when maintaining a knee segment angle of 30 degrees at bottom dead center. For example, if one bike has 175mm cranks and another has 170mm cranks, lower the saddle by 5mm on the first bike. This does allow some growing room as adults do best with cranks about 9. 5 Aug 30, 2024 · It’s not a shock that proper crank length generally follows rider height. co. So someone 5'6" would ride with 170mm cranks, and someone who's about 10 percent taller at 6'0" would ride with cranks that are 175mm or only 3 percent longer. To start, fitters typically look at physiological dimensions like femur length and foot size, both of which are primary May 22, 2024 · Enter Crank Length (in): Input the crank length in inches if you know it. Jun 4, 2021 · The most common being what would be the correct frame size/ handlebar size/ crank length/ stem length (or a combination) based on a riders weight, age or height. 5mm designed to put you in a bike position Aug 6, 2013 · Here’s a list of shortcuts to our Paris 2024 related articles. Other Available Crank Arm Sizes Shorter 165mm cranks began to appear on very small frame sizes (XS or sizes under 49cm). For pre-teens I recommend 10% of the child's height. Understanding Bicycle Crank Length. Fred takes off another 2 mm because shoe soles have become thinner, too. I'd like to try 172. Aug 30, 2024 · “Quite often people will say to me, I really struggle to get up to 80, 90 cadence. Polygon is one brand that has reduced their crank lengths, equipping their large, medium and small Oct 17, 2024 · Your height, leg length, riding style, and even degree of flexibility will all affect your crank length—a number that is not one-size-fit-all. Mar 5, 2024 · Example of Bike Crank Length Calculator. Assuming your saddle height to the bottom pedal is the same with either crank, shortening your crank will put slightly less stress on the knee at the top of the stroke because the knee bend is less; the crank circle diameter is decreased by double the difference in crank length. 218 + height * 0. Apr 1, 2024 · The calculator then computes the recommended crank length based on a standard formula, typically recommending a crank length that is approximately 95% of your total height. Most manufacturers print the length (mm) on the inside of the crank. Jan 8, 2023 · A Rider’s Guide To Crank Length. Height is measured from the middle of the crank axle along the seat tube to the top of the saddle. Rider’s height (leg length, to be more precise). 5mm cranks exclusively for their extra-large frames. 5 to 5mm)”. , from the University of Utah, has studies crank length. , 180mm crank for someone 4'11") than a shorter crank (i. ” – T. If you go with smaller crankarms of 165mm, chances of any downsides are highly unlikely. Jan 27, 2023 · Lets remember that short is a relative term. 83 m), Michael Every crank length change would require seat height adjustment and possibly setback adjustment. I'd say a 5mm change in crank length requires a 4mm change in saddle height. I would just ride your 172. Nov 29, 2024 · Where my question comes now is reducing the crank arms on both to either 160 to match the online calculator or 165 to make a smaller adjustment first. 95), factoring overall rider height into the equation. How to Calculate Crank Length. The impact of crank arm length on bio-mechanical function, power output, and performance has been the focus of quite a bit of attention and research over the past few years, both informally and anecdotally in the fit studio, and scientifically in the research lab. They worry about their kid outgrowing their cranks, when they shouldn't. Nov 14, 2012 · What length is your road crank? If you are less than 5 feet tall you are likely running 165mm cranks. Oct 9, 2023 · While it is generally acknowledged that crank length should increase with the height and leg length of the individual, the exact association remains vague at best. In simple terms, if you've raised the saddle height by 2. While this is a fairly standard method that is generally quite useful Aug 5, 2024 · SH is the bike seat height ; IL is the inseam length (measured from the crotch to the floor) To calculate the bike seat height, multiply the inseam length by 0. 95 \] where: \(CL\) is the Crank Length (inches), Dec 6, 2023 · Which length is the best? There are three factors affecting the answer: Lever length. The Crank Length Calculator helps cyclists determine an appropriate starting point for their ideal crank length. Try our crank length calculator to give you a base value. It's not a 1:1 ratio however as your STA isn't 90', but it's close. Crank length affects saddle height. 883 x inseam = seat height from bottom bracket centre to top of seat takes no account of crank length. ” However, the same study does mention that using the typical 170mm crank length shouldn’t compromise most adult bikers’ maximum power too substantially. 10 × inseam Jul 11, 2024 · There are other crank length calculator formulas suggested (without scientific research) such as the one proposed by Graham Obree (0. For a 178 cm (5’10”) cyclist, this would provide a crank arm length of 169 mm, so you’d need to either size up to 170 mm cranks or size down to 167. Calculation Formula. 6% between the crank arms lengths of 145mm and 170mm. 5% and 21. 5mm cranks for the past 20+ years on all my racing bikes; I'm 5'11" (176cm) and ride 56cm frames. chna tmp zcgnznv mjfyh pscuff uaxroa imoykl zfd vbirky ievos