Question about Lemond Geometry
04-26-14, 12:08 PM
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Question about Lemond Geometry
I am considering picking up a used early 2000s Lemond Buenos Aires. Frame is 53. My current bike is a 54. Current bike is a semi compact modern frame with 545mm effective top tube. I've found that 545mm eff tt is my limit on the small end and 545-555 is my sweet spot from other bikes I've owned and rode.
The person selling the frame says his measurement center seat post to center of head tube is 550mm. To me that sounds like it will fit me but I was looking at the Lemond mechanic's guide guide I found online doesn't list the eff top tube but it says a 53 is good for rider around 68 inches/5'8". I'm 5'10". Do you think the 53 would be way too small for me? I've read something about how seat post angles and stuff on the Lemond make the eff top tube measurements misleading?
The person selling the frame says his measurement center seat post to center of head tube is 550mm. To me that sounds like it will fit me but I was looking at the Lemond mechanic's guide guide I found online doesn't list the eff top tube but it says a 53 is good for rider around 68 inches/5'8". I'm 5'10". Do you think the 53 would be way too small for me? I've read something about how seat post angles and stuff on the Lemond make the eff top tube measurements misleading?
04-26-14, 02:54 PM
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I think the 53cm BA is a 545ETT; this may help: https://www.vintage-trek.com/Trek-Fis...nualLemond.pdf
04-26-14, 05:16 PM
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I think the 53cm BA is a 545ETT; this may help: https://www.vintage-trek.com/Trek-Fis...nualLemond.pdf
04-26-14, 11:38 PM
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I'm getting more confused the more I read. Yes the 53 has a 545mm ETT which is what I have on my current road bike, and the 55 has a 565mm ETT. I have found a 53 and 55 frame for sale. Seems like the 53 would be the way to go but I have read that the Lemonds have shallow seat tube angles so it makes the top tube/reach seem shorter than it actually is. I think 545mm ETT is the shortest I can go so that worries me that the 53 will feel too cramped even if the ETT is the same as on my current frame
04-27-14, 06:40 AM
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It is confusing, because it's a complicated matter compounded by a lack of precise definition being used. I think there are a couple of important issues to sort that can help bring clarity.
First, the oft repeated and conventional wisdom that Lemonds have long top tubes (TT) and slack seat tubes (ST) is derived from an era in bike design when the majority were shorter and steeper, a situation very different from where we are today. Lemond was an era before sloping TT and before frame size designations lost any connection to actual tube lengths; the old standard was same length TT and ST, so a 56 frame had a 56cm TT and 56cm ST. That is the context within which "Lemond geometry" means something. Today, "Lemond geometry" means nothing, because you find the standard to be something like a size 56 with a 53cm ST and 54.5cm ETT.
Mention of ETT brings us to the definition issue. It needs to be clear, when talking about ST angle (STA), whether one is also talking about keeping TT length and position the same. If TT length and position remain the same, then yes, slackening STA will reduce distance from saddle to head tube (HT) centerline (HTC) because slackening would take place at the bottom bracket (BB) by moving it forward. Think of it this way: the ST/TT junction is the pinned pivot, so to adjust the STA, you swing the bottom, the BB, fore or aft.
Now, the other given is that the rider will have a fixed seat position relative to BB, meaning that if the BB is swung either fore or aft of that ideal relative seat/BB location, the seat will need to follow. Going back to the the slackening ST example, doing so will require the saddle to be pushed forward to maintain the saddle/BB relationship. Remember, the TT length we said was fixed, so of course, moving the saddle further forward effectively shortens the reach distance to HTC.
Of course, TT length and location need not be fixed, so you can slacken (or steepen) STA and keep reach (to HTC) the same by lengthening the TT, steepening the HTA, etc. Because of these variables, it's really most helpful to know your preferred "frame reach," which is the horizontal distance from BB centerline (BBC) to HTC:
Knowing frame reach simplifies things, and removes the necessity of knowing a bunch of other frame dimension and geometry info, and allows for apples-to-apples comparison.
Without knowing more about how Rms13 likes to fit on the bike and having more specific physical dimensions, it's hard to say what will fit and what won't. My recommendation would be to try to compare STA and TT between the bike that fits and the new one, and see how close the reaches are. I know Lemond did not publish reach measurements-- it is becoming more standard today, however-- so short of finding a true to size diagram off which to measure, there's no easy way to do this. I suppose there are frame reach calculators out there, but I've not used one. A quick Google turned up this one: bb2stem: Stack & Reach Calculator v1.00
Hope that helps.
First, the oft repeated and conventional wisdom that Lemonds have long top tubes (TT) and slack seat tubes (ST) is derived from an era in bike design when the majority were shorter and steeper, a situation very different from where we are today. Lemond was an era before sloping TT and before frame size designations lost any connection to actual tube lengths; the old standard was same length TT and ST, so a 56 frame had a 56cm TT and 56cm ST. That is the context within which "Lemond geometry" means something. Today, "Lemond geometry" means nothing, because you find the standard to be something like a size 56 with a 53cm ST and 54.5cm ETT.
Mention of ETT brings us to the definition issue. It needs to be clear, when talking about ST angle (STA), whether one is also talking about keeping TT length and position the same. If TT length and position remain the same, then yes, slackening STA will reduce distance from saddle to head tube (HT) centerline (HTC) because slackening would take place at the bottom bracket (BB) by moving it forward. Think of it this way: the ST/TT junction is the pinned pivot, so to adjust the STA, you swing the bottom, the BB, fore or aft.
Now, the other given is that the rider will have a fixed seat position relative to BB, meaning that if the BB is swung either fore or aft of that ideal relative seat/BB location, the seat will need to follow. Going back to the the slackening ST example, doing so will require the saddle to be pushed forward to maintain the saddle/BB relationship. Remember, the TT length we said was fixed, so of course, moving the saddle further forward effectively shortens the reach distance to HTC.
Of course, TT length and location need not be fixed, so you can slacken (or steepen) STA and keep reach (to HTC) the same by lengthening the TT, steepening the HTA, etc. Because of these variables, it's really most helpful to know your preferred "frame reach," which is the horizontal distance from BB centerline (BBC) to HTC:
Knowing frame reach simplifies things, and removes the necessity of knowing a bunch of other frame dimension and geometry info, and allows for apples-to-apples comparison.
Without knowing more about how Rms13 likes to fit on the bike and having more specific physical dimensions, it's hard to say what will fit and what won't. My recommendation would be to try to compare STA and TT between the bike that fits and the new one, and see how close the reaches are. I know Lemond did not publish reach measurements-- it is becoming more standard today, however-- so short of finding a true to size diagram off which to measure, there's no easy way to do this. I suppose there are frame reach calculators out there, but I've not used one. A quick Google turned up this one: bb2stem: Stack & Reach Calculator v1.00
Hope that helps.
04-27-14, 09:42 AM
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Thanks Chaadster, very detailed response!
I'm guessing the 53 would be the better fit for me.
my current bike: 543 ETT , 73 HT, 73.7 ST
53 lemond: 545 ETT, 73 HT, 73 ST
Seems like it's close enough that I should be able to make it fit with saddle fore/aft and stem height and length adjustments better than going with the 55.
I think people have gotten used to smaller frames these days to so theory on fit is different. When I look at old forum posts from when these bikes were current people with pretty similar measurements to me where going with 55 and even 57 Lemonds. A lot of personal preference I guess.
I'm guessing the 53 would be the better fit for me.
my current bike: 543 ETT , 73 HT, 73.7 ST
53 lemond: 545 ETT, 73 HT, 73 ST
Seems like it's close enough that I should be able to make it fit with saddle fore/aft and stem height and length adjustments better than going with the 55.
I think people have gotten used to smaller frames these days to so theory on fit is different. When I look at old forum posts from when these bikes were current people with pretty similar measurements to me where going with 55 and even 57 Lemonds. A lot of personal preference I guess.
04-27-14, 08:14 PM
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It is confusing, because it's a complicated matter compounded by a lack of precise definition being used. I think there are a couple of important issues to sort that can help bring clarity.
First, the oft repeated and conventional wisdom that Lemonds have long top tubes (TT) and slack seat tubes (ST) is derived from an era in bike design when the majority were shorter and steeper, a situation very different from where we are today. Lemond was an era before sloping TT and before frame size designations lost any connection to actual tube lengths; the old standard was same length TT and ST, so a 56 frame had a 56cm TT and 56cm ST. That is the context within which "Lemond geometry" means something. Today, "Lemond geometry" means nothing, because you find the standard to be something like a size 56 with a 53cm ST and 54.5cm ETT.
Mention of ETT brings us to the definition issue. It needs to be clear, when talking about ST angle (STA), whether one is also talking about keeping TT length and position the same. If TT length and position remain the same, then yes, slackening STA will reduce distance from saddle to head tube (HT) centerline (HTC) because slackening would take place at the bottom bracket (BB) by moving it forward. Think of it this way: the ST/TT junction is the pinned pivot, so to adjust the STA, you swing the bottom, the BB, fore or aft.
Now, the other given is that the rider will have a fixed seat position relative to BB, meaning that if the BB is swung either fore or aft of that ideal relative seat/BB location, the seat will need to follow. Going back to the the slackening ST example, doing so will require the saddle to be pushed forward to maintain the saddle/BB relationship. Remember, the TT length we said was fixed, so of course, moving the saddle further forward effectively shortens the reach distance to HTC.
Of course, TT length and location need not be fixed, so you can slacken (or steepen) STA and keep reach (to HTC) the same by lengthening the TT, steepening the HTA, etc. Because of these variables, it's really most helpful to know your preferred "frame reach," which is the horizontal distance from BB centerline (BBC) to HTC:
Knowing frame reach simplifies things, and removes the necessity of knowing a bunch of other frame dimension and geometry info, and allows for apples-to-apples comparison.
Without knowing more about how Rms13 likes to fit on the bike and having more specific physical dimensions, it's hard to say what will fit and what won't. My recommendation would be to try to compare STA and TT between the bike that fits and the new one, and see how close the reaches are. I know Lemond did not publish reach measurements-- it is becoming more standard today, however-- so short of finding a true to size diagram off which to measure, there's no easy way to do this. I suppose there are frame reach calculators out there, but I've not used one. A quick Google turned up this one: bb2stem: Stack & Reach Calculator v1.00
Hope that helps.
First, the oft repeated and conventional wisdom that Lemonds have long top tubes (TT) and slack seat tubes (ST) is derived from an era in bike design when the majority were shorter and steeper, a situation very different from where we are today. Lemond was an era before sloping TT and before frame size designations lost any connection to actual tube lengths; the old standard was same length TT and ST, so a 56 frame had a 56cm TT and 56cm ST. That is the context within which "Lemond geometry" means something. Today, "Lemond geometry" means nothing, because you find the standard to be something like a size 56 with a 53cm ST and 54.5cm ETT.
Mention of ETT brings us to the definition issue. It needs to be clear, when talking about ST angle (STA), whether one is also talking about keeping TT length and position the same. If TT length and position remain the same, then yes, slackening STA will reduce distance from saddle to head tube (HT) centerline (HTC) because slackening would take place at the bottom bracket (BB) by moving it forward. Think of it this way: the ST/TT junction is the pinned pivot, so to adjust the STA, you swing the bottom, the BB, fore or aft.
Now, the other given is that the rider will have a fixed seat position relative to BB, meaning that if the BB is swung either fore or aft of that ideal relative seat/BB location, the seat will need to follow. Going back to the the slackening ST example, doing so will require the saddle to be pushed forward to maintain the saddle/BB relationship. Remember, the TT length we said was fixed, so of course, moving the saddle further forward effectively shortens the reach distance to HTC.
Of course, TT length and location need not be fixed, so you can slacken (or steepen) STA and keep reach (to HTC) the same by lengthening the TT, steepening the HTA, etc. Because of these variables, it's really most helpful to know your preferred "frame reach," which is the horizontal distance from BB centerline (BBC) to HTC:
Knowing frame reach simplifies things, and removes the necessity of knowing a bunch of other frame dimension and geometry info, and allows for apples-to-apples comparison.
Without knowing more about how Rms13 likes to fit on the bike and having more specific physical dimensions, it's hard to say what will fit and what won't. My recommendation would be to try to compare STA and TT between the bike that fits and the new one, and see how close the reaches are. I know Lemond did not publish reach measurements-- it is becoming more standard today, however-- so short of finding a true to size diagram off which to measure, there's no easy way to do this. I suppose there are frame reach calculators out there, but I've not used one. A quick Google turned up this one: bb2stem: Stack & Reach Calculator v1.00
Hope that helps.
04-28-14, 01:40 AM
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04-28-14, 09:43 AM
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I have found people selling frames online or CL often mis-measure top tube, especially in sloping TT frames.
If it is a close call, look up the geo chart and get the seller to measure the head tube to confirm frame size. It's much harder to botch that one.
If it works, enjoy the Lemond, they are super
If it is a close call, look up the geo chart and get the seller to measure the head tube to confirm frame size. It's much harder to botch that one.
If it works, enjoy the Lemond, they are super
05-09-14, 02:05 PM
#10
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"I'm getting more confused the more I read. Yes the 53 has a 545mm ETT which is what I have on my current road bike, and the 55 has a 565mm ETT. I have found a 53 and 55 frame for sale. Seems like the 53 would be the way to go but I have read that the Lemonds have shallow seat tube angles so it makes the top tube/reach seem shorter than it actually is...................."
RMS.................. No, the shallower - (more relaxed) seat angle, or greater set back effectively increases tt length.
LeMond's formula, in fact that of Guimard places greater position behind the pedal, not above, utilizing greater physiological power (leverage) by using more muscle groups evenly and efficiently. The greater set back is beneficial to a greater number of cyclists on average.
Think about it.
RMS.................. No, the shallower - (more relaxed) seat angle, or greater set back effectively increases tt length.
LeMond's formula, in fact that of Guimard places greater position behind the pedal, not above, utilizing greater physiological power (leverage) by using more muscle groups evenly and efficiently. The greater set back is beneficial to a greater number of cyclists on average.
Think about it.
05-09-14, 03:34 PM
#11
Banned
DIY OPINION FORMING .. 
Go find bikes in a shop and stand over them ..
ride it around the block , bring a tape measure and write down the numbers .
Go find bikes in a shop and stand over them .. ride it around the block , bring a tape measure and write down the numbers .
05-11-14, 08:13 AM
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Thanks Chaadster, very detailed response!
I'm guessing the 53 would be the better fit for me.
my current bike: 543 ETT , 73 HT, 73.7 ST
53 lemond: 545 ETT, 73 HT, 73 ST
Seems like it's close enough that I should be able to make it fit with saddle fore/aft and stem height and length adjustments better than going with the 55.
I think people have gotten used to smaller frames these days to so theory on fit is different. When I look at old forum posts from when these bikes were current people with pretty similar measurements to me where going with 55 and even 57 Lemonds. A lot of personal preference I guess.
I'm guessing the 53 would be the better fit for me.
my current bike: 543 ETT , 73 HT, 73.7 ST
53 lemond: 545 ETT, 73 HT, 73 ST
Seems like it's close enough that I should be able to make it fit with saddle fore/aft and stem height and length adjustments better than going with the 55.
I think people have gotten used to smaller frames these days to so theory on fit is different. When I look at old forum posts from when these bikes were current people with pretty similar measurements to me where going with 55 and even 57 Lemonds. A lot of personal preference I guess.
I think you also said the LeMond is 53 cm, 73 seat tube angle, and 54.3 cm ETT. So then the setback at 53 cm is 15.5 cm, 3 mm longer than for your current bike. With the LeMond top tube of 54.3 cm, it's reach is 38.8 cm, just 5 mm shorter than for your current bike.
As sizing goes, these are very very close to each other. I would not worry buying the LeMond. You can compensate any short reach issues with a stem 1 centimeter longer.
Last edited by Road Fan; 05-11-14 at 12:10 PM.
