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LeMond frame geometry(21 posts)

LeMond frame geometryalyssa
Feb 13, 2002 5:42 AM
What are the advantages of having a LeMond frame over other brands for road biking?
website propaganda....C-40
Feb 13, 2002 9:52 AM
http://www.lemondbikes.com/tech-center/tech_geometry.html

This site has the geometry and alleged advantages. In reality there may be no difference at all, depending on the exact frame size.

Lemond frames are measured center to center. Add 1.5cm to compare with a frame measured c-t.

In the larger sizes you may find the top tube length to be up to 1cm longer and the seat tube angle up to 1 degree less. This geometry favors riders with long femurs or those who like the knee positioned further behind the pedal spindle.

Remember that top tube length can't be directly compared between brands, if the seat tube angle is not the same. Slack seat tube angles effectively shorten the top tube length by 1 to 1.5cm per degree (depending on frame size).
website propaganda....leek
Feb 13, 2002 3:12 PM
Slacker seat tube angles effectively shorten the top tube length? Wouldn't they increase them, just as you point out in the preceding paragraph?

Lee
common misconception...C-40
Feb 13, 2002 7:39 PM
To compare frames with different geometry it is generally assumed that a rider has particular knee over pedal (KOP) position that is considered optimum.

A frame with a slack seat tube angle (like 72 degrees)requires the saddle to be moved forward to achieve the same postion relative to the bottom bracket. This saddle movement effectively shortens the top tube length. The opposite is true of frames with steep seat tube angles (like 74 degrees).

My 55cm C-40 for example, with a 74 degree STA and a 54.3cm TT length has the same fit as a 55cm Litespeed which has a 73 degree STA with a 55.5cm TT. Only the nominal saddle position on the seat post is different.
I have trouble grasping this.dzrider
Feb 14, 2002 5:38 AM
I like to ride with my knee behind the pedal spindle. Bikes with steeper seat angles make it impossible to get the seat far enough back to do so. Bikes with short top tubes force me to use a very long stem or ride with my arms straight to keep my knees from hitting my elbows.

I understand that moving one's saddle forward shortens the the effective top tube length. So my questions are:

How does the seat angle effect top tube length if one's saddle is pushed all the way back? I'd think not at all.

Do longer stems change the effective top tube length? I'd say yes.
I have trouble grasping this.davtnyc
Feb 14, 2002 7:40 AM
the loose seat angle "shortens" the top tube due to the angle which the upper body reaches for the bars i.e. lower, flatter back with forearms more parrellel to the ground.

simple!
making it too difficult....C-40
Feb 14, 2002 2:52 PM
If you use a traditional road seatpost with setback (like campy or shimano) and can't get the saddle back far enough to position the knee at the desired KOP position, you should look at frames with less seat tube angle.

If your current bike has a 73 degree STA and 55cm TT for example, a new frame with a 72 degree STA and 56.2cm TT would position the knee exactly the same when the saddle was moved forward by 1.2cm. The reach to the bars would also be unchanged (with the same stem length). The change is STA would give you some extra room to move the saddle further back, if desired.

If you choose to move the saddle "all the way back" on this hypothetical new frame, your knee would be 1.2cm further behind the pedal spindle. This saddle movement would obviously increase the effective top tube length by 1.2cm and require a shorter stem to achieve the same reach to the bars.
Confused!cyclequip
Feb 14, 2002 5:44 AM
Comparing frames with different geometry means comparing different riding positions, not trying to assume some mythical 'correct' position over the pedal spindle. LeMond's bike geometry was actually based on saddle setback - behind the bottom bracket - nothing to do with top tube lengths. His belief was that a big set-back led to a more resilient peadling style - nothing to do with long femurs or KOPS.
So in your example your fit is NOT the same, despite your moving the saddle. And what about head-tube angle?
By the way, what is the supposed 'optimum' KOPS anyway? Most of the pro's ride behind the spindle, triathletes the other side. Most endurance riders gravitate further back as they develop, climbers the same.
Lemond TT and KOPjtolleson
Feb 14, 2002 7:24 AM
It is a common statement (even on bike shop sales floor) that the Lemond's effective top tube length isn't a problem, because once you move your seat forward on the rails to achieve KOP, then it is basically a non-issue.

The problem is that Lemond designed his bikes for a change in knee-over-pedal position; I.e., to put the rider back and "pushing" a bit from behind the pedal spindle. A setup true to the intentions of the designers would keep the saddle back close to centered on the rails and thus keep the long effective TT length.

The original intention is that it would truly create a slightly different riding position. Those applying traditional fit-kit principles to the Lemond may moot the implications of the seat post angle, which is fine by me but a rider buying a Lemond should think about it, it seems to me.

Did that make any sense?
not confused at all...C-40
Feb 14, 2002 9:39 AM
You're misconstruing my statements. Comparing frames with different geometries does NOT mean comparing different riding positions. The idea is to determine how to achieve the SAME position with different frame geometries. This will require moving the saddle if the STA's are different, and changing the stem length IF the top tube length is "effectively" different, AFTER the change in reach caused by the saddle movement is taken into account.

My C-40/Litespeed comparison shows how two frames with different geometry can fit exactly the same, using the same stem length. The C-40 requires the saddle to be moved back 1.2cm more than the Litespeed to place the rider in the SAME position relative to the BB. This saddle movement increases the reach to the bars by 1.2cm which just happens to be the difference in top tube length between the two. These two frames will fit the rider, exactly the same.

The only difference between the C-40 & Litespeed is the position of the saddle on the seat post. There are limitations to saddle movement that must be considered. Some riders may find the the C-40's 74 degree STA does not permit the saddle to be moved back far enough to achieve the position that they desire. If this is the case, the Litespeed would permit the saddle to be moved another 1.2cm further back (assuming the same seatpost).

I've ridden both and achieved the same position on both, using a 110mm stem. Only the placement of the saddle on the seatpost was different.
and which one has the best handling for you?colker
Feb 14, 2002 10:29 AM
let me guess.. it begins with a c and ends with an o.
and which one has the best handling for you?lulu
Feb 14, 2002 11:08 AM
COLNAGO?
handling is another issue entirely...C-40
Feb 14, 2002 2:21 PM
I don't race, so I don't have a need or desire to push either bike to it's cornering limit.

Handling is affected by the head tube angle, the fork rake (and the resulting trail), the wheelbase and overall stiffness of the frame.

My 55cm Litespeed was an Ultimate model that I found to be too stiff for my 135-140 weight. I set the bike up with a 40mm rake to increase trail to 61mm for the most stability. The bike cornered,climbed and descended great but beat my butt to death.

The C-40 rides a lot like fine steel, but with less high frequency vibration. A great mixture of liveliness with vibration dampening. It's a lot easier to control on rough pavement. The C-40 has even more trail than the Ultimate (about 67mm).
common misconception...leek
Feb 14, 2002 3:46 PM
Oh, okay. So you're actually referring to rider position, versus physical frame dimensions.

Thanks for the clarification.

Lee
DOESN'T MATTER!!!ebednarz
Feb 19, 2002 7:51 AM
There is no advantages of frame geometry from one bike to another. It's all about what fits you. If you have a local bike shop near you go get a fit kit done so that you know exactly what specs you need to look for in a frame. Personally, I have a larger upper torso and shorter lower torso, so I need a bike with a larger top tube but smaller seat tube, etc. just as an example. Being a racer it's rather important to be on a bike that fits and not on one that has the "NAME"
re: LeMond frame geometryciclista
Feb 14, 2002 6:13 AM
1999 steel frame is a very comfortable ride, the construction is very decent and pleasing to the eye and the purse. There aren't too many steel/traditional style production frames on the market these days so it's a good deal.
re: LeMond frame geometryGalibier
Feb 14, 2002 6:35 AM
As you (now) know, LeMond claims his geometry provides a more comfortable, stable ride. Frankly, the discussion above regarding angles, measurements, and KOPS is lost on me. What I can tell you is that about one year ago I switched from a Trek OCLV (60cm) to a 2000 LeMond Maillot Jaune (aluminum, 58cm). I am a climber, I race, and my long rides are centuries. In my opinion, the LeMond is both more comfortable and more responsive, and it handles better. Doubtless, some others would disagree with my conclusions, but there you have it.
re: LeMond frame geometryMasterBlaster
Feb 14, 2002 3:01 PM
All I know is my Lemond Poprad (cyclocross) fits me perfectly. A 59cm is essentially a 59 square. I have a longer torso with lanky arms and shorter legs (don't call me a freak!) for for being 6'2". My style of riding is set back so I push the pedal as I ride. The TT length was a major factor in my purchase due to the fact the longer TT allowed my upper body to ride in a more natural position which in turn helped me out in the breathing capacity department. Most of the Euro frames I tried the TT length was too short and felt uncomfortable. If anyone has doubts you should go to your LBS that sells Lemond bikes
and take it out for a test ride.
re: LeMond frame geometryKOPS is a mirage
Feb 14, 2002 5:59 PM
To actually try to tell everyone with completely different physiologies that there is one ultimate or suggested knee over pedal position is absurd. In the end, it all comes down to the individual rider himself and what workks best.

Probably even more important than the Lemond relatively long top tube length is the fact that if you ride the bike as he intended (ie. not moving your saddle excessively far forward to make you position the same as on a bike with a steeper seatube angle) you will notice that as others have asserted, your pedal stroke has become much more of a pushing the pedal over the top stroke versus a pushing the pedal down stroke. The Lemond concept really has little to do with intentionally creating a longer toptube for fitting purposes.
KOP is valuable...C-40
Feb 14, 2002 7:26 PM
I don't think that anyone here claimed that there was only one perfect knee position for everyone. Experienced riders eventually learn the position that works best for them through experimentation. The position might be directly over the pedal spindle or several centimeters behind. People often misinterpret KOP to mean placing the knee only directly over the pedal. The KOP position could be any distance in front or behind the pedal spindle.

Once a rider determines his own optimum position, a seat tube angle can be selected to produce a nominal saddle position that permits both fore and aft movement of the saddle. I've always placed my knee 1-2cm behind the pedal spindle, but I don't need a 72 degree STA to achieve this position. STA's in the 73-74 degree range work for me.

Riders with long femurs or those who ride effectively with the knee more than a couple of centimeters behind the pedal spindle will find the geometry of Lemond bikes an advantage. As I noted in one of my early posts, the current geometry is not consistent. The smaller sizes have seat tube angles that are no different than a lot of other brands. LOOK frames have more consistently slack STA's (72.5 for all sizes) than Lemond frames.
KOP is valuable...Mark Treble
Feb 17, 2002 8:36 PM
If the KOP position can be any distance in front of or behind the pedal position as you claim then it sounds to me like it's pretty much meaningless. Am I missing something?