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Hi,

I have always wondered what the best frame size is for me. I currently have a Lemond in a size 53. I have fairly short legs with a longer torso-----I am 5-8 with about a 31 inch inseam. My current setup has a 110 stem which results in a good fit for length.

I am debating over going to a smaller size 51 frame. I think it would be better for my shorter legs but would require a longer stem----a 120 or longer. This seems like kind of a long stem for a smaller frame size like this which might result in poor handling????

What do you think?

thanks

matt
 

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bowler1 said:
Hi,

I have always wondered what the best frame size is for me. I currently have a Lemond in a size 53. I have fairly short legs with a longer torso-----I am 5-8 with about a 31 inch inseam. My current setup has a 110 stem which results in a good fit for length.

I am debating over going to a smaller size 51 frame. I think it would be better for my shorter legs but would require a longer stem----a 120 or longer. This seems like kind of a long stem for a smaller frame size like this which might result in poor handling????

What do you think?

thanks

matt
A 120 stem is not so long as to adversely effect handling. You'll feel a slight difference in steering (slower). Bigger question is that on the 51, the head tube will be shorter and lower, and the bars will be shorter and lower. Will the saddle to bar drop be right for you, or will you have to jury rig it with spacers or a riser stem?

Is your 31 inch inseam a true cycling inseam? How much standover do you have on the 53? I guess I'm just puzzled as to why you want to make this change if your current setup is working.
 

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To the wrenchscience sizing tool and then ...

Try going to the wrenchscience sizing tool.

It measures you up and then gives you a good indication of 'real' size.

http://www.wrenchscience.com/WS1/default.asp

Finally, check the geometry of the bike you are looking at (see their web site) against the 'real' sizes from the tool.

I hope this works for you.

Cheers,

craigg.
 

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Interesting comparison

bowler1 said:
Hi,

I have always wondered what the best frame size is for me. I currently have a Lemond in a size 53. I have fairly short legs with a longer torso-----I am 5-8 with about a 31 inch inseam. My current setup has a 110 stem which results in a good fit for length.

I am debating over going to a smaller size 51 frame. I think it would be better for my shorter legs but would require a longer stem----a 120 or longer. This seems like kind of a long stem for a smaller frame size like this which might result in poor handling????

What do you think?

thanks

matt
120 isn't a problem... plenty of pros are using 130 and 140 mm stems. I use a 140mm stem.

By the way, I'm 5'-8-1/4" and I have a 31-1/4" inseam.

Your question is interesting to me because of how we compare. How long are your thighs and arms?

Your size 53 LeMond has a 54.5cm tt and a 73.25 st angle and you use a 110mm stem.

My Time VXRS is a size 53 which has a 54cm tt and a 73 st angle. Like I mentioned I use a 140mm stem. I have a proportionally long femur so I use just about all the setback I can get. I have a longo torso like you but I don't have particularly long arms.

Bottom line is that you're riding on a bike with at least 4 cm less cockpit room than my bike has. That's a big difference. I couldn't ride your setup. No way.

Anyway, if you have enough reach with 51cm frame with a 53.2 cm tt and a 120mm stem then go for it. No worries.
 

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not nearly enough info...

I would suspect that your 31 inch (79cm) "inseam" is a pants inseam, not a cycling inseam. Cycling inseam is measured from the floor to saddle like crotch contact in bare feet.

A 53cm c-c frame would usually have a standover height of nearly 79cm, which would only leave your shoes providing standover clearance. That's probably not the case, but some people have been recommended a frame size that large.

Using a 120mm stem is not nearly as big a potential problem as getting the handlebars up to the desired height with a 2cm shorter head tube.

What has also been overlooked in all this discussion of satem length is your saddle to handlebar height difference. Placing the bars higher allows a longer stem to be used. A simple graphical analysis will show that a 7mm increase in spacer under the stem will produce the same torso position with a stem that's about 10mm longer.

Saddle fore/aft position can also make a big difference in the stem length used. There are a lot of theories about "proper" saddle fore/aft position, but I've never read a shred of evidence proving that a particular knee to pedal relationship provides optimum power. In my experience, moving the saddle further back promotes a higer torque pedaling style and a more forward position promotes a higer cadence, lower torque style.

Moving the saddle too far back can have a detrimental effect on high speed corning by reducing the weight on the front of the bike. Most folks never notice this unless they ride winding mountain descents at high speeds (like I do). Keeping the weight on the front up to 45-46% works well. A frame that's too large will most likely have a longer front-center and less weight on the front than a smaller frame.

Here's some basic fit info to get started.

http://www.coloradocyclist.com/bikefit/
 

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C-40 said:
What has also been overlooked in all this discussion of satem length is your saddle to handlebar height difference.

Actually, that was the very issue I flagged in the first response.
 

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At least for me, stem length is overrated as a factor

FWIW, when I embarked on a quest a few years ago to build the perfect commute bike (just a winter parts bin project), I tried stems from 60mm to 150 on three different frames, looking for a balance between comfort and an upright position for good visibility. There was a noticeable difference, but nothing dramatic, and certainly nothing that affected rideability or control. There was no adjustment period, even with the biggest changes--I just got on and rode.
 

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quite poorly though...

While a smaller frame might create a larger saddle to bar height difference, it does not have to. That's what higher rise stem angles and spacers are for. I've got more inseam (83cm) and ride a 51cm c-c frame. I could easily ride a 49cm just by flipping an 84 degree stem (that's one size longer). I could also ride a 53cm just by using a 1 size shorter stem with an 80 degree angle and 1cm less spacer (none for me). What this shows is that from a nominal frame size, it's not that thard to make a smaller or larger frame "fit" the same, but there will be differences in the weight balance.

I see no mention of the relationship between bar to saddle height difference and stem length. You give yourself too much credit.
 

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C-40 said:
While a smaller frame might create a larger saddle to bar height difference, it does not have to. That's what higher rise stem angles and spacers are for. I've got more inseam (83cm) and ride a 51cm c-c frame. I could easily ride a 49cm just by flipping an 84 degree stem (that's one size longer). I could also ride a 53cm just by using a 1 size shorter stem with an 80 degree angle and 1cm less spacer (none for me). What this shows is that from a nominal frame size, it's not that thard to make a smaller or larger frame "fit" the same, but there will be differences in the weight balance.

I see no mention of the relationship between bar to saddle height difference and stem length. You give yourself too much credit.

Oooh, harsh. What's the deal? I did mention that otherwise the differential would need to be addressed with stem and spacer. I wasn't taking "credit," I was teasing you for stating that no one had mentioned it above, and noting that the biggest issue addressed by downsizing a frame as discussed would likely be bar height, which would in turn need to be addressed with spacers or a riser stem, possibly.

Ouch. I thought you and I knew each other better than that. But I guess the internet, like
s the automobile, makes folks a little hard on each other.

Julie
 

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still missing the point...

The fact that a smaller frame requires more spacer or stem rise is NOT the point I was making. The more important point was the fact that riders who use a lot of stem to bar height difference, like 8-10cm, may use a shorter stem than riders who only use 4-6cm.

Either height difference can produce the same torso angle with the appropriate stem length. The angle between the arms and torso won't be the same though. The longer/higher setup can put more strain on the shoulder due to the increased angle between the arm and shoulder. It's a balancing act that's often overlooked or misunderstood, particularly by those who advocate a very small height difference between the bars and saddle as the key to comfort. I've read posts by "expert" fitters who think that an 8-9cm saddle to bar height difference like I use is way too much for someone of my size.

This situation isn't hard to analyze graphically. It's just an oblique triangle with two sides of fixed length (torso and arms) and one side of variable height and length (a line from the hip joint to the hands). If for example, the arms are at a 45 degree angle, height and stem lengh changes have a very similar effect. The problem with a "height" change with spacers is that every 1cm of spacer reduction move the bars forward by 3mm, so a true change in height only is tough to achieve.
 

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Yup, there's a great illustration of the interplay between bar height and stem length on www.sheldonbrown.com.

But I wasn't disagreeing with you about any of that, just genuinely surprised at the ad hominem attack on me. THAT was my point, which you either missed or chose to ignore. I PM'd you about it, but doesn't sound like you wish to discuss.

Peace out.
 
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