Jason Lim

However i heard that you may need much more hand strength when it comes to lower stem length due to increased castor effect. Rake angle is already protruding with the 70mm on this bike and its sort of already below the normal safe limit. Would this be dangerous, or would there be any situations where this would be dangerous if i lack the hand strength to manage it.

Kontact

It doesn't take any hand strength to turn a bicycle. The problem with really short stems the way it makes steering feel - smaller movements produce greater effects due to the short lever arm.

Take a short ride with your hands balled into fists and your thumbs hooked over the handlebar tops close to the bend, as if your fists were clenching a section of handlebar tubing pointing back at you. That's what a much shorter stem will feel like in terms of handling.

Jason Lim

I heard it would be dangerous during downhills and crosswinds that you would need hand strength to keep it stabilized

Carbonfiberboy 

One should ride the length of stem which is comfortable. There's no point in talking about it. Stems are really cheap. Go buy a stem, try it out, and stop talking about it until you've tried a new stem for a few hundred miles.

Kontact

Nope.

cyclezen

Hi Jason,
Sorry I hadn;t responded sooner, but just back from a week of backpacking, so offline.
So, things which are discussed here, online, by natuer of the project, are going to be incomplete and can only give some insight on places to look for getting closer to some resolution.
If your measurements are accurate, the certainly you have a short torso and longer legs. But what about the arms? What about saddle setback? There are so many points of consideration for which you've given no info. And still, there are no 'exact' things, just places to look/consider. ALL these things are interlinked.
Comments by others, since you made this post, have mostly given good things to consider. But they're limited by your 'curated' info, lacking much info which would help provide more ideas.
So here are so of my observations.
1. Your leg length issue - affects EVERYTHING greatly. That is the 1st thing I recommend you resolve in some acceptable manner. This affects the orientation of your hips, pelvis, spine, shoulders, neck, arms - hmmm, just about everything.
2. You have 5 points of contact with your road bike - saddle, 2 pedals and hands on the bars. But the saddle/butt/pelvis is the anchor point from which everything else is formed. WHere is your saddle? Height and setback - and any 'angle' other than mostly horizontal...
3. Going from 20 mm setback to 0 setback is counterintuitive to what might be need for a 'tall' person on very small 2XS frame.
4. A 2XS frame 'stack' is going to be considerably lower than a 'normal' size frame in M or S. Putting you in a much lower torso lean angle, unless you're also using a very large degree up-angle stem. All that might also contribute to a 'comfort' position.

Forget the 'stem' thing for now.
If not done, get the leg length issue resolved as best as possible. Then get your saddle situated for a good allround road riding position.
After that the Stem/bars/shifters placement is worked on to give you the combination which suits you, for your body and your riding. After, not before.
Re-measure your inseam using 2-3 cm thick book, in your crotch, standing as upright as possible without shoes, heels and back against wall, measuring floor to spine of book. Best if you have someone do the measurement for you, while you hold the book up inside crotch. Report back
Good Luck
Ride On Yuri

cyclezen

Hi Jason,
Sorry I hadn;t responded sooner, but just back from a week of backpacking, so offline.
So, things which are discussed here, online, by natuer of the project, are going to be incomplete and can only give some insight on places to look for getting closer to some resolution.
If your measurements are accurate, the certainly you have a short torso and longer legs. But what about the arms? What about saddle setback? There are so many points of consideration for which you've given no info. And still, there are no 'exact' things, just places to look/consider. ALL these things are interlinked.
Comments by others, since you made this post, have mostly given good things to consider. But they're limited by your 'curated' info, lacking much info which would help provide more ideas.
So here are so of my observations.
1. Your leg length issue - affects EVERYTHING greatly. That is the 1st thing I recommend you resolve in some acceptable manner. This affects the orientation of your hips, pelvis, spine, shoulders, neck, arms - hmmm, just about everything.
2. You have 5 points of contact with your road bike - saddle, 2 pedals and hands on the bars. But the saddle/butt/pelvis is the anchor point from which everything else is formed. WHere is your saddle? Height and setback - and any 'angle' other than mostly horizontal...
3. Going from 20 mm setback to 0 setback is counterintuitive to what might be need for a 'tall' person on very small 2XS frame.
4. A 2XS frame 'stack' is going to be considerably lower than a 'normal' size frame in M or S. Putting you in a much lower torso lean angle, unless you're also using a very large degree up-angle stem. All that might also contribute to a 'comfort' position.

Forget the 'stem' thing for now.
If not done, get the leg length issue resolved as best as possible. Then get your saddle situated for a good allround road riding position.
After that the Stem/bars/shifters placement is worked on to give you the combination which suits you, for your body and your riding. After, not before.
Re-measure your inseam using 2-3 cm thick book, in your crotch, standing as upright as possible without shoes, heels and back against wall, measuring floor to spine of book. Best if you have someone do the measurement for you, while you hold the book up inside crotch.
Report back
Good Luck
Ride On Yuri

Jason Lim

i will look into it and be providing you more details in the future. Thanks for the reply. here is the reference for my bikes geometry:
https://www.canyon.com/en-us/gravel-bikes/performance/grail/al/grail-7-wmn/2373.html?dwvar_2373_pv_rahmenfarbe=RD%2FBK&dwvar_2373_pv_rahmengroesse=2XS

cyclezen

One measurement I didn't outline - Arm length - measure, center to center, from the occiptal bone in neck to the styloid process (bone at end of Ulna/wrist) - with the arm straight out at shoulder level. That's your effective sleeve length/arm length. Some do 2 measurements, occipital to shoulder then shoulder to styloid - I think that introduces an opportunity for mis-measurement...
Torso can be inferred from the leg inseam and overall height.
I do measure for 'backpack' size and that gives a relative number for sizing packs, for the general population ( and also confirms relative torso length)
That is done by measuring along the spine, from a line across the Iliac crests up to the occipital. A good outdoor shop can do that for you. REI, here in the US, has an actual gauge to measure that. This number is compared to actual height, But anything shorter than 17" (43 cm) would be a 'Small' back/pack size. Shorter of course, means shorter torso...
Yeah, anyway, best is to resolve the leg length discrepancy, then situate the saddle. I still prefer using KOPS as a starting point (for many reasons) - again, it is a starting point. It should get you positioned close to the point where your torso mass is well supported by the saddle.
Good Luck
Ride On
Yuri

ctripblog

How to know if your legs are longer than your torso?

Kontact

I don't think I said legs longer than torso. But the discussion is about proportions, and if you are used to reading people's numbers it becomes clear when an inseam is long or short for a person's height.

Someone listed a proportion range in the first part of the thread that seemed reasonably accurate.

Iride01 

Do you need a formula? Seems pretty simple math to me.

However for the purposes of the conversations here, I've always felt that torso includes head and is everything that isn't considered leg length. Though actually leg length and inseam aren't the same thing or measured the same way. So depending one whether you want to use leg length or inseam will also make a difference.

So you can't quite go by the literal definition of Torso.

Yes maybe I'm somewhat trying to be a smart ass here, but there are some things in my statements above that are fact and need consideration if you wish to follow the train of thought in the conversations in other threads.

Welcome to BF!

Eharasim

[QUOTE=Iride01;22630914]I'm 180 cm or a tad less with 87.6 cm inseam. I use to ride way oversize for me frames with comfort. Not just 12 years ago I had been on a 25" ( 63.5 cm) bike for over 30 years. However in my older age I'm finding smaller frames better and have progressed down with 59 and 60 cm bikes to a 56 cm bike that is currently the lower recommendation out of the two sizes I was between. And I think I could have gone to a 54 cm bike, but probably that would have needed to be a different model with higher stack.

So while yes the manufacturers do build for the average proportions of what they feel their customer is, you should be able to find something that fits you well if you realize reach and stack as well as other geometry are different for different models of bike.

If you go with a smaller bike of the same model, then your stack height will get lower as the bike size decreases. And since on a road bike geometry your saddle height will always be pretty much the same distance from the BB or pedal, then your bar drop from the saddle will be more. Reach also decreases, but I've not found reach as big an issue and that can more easily be corrected with other adjustments.

So for the Tarmac SL6 in a 56 cm frame right now, if I was to go to a 54 cm frame I would probably be too aggressive a position for me with a lot of bar drop from the saddle. I might could just keep a lot of spacers under the stem, but a Roubaix with a more relaxed geometry and higher stack would probably be a better choice in a smaller size than recommended frame.

So to me, trying to figure out the correct size of bike to get form number calculations is silly... unless you already know from experience what works for you. You really need to just try on different models in different sizes and probably even a size out from the manufacturer recommended sizes. And remembering that a particular size, say a 56 cm bike in one model might be entirely different fit than a 56 cm of another model. Again, primarily due to reach and stack differences. Some go by horizontal top tube length instead of reach, but a road bike is going to have pretty much the same seat tube angle within a few degrees to make that a insignificant difference for whether using TT length over reach.

As for long legged people needing higher bars and shorter stems, I can't agree. I went lower on the bars when I got my 56 cm bike than I ever was on my other bikes. It's really just a matter of getting use to a new position. And that does take some effort. It's a tad uncomfortable at first to have your head so low and feel like it's the battering ram for whatever you might crash into. But you do get over that. At least I have.

I did right after I got my bike swap the 100 mm stem for a 70 mm stem of the same angle. And I thought it helped. However I just put the other 100 mm stem on about 4 or 5 rides ago after using the shorter for a long time, and I'm not really sure that I see the difference I thought it made. The 100 mm stems seems to be doing just as well for me.

Another thing I'm finding as I age and have entered retirement is that my muscle strength and mass is decreasing in my arms, hands and elsewhere on my body since they don't get used as much. And I'd have the odd hand numbness where I never had it before and other odd pains. As I've always found even when younger, that exercising those muscles and keeping them toned up... not necessarily building more muscle in those places that bother me really seems to help with aches, pains and numbness of things when on a bike. I keep a set of those hand exercisers with the springs next to my easy chair to help keep my grip strong so I don't get numb hands. Though the position of your STI's and angle of your drops as well as width of your handlebars makes some contribution too.

As for large frame bikes stretching out your hand position far in front of you, that does work well if you like the lower head first battering ram position. I did and being stretched out prevented shoulder, elbow and hand pain. With the smaller size bikes I'm riding now, I'm finding I have to keep a good bend in my elbows to avoid the issues with shoulders and elbows and hands. And for someone that spent most of their life with straight outstretched arms,

Please show mesome exercices (photos or short videos) at my email eugenharasim@yahoo.com for hands numb. Thank you!

bruce19

Back in the day this is what the pros did because the smaller the frame the lighter the weight.