Frame size, new bike fitting, questions

Discuss light weight issues concerning road bikes & parts.
TobinHatesYou
Posts: 5080
Joined: Mon Jul 24, 2017 12:02 pm

by TobinHatesYou

Fewer spacers is invariably increased reach. Since the SystemSix has a -17deg stem and only a +4mm frame stack, you will probably still need to ADD spacers to achieve the same bar stack. That will also shorten the reach. Get the 54cm.

TurboKoo
Posts: 568
Joined: Wed Oct 29, 2008 7:55 pm

by TurboKoo

You can also use stem from supersix as it’s -6.
Image
Scott Foil
Shimano 9150
Shimano FCR-9100-P
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by Weenie


Talsuwaidi
Posts: 3
Joined: Sat Feb 15, 2020 9:51 am

by Talsuwaidi

TobinHatesYou wrote:
Sun Feb 16, 2020 1:07 pm
Fewer spacers is invariably increased reach. Since the SystemSix has a -17deg stem and only a +4mm frame stack, you will probably still need to ADD spacers to achieve the same bar stack. That will also shorten the reach. Get the 54cm.
Thanks.. That kind of confirmed what I've been thinking. :thumbup:

Talsuwaidi
Posts: 3
Joined: Sat Feb 15, 2020 9:51 am

by Talsuwaidi

TurboKoo wrote:
Sun Feb 16, 2020 2:06 pm
You can also use stem from supersix as it’s -6.
Image

Thanks for the idea but I like the knot stem. Am trying to keep it with using specific systemsix parts if possible...

tranty0719
Posts: 1
Joined: Wed Feb 12, 2020 5:42 am

by tranty0719

I’m 5’8 and rides a 48cm Cervelo S5 with a set of Enve 6.7


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Yoln
Posts: 60
Joined: Thu Nov 14, 2019 10:26 pm

by Yoln

Hi,

Not sure this is the best place for posting this, but since I won't see any fitter in NYC anytime soon, I thought I'd give it a try at home fitting.

Started to use the BFF Elite app on my phone and I got the below pictures, any first thought on my current position/fit and what I could improve?

Resting position, leg at max extension:
Image

On the drops, legs at max flexion:
Image

Aero-ish position that I use pretty often:
Image

User avatar
silvalis
Posts: 761
Joined: Mon Sep 07, 2015 1:02 am
Location: Aus

by silvalis

Yoln wrote:
Wed Apr 01, 2020 9:33 pm

Started to use the BFF Elite app on my phone and I got the below pictures, any first thought on my current position/fit and what I could improve?
Roll your hips forward and straighten your back while lower down so you get rid of that kink in your lower back.
Chasse patate

TobinHatesYou
Posts: 5080
Joined: Mon Jul 24, 2017 12:02 pm

by TobinHatesYou

I was about to say the same. A lot of people hinge twice, once at the hips and again in the lower back. If you can straighten your back, you might be able to run less setback and a slightly higher saddle position. You’ll feel less stretched out and have less impingement at the top of your pedal stroke.

Yoln
Posts: 60
Joined: Thu Nov 14, 2019 10:26 pm

by Yoln

Thank I can definitely see that now that you mention it. But, I am actually arched back close to my maximum in the top picture. I'll try to take a picture tonight while trying to really rotate the hips forward and arch more the back, but not sure there is much room for improvement.

The interesting part is that this stiffness is due to my back flexibility instead of my hips. I have very good forward flexibility (back or hips tilt, I can can easily set my hand below my feet with straight legs, and almost touch my knees with my chest for example), but on the other hand, my back-arching barckward is very very limited, I probably have some work to do in that direction. Does it make sense?

alanyu
Posts: 347
Joined: Thu Jun 06, 2019 1:10 pm

by alanyu

Do you feel any uncomfort or pain at your lower back? If not, this is somewhere close to your natural position, no need to "correct" it deliberately.
1.PNG
2.PNG

Yoln
Posts: 60
Joined: Thu Nov 14, 2019 10:26 pm

by Yoln

Should have mentioned it, but yes I do have lower back pain on my longer rides. For years I just assumed I had to toughen up, and since it's always been manageable on shorter training and races I never really adressed it

TobinHatesYou
Posts: 5080
Joined: Mon Jul 24, 2017 12:02 pm

by TobinHatesYou

alanyu wrote:
Thu Apr 02, 2020 6:43 pm
Do you feel any uncomfort or pain at your lower back? If not, this is somewhere close to your natural position, no need to "correct" it deliberately. 1.PNG2.PNG

Caveat is both riders are in a TT position with way less setback and a higher saddle. You can see Yoln's legs nearly hitting his abdomen in some of his captures.

alanyu
Posts: 347
Joined: Thu Jun 06, 2019 1:10 pm

by alanyu

TobinHatesYou wrote:
Fri Apr 03, 2020 3:40 am
alanyu wrote:
Thu Apr 02, 2020 6:43 pm
Do you feel any uncomfort or pain at your lower back? If not, this is somewhere close to your natural position, no need to "correct" it deliberately. 1.PNG2.PNG

Caveat is both riders are in a TT position with way less setback and a higher saddle. You can see Yoln's legs nearly hitting his abdomen in some of his captures.
I should have stated it more clearly. What I wanted to say is rolling the pack or rolling the hip. None is more correct or wrong. One should keep his natural posture.

As to saddle height, it really seems a bit lower. If his fixed points are accurate, he needs to increase saddle height about 5-15mm to get around 135-145º. However, since he added he feels pain on long ride but Okish on short ride/training, the drop from saddle to bar will be a problem if saddle is higher, which may makes him feel pain earlier.

Yoln
Posts: 60
Joined: Thu Nov 14, 2019 10:26 pm

by Yoln

alanyu wrote:
Fri Apr 03, 2020 6:52 am
TobinHatesYou wrote:
Fri Apr 03, 2020 3:40 am
alanyu wrote:
Thu Apr 02, 2020 6:43 pm
Do you feel any uncomfort or pain at your lower back? If not, this is somewhere close to your natural position, no need to "correct" it deliberately. 1.PNG2.PNG

Caveat is both riders are in a TT position with way less setback and a higher saddle. You can see Yoln's legs nearly hitting his abdomen in some of his captures.
I should have stated it more clearly. What I wanted to say is rolling the pack or rolling the hip. None is more correct or wrong. One should keep his natural posture.

As to saddle height, it really seems a bit lower. If his fixed points are accurate, he needs to increase saddle height about 5-15mm to get around 135-145º. However, since he added he feels pain on long ride but Okish on short ride/training, the drop from saddle to bar will be a problem if saddle is higher, which may makes him feel pain earlier.
Thanks for your comments guys.

I guess what this discussion helped me is to identify several problems with my posture (on the bike partly, but also while sitting at my office chair) called Posterior Pelvic Tilt (https://posturedirect.com/how-to-fix-a- ... lvic-tilt/), and I believe I have to work on strenghtening my back/core and improving stretching/flexibility of that area. Actually these confinement times might be good for that.

Regarding the saddle height, yes, it can definitely use a small increase to pass 135º. Hopefully working on the posture will help pushing the pain to happen later and later in my rides.

Last question for you though. Regarding my saddle fore-aft, what would you consider as "neutral" with a seatpost with a strong setback? Do I align the saddle "0" with the center of the seatpost (A in the below picture) or with the clamp bolt (B in the pic)? disregard any other saddle settings, I am in the process of switching saddles and was just using this as an example.

Image

alanyu
Posts: 347
Joined: Thu Jun 06, 2019 1:10 pm

by alanyu

Yoln wrote:
Fri Apr 03, 2020 5:05 pm
Thanks for your comments guys.

I guess what this discussion helped me is to identify several problems with my posture (on the bike partly, but also while sitting at my office chair) called Posterior Pelvic Tilt (https://posturedirect.com/how-to-fix-a- ... lvic-tilt/), and I believe I have to work on strenghtening my back/core and improving stretching/flexibility of that area. Actually these confinement times might be good for that.

Regarding the saddle height, yes, it can definitely use a small increase to pass 135º. Hopefully working on the posture will help pushing the pain to happen later and later in my rides.

Last question for you though. Regarding my saddle fore-aft, what would you consider as "neutral" with a seatpost with a strong setback? Do I align the saddle "0" with the center of the seatpost (A in the below picture) or with the clamp bolt (B in the pic)? disregard any other saddle settings, I am in the process of switching saddles and was just using this as an example.

Image
I would recommend the old school method of the knee-pedal alignment for the neutral saddle setback, though it is not so scientific (which part of the knee could result in over 2 cm difference) in the view of dynamic fitting nowadays.

by Weenie


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