Frame size, new bike fitting, questions

Discuss light weight issues concerning road bikes & parts.
icantaffordcycling
Posts: 953
Joined: Wed Jan 09, 2019 5:03 am

by icantaffordcycling

Hey guys!
I need some help with my bike fit. I have lots of space to play with at the moment (130mm stem so options to go longer or shorter, the video shows my position slammed with 35mm above the stem, lots of seat-post and can cut a lot more if needed). I recently tried slamming my stem and seeing how my position on the bike would change. Everything looks and feels fine on the tops with my elbows bent to 90* but the problems show up when I get into my drops and try to bend my elbows. I think I am too fat / my cranks are too long to get that low but I am not sure what to do. Do I have to move my bars back up and are there any other red flags with my fit?
Position on the tops.
Position in the drops.

zefs
Posts: 446
Joined: Sat Aug 05, 2017 8:40 pm

by zefs

To me it looks like you are trying to force a too aggressive aero position, even more so than a TT bike. Your saddle seems a bit too low (and too forward) and I can see some restriction on the hip motion due to that and the very low handlebar position. Would recommend a professional bike fit since you seem to be aiming for racing/competition but the position is off.

by Weenie


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silvalis
Posts: 762
Joined: Mon Sep 07, 2015 1:02 am
Location: Aus

by silvalis

Yep, looks like you toe pedal a bit so you aren't getting as much knee extension. No idea if this is due to you trying to get super low and aero and your hammys are saying no. Your pedalling might be completely different when you're sitting up on the hoods.

Anyway, if its not your hammys, zefs suggestion is good. Your arched back in the drops is a reasonable indication that you're cramped up too much.
Chasse patate

addictR1
Posts: 1828
Joined: Sun Jun 10, 2012 1:11 am

by addictR1

hi all... i'm trying to figure out the proper frame size. currently riding a 51cm Scott Addict R1 and 48cm BMC TMR02; both using 170mm cranks. i've always felt stretched out and felt ok but not 100% comfy. i've been to a PFit fitter in SF and turned out with a knee injury 1.5wks into riding that left me off the bike for close to 2 months.

anyways.. long story short, i tried wrenchscience bike fit and pedalforce bike fit. can't believe based on the measurements, my bikes are too big for me. is this pretty accurate or should i get a retul bike fit for a new frame? thinking of going Ti for a keeper, so want to get it as dialed in as possible.

any recommendations on where to get fitted or measured would be greatly appreciated. i'm in santa clara county area in california. thanks.
Attachments
Bike Fit 2.JPG
Pedalforce Bike Fit - Recommend.JPG

zefs
Posts: 446
Joined: Sat Aug 05, 2017 8:40 pm

by zefs

Bike sizing seems correct for your measurements (only checked the bmc). You might wanna try 165mm cranks as you have short legs for your height. Not sure about your reach without seeing you on the bike, have you tried a shorter stem?

addictR1
Posts: 1828
Joined: Sun Jun 10, 2012 1:11 am

by addictR1

zefs wrote:Bike sizing seems correct for your measurements (only checked the bmc). You might wanna try 165mm cranks as you have short legs for your height. Not sure about your reach without seeing you on the bike, have you tried a shorter stem?
Well I first started with a 85mm stem and 90mm but both of those I couldn’t slam that stem. Then I went to the fitter and he suggested 100mm and got one that is -17 degree so it’s slammed.

Maybe I should get a 80-90 version in -17?


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zefs
Posts: 446
Joined: Sat Aug 05, 2017 8:40 pm

by zefs

Not sure without seeing your position, but you can can use this website to see the difference when switching between stems:
http://yojimg.net/bike/web_tools/stem.php

If you can't reach the brake levers comfortably maybe that is causing your issue? just a suggestion as they are adjustable.

addictR1
Posts: 1828
Joined: Sun Jun 10, 2012 1:11 am

by addictR1

zefs wrote:Not sure without seeing your position, but you can can use this website to see the difference when switching between stems:
http://yojimg.net/bike/web_tools/stem.php

If you can't reach the brake levers comfortably maybe that is causing your issue? just a suggestion as they are adjustable.
Thanks for the link. I’ll play with that and see. Right now I can reach my brakes in the drops, but my arms are somewhat straight if I want to remain my sitbone planted.


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silvalis
Posts: 762
Joined: Mon Sep 07, 2015 1:02 am
Location: Aus

by silvalis

addictR1 wrote:
Sun May 26, 2019 9:02 pm
Thanks for the link. I’ll play with that and see. Right now I can reach my brakes in the drops, but my arms are somewhat straight if I want to remain my sitbone planted.
Does "remain my sitbone planted" mean you're trying not to rotate your pelvis in order to reach the drops?

addictR1 wrote:
Sun May 26, 2019 5:09 pm
Well I first started with a 85mm stem and 90mm but both of those I couldn’t slam that stem. Then I went to the fitter and he suggested 100mm and got one that is -17 degree so it’s slammed.

Maybe I should get a 80-90 version in -17?
Hang on, so you feel too stretched out but went longer and lower?
Chasse patate

zefs
Posts: 446
Joined: Sat Aug 05, 2017 8:40 pm

by zefs

That probably means you are a bit low/long and you are straightening your hands to try and push your pelvis back to feel the sitbones (to alleviate pressure in the perineum). Same thing can happen in the hoods, straight arms means you are not comfortable/relaxed in the saddle area.

It can also be related to short reach but probably not the case here.

addictR1
Posts: 1828
Joined: Sun Jun 10, 2012 1:11 am

by addictR1

silvalis wrote:
addictR1 wrote:
Sun May 26, 2019 9:02 pm
Thanks for the link. I’ll play with that and see. Right now I can reach my brakes in the drops, but my arms are somewhat straight if I want to remain my sitbone planted.
Does "remain my sitbone planted" mean you're trying not to rotate your pelvis in order to reach the drops?

addictR1 wrote:
Sun May 26, 2019 5:09 pm
Well I first started with a 85mm stem and 90mm but both of those I couldn’t slam that stem. Then I went to the fitter and he suggested 100mm and got one that is -17 degree so it’s slammed.

Maybe I should get a 80-90 version in -17?
Hang on, so you feel too stretched out but went longer and lower?
By not having to slide forward in my saddle.
I feel stretched out with the 100mm stem that was recommended to me by the fitter. Originally I had a 90mm which I’m gonna go back to.


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silvalis
Posts: 762
Joined: Mon Sep 07, 2015 1:02 am
Location: Aus

by silvalis

Interesting sliding forward to get bent arms in the drops. Your drops have a shorter reach than your hoods so I would have guessed you'd slide backwards. Arching your back maybe?
Chasse patate

addictR1
Posts: 1828
Joined: Sun Jun 10, 2012 1:11 am

by addictR1

silvalis wrote:Interesting sliding forward to get bent arms in the drops. Your drops have a shorter reach than your hoods so I would have guessed you'd slide backwards. Arching your back maybe?
Yea I have really bad posture and form. Slouch very often it’s like a norm. Need to find some exercise that can fix my slouching and weak core.

Btw, any recommendations on fitters in the Bay Area, Cali?

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jadedaid
Posts: 16
Joined: Fri Feb 22, 2019 7:43 pm

by jadedaid

Hi everyone,

I'm in the fortunate position to be getting a custom frame. I have lanky proportions (i.e. long legs and no torso) which means I have to ride short stems on regular bikes. I have a 56cm Great Divide from No.22 on a 90mm stem and it sometimes feels like I'm piloting a boat that's in front of me, rather than a bike that I am 'inside' of. This is one of the reasons I am looking at replacing the frame.

Going forward, I have the choice of either building the frame around a 100mm stem (55cm top tube on a 73d seatube with my beloved 3T bar) or 110mm stem (54.5cm top tube on a 73d seatube, using a bar with a shorter reach). The sketch which came back from the builders put me on a 100m stem and 55cm top tube, the concern with going shorter was down to toe overlap going from Small Annoyance to Big Annoyance.

Any advice from you folks as to which way you would go if in the same boat?

by Weenie


win32
Posts: 31
Joined: Thu Jun 06, 2019 11:01 am

by win32

Hi to all! :)

I'm between sizes for Bainchi Aria and now I need advice what one is better choice.
My hight is 178 cm, my inseam is 82-83 cm.
My old bike was Specialized Allez in size 56" and it was relative ok with 80 mm stem.
I was try Specialized Allez from 2014 in size 54" ant that one was ok.

Now I want to buy Aria but I'm stuck between sizes. I'm little streched on 55". Aria have 2 cm offset on seatpost and with default it have 110 mm stem. Maybe if there is no offset and if I take 90-100 mm stem all that will be better? Did I need to be more streched on Aria than on Specialized Allez? Aero position is great for me and I'm just worried for that streched position with that offset and 110 mm stem.

From some of yours experience, take shorter 90-100 mm stem and try to fix that or to take smaller bike?
Smaller, 53" Arioa have 170 mm crank and I don't know is that ok for my inseam and hight (I never ride with 170 mm)?

Here is basic info abou Specialized Allez Race in 54" and that one was ok:

Reach: 387 mm
Stack: 547 mm
Top tube lenght: 548 mm
Seat tube lenght (BB to top): 500 mm
Head tube lenght: 145 mm
Stand over height: 798 mm
Head tube angle: 73°
Seat tube angle: 73,5°

Here is info basic info of Aria in size 55":

Reach: 390 mm
Stack: 541 mm
Top tube lenght: 550 mm - B1 on picture (or 541 - BS on picture)
Seat tube lenght (BB to top): 520 mm (AS on picture)
Head tube lenght: 140 mm
Stand over height: no info
Head tube angle: 72,5°
Seat tube angle: 73,5°

Aria in 53":

Reach: 385 mm
Stack: 525 mm
Top tube lenght: 535 mm - B1 on picture, or 528 mm - BS on picture)
Seat tube lenght (BB to top): 500 mm (AS on picture)
Head tube lenght: 125 mm
Stand over height: no info
Head tube angle: 72°
Seat tube angle: 74°

And here you can see detailed geometry of Specialized Allez in 56":

http://imgur.com/hr8fAJy

Complete Aria geometry:

Complete Aria geometry:

https://cdn.shopify.com/s/files/1/1099/ ... 1557791726

Thanks for all your help because I really need it (there is no any kind of fitters around me or in any close town, maybe only in another country like Slovenia).

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