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Help with Cervelo sizing

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Help with Cervelo sizing

Old 03-10-21, 06:57 PM
  #26  
mdzukunft
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Well, I think the plan is the same. Get post cut with some room for play (going tomorrow AM). Redo the video fit for knee angle. Then check BB-saddle setback, lower stem/bars and recheck video fit. And refinement from there.

This all really started due to lower back pain (likely from rocking so much in the saddle) and neuropathy in the hands (mainly ulnar > median). So I'm hoping if I can take care of at least one of those issues, I can make it 1-2 months prior to a proper fitting session.
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Old 03-10-21, 07:01 PM
  #27  
big john
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Originally Posted by DaveSSS
I'm sorry, but you are wrong. A given saddle height can be correlated to a specific saddle to bar drop. There's so much information missing here that all others can do is post some information, so the OP can determine what frame size he really has and what the stack and reach might really be. One rider might think that a 4cm saddle to bar drop is plenty, but even as a small rider, I use 10cm. Large riders might use 15cm or more. Large riders may also use extremely long stem and a lot of handlebar reach. I've read of one extremely tall pro rider using at least a 170mm custom made stem. I'm assuming that a person buying an S5 doesn't want to make an endurance bike out of it, but who knows.
I'm a little shorter than the OP. When I was in my 30s I would run 10cm drop. Now in my 60s I can't tolerate that much and instead use only 25-35mm. Bike fit is an individual thing for some of us and conventional thinking doesn't always work.
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Old 03-10-21, 07:24 PM
  #28  
Dean V
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Originally Posted by mdzukunft
P.S. And 35" is a short inseam? Since when?!
It is for someone that is 1.95m tall.
Mine is only 1/2" less but I am 1.8m.
As I said previously the numbers from your fit calculators were very similar to mine and I just can't see how someone 6" taller would ride the same fit as me.
Something is off and the best way to solve it would be to sort it out in person with someone that is suitably experienced.
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Old 03-11-21, 02:15 AM
  #29  
mdzukunft
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Well, in approximately 2 posts (including this one), I can link pictures of the geometries and the videos of me on the bike. I do not believe anyone will think my frame is too large. Now one post to go...
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Old 03-11-21, 02:16 AM
  #30  
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And here's number 10.
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Old 03-11-21, 05:41 AM
  #31  
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This thread has me really wondering how odd my form might be. I have an 85cm cycling inseam, and my saddle is set at 80cm. fwiw I'm 188cm tall
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Old 03-11-21, 09:00 AM
  #32  
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Back to the facts, saddle height and stack predict the saddle to bar drop. With a 73cm saddle height and 530 stack, I'd get a saddle to bar drop of no more than 10cm, with the standard 15mm headset top, no spacers and a -17 stem. A person with a 79cm saddle height would need a stack of 590 to get about the same saddle to bar drop. Your bike has a 630 stack with a lot of spacer and a high rise stem, so there is very little saddle to bar drop. All those spacers and the stem rise all reduce the reach, too. Try removing all spacers and flipping the stem down to create more saddle to bar drop. You'll increase both reach and drop. With a stack that limits the drop to around 6cm with no spacers and a -17 stem angle, there's no way you'll ever have too much drop.

The foot angle of 25 degrees is too much. The saddle should be low enough to allow your heel to drop 2-3cm below horizontal, with the leg fully extended at the bottom of the stroke.
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Old 03-11-21, 11:37 AM
  #33  
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Right. Which is why I believe the first step is to trim the post to allow 770-790 mm of height, readjust the saddle setback and then work on the cockpit (of course the stem will come down proportionally with the saddle). Going to the LBS this morning and hopefully with have back same-day to readjust everything and redo the video fit.
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Old 03-11-21, 12:00 PM
  #34  
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Originally Posted by mdzukunft
And here's number 10.
If you hadn't ignored my advice in post #14 you could have been showing us this stuff much sooner. <grin>

Spam police aren't going to come after you if you aren't a spammer.
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Old 03-11-21, 12:25 PM
  #35  
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Originally Posted by mdzukunft
Right. Which is why I believe the first step is to trim the post to allow 770-790 mm of height, readjust the saddle setback and then work on the cockpit (of course the stem will come down proportionally with the saddle). Going to the LBS this morning and hopefully with have back same-day to readjust everything and redo the video fit.
I think you need to determine whether you have a natural "toe down" riding style or if you're pointing your toes to compensate for the saddle being too high.
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Old 03-11-21, 12:34 PM
  #36  
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So...

I confirmed new forum users canít post images or in-line links (like you suggested) until 10 posts. Sorry. Forum rules, not mine.

As far as being a toe down rider, I probably am to a slight degree. But after some experimentation and being very cognizant of my pedal stroke, it is certainly exaggerated by my efforts to reach the 180 degree crank position due to saddle being too high. The video of the aft position makes that clear. We will see when I get the saddle back later today.
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Old 03-11-21, 02:24 PM
  #37  
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Originally Posted by mdzukunft
So...

I confirmed new forum users canít post images or in-line links (like you suggested) until 10 posts. Sorry. Forum rules, not mine.

As far as being a toe down rider, I probably am to a slight degree. But after some experimentation and being very cognizant of my pedal stroke, it is certainly exaggerated by my efforts to reach the 180 degree crank position due to saddle being too high. The video of the aft position makes that clear. We will see when I get the saddle back later today.
It is for spam control that they put that criteria on new members. You aren't a spammer, they will not have cared one bit. Many other new members have done this with and without my suggestion.

But come to think of it... they haven't posted much lately. Maybe they did get sent to the spammer prison! <grin>
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Old 03-11-21, 05:23 PM
  #38  
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Okay! The post was cut 55 mm. The bike went back onto the trainer. Apart from hiccups with the damned stickers falling off my hip, here are the results... Drum roll please...

Saddle set at 800 mm from 825 mm. Saddle setback moved to 98 mm from 90 mm. Cockpit lowered to 100 cm from 103.5 cm resulting in a drop of 6.5 cm (saddle-ground 106.5, bar-ground 100.0). Not certain my core can take much more than that right now. ;-)

I instantly felt the difference. Don't feel I'm rocking like the open seas. My foot is not straining on the down stroke (far more flat pedal stroke). My hands don't hurt as much (less forward weight). I know it isn't perfect but it's a lot better until the formal bike fit in 1-2 months.


Initially, installed the saddle @ 770 mm without changing the saddle setback



Plan: Raise saddle to 800 mm and saddle setback to ~ 98 mm. Checked knee-shaft with plumb bob and dead-center over crank @ 98 mm. Not sure about the extra 12 mm. I know taller riders sometimes have a little crank setback ~ 10 mm - something to ask the bike fitter about



Plan: Lower cockpit by 35 mm. Leave length as-is



The re-check (some of the dots kept falling off so I think there's some error here and made no additional changes)



Velo au natural
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Old 03-12-21, 08:39 PM
  #39  
Dean V
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Looks like it is near enough to start riding and see how you like it on the road.
Quite an upright riding position, but that is just personal preference.
I would rotate the bars down a bit though. Not the levers so much, just the bars.
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Old 03-12-21, 09:48 PM
  #40  
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More pictures of bike, please.
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Old 03-16-21, 10:17 AM
  #41  
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What pictures specifically?
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