Saddle height and BPH

[Jay Lonner]

I just took delivery of a new (non-Riv) bike and am dialing in the fit. I’m a little worried that the frame is too big for me, since I only have maybe 2” standover, which seems tight for a gravel bike.

So I went out and measured the saddle height on my Hunq (which is a size 62). It came in at about 75cm. This gives me a solid fistful of seatpost. Then I remeasured my PBH, which is 93-94 cm depending on hard I pull. For reference, here’s the relevant page from HQ:

https://www.rivbike.com/pages/pubic-bone-height-how-to-measure-your-pbh

This suggests that based on my  PBH my saddle height should be closer to 83 cm – an 8cm discrepancy. Before riding in this morning I raised my saddle height to 79 cm, basically splitting the difference. It felt weird, which of course it would after so many years at 75cm. But I made it in and my feet were in full contact with the pedals without any tippytoe maneuvers. So I guess I’ve been doing it wrong this whole time? Kind of embarrassing. Even so, according to the Riv method my saddle height is still ~4cm lower than my PBH would suggest. 

So I guess I’m wondering about alternative ways of determining saddle height somewhat objectively, and/or whether I should now be looking at other variables such as a fore-aft saddle positioning, saddle angle, and even saddle type (currently a B68, slammed back as far as it can go on a S83, with the nose pitched up ~10 degrees or so). Other relevant factors might be crank arm length (175mm), pedal height (Pedaling Innovations platform pedals), and shoes (Chuck Taylors, typically). Looking for the optimum balance of comfort, efficiency, and protecting my perineum.

Jay Lonner

Bellingham, WA

[Jay Lonner]

Please note the typo in the subject heading - I am referring to PBH (pubic bone height) and not BPH (benign prostatic hypertrophy) which is another, separate factor of potential interest to bike riding men of a certain age…

Sent from my Atari 400

On Dec 12, 2022, at 9:49 AM, Jay Lonner <jay.l...@gmail.com> wrote:

I just took delivery of a new (non-Riv) bike and am dialing in the fit. I’m a little worried that the frame is too big for me, since I only have maybe 2” standover, which seems tight for a gravel bike.

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[Justus G]

Standover is generally a non-issue and should be of limited consideration for fit purposes, all things being equal.

I do believe your saddle height has been very low based on the fact that I have an 83cm PBH and run a height of 72cm.  The Riv guidance looks to be within expected range.

Generally recommend dialing in saddle setback first and since yours is slammed back, I would recommend centering it on the rails and raising it a little further.  If you can sit  on the bike (with someone holding it upright for you) and hover your hands over the bars without engaging too much core strength, you are probably in a good spot with respect to saddle setback (and its relation to bar height).  If your weight distribution with the new setback leans you into the bars and puts weight on your wrists, then still work to do (fore, aft, tilt, relationship to bars etc.)  

Saddle height should be such that your legs come close to full extension on downstroke but do not lock out and does not create side to side hip movement (reaching for the pedals).

[Eliot B]

If you put the heel of your foot on the pedal and rotate it to the furthest point away from you, you should be just about locked out. When you then put the ball of your foot on the pedal like you normally ride, you will be just shy of full extension which should be a good ball park. You want the saddle as high as it will go without causing rocking in your hips or over extension in your legs. 

[Paul Clifton]

IME, there's no objective way to get the "right" saddle height, but the Riv method gets me in the ballpark. I do change my saddle height +/- a cm or so, even on the same bike, depending on the kind of riding I'm doing (single track vs path/road/gravel) and how flexible I'm feeling at any given time. I'm not searching for the most efficient position in terms of power transfer, but the most comfortable in terms of my muscles, joints, and movements on the bike.

What the others have said (heel on pedal to almost lock out, and adjusting the fore/aft/tilt) is good advice, but how straight to get your knee at the bottom of the pedal stroke is subjective in my opinion. I'd say jack the seat up another 4cm and see how it feels, but don't be shy about lowering it back down either. I think some of the individual differences have to do with femur-to-fibula ratios, hip flexibility, quad-to-calf strength ratios, and butt size, not to mention upright vs leaned forward riding position.

Another Riv method that I like is

1. Move the seat way up. Get it high enough that when you ride, you notice your hips moving from side to side, like you're trying to get a little more extension to reach the bottom of the pedal stroke.

2. Move the saddle down 1/2 to 1 cm at a time until you feel that hip rocking stop.

That's gonna get you your maximum acceptable saddle height, which I would consider "leaned-forward, go fast, roadie saddle height". Go down from there based on what feels comfortable to your knees and hips on the type of riding you're doing.

These are just my thoughts as I've searched for saddle height nirvana and found that it only really exists in the moment.

Paul in AR

[Alan Barnard]

Like others have intimated, it sounds as if you’ve been running your saddle much lower than recommended. I would suggest measuring your PBH one more time with an assistant to be absolutely sure it’s correct, then adjust your saddle to PBH minus 10-10.5 cm.

Alternatively, you could use the LeMond method which is essentially the same using different math. His formula is PBH x .883. 

[lconley]

I have never understood why any body is concerned "saddle height" which as I understand it is the distance from the CL of the crank to the top of the saddle, inline with the seat tube. It is very hard to measure from the center of the crank and what if you have bikes with different crank lengths?. I put the crank low and in-line with the seat tube and measure from the top of the pedal axle to the top of the saddle,  inline with the seat tube - takes the crank length out of the equation. I used 35" when I was younger, but now use 34". It is constant from bike to bike, no worrying about crank length, nor trying to line up the end of the tape with the centerline of the crank at the same time as trying read the tape at the saddle.

Laing

Delray Beach FL

[George Schick]

Laing - I agree with you about the crank length.  But then, I'm old and have dealt with the issues of frame size v. saddle height v. crank length so many times over the years that I can't recall them all.  Nevertheless, I seem to have dialed into some kind of combination of these that I have managed to accommodate the differences well enough to "just ride."  Enough is enough.

[Eric Daume]

I'm about your same size (36"/91cm PBH), but I run a 32"/81cm saddle height (bottom bracket center to top of my (of course) level saddle). I couldn't imagine pedaling with my saddle 6cm lower.

When I played around with mid foot pedaling, I found I had to drop my saddle, but less than an inch. 

Eric

[Paul Clifton]

Laing, I've puzzled about how to take crank length into account and this seems like a great idea. I'll give it a try. But at the end of the day, anything that is a fairly reproducible number for an individual gets the job done. I have a seamstress tape with a little rivet on the end that grabs the top of the hole where the crank bolt goes and it gets the zero point of the tape close enough to the center of the crank that it's never been a problem, or at least it keeps my measurements fairly consistent.

Paul in AR

On Monday, December 12, 2022 at 2:41:33 PM UTC-6 lconley wrote:

[Richard Rose]

Jay, I noticed your mention of the Pedaling Innovations Catalyst pedal. If you are using a mid-foot position on your pedals ( I do) you may need to adjust your saddle down 2-3 cm. I discovered this on my own then confirmed it with Pedaling Innovations. For this and other reasons I do not favor the PBH method of determining saddle height. It’s more a guideline than a rule. I have used the knee slightly bent at bottom of stroke for 50 years without injury or incident.

Sent from my iPhone

On Dec 12, 2022, at 12:49 PM, Jay Lonner <jay.l...@gmail.com> wrote:

I just took delivery of a new (non-Riv) bike and am dialing in the fit. I’m a little worried that the frame is too big for me, since I only have maybe 2” standover, which seems tight for a gravel bike.

[Mackenzy Albright]

I find a more slack seat tube I run my saddle a bit lower than a steeper counterpart. 

Ride whatever is comfortable. Don't worry too much about stand over. French fit looks great. 

[Slacky Mac]

Thanks (thank you, thank you) for bringing attention to the the Catalyst pedal - I think it will be a godsend for me.  I deal with an injury related neuropathy in my left calf muscle which prevents me from doing things like a tippy toe on that side.  Had to sell my pristine manual ‘07 Honda S2000 as I could no longer use the clutch safely - a tragedy!  Being able to incorporate more of my foot on the pedal will be wonderful as I half-foot my left pedal now and it is a struggle.  I measure to a 76cm saddle height based on PBH, but it runs closer to 70cm in actual use.  Not ideal, but better than siting on the couch.

With a new Sam ordered, I now think I will now request the smaller 170MM crank as part of the build to help balance things out.

Sure glad I found this group!

[John Hawrylak]

Jay

The most accurate SH would be using a gonimeter to measure your leg angle and adjust SH to get the optimum leg angle (I forgot the value).  The bike is bike is on a trainer and the front wheel is leveled.   The gonimeter measures the leg angle at the bottom of the pedal stroke. 

Typically this is a bike shop and costs about $50 to $75.   I had it done and the result was within 2mm of both the LeMond 88.3% of PBH (BB center to saddle) and the 109% of PBH when adding your crank length.

Heres a link to 1 of the many websites   How to Determine the Correct Saddle Height - Mantel    He discusses the leg angle method.

John Hawrylak

Woodstown NJ

On Monday, December 12, 2022 at 12:49:07 PM UTC-5 Jay Lonner wrote:

[Patrick Moore]

I agree that rules of thumb are only starting points. The heel-on-pedal at max leg extension puts my saddle a good 3 cm too low as I like a lot of leg extension and tend to pedal toe-down. But it's a good starting point.

And get your saddle set back to where it is comfortable before doing anything else; IMO and IME, saddle height and setback are the 2 primary adjustments around which all others are determined. 

But heck, if you've been comfortable with your previous "4-inches-too-low" and slammed back saddle -- no hip-rockin', no aching quads, no strained whatever it is along the inside of the thigh, you have been doing it right.

But I disagree that standover is a negligible part of fit; try an emergency dismount on a steep slope facing uphill.

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Patrick Moore

Alburquerque, Nuevo Mexico, Etats Unis d'Amerique, Orbis Terrarum

[Patrick Moore]

Whoops, that's 4 centimeters ...

[Andy Beichler]

I am not very flexible.  Even when I was young, before I hit my growth spurt, touching my toes was difficult at best.  I have a 92 PBH and run my saddle around 78 cm.  Anything higher and I feel like I am reaching for the pedal.  I usually just get it in the ballpark and adjust it if I start to hurt.