Downside to Cut-Out Saddles?

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SolidSnake03
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by SolidSnake03

Hey Everyone,

I have been thinking about saddles a good bit recently while trying to find one that really works well for me. Having tried a few saddle's it isn't that they are uncomfortable but just haven't have that "aaaahhh" moment where it just clicks so to speak.

Anyhow, this got me thinking about cut-out or channel saddles and after trying a few vs. non-cut out I'm wondering what, if any, real disadvantages are there? I'm trying to understand in my mind why someone wouldn't want a cut-out or what reason there would be for selecting against one. For example, with the Selle Italia SLR in past years it was cut out or not, why would you want the non-cut out?

For the purpose of this thought experiment type thing I'm NOT considering saddles with massive gaping holes in them *SMP*, I understand that those feel distinctly different and do have a very different feel. For the purpose of this I'm looking specifically at things like the SLR or the Toupe that have a modest cut out with plenty of "saddle" around it.

Same thinking goes for things like Prologo+'s where there is a bit of a center channel but again it's not like the saddle is radically different.

*NOTE* this is not a discussion about whether cut-outs are needed, better for you or any of that stuff.
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wpccrunner
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by wpccrunner

they tend to wear out faster, from the higher stresses concentrated around the cutout. They are typically a bit heavier than their non-cutout counterparts

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Rick
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by Rick

And if you ride through water, it can spash up into your crotch.

eric
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by eric

I've not noticed a downside to my Specialized Toupe saddles. No extra splashing (the seat post and seat bag block that). Since there is no model without a cutout it is difficult to say if the cutout makes the saddle heavier or lighter.

lannes
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by lannes

I kinda like the Fizik Twin Flex concept, combine this with wingflex and it's a good solution for some as you get a bit of the "cut out" benefit.

http://www.fizik.com/products/technologies/twin-flex/" onclick="window.open(this.href);return false;" onclick="window.open(this.href);return false;

dmp
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by dmp

wpccrunner wrote:they tend to wear out faster, from the higher stresses concentrated around the cutout.


And where are the data to support this statement?

I think it is all a matter of fit and comfort, nothing more. The SLR has come in both a cut out ("flow") and non cutout version for years. Not having ridden the non-cut out version I really can't give a good answer for you, but I have been on cut out saddles (SLK for about 3 years, and SLR flow for the past 3) for years and have never had a problem with them, and have had relief from the dreaded numbness since switching to them.

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SolidSnake03
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by SolidSnake03

I agree that I haven't seen any data or science really to back up the idea that cut out saddle either wear or break faster. To me, it seems like why wouldn't you go for one regardless of if you have detected any numbness or not? I don't see any real downside to the more modest cut out designs which is why I was posing the question, wanted to see if there really was any negatives out there I wasn't aware of.

Also, haven't notice any water spray either, agree with the other poster that the seatpost and or saddle bag seem to prevent that *although something like an SMP might be different
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dereksmalls
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by dereksmalls

I've got a Toupe on my CX bike which I really like and a non cut out SLR on my road bike. Both of these I bought second hand as I can't afford a brand new unused one. After my race in two weeks I'm going to switch the SLR for a Chinese full carbon Toupe copy I got cheap off eBay and see how we go. Don't want to alter anything in my current set up this close to a race. If I could afford a new SLR Carbonio Flow I would buy one in a flash

tinozee
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by tinozee

I use a fizik antares with no cut out and a Adamo Breakaway with a full length cut out. Both are great for my body, but the adamo allows me to rotate the pelvis to the ideal spot (which changes over 100 miles and varied power efforts) and get lower longer without any pressure on the crotch bulge (perenium?). On the antares I still get low, but I bend more in the low back than at the hips. It's not ideal when you start to lean on the bulge.

No disadvantage - you can ride upright, no-handed, all of that like a normal saddle on the adamo. Oh, weight is a disadvantage. So if weight matters you could get a Dash (I want).

davidalone
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by davidalone

From an engineering point of view, it is aalmost definite that they will wear out faster, but this depends on the design and material of individual cutout. A full cutout introduces what engineers call a stress riser into your saddle, meaning certain regions are going to be loaded more highly than others and more likely to crack and fatigue.

Like I said it depends if the saddle was designed with this in mind, but all things being equal if two saddles had the same design and material as each other the non cutout version would last longer.

davidalone
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by davidalone

From an engineering point of view, it is aalmost definite that they will wear out faster, but this depends on the design and material of individual cutout. A full cutout introduces what engineers call a stress riser into your saddle, meaning certain regions are going to be loaded more highly than others and more likely to crack and fatigue.

Like I said it depends if the saddle was designed with this in mind, but all things being equal if two saddles had the same design and material as each other the non cutout version would last longer.

wpccrunner
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by wpccrunner

dmp wrote:
wpccrunner wrote:they tend to wear out faster, from the higher stresses concentrated around the cutout.


And where are the data to support this statement?

I think it is all a matter of fit and comfort, nothing more. The SLR has come in both a cut out ("flow") and non cutout version for years. Not having ridden the non-cut out version I really can't give a good answer for you, but I have been on cut out saddles (SLK for about 3 years, and SLR flow for the past 3) for years and have never had a problem with them, and have had relief from the dreaded numbness since switching to them.


Any knowledge of structural/mechanical engineering lends to common knowledge of higher stress concentration around any kind of cut-out of void in a structure. Any other engineer on this forum can back up my statement, as Davidalone has just done. The engineers designing these saddles know about the higher stresses and therefore reinforce the saddle shells to compensate for the higher stresses thus resulting in a heavier saddle, due to the extra material.

eric
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by eric

It's handy that Selle Italia makes cut out and non cut out versions of the same saddle, the "Flow" models having the cut out.

In these saddles the cut out version is lighter:

SLR Monolink Team Edition: 165g
SLR Monolink Team Edition Flow: 160g
SLR Kit Carbonio: 125g
SLR Kit Carbonio Flow: 120g

The SLR Tekno is 95g while the
SLR Tekno Flow is 115. However the Tekno Flow has a cover (and presumeably some padding) while the regular Tekno is bare carbon, so they are not equivalent saddles with the cutout being the only difference.

From this data I suggest there is no direct correlation between saddle cut out and weight.

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SolidSnake03
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by SolidSnake03

I can see how this logically makes sense but in terms of practical use is that really a concern people have? Again, I'm not really "pro" either type of saddle, honestly to me it's just use whatever works for you but I'm curious to have a better understanding of riders selection against cut-out.

*edit*

Interesting point about the Selle Italia weights and cut out. I have found in the case of companies like Prologo and Fizik that have a built up "channel" vs. an actual cut out there does seem to be a small weight penalty vs. the regular version but aside from those companies I don't think cut-out=heavier
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deltree
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by deltree

http://www.cervelo.com/en/engineering/a ... dles-.html

Interesting Ask the Engineers article all about saddles.

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