Your hip angle is going to feel quite constricted.

150mm cranks would solve the problem.

150 cranks would allow you to raise the seat 20mm and lower the height of your pedal stroke by 40mm. This will dramatically open up your hip angle. This is the power of the short crank. Rotor has a really good set. I am 5’6” and use 155 cranks. I would also consider with this change moving the pads a little foward and extending the bars.

More likely your current stem is -6 degrees, give or take a degree. The stem on the Shiv on the Spesh website has a slight downward angle. So assuming that you got your pad X/Y measurements correct, going from a 90mm -6 stem to a 120mm -17 will give you roughly 470/615 using the same bars. If you really do need something closer to 499/606, you can see that this is going to require jumping through some hoops to achieve that on a Shiv.

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"I'm thinking of a number between 1 and 10, and I don't know why!"

I find it kind of amazing and amusing how much run Fredo_Adagio has gotten on someone else’s bike fit critique post. Especially since Fredo_Adagio’s foray into this was an off-topic rant about bike marketing or something like that.

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Mike Sparks


I have competed well, I have finished the race, I have kept the faith.

He also jumped in on this thread:

https://forum.slowtwitch.com/.../?page=unread#unread

Wow! Tough crowd.

Regarding jumping in on other people's threads, what can I say? I'm all over this forum spreading hate and discontent.

Regarding the standard stem on the older-style Shiv for size S, it's a 90 mm / 0 deg stem. That's what is listed on the website, and those are the numbers printed on the actual stem.

Regarding trying to get to a Pad Center X of 499 mm, that number can't be right. The longest reach bike in the list I provided (Quintana Roo PRFIVE Size 52, 410 mm) is 25 mm longer than my Shiv. Adding 25 mm to the estimated Pad Center X with my new stem would only get me to 498 mm. For a Pad Y dimension of 606 mm, the center of the blue "MIdrange Pro and Top AG" band on the Pad Center X versus Pad Y chart is about 485 mm.

Regarding hip angle, I hadn't perceived that it's a problem with my current setup. I'll try shorter crank arms if I perceive it's a problem after I change the stem. Following my initial rant on this thread, there were comments about moving the seat aft, which would have taken the hip angle in the opposite direction.

I might as well ask this question since it seems to be the elephant in the room.


For those who are experienced with bike fit, which frames do you consider best for a person with average proportions?

Jumping in on a thread isn't a big deal, but you would get more help if you started your own thread with a video for critique.

You could actually achieve the 606/499 on 48 PRFive. QR's sizing chart measures to the back of the pad, not the center. There are a handful of configurations listed with both the 90mm and 110mm stem that will get you there. No jumping through hoops required to get you to that position.



I don't recall anyone telling you to move your seat back. There were people (like myself) stating that they use a saddle position similar to what is on the Shiv website photo, and that the photo was not an unreasonable position. Part of the reason this position works well for me is that I use shorter cranks than you do, and I'm taller. My hip angle at TDC is more open than yours. And at least in the pictures you posted, you're sitting farther back on your saddle than I do...

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"I'm thinking of a number between 1 and 10, and I don't know why!"

First, read some of the post again. You see several more experienced people saying you need to switch to 150 or 155 cranks. You cime back suggesting you are most likely to try 165 or 160 mm. Just not enough to have the right effect. A little better, but not enough.

Second, there isn’t something like an ideal frame for someone with average proportions. Even 2 guys with the dame proportions can cime out of a fit with different fit’s. There are just too much individual variables. I could make a list, but that wouldn’t suggest that they are also the right fit for you.

And as Warbird also is saying you sit a bit further back on your saddle then most do on that time of saddle. I just don’t think you were really ‘ fitted’ by your shop rather they ‘fitted’ you to sell you that particular bike.
There is a difference by being fit and being fit.

For example, we do fit’s, a lot of them are tri’s, 80%, we sell bikes but we don’t stock any of them. We advice objectively without the need to sell inventory.
We just have some showmodels on the studio floor to look, feel and see.
So we can say to a customer if a Canyon fits, a QR, a Cervelo or whatever.
Some buy from us, some not.
Personal choice of the customer.

Jeroen

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Owner at TRIPRO, The Netherlands

My LBS is a dealer for Giant, Felt, and Specialized.

I did not buy my Specialized Shiv Elite off the shop floor. The shop special ordered it at my request. The shop staff did go over the sizing options with me before ordering the bike.

I did not seriously consider buying a Giant. I do not know anybody who rides a Giant. The company is unknown to me.

I did consider buying a Felt IA, but it was more expensive, and I only know two people who ride Felts.

Factors in favor of the Shiv were that it was cheaper than the Felt IA, I know lots of people who ride Specialized bikes, including the LBS staff, and Specialized generally has favorable reviews online. Hambini even has PowerPoint slides showing that Specialized's tolerances aren't quite as bad as a lot of other major manufacturers.

In short, my LBS didn't pressure me to buy the Shiv. That was my choice.

Okay, you are wearing me down.

Does anyone know a reason this wouldn't be a suitable replacement for the crank arms and spider on my bike? The current crank arms and spider are Praxis Zayante AL.

Origin8 Alloy Crank Set, 155mm, 110x5-Bolt, Black
https://www.modernbike.com/...5mm-110x5-bolt-black

I consider this a science experiment, so I'm not inclined to go with anything high end.

Is there a better option for under $100?

https://speedandcomfort.com/...s/alloy-short-cranks

I am about the same height as you and I would get 145mm.

I have lightly used set of those cranks that I'll sell you for $25 along with a promise not to hijack other people's threads. You'll need to come up with your own bottom bracket (square taper). I tried them about seven years ago purely as an experiment, and my conclusion was ... meh. They were fine, but not magical. I didn't really like the higher cadence that I tended to ride at with them. I wasn't having fit issues before I tried them, so I went back to my 172.5s. YRMV.

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Mike Sparks


I have competed well, I have finished the race, I have kept the faith.

Rats! I hadn't noticed the square cut socket.

I hesitate to make any promise that I might not be able to keep regarding hijacking threads.

Sure, but they should have done a-fit-first so you would have noticed that it was not a good fit in the fitst place.
And that has nothing to do with the bike being on stock or not but all about getting you on the right bike, with the right fit and with the correct components to avoid what you have now ;-)

Jeroen

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Owner at TRIPRO, The Netherlands

But then I'd be missing all this fun with you guys!

Hahaha, that is indeed a good one ;-)

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Owner at TRIPRO, The Netherlands

Dude, you have a couple of the very best bike fitters in the world giving you free advice and you are arguing their recommendations?
You don't know anything about Giant?
I don't think you are interpreting all of these X/Y coordinates properly. You are mixing pad X/Y and frame stack/reach and not all manufactures list the same measurement points for their X/Y data.

1. I'm not ignoring the advice that has been given here. I'm actually following the advice. I have a 155 mm crankset on order, and I will give it a try. I do have concern that the shorter cranks might improve my bike fit but will bring other problems.
2. I did not mean to imply that I am unfamiliar with the Giant brand. What I stated is that I don't know anyone who rides a Giant. I've been seeing Giant's advertising for decades. I remember when they tried to cover the entire size range with just three frames and a collection of extra long seatposts and stems. I wasn't impressed, but this seems sort of like where I'm going with my Shiv.
3. I provided the Reach and Stack numbers for various bikes because that is the data readily available on most manufacturer's websites. It makes sense that the manufacturers would provide Reach and Stack data since those dimensions are specific to each frame size and are independent of any bike fit adjustments. Yeah, I fully understand Reach and Stack are not the same as Pad Center X and Pad Y. I also fully understand that some manufacturers provide bike fit charts that use Pad Back Edge X rather than Pad Center X.
4. There are some things that have been discussed here that I was tempted to argue but just let pass. For instance, there have been comments that I sit too far aft on the saddle. I actually sit so far forward on the saddle that the frank and beans are forward of the saddle nose. The saddle is an ISM PN 1.1. I don't think I could sit any further forward on the saddle without falling off.
5. Through all of this, I am keeping in mind the examples I've seen of experienced bike fitters who have produced bike fit solutions that look very different. There is an example of this in one of the bike fit articles on the Slowtwitch website. If you really wanted to get this right, you would have the cyclist ride the bike in a wind tunnel while collecting wattage data. I understand some of the pros actually do this.

" I do have concern that the shorter cranks might improve my bike fit but will bring other problems."


What problems are you referring to?


"For instance, there have been comments that I sit too far aft on the saddle. I actually sit so far forward on the saddle that the frank and beans are forward of the saddle nose. The saddle is an ISM PN 1.1. I don't think I could sit any further forward on the saddle without falling off."


The pictures that you posted before showed you riding back on the saddle.

A video would show how you actually ride.

Regarding shorter cranks, the following was posted by Mike Sparks above.

"... I tried them about seven years ago purely as an experiment, and my conclusion was ... meh. They were fine, but not magical. I didn't really like the higher cadence that I tended to ride at with them. I wasn't having fit issues before I tried them, so I went back to my 172.5s. YRMV."

Regarding video, I am contemplating a comparison with my present setup, then the longer stem, then the longer stem and shorter cranks.

Multiple videos would be the best.

I wasn't having any fit issues that I was attempting to solve by switching to 155s. My bike fit like a glove, and I could comfortably ride in the position below (which is with the 172.5s) for 56 miles, and 112 with the front end only slightly higher. I was simply just curious, mostly to see if I would generate more power by slightly opening up my hip angle at the top of the pedal stroke. I frankly don't recall if I generated more power, but even if it did, it wasn't significant enough to make me want to stick with the 155s. I switched back to the 172.5s and haven't looked back since. The 155s simply collect dust in my garage now.

But as I said, your results may vary. Try them, you might like them.

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Mike Sparks


I have competed well, I have finished the race, I have kept the faith.

4. There are some things that have been discussed here that I was tempted to argue but just let pass. For instance, there have been comments that I sit too far aft on the saddle. I actually sit so far forward on the saddle that the frank and beans are forward of the saddle nose. The saddle is an ISM PN 1.1. I don't think I could sit any further forward on the saddle without falling off.

This is is how forward you can sit on the ISM PN1.1 without falling off the front. Not saying you should go forward if you don’t have issues, but sitting that far back makes that specific model actually quite a wide saddle which for most could lead to shaving issues.


I do wonder what problems you think might come up using 155 mm cranks based on just 1 guy saying ‘meh’. Not to offend you by any means but you and him are built totally different. He can use 172,5 mm and still feel not cramped, but you are already crunched and cramped in your fit. He is having a slim, well trained body and you are a bit heavier. Especially around the waist where the upper leg meets the upper body. You just want some more room in that area.

There is no power loss with the 155’s and experience learns that the higher cadence at first comes back to normal due to choosing different gears, etc.

Jeroen

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Owner at TRIPRO, The Netherlands