Figuring out Soma Smoothie ES fit

[jasonification]

Hoping to snag one of the Soma Smoothie ES for my fiance. She's 5"4 with maybe a 28-9" inseam (long legs, shorter torso). Am wondering if the 48cm would fit her. My main concern is that 51cm tt, though I probably could compensate with a shorter stem. Thoughts?

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[Clean39T]

My wife would be fine with me selling her Soma Smoothie ES that I built for her about 6-7 years ago - she's ridden it 2-3 times total.. Burgundy w steel fork, 105 silver 10spd w Soma silver crank and Ultegra silver RD, silver post/stem/bars and Tektro silver brakes. My wife is 5'6" and I think we did the 51cm for her. 700c wheels. Price will be cheap

[jasonification]

Originally Posted by Clean39T

My wife would be fine with me selling her Soma Smoothie ES that I built for her about 6-7 years ago - she's ridden it 2-3 times total.. Burgundy w steel fork, 105 silver 10spd w Soma silver crank and Ultegra silver RD, silver post/stem/bars and Tektro silver brakes. My wife is 5'6" and I think we did the 51cm for her. 700c wheels. Price will be cheap

So tempted!! I'm pretty sure the 51cm might be stretching her out a bit too much..funny how a few inches in height can impact fit!

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[charliedid]

I hate doing these sight unseen but 48 is too small. Maybe chat with Clean39T

Also guessing at inseam is not an option. You need to know actual pubic bone height.

[Clean39T]

Originally Posted by jasonification

So tempted!! I'm pretty sure the 51cm might be stretching her out a bit too much..funny how a few inches in height can impact fit!

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It's a 50cm, so maybe from the previous version?

I'll figure out a price to stay in compliance..

[Dave]

Stack and reach tell the story. If the rider's inseam is only 73cm, the frame should be plenty tall, with the headset added.

The reach is 10mm shorter than the 48cm colnago that I ride. I'm 2 inches taller but my inseam is 83cm and my saddle height much higher, at 73cm. The stack on my frame is 527, plus 15mm added for the headset top. I use a -17 stem and no spacers.

Use bars with 75-80mm reach.

The steep 75 degree STA might be an issue, but it is very common. I've never understood the idea behind it. Most of the frames I've owned have had 74-74.5 STA, so I always use a 25mm setback post. With a 75 degree, I'd need a 32mm setback, even though my tall saddle height moves the saddle further back. Most frames that are one size smaller than I ride have a 75 degree STA.

[oldpotatoe]

(long legs, shorter torso)

75 degree seat tube angle and long femurs??..might be an issue getting her knee at the small constant 'kops'...AND remember, 1 degree aft=1cm of top tube/stem length..so even at 74 degrees for the 51..getting the saddle aft far enough..the top tube might be too long...

Also the 51 has a 30.5in standover..she has a 28-9inch some inseam? The 48..me thinks

[josephr]

that smoothie ES is sweet!

[GutiSteve]

I would be concerned about that TT also, it’s 51.8 which is basically 52. Check out Surly options, a lot of their frames go down to 50cm TT’s and have smaller wheel options (26in, 650b) which may have better handling with a smaller frame.


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[cmg]

the reach is going to be too long. you'll have to put a 8cm stem which will make it twitchy. it's the sta 75 that's the problem. the setback needed will push her further back making 51.8 top tube even longer. you need to get a cervelo in a 48 because it has 73* STA and a slightly shorter top tube lenght. the 51 soma while a beautiful frame won't work either.

[jasonification]

Originally Posted by cmg

the reach is going to be too long. you'll have to put a 8cm stem which will make it twitchy. it's the sta 75 that's the problem. the setback needed will push her further back making 51.8 top tube even longer. you need to get a cervelo in a 48 because it has 73* STA and a slightly shorter top tube lenght. the 51 soma while a beautiful frame won't work either.

Thanks! This makes sense

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[Dave]

Stack and reach values are still the most important. Compare those to a cervelo. The sta only affects your choice of seat post setback.

If two bikes have the same reach, but the sta is 2 degrees steeper on one of them, that bike will require about 20mm more saddle setback to produce the same reach to the bars.

I owned a cervelo r3, back when it first came out. I rode up and down my regular 10 mile mountain climb twice and hated it. Tore it down to the frame and sold it.

[oldpotatoe]

Originally Posted by Dave

Stack and reach values are still the most important. Compare those to a cervelo. The sta only affects your choice of seat post setback.

Correct altho with steep STA and long femurs..proper, small 'c' constant kops may not be possible. PLUS getting the saddle back far enough effects top tube length a lot, ie; it effectively makes the top tube 'longer'...

[Dave]

The sta does not change the reach. The definition of reach is relative to the BB center.

Makes no sense to me that nearly every brand has around 75 degree sta on the smallest sizes.

According to Kirk KOP is meaningless.

[oldpotatoe]

Originally Posted by Dave

The sta does not change the reach. The definition of reach is relative to the BB center.

Makes no sense to me that nearly every brand has around 75 degree sta on the smallest sizes.

According to Kirk KOP is meaningless.

Small sizes generally means smaller riders which generally means shorter femurs. NOT saying KOPS is the very foundation of bike fit brought down from the mountain top but a small 'c' constant that is a VERY useful place to start the fit..along with the knee bend 'range'...