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BMC SLR01 sizing question

by dazzle
Tue, Oct 21, 2014 15:23
5

I've currently got a Colnago C60 in a 52s size frame, fits me superb, 1 small spacer below the headset, although its closer to a 56cm effective top tube its still more like a 55/54cm size.

How does a BMC SLR01 http://www.bmc-racing.com/int-en/bikes/road/platform/altitude/teammachin... size 54cm or 56cm compare to the Colnago in a 52s (sloping) http://colnago.com/geometry-c60-2-2/?lang=am I really struggle to make sense of the various geometry charts, I know the stem length and bars width of the BMC in a 56cm does not suit me, briefly tried a 54cm size and it felt ok.

inseam 84cm
trunk 61cm
forearm 34.5cm
arm 68cm
thigh 60.5cm
lower leg 56cm
sternal notch 144cm
total height 178cm

Any advice regarding sizing would be appreciated because I'm struggling to choose between the BMC in a 54 or 56, edging towards the 54.

If you're new please join in and if you have questions pop them below and the forum regulars will answer as best we can.

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5 comments

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dazzle | 10 years ago
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Yes deda bars too, tried the 42's first and they were way too narrow and cramped even though in theory they should have fit my 38cm shoulders better, I was thinking a 110mm stem on the 56 bmc, love the bianchi oltre just can't buy them round my way unfortunately 2

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ajmarshal1 replied to dazzle | 10 years ago
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dazzle wrote:

Yes deda bars too, tried the 42's first and they were way too narrow and cramped even though in theory they should have fit my 38cm shoulders better, I was thinking a 110mm stem on the 56 bmc, love the bianchi oltre just can't buy them round my way unfortunately 2

Try the 110 by all means, but a 100mm stem would create nearly the exact same reach as you have on your C60.

Deda measure their bars from outside to outside where most others measure centre to centre, thus a 42 Deda bar is more like a 44. I always size up with Deda.

I recommend trying 3T Ergonovas in 42, I have the 44s and I've never looked back

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ajmarshal1 | 10 years ago
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Yup, the 54 BMC will have a bigger saddle to bar drop than your C60. Put a 100mm stem on and move your spacer over to the 56 BMC and you're very nearly at the same geometry as your C60.

Are your bars Deda? I only ask as 44 Dedas seem to be everyone else's 42s. Which may be why the bars felt wrong on the 56 SLR01 you tried too.

Good luck whichever you choose. I very nearly bought a BMC SLR01 frame last month (In a 56 as it happens, I'm 2cm taller than you but like a fairly big drop) but ended up with a 57 Oltre XR2. The BMC is a lovely frame.

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dazzle | 10 years ago
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Thanks very much, I currently use deda 110mm stem and 44cm outside to outside bars, http://www.wiggle.co.uk/deda-superleggero-stem/

I'm sure the 56cm size bmc as is will be too big of a stretch and need a few adjustments to fit, it's a shame only Evans sell these bikes and don't understand, can't advise on fit etc.

I rode a BMC slr02 in a 54cm and found the saddle to bar drop didn't feel right, reach was fine, maybe a 56cm frame with a 110mm stem and not many spacers is the best way to go. Thanks for your input, dimensions and numbers just baffle me 2

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ajmarshal1 | 10 years ago
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IMO Stack and reach (and perhaps stand over height if you have stubby legs and monkey arms) are the only figures you need when it comes to bike sizing. I use it when buying all my frames and it's been bang on every time.

Your C60 has a 565mm stack with a 384mm reach. Assuming your spacer is 1cm then that gives you a stack height of 575mm.

Now, whilst the reach of a size 54 SLR01 is similar at 387mm it has a shorter head tube making the stack height 550mm meaning that you'd need 2.5cm of spacers to put you in a similar position to your C60.

Conversely, the 56 SLR01 has the same stack height as your C60 (565mm) but a reach of 392mm. Therefore, fit a 1cm shorter stem on the 56 SLR01 than you currently run, swap your spacer over and you have a bike that has the same stack and just a 2mm shorter reach than your C60. It's six to one, half a dozen the other really but my decision would be to go with the 56 if I were in that situation purely on aesthetics and not wanting a 2.5cm spacer stack. Others may prefer the look of a smaller frame and not mind the spacer stack.

How long and what angle is the stem on your C60?

In addition, when buying bikes at this end of the market, I personally fully expect to have the stem and / or bars swapped out to ones that fit me correctly when buying. I've never had anyone deny me that as part of the sale. If you didn't like the bar size on the 56 SLR01, get them to fit a size down.

The only real way to know is to have the bikes set up as above on a trainer and see how they feel. That isn't always possible I know but I hope the above has proven helpful.

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