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Stack and Reach question

Posted: Wed Aug 30, 2017 8:11 pm
by Lookryder
I'm trying to determine the stack and reach of my current frame, a 2008 Look 586 size XL.

can anyone help me?

I think I calculated the reach at 408 mm , but this seems too long.

The geometry chart does not have it listed:

Image

Re: Stack and Reach question

Posted: Wed Aug 30, 2017 8:27 pm
by Alexandrumarian
Sounds right, b-e. Seems normal for an xl. Giant tcr xl is 412.

Re: Stack and Reach question

Posted: Wed Aug 30, 2017 8:27 pm
by Weenie

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Re: Stack and Reach question

Posted: Wed Aug 30, 2017 8:35 pm
by Lookryder
how about the stack?

Re: Stack and Reach question

Posted: Wed Aug 30, 2017 8:49 pm
by FilmAt11
Based on that chart, I calculated:

stack: 580mm
reach: 398mm

Re: Stack and Reach question

Posted: Wed Aug 30, 2017 8:54 pm
by Lookryder
Thank you so much!! I knew I was off a bit.

Re: Stack and Reach question

Posted: Wed Aug 30, 2017 8:55 pm
by mike001100
Hiya, I wholeheartedly recommend the Velogic Fit app... registration is free and the "bike comparison tool" is also free... it is very helpful when comparing bikes, as the database seems to be quite up to date...

I put in your Look, the app says: Reach 398, Stack 581

All other measurements are there too...

Re: Stack and Reach question

Posted: Thu Aug 31, 2017 7:40 am
by wingguy
Lookryder wrote:Thank you so much!! I knew I was off a bit.

You know it's very easy to physically measure it as well, right? All you need is a flat floor, vertical wall and a tape measure...

Re: Stack and Reach question

Posted: Thu Aug 31, 2017 8:18 pm
by Lookryder
wingguy wrote:
Lookryder wrote:Thank you so much!! I knew I was off a bit.

You know it's very easy to physically measure it as well, right? All you need is a flat floor, vertical wall and a tape measure...


I know. I did meausre it myself several times and the repeatability of the measurements was not good enough for me; it would vary by a few mm every time. I wanted to know what was listed on the the geo chart as I'm trying to find a frame of similar stack and reach. The more data the better.

Re: Stack and Reach question

Posted: Thu Aug 31, 2017 8:21 pm
by Valbrona
But in the above chart doesn't B' show reach?

Re: Stack and Reach question

Posted: Thu Aug 31, 2017 8:36 pm
by TobinHatesYou
Valbrona wrote:But in the above chart doesn't B' show reach?


B' is actual top tube length. Frame reach is B minus E.

Re: Stack and Reach question

Posted: Thu Aug 31, 2017 9:36 pm
by cyclenutnz
mike001100 wrote:Hiya, I wholeheartedly recommend the Velogic Fit app... registration is free and the "bike comparison tool" is also free... it is very helpful when comparing bikes, as the database seems to be quite up to date...


Just a note on using the database - if you scroll to the bottom of the frame specifications you'll see the 'Calculated Measures' field. Which tells you which metrics I've had to calculate.
In the case of the 586 - that's wheelbase, reach and stack. I have a very robust algorithm for doing that and Look provide really good information on other measures, so there is pretty high confidence. But there is a little more uncertainty than if the manufacturer had provided the XY data.

Having said that, I frequently find errors in the geometry charts of large companies that make a lot of noise about bike fit. So the overall standard of the database is more reliable than other sources.

Re: Stack and Reach question

Posted: Fri Sep 01, 2017 12:23 pm
by silvalis
TobinHatesYou wrote:
Valbrona wrote:But in the above chart doesn't B' show reach?


B' is actual top tube length. Frame reach is B minus E.


Keep in mind that if you measure reach doing this, the geo chart indicates that it is measured to the centre/centre intersection of the top tube/head tube junction. Typically reach/stack is measured to the centre of the top of the headtube.

So to compare to others measured as above, you'd need to also look at the headtube measurements (K, KO), read the ht angle, do a bit of trig and subtract a few mm...

Re: Stack and Reach question

Posted: Fri Sep 01, 2017 12:23 pm
by Weenie

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