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Geometry Question - Massive Stack Difference?

Posted: Mon Sep 17, 2018 11:05 am
by robertbb
Hi Weenies,

I'm comparing two alloy bikes - Ridley Helium SLA and Fuju Roubaix. I'm a bit stumped as to how the stack could be so different given the other numbers are basically the same.... any gurus out there who could explain what might be going on here?

Helium (S) Roubaix (M)
ETT 54.5 54.5
Stack 573 543
Reach 384 384

ST Length 510 500
HT Length 142 140

ST Angle 73.5 73.5
HT Angle 73 73

BB Drop 66 68

Wheelbase 977 978
Chainstay 405 405

Geometry Question - Massive Stack Difference?

Posted: Mon Sep 17, 2018 11:05 am
by Weenie

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Re: Geometry Question - Massive Stack Difference?

Posted: Mon Sep 17, 2018 11:16 am
by sungod
roubaix m stack 543... https://weightweenies.starbike.com/foru ... 0#p1430070
helium sla s stack 543... https://www.ridley-bikes.com/project/helium-sla/

did you look at the wrong column for the sla? m is 573

Re: Geometry Question - Massive Stack Difference?

Posted: Mon Sep 17, 2018 11:41 am
by robertbb
Thanks....

I'm looking at this:

https://ridleybikes-ridley2.netdna-ssl. ... t_2017.pdf

Clearly lists the stack @ 573 for both the S and the M...

Re: Geometry Question - Massive Stack Difference?

Posted: Mon Sep 17, 2018 11:49 am
by sungod
seems clear ridley made a mistake in either the website or their pdf (or both!)

but given that in the pdf the only two sizes with the same stack height are s and m, whereas all other sizes differ, i'd trust the website more than the pdf

you can contact them and ask which is correct

Re: Geometry Question - Massive Stack Difference?

Posted: Mon Sep 17, 2018 12:01 pm
by robertbb
Will do, thanks for the second pair of eyes!....I think you're right RE: the only two identical sizes in the pdf.

Thanks again :)

Re: Geometry Question - Massive Stack Difference?

Posted: Mon Sep 17, 2018 7:45 pm
by flying
BTW Robert: Ridley US distributor sent me this pic of a new SLA color next year
HAX02As.jpg
These were already available previously blk/red anodized & blue/blk painted I think
_DSC5834.jpg

Re: Geometry Question - Massive Stack Difference?

Posted: Mon Sep 17, 2018 9:24 pm
by kytyree
The rest of those numbers look normal for a small Ridley, pretty sure it's a mistake. 543 sounds about right for a size small Ridley.

Re: Geometry Question - Massive Stack Difference?

Posted: Mon Sep 17, 2018 11:18 pm
by robertbb
@flying: Unfortunately a red and black bike is a no-go zone for me. We have this professional Aussie rules football team here called Essendon who were a few years ago found guilty by WADA for systematic clib-wide doping and about 30 players banned for the year. The mere sight of red and black together makes my blood boil.... ;-) I'm very much against doping in sports. Which explains my ove of cycling............. lol.

I think the Fuji Roubaix edges out the Helium SLA. It supports both mechanical and electronic. The seat tube is a cm shorter, which will leave more post exposed for better comfort. The fork looks a better design and the cable routing is a bit neater at the BB. The down tube is a bit more worked too and on shape alone should be a bit stiffer...

Re: Geometry Question - Massive Stack Difference?

Posted: Tue Sep 18, 2018 12:44 am
by flying
@robertbb :D :D That is pretty funny about red & black :wink:

Yes as I said also on that Fuji it is a really great deal & usually can be found for less than
600USD

No complaints & might also grab another. I am just waiting till I get home in January
because I may see something special in Asia on my trip too.

Re: Geometry Question - Massive Stack Difference?

Posted: Tue Sep 18, 2018 12:54 am
by flying
robertbb wrote:
Mon Sep 17, 2018 11:18 pm


I think the Fuji Roubaix edges out the Helium SLA. The seat tube is a cm shorter,which will leave more post exposed for better comfort.
Just curious but...
Which size are you comparing?

I have the 54 Fuji it has a 540 seat tube
According to Ridley has a 510 seat tube in the S size which is basically their 54 yes?

Or did you mean the Ridley edges out the Fuji for you? :D

Re: Geometry Question - Massive Stack Difference?

Posted: Tue Sep 18, 2018 1:48 am
by robertbb
According to Fuji site, the Roubaix (Medium) has an actual seat tube of 500. The "effective" seat tube is 540.

More post = more comfort, generally. Especially in 27.2mm diameter

Re: Geometry Question - Massive Stack Difference?

Posted: Tue Sep 18, 2018 2:11 am
by flying
robertbb wrote:
Tue Sep 18, 2018 1:48 am
According to Fuji site, the Roubaix (Medium) has an actual seat tube of 500. The "effective" seat tube is 540.

More post = more comfort, generally. Especially in 27.2mm diameter

Yes I see that on Fuji site but.....I have the Fuji 54 frame here & the seat tube center BB to top is 540. So "effective" is actual C-T reality in this case

So it is 30mm taller than the Ridley as far as I know...meaning if Ridley info of 510 seat tube center to top is accurate

Re: Geometry Question - Massive Stack Difference?

Posted: Tue Sep 18, 2018 10:05 am
by robertbb
flying wrote:
Tue Sep 18, 2018 2:11 am
robertbb wrote:
Tue Sep 18, 2018 1:48 am
According to Fuji site, the Roubaix (Medium) has an actual seat tube of 500. The "effective" seat tube is 540.

More post = more comfort, generally. Especially in 27.2mm diameter

Yes I see that on Fuji site but.....I have the Fuji 54 frame here & the seat tube center BB to top is 540. So "effective" is actual C-T reality in this case

So it is 30mm taller than the Ridley as far as I know...meaning if Ridley info of 510 seat tube center to top is accurate
Hmm.. that's strange. What year is your Roubaix?

Re: Geometry Question - Massive Stack Difference?

Posted: Tue Sep 18, 2018 5:53 pm
by flying
robertbb wrote:
Tue Sep 18, 2018 10:05 am

Hmm.. that's strange. What year is your Roubaix?
2016 but I have the spec sheet from that year & I believe it is identical to spec sheet today for Seat Tube & Top Tube
Except then they just said "effective" TT or ST etc Not C-T
But reality is measured C-T as I have here & it is their effective measurement listed in my spec sheet

First sheet below is my model

Second sheet is their new listing for 2019 model which was same for 2018

But you can also use their archive to go back year by year here ( nice feature of their website)
http://www.fujibikes.com/usa/archive
fuji size.gif
fuji 2019 spec.jpg

Re: Geometry Question - Massive Stack Difference?

Posted: Tue Sep 18, 2018 5:53 pm
by Weenie

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Great Prices ✓    Broad Selection ✓    Worldwide Delivery ✓

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Re: Geometry Question - Massive Stack Difference?

Posted: Wed Sep 19, 2018 1:43 am
by robertbb
THe 2016 and 2017/2018 Roubaix frames are different:

https://archive.fujibikes.com/2016/Fuji/roubaix-13-

https://archive.fujibikes.com/2017/Fuji/roubaix-133

Flick between the two and you'll see; the geometry is now more Giant style "compact road" and the tube shapes (top tube, chainstays, down tube) are different as is the shift cable routing.