Need help understanding strange sizing for Storck Scentron

Discuss light weight issues concerning road bikes & parts.
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jano
Posts: 140
Joined: Sun Oct 21, 2012 8:15 pm

by jano

Hello,
I am considering buying a Storck Scentron G1 frame and while trying to figure out the right size I got stuck due to what seems to be strange reach vs Effective TT lengths.
I need to chose between the size 47 and 51 frames and these are the Effective TT and Reach values for these two sizes according to Storck's catalog (see attached image):

Size: 47 Eff TT : 524 mm Reach: 387 mm
Size: 51 Eff TT : 548 mm Reach: 378 mm

Maybe I am missing something here, however this seems counter intuitive to me.

Also upon checking the sizing for other Storck bikes (Fenomalist, Aernario, Fascenario) the smaller bikes always has the shorter Eff TT and shorter reach.

Is this a printing mistake in the catalog or maybe the Scentron frames have a strange geometry?

Many thanks for your help.
Kind regards,
Jano
Attachments
Storck Scentron sizing.jpg

Jaroslaw
Posts: 43
Joined: Wed Mar 26, 2014 11:15 am

by Jaroslaw

If you plan on getting a Storck, why not get a fitting session to help to decide on the sizing?
Stock dimensions rarely work and although it might seem weird, a few millimeters here, a centimeter there really can make all the difference.

by Weenie


jano
Posts: 140
Joined: Sun Oct 21, 2012 8:15 pm

by jano

Hi Jaroslaw,
Thanks for your kind reply.
The issue is there is no Storck dealer around here, even those mentioned on their site do not have the frames available.
All I have left is to compare the geometries of the two bikes and when I try this, the reach and Effective TT do not make sense.
I am trying to get an answer from a dealer, maybe they mixed the reach values between the 47cm and 51cm size frames.
Kind regards,
Jano

5 8 5
Posts: 1353
Joined: Sat Jul 29, 2006 2:36 am
Location: UK

by 5 8 5

A quick search shows that the geometry was the same in 2012 so I don't think it's a typo. Also other models have similar differences between the 47 & 50 sizes.

The 47 has a much steeper seat angle (75deg) versus the 50 (74). This accounts for a big chunk of the reach difference.

jano
Posts: 140
Joined: Sun Oct 21, 2012 8:15 pm

by jano

Hi 585,
Thanks for taking time to research the sizing for the Scentron, indeed they use the same sizing since 2012 when it was launched.
The issue I have is that the 1 degree difference in the Seat Tube angle can not make up that difference in reach, especially when you consider the Effective TT length difference of 24 mm.

I did try to draft both of the frame geometries in 2D, and this is what I get (dimensions are in centimeters):

Image

Maybe I am making a mistake somewhere, please bear with me on this one, I really want to make sure I chose the right frame.
I am 168 cm tall and according to Storck the 47 size is for up to 167 cm, while the 51 size is for 165 to 172 cm tall riders.
Right now I am riding a Litespeed Ghisallo, size M, which might be a tad to big, and my issue is to chose the right size Scentron frame, I am however not sure how they got to those reach values they mention for the two frame sizes.

Thank you.

mike
Resident Pro
Posts: 2441
Joined: Tue Mar 18, 2003 9:42 pm

by mike

it is not a mistake. go with the effective top tube length. storcks have longer effective top tubes than any other brand i know for small frames, so you can go with a shorter stem and/or a sweeping bar like the MCFK.

jano
Posts: 140
Joined: Sun Oct 21, 2012 8:15 pm

by jano

Thanks Mike,
I guess I'll go with the 47 then, the 524 mm Effective TT would allow me a more aggressive stance, and if needed I can always use a slightly longer stem.
Let's see how it goes.

5 8 5
Posts: 1353
Joined: Sat Jul 29, 2006 2:36 am
Location: UK

by 5 8 5

jano, on your 51 drawing, the Seat tube should be 50.

Here's a pic showing the geo. The ETT is to the centre of the TT / Headtube and not the top of the headtube (stack and reach).
Image

There isn't enough info to draw it properly. It would be useful to have the BB drop etc.

BTW I believe Storck forks are longer than standard (380 versus 368/370). Not sure if this is important.
Scott do the same and I got caught out because it wasn't on the geo chart.

by Weenie


mike
Resident Pro
Posts: 2441
Joined: Tue Mar 18, 2003 9:42 pm

by mike

you made the right choice. you will be pleased. I especially like the horizontal dropouts so you wont lose your wheel slipping.

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