Bike Sizing (Stack & Reach) - Orbea Orca Sizing

Discuss light weight issues concerning road bikes & parts.
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JoshMA87
Posts: 6
Joined: Sun Jan 21, 2018 10:30 am

by JoshMA87

Hi all,

Hope you can help me.

I had my bikes nicked a couple of weeks ago, the road bike was a 2009 Sabbath Monday's Child. On the policy I have, I have narrowed down the road replacement to either a Orbea Orca M30 or a Giant TCR Advanced 2 and have to order from this website wheelies.co.uk

The problem I have is I am unsure on sizing, fortunately having spent a lot of time riding and racing bikes until the end of 2010 I understand the importance of this, the unfortunate thing is that I can't find the Geometry of the 2009 Monday's Child nor my old set up measurements - the new/current model looks a lot different (it is fair to say I have drifted from the sport). When getting new team bikes I used to simply set them up the same way as the old...but having your bike nicked puts a stop to that approach!

Where I am at - is I would probably go for the Orca but feel I am inbetween a 51 and 53 - the stack height on them looks quite high to all the other measures and compared to the Giant, so my question is, is there a way I can take body measurements to calculate ideal stack and reach measurements?

In rough terms I am 173cm tall with a measured inseam of 83cm - I am looking to getting back into cycling this summer after running a Marathon in April so it's important to get right!

Any help much appreciated

Hexsense
Posts: 323
Joined: Wed Dec 30, 2015 12:41 am

by Hexsense

unfortunately there is no such thing as ideal stack and reach for the body height.
It entirely depend on rider's position.
Which then depend on rider's body flexibility and core muscle strength.

You'll see most pros run smaller size than usual to bring stack down then compensate for short of reach by using very long stem.
Smaller bike may also be more agile and stiffer.
And you'll also see fat or inflexible people or whatever reason can not hold low position for long, best served by bigger size bike to avoid super tall spacers. Even-though bigger size bike is also longer which call for short stem but that's the compromise to be made for sit tall and comfortable.
Bigger frame size tend to have longer wheelbase and also more stable... although if you use short stem that'll spoil handling a little bit.

if you think you can still hold racer's long and low position, when in doubt, go for smaller frame.
51 is not really small. IMO,
Richie Porte (172 cm tall) use BMC size 47. Now that is small.
http://www.cyclingnews.com/features/ric ... gallery-2/

by Weenie


wingguy
Posts: 3507
Joined: Thu Mar 08, 2012 11:43 pm

by wingguy

JoshMA87 wrote:
Sun Jan 21, 2018 10:42 am
The problem I have is I am unsure on sizing, fortunately having spent a lot of time riding and racing bikes until the end of 2010 I understand the importance of this, the unfortunate thing is that I can't find the Geometry of the 2009 Monday's Child nor my old set up measurements - the new/current model looks a lot different
What size was your Monday's Child?

A quick bit of googling found a limited copy of the old Monday's child geometry and it has the same effective TT, same angles and a 2cm shorter HT in each size than the current version - which has stack and reach published. A bit of quick and dirty reverse engineering would get you the old stack and reach values near as you need it for comparison purposes.

JoshMA87
Posts: 6
Joined: Sun Jan 21, 2018 10:30 am

by JoshMA87

wingguy wrote:
Sun Jan 21, 2018 10:56 pm
JoshMA87 wrote:
Sun Jan 21, 2018 10:42 am
The problem I have is I am unsure on sizing, fortunately having spent a lot of time riding and racing bikes until the end of 2010 I understand the importance of this, the unfortunate thing is that I can't find the Geometry of the 2009 Monday's Child nor my old set up measurements - the new/current model looks a lot different
What size was your Monday's Child?

A quick bit of googling found a limited copy of the old Monday's child geometry and it has the same effective TT, same angles and a 2cm shorter HT in each size than the current version - which has stack and reach published. A bit of quick and dirty reverse engineering would get you the old stack and reach values near as you need it for comparison purposes.
Hey I have just pm’ed you

Thanks

joejack951
Posts: 276
Joined: Fri Feb 18, 2005 6:50 pm
Location: Wilmington, DE

by joejack951

JoshMA87 wrote:
Sun Jan 21, 2018 10:42 am
Where I am at - is I would probably go for the Orca but feel I am inbetween a 51 and 53 - the stack height on them looks quite high to all the other measures and compared to the Giant, so my question is, is there a way I can take body measurements to calculate ideal stack and reach measurements?
Stack and reach of the frame are fixed by steerer tube length (to a degree), stem length and rise, and handlebar geometry are wide open. I am very similar in height and inseam (174cm tall, 81.5cm inseam) and ride 50, 51, and 53cm frames. Aside from differences in how that frame size is actually measured, the smaller frames allow me more saddle to bar drop for aero reasons while the larger frame has the handlebars higher for better visibility in traffic (commuter bike). The larger triangle also makes it easier to carry two large water bottles and/or use a top tube mounted battery for a headlight.

If your plan is to race this frame and assuming you are reasonably flexible, I'd go with the 51cm, no question. If you want a more relaxed position, get the 53. With your long inseam standover height is a non-issue on the larger frame. Buy handlebars that have a shape you like then find a shop/friend with a bunch of different stem lengths and angles to try, or buy cheap Kalloy parts for testing until you find the right geometry then buy some better if desired. Leave your steerer tube long at first to allow for adding spacers as necessary. It would suck to have a run an upturned 17 degree stem to get the right bar height.

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