maxwolfie13

Calculator:
Competitive Cyclist

Calculator inputs:

Actual Inseam 86 Cm
Trunk 70 Cm
Forearm 37 Cm
Arm 68 Cm
Thigh 63 Cm
Lower Leg 58 Cm
Sternal Notch 158 Cm
Total Height 189 Cm

Calculator outputs:

The Eddy Fit:
Top Tube Length 57.3 - 57.7 Cm
Seat Tube Range CC 56.9 - 57.4 Cm
Seat Tube Range CT 58.6 - 59.1 Cm

The Competitive Fit:
Top Tube Length 57.3 - 57.7 Cm
Seat Tube Range CC 55.7 - 56.2 Cm
Seat Tube Range CT 57.4 - 57.9 Cm

The French Fit:
Top Tube Length 58.5 - 58.9 Cm
Seat Tube Range CC 58.6 - 59.1 Cm
Seat Tube Range CT 60.3 - 60.8 Cm

Bike:
Merida Scultura 4000

Should I go with a Large or an XL?

Iride01 

What is your previous experience on bikes? And what type, model and size where they? I selected my new bike after riding two different size frames of one model after a 10 mile ride on each. Not surprisingly for the sales person, and only slightly surprising for me, the more comfortable one.... but only slightly, was the one that that bikes manufacturer's sizing guide said was the appropriate one for me.

If you are only going to be doing short rides, not more than two hours, I wouldn't worry too much about one size or the other.

maxwolfie13

My first road bike, a 2009 Argon 18 Plutonium in Large, was a great bike. It felt perfect. It had endurance/commuter geometry.

Then I upgraded to a 2011 Argon 18 Krypton in XL and hated it. I felt far too stretched out.

Iride01 

So can you find the geometries and dimensions of those two bike and compare them with what you are wanting to get? If Argon doesn't have archives available, you might find the info in catalogs of that years model line that someone put out on the web.

I'll never agree that fit is a number calculation that a formula, no matter how many factors it includes will be correct for anyone. If you can't test ride a bike, then stick with what the mfr suggest for you. If you are on the overlap of two, then if you have long arms and legs with a short torso, then you might go with the bigger size. But, you wouldn't be terribly wrong going with the small size either. IMO. However you did say you felt stretched out on one bike.

You can change the stem to adjust your reach fairly easy on most bikes.......unless you are going with an integrated stem/handlebar setup.

Are you planning on doing long rides and spending a lot of time in the saddle? If you are only going out for an hour, then it shouldn't be a big deal.

Carbonfiberboy 

I size my bikes by the TT length, so IMO, large is perfect for you. ST doesn't matter much because the saddle goes up and down a lot, right? With the sloped top tube, these bikes will have ST lengths much shorter than a bike with a level TT, i.e. effective ST length is much longer than spec.

maxwolfie13

OK, now we are in business - I’ve got the stack and reach from the bike I loved (the Plutonium).

Plutonium:
Reach: 386
Stack: 600

Given that the main geometry of the Large Scultura is within +/- 10mm of the geometry that I found comfortable, I assume this would be the way to go?

For reference again:
Large:
Reach: 394 (8mm longer)
Stack: 593 (7mm lower)

XL:
Reach: 401 (15mm longer)
Stack: 619 (19mm higher)

I STILL can’t understand which (between L and XL) would be more “relaxed”, though. Help?

tangerineowl

XL would be the more relaxed but only if you suddenly grew 15mm longer arms

Personally I think both sizes are a little too off what you ideally require, if laying down the cash.

Are you locked into the Merida?

maxwolfie13

Yes and no. I’ve put down a deposit.

What is it about the Large that you think isn’t ideal?

Although the Plutonium felt good, it was by no means “fitted” to me.

tFUnK

Based on the TT numbers I think that translates into XL for most brands I'm familiar with. Merida is not one of those brands, however. Advice still applies though. Look for a frame with TT that matches your fit. Look for endurance geometry bikes instead of race geometry bikes.

tFUnK

The stack and reach are in the opposite direction of what you want (lower stack and longer reach will make you more stretched out).

The XL has longer reach and higher stack. The higher stack effectiveness reduces the actual reach to offset the longer frame reach.

maxwolfie13

I guess this is the thing I am still trying to figure out. Does 10mm lower stack and 10mm longer reach effectively cancel each other out, providing a similar “actual reach”?

In other words, is there a mathematical relationship between stack and reach?