Frame Size Confusion

markgoldstein

I'm trying to decide if the Merckx EMX-5 52cm frame that's currently on sale at Ribble would be a suitable fit for me.

I currently ride a more endurance-focused Scott CR1 (54cm), which has a very similar reach and effective top tube, but a very different stack and head tube length to the racier EMX-5.

Here's the measurements:
Stack Reach Eff. Top Tube Head Tube
Merckx EMX-5 527 387 545mm 129mm
Scott CR1 565 383 545mm 156mm

Is the EMX-5 simply too small?
Any advice greatly appreciated!

rafletcher

Doesn't look it to me - reach only 4mm difference if I read your figures correctly. But of course the Merckx has a much shorter head tube and therefore much lower front end. Up to you to decide if you can ride that much more head down.

mfin

Would you ride lower than you are? Is your Scott's stem slammed and you wish you could get lower?

If you're already running spacers on your Scott then forget it.

Also, does the scott fit you like a glove? What length stem and angle are you running, as well as the spacer question.

markgoldstein

rafletcher wrote:

Doesn't look it to me - reach only 4mm difference if I read your figures correctly. But of course the Merckx has a much shorter head tube and therefore much lower front end. Up to you to decide if you can ride that much more head down.

Thanks for the input. I think the frame comes with 30mm of spacers, so I could always match it to the Scott's head-tube length if necessary (I'm not running any spacers on the Scott).

But what about the big difference in stack? What effect will that have?

markgoldstein

mfin wrote:

Would you ride lower than you are? Is your Scott's stem slammed and you wish you could get lower?

If you're already running spacers on your Scott then forget it.

Also, does the scott fit you like a glove? What length stem and angle are you running, as well as the spacer question.

Yes, I could ride slightly lower - the Scott's stem is 110mm/+6degrees and is running with no spacers at all. I would describe the setup as "endurance/comfortable" and can ride a century on it without any discomfort.

darkhairedlord

what about next size up with a shorter stem?

darkhairedlord

if you stick a pile spacers on top you will also reduce the reach.

markgoldstein

darkhairedlord wrote:

what about next size up with a shorter stem?

The next size up isn't available...

markgoldstein

darkhairedlord wrote:

if you stick a pile spacers on top you will also reduce the reach.

Any idea by how much? (say, for 30mm of spacers...)

mfin

by 8/9mm if the headtube angle is 73deg for example over a length of 30mm

I wouldn't wanna run more than 15mm of spacers (don't even like that), if it's more you are in the territory of making a bike fit that doesn't really have ideal geometry for you.

I think you should be on the 54 merckx really. Would be ETT of 555 which is 10 longer than Scott but the seattube is 1deg slacker to wipe out most of that (saddle would be put on the rails where the saddle tip is same distance behind the BB as you currently have it, presuming you know your setup is right already here). There's only 2mm difference in the BB drop so with the same height headset topcap you have the potential to be 10mm lower, slightly racier.

Here are the geo tables for other people...

markgoldstein

mfin, thanks for your valuable input - I'm going to agree with you that I'm probably trying to make the wrong shoe fit

Unfortunately Ribble don't have the 54cm in stock - a shame really as it's just £520 atm...

tomisitt

Your Scott has a stack-to-reach ratio of 1.47, the Merckx is 1.36, so the Merckx is far more stretched out and racy than your Scott. Not even a big stack of spacers will replicate your current riding position.