Larger Frame or Longer Stem?
 

Hi there.

It's time to replace my old hybrid mountain bike that I use for mostly city commuting.

Today when I was test riding a couple of bikes - I couldn't decide which format I liked better.

The models I was test riding were Cannondale Quick CX.

The bike I am currently going to be replacing is a Cannondale F800 with a Lefty Jake. Its frame size is a large with a longer stem to give me a bit of extension when I ride.

I took out a bike with a large frame and stock stem - which rode nicely - but I felt I was too upright. This of course could be corrected with a longer stem.

The second bike I took out was an XL frame with stock stem. The extension felt about right.

Is there a benefit to going with an extra large frame? Or should I stick to a large frame and get a longer stem?

I'm 5' 11" ...

Thanks

SparkyCanada

Can you easily stand over the XL? I'd go with the bike that fits right stock.

I'm between sizes in a lot of brands and usually lean toward the larger size. However, I'm 6'2' with a long torso so reach is the main factor.

Larger frame = longer wheelbase = slightly more stable. But a longer stem adds a different kind of stability.

I suspect you'll have better luck, in the long run, with the smaller one.

I recommend going with the frame size which allows the use of a "normal" size stem. Normal is in quotes because, what's "normal?" I can't really define normal, but I know when it's not. Have you ever spent time riding a road bike with a 50mm stem? How about a 140mm stem? The point is, at either end of the spectrum, handling starts to get a bit weird. There are benefits to go bigger frame, and benefits to go smaller frame. There are also drawbacks either way. If your frame size choice puts you at either extreme for a stem, then you're probably not gonna be happy in the long run. Personally, I'm ok with 90 - 110 stems on drop bar bikes. I feel comfortable going a bit shorter with flat bar setups. It's all a matter of personal choice but I wouldn't put myself at one extreme or the other.


-Kedosto

Longer stem increases the rotational inertia of the steering assembly (wheel/fork/bars).

And forward pressure on bars with a long stem tends to straighten the wheel more so than with a short stem.

And a longer stem requires more handlebar movement to turn the wheel.

https://cimg7.ibsrv.net/gimg/bikefor...ab12cb6552.jpg

https://cyclingtips.com/2015/03/how-...-and-handling/

Ah, right!

I meant the frame. I'll give you two reasons.

First, because I think this is important: In my experience, when I'm caught between two frame sizes, I'll find even if the smaller frame size may give me a bit of a pain in the neck, it's actually more fun to ride than the bigger one. I've experienced this with two pairs of bikes, where I've done a lot of riding on both the 58 and a 60 cm versions of basically the same bike. Long story. I am guessing if you bought both bikes, you'd find you would ride the smaller one more.

Second, this is obvious but worth mentioning anyway. Your question about the stem demonstrates how it's pretty easy to modify a small bike to fit a taller rider. Change the stem, the handlebar, the seat post, even the crank arms, and you can dial in the fit pretty perfectly. A bigger frame will necessarily limit the adjustments you can make. If it turns out that the fit is not ideal right out of the box, your options for adjustments are limited.

Bigger frame = More stable, more comfort. Good for straight-line riding.

Smaller frame = More "flick-able", meaning the frame is easier to throw around while climbing or sprinting. Good for racing and climbing.

I would decide which is more important to you, and then choose accordingly.

I'm not looking up charts right now but I suspect the hybrid is supposed to sit easier than your old MTB.

Thanks for the explanation and link - very helpful!

SparkyCanada

Thanks for the advice - leaning towards the larger frame since it will mostly be city commuting...

SparkyCanada

I've "hybridized" the MTB to make it more suited to city commuting. Smoother tires and not quite as downward positioned as my road bike - but not upright either...

Thanks,

SparkyCanada

If you intend to put some real fenders on there I'd say it better with a larger frame and shorter stem. Otherwise you will have toe overlap. All my frames are slightly too large for me really but its the only way I can fit real fenders. You get used to a short stem in like 2 hours. On one bike i even got a fork with 10mm extra rake to solve this problem. You get used to this quite fast too.