how to read stack height numbers

[qclabrat]

Haven't really looked at geo numbers much for mtbs except for effective top tube and reach. But how does stack height impact the feel if TT and/or reach are the comparable? Is it more noticeable standing vs on the saddle? or both?

examples:
- Banshee and Evil/Yeti have similar reach but the stack much higher for the Banshee
- Pivot similar in reach to Ibis, but significant difference in stack

threw in my two current frames even though they are fairly different bikes from the rest
signed, Curious

 

[Karate Monkey]

It's more a question of "how low can you go" rather than how high, imo. I'm sure someone else will come by with something more profound, but it's the baseline position of the stem, slammed into the frame.

By itself, it doesn't impact handling/standing/whatever, since you are fit to the frame in the position you want to ride in, achieved with spacers/stems/handlebars, which for most people isn't coming down that far.

 

[soulchild]

If you're more of a visual guy, check out bikegeo.net and enter bike specs.

 

[Steve Vai]

Newer school bikes will use a longer top tube and shorter stem to make the bike handle more betterer. You honestly can't compare the old with the new, only new with new and old with old. Unless you do what I did and make a new bike feel old, then you need math, which I'm sure you're good at.

 

[Delish]

Stack is a great number for knowing how many inches of spacers you will need to put under the +17 degree stem on a Madone to make it fit like a hybrid but is useless when you are comparing apples and orangutans. The internet can't tell you how a bike feels. Go demos some bikes.

 

[gtluke]

Stack height is most useful to know if your current fork will fit or if the steerer was cut too short. Or what size lefty you need.
I find stack height semi relevant cause I'm short, and on 29ers with the big wheels, the ever elongating forks, and with a big stack height you'll wind up with a rather tall bike. the early cannondale 29ers had notoriously high front ends.
My Ibis on the other hand has an very low stack height for it's class, keeping the front end low. Which works out because I put a lefty on it and by design the lefty adds a CM of stack height to deal with the top clamp. So I was still able to put a medium lefty on it even though I don't have a fully inset top bearing.

 

[Santapez]

Stack height is most useful to know if your current fork will fit or if the steerer was cut too short. Or what size lefty you need.
I find stack height semi relevant cause I'm short, and on 29ers with the big wheels, the ever elongating forks, and with a big stack height you'll wind up with a rather tall bike. the early cannondale 29ers had notoriously high front ends.
My Ibis on the other hand has an very low stack height for it's class, keeping the front end low. Which works out because I put a lefty on it and by design the lefty adds a CM of stack height to deal with the top clamp. So I was still able to put a medium lefty on it even though I don't have a fully inset top bearing.

I believe you're getting head tube length mixed up with Stack. Although head tube length is a factor in Stack.

 

[Jmann]

I had a misadventure with stack height when I ordered my tallboy. I paid all my attention to reach and didn't notice the tallboy has low stack. And the dealer cut the steerer to a standard length. So since I have long ish legs I have a significant saddle to bar drop. Mostly it's fine but I'm going to have to put riser bars on it eventually. Which could have been avoided with an extra 20-30mm of steerer.

 

[gtluke]

I believe you're getting head tube length mixed up with Stack. Although head tube length is a factor in Stack.

Derrrr I read the title and didn't look at his chart. He's talking about stack, not stack height. So I started talking about stack height. Which I guess is a factor in overall stack.

 

[qclabrat]

Derrrr I read the title and didn't look at his chart. He's talking about stack, not stack height. So I started talking about stack height. Which I guess is a factor in overall stack.

Yeah, I guess I mean stack, but some call it stack height but agree height refers to spacer options under the stem

Here's a good quick read on stack height and can now see how the "stack" dimension contributes to the fit from the reach and TT measurements
I think stack numbers are more important if you have "abnormally" long/short arms, legs or torso.
https://www.mtb-mag.com/en/tech-corner-how-to-set-your-stack-height/