Explain to me stack height

[Paul H]

I am probably not understand this correctly...
My Hightower is 613mm stack height and the Marley has 619mm.
Head tube angle is 67 on the HT and 65.5 on the Marley.
50mm with 0 degree stem on HT and 40mm with 0 degrees stem on Marley.

Shouldn't I be using a similar rise bar?
Despite the higher stack height on the Marley, I need a 40mm rise on the Marley where I am perfectly fine with a 20 rise on the HT. Is the rear suspension on the HT the difference?

 

[JDurk]

I think you need to consider reach while also looking at the stack height.

Plug the numbers into this to compare the 2 bikes. https://geometrygeeks.bike/

 

[Paul H]

Reach is 450 (HT) vs 455 (Marley)
Also fairly sure same amount of stem spacers and zero stack headset on both bikes

 

[Ryan.P]

Is the rear suspension on the HT the difference

Yes , it sags more than the fork so shortening reach and raising stack to bb . HT does opposite as it only sags in front increasing reach and lowering stack .

 

[JDurk]

Yes , it sags more than the fork so shortening reach and raising stack to bb . HT does opposite as it only sags in front increasing reach and lowering stack .

I believe HT in this case means HighTower, not HardTail.

 

[djm]

BB height has an impact here.

 

[Paul H]

BB height has an impact here.

Stack height is from BB height to top of top tube no?

 

[JDurk]

Stack height is from BB height to top of top tube no?

No, top of head tube where upper headset sits.

 

[djm]

Stack height is from BB height to top of top tube no?