If you are choosing a bike based on stack and reach then note that they are related. The reach and stack are measured from the same point (join of top tube and head tube). So if you see a bike that has 20mm more stack and 10mm more reach than another then it actually may have 16mm more reach at the same stack height from the bottom bracket as the smaller bike, (depending on head tube angle) so it's longer than you think.
Bicycle Geometry Terms
61–70 of 78 posts
Re: Bicycle Geometry Terms
#62Great explanations! It’s really silly that seat tube length is used as the single measure of frame size. Much more important is reach and standover height, since those can’t easily be changed. A longer or shorter stem will adjust reach at the expense of changing how responsive the steering is, whereas a short seat tube can be fixed with a longer seat post. Seat tube length is also measured differently by different ma…
My thoughts exactly. Being on the shorter side what matters is the stand over height - too high and it greatly limits on/off/standing manoeuvrability and agility. I was surprised to learn that the smallest adult bikes tend to have a stand over height of 68-70cm. For some bikes, it’s even higher. For the lower tail of the adult height distribution, this is too tall to use comfortably.
This is a sad topic for me. It just doesn't exist a premium model all mountain bike, that I have even 1mm of clearance between me and the top tube. Even when standing on my toes.
Re: Bicycle Geometry Terms
#63If you are interested in messing around with these settings and many more, look at the great parametric bicycle cad system “Bikecad”. Brett curry maintains and updates it for eons now. And crazy licensing — one time payment gets lifetime of updates.
Nice! https://www.bikecad.ca/ Costs CAD500 is a one time fee. Runs on Linux, Mac and Windows. A Free online version is also available. It takes >5min to load, just be patient.
There is also rattleCAD app developed by Manfred Rosenberger.[0]
rattleCAD rattleCAD 4.0 is proprietary with freeware/demo version & few subscription modes.[1]
Re: Bicycle Geometry Terms
#64For a deep dive into all things bicycle, I always recommend Sheldon Brown's delightful knowledgebase, which started in the late 90s:
(sadly Mr. Brown is no longer with us, but his web archive lives on)
And there's always Bicycling Science for the serious nerds among us
https://www.amazon.com/Bicycling-Science-Press-Gordon-Wilson...
Re: Bicycle Geometry Terms
#65As a bicyclist, I'm amused this made it on to the HN front page. I'm not sure I agree with the description of stack. Cockpit height can be adjusted with riser stems and different handlebar shapes; it's not solely a function of axle-crown and headtube length. Without getting into it too much, some other descriptions are not great either. The general overview is ok but they make some overly strong claims. I'm not sure…
Thanks for the feedback. We tried to keep these succinct and approachable, and have probably over-simplified some things as a result. I agree that we've left out some important details, and are probably too focused on the frame geometry without clearly explaining how it relates to the contact points on a complete build. We'll try to make some improvements here. If you feel inclined to point out more specifics where you feel we missed the mark I'd love to hear so we can improve the site. You can reach me at bryan@99spokes.com, or use the feedback form on the site.
Re: Bicycle Geometry Terms
#66Although I'm an avid reader, this is my first ever comment. I built this site https://comparemtb.com/ to give people a way to visually compare the geometries of many different mountain bikes. I'd be interested in any feedback. Thanks.
Also https://bikeinsights.com/
CompareMTB guy here. Thanks for sharing your site. Didn't know you existed. Nice work.
Re: Bicycle Geometry Terms
#67I dont ecen know where to begin. So much of this is alightly incorrect its maddening. As someone who has setup race motorcycles please look elsewhere for correct terms and physics.
Re: Bicycle Geometry Terms
#68As a bicyclist, I'm amused this made it on to the HN front page. I'm not sure I agree with the description of stack. Cockpit height can be adjusted with riser stems and different handlebar shapes; it's not solely a function of axle-crown and headtube length. Without getting into it too much, some other descriptions are not great either. The general overview is ok but they make some overly strong claims. I'm not sure…
Too many risers or an unorthodox stem can adversely affect the handling, aerodynamics, and structural integrity of a bike. Not to mention they can adversely affect the aesthetics.
While other measurements (wheel base, trail, rake, bottom bracket drop, etc.) may more significantly affect the performance and handling characteristics of a bike, no measurements are more important to the correct sizing of a bike than stack and reach.
Dan Empfield has written extensively about this at Slowtwitch.com if anyone out there wants to read more about why stack and reach are essential measurements when correctly sizing a bike.
Re: Bicycle Geometry Terms
#69Earlier quoted context omitted.
Wheelbase is one of the most important measurements for mountain bikes. It determines stability at the cost of the ability to turn quickly.
It's definitely also important for road / track bikes! My observation is just that it usually isn't described by that name (or even necessarily that specific measurement). (In my experience, YMMV, etc.) For example, Look publishes Chainstay (sometimes called "Rear Center") and "Front Center" (BB to front axle) measurements, separately, for their frames, but does not publish axle-to-axle / wheelbase measurement. Somet…
Mountain bike reviews will frequently mention wheelbase, and most brands I’ve been perusing lately will mention wheelbase in their geometry section.
Re: Bicycle Geometry Terms
#70As a bicyclist, I'm amused this made it on to the HN front page. I'm not sure I agree with the description of stack. Cockpit height can be adjusted with riser stems and different handlebar shapes; it's not solely a function of axle-crown and headtube length. Without getting into it too much, some other descriptions are not great either. The general overview is ok but they make some overly strong claims. I'm not sure…
Everyone should think about this comment the next time they’re wow’ed by some link here. When you’re knowledgeable about something and read an article/blog/whatever about that topic, it’s shocking how much is either somewhat off-base or just plain wrong . The articles that aren’t about your areas of expertise are no different.
I agree with your general point but I think OP is being a bit picky about this particular page. The descriptions are pretty good and wheelbase is indeed a common bicycling term (I see it all the time in reviews and it’s listed on the product pages for the last three road bikes I bought—I just checked).
This website overall is a great resource for bike nerds, specifically their bike database; there’s nothing else like it AFAIK.