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Bicycle Geometry Terms
21–30 of 78 posts
Re: Bicycle Geometry Terms
#22Great 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…
> Much more important is reach and standover height, since those can’t easily be changed.
I try, buy and build quite a lot of bikes (6 this year). Reach has never been very helpful for me. Seat tube angles differ quite a lot and the position of the bottom bracket on the x axis does not affect me that much. Effective top tube and stack is what I look for.
Being a long legged person, standover has never been an issue. I can straddle most any bike. Stack is important because that gives me a hint if I can get the saddle and handlebars on the same height without crazy stem solutions. I ride bikes from the horizontal top tube era that favor the "fistful of seatpost" rule, so C-T seat tube length is also very important to me (for purely aesthetic reasons.)
Re: Bicycle Geometry Terms
#23If 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.
https://www.bikegeocalc.com if you want something more simple. Use it all the time.
Re: Bicycle Geometry Terms
#24Do you think people who fix bikes or are bike enthusiasts know which of these components affect which aspect of riding? I can imagine knowing all the specific names for the parts is difficult but their affect on biking experience seems very relevant. Something that was not so obvious to me.
In my experience knowing and caring about bike geometry to this level of detail is definitely for the advanced enthusiast. Just knowing it doesn't mean you can apply it either. I knew the terms in the article, I even knew what I personally prefer and how a bike might feel by reading the numbers, but I won't be offering to do anyone's bike fit any time soon!
Re: Bicycle Geometry Terms
#25Do you think people who fix bikes or are bike enthusiasts know which of these components affect which aspect of riding? I can imagine knowing all the specific names for the parts is difficult but their affect on biking experience seems very relevant. Something that was not so obvious to me.
yes. most people probably haven't read a guide like this, but if you've ridden a good variety of bikes you get a sense for how the bb height affects stability, or how the head tube angle and the trail affect your steering. some bikes even offer adjustable geometries by moving a bolt to a different position, which really makes it easy to understand how a change in geometry affects the handling characteristics.
I got a rapid lesson in how changing the length of the seat stay to slacken the head tube angle leads to a reduced bottom bracket height. A rock I would normally clear snagged a pedal and I went careening over the bars. A good example of how all of these variables influence each other and how bike fit and geometry is always a balancing act.
Re: Bicycle Geometry Terms
#26Do you think people who fix bikes or are bike enthusiasts know which of these components affect which aspect of riding? I can imagine knowing all the specific names for the parts is difficult but their affect on biking experience seems very relevant. Something that was not so obvious to me.
For your second bike, yes. ;-)
Granted, different people are enthusiasts for different reasons, for instance I rely on my bike for getting around town, but will never be a competitive rider. So, the interest in geometry ranges from just being safe and comfortable to ride, up to performance aspects of activities such as mountain biking, racing, or touring.
One hassle is that different makers sometimes supply a different set of measurements, especially inexpensive or older bikes, so you have to figure things out a bit. Also, a short test ride might not tell you how happy you will be after 100 miles. If there are things that you are happy or unhappy about on your existing bike, I suggest measuring it and try to figure some things out that way. When shopping for a bike (or hunting through piles of used bikes, as I've done), bring a tape measure.
Re: Bicycle Geometry Terms
#27Do you think people who fix bikes or are bike enthusiasts know which of these components affect which aspect of riding? I can imagine knowing all the specific names for the parts is difficult but their affect on biking experience seems very relevant. Something that was not so obvious to me.
There are professional "bike fitters" that know how to adjust all these things (those that can be adjusted) and more in such a way you get everything set up the best given your body and goals. For instance, given a bike and a rider, one can adjust seat height, seat position, stem length, handlebarhheight, crank arm length and possible more things to get the correct reach and stem height. However, all that also has to…
I agree with you a 100%. Your bike should help you maintain good riding posture even when you are becoming road tired. Just be careful about who you pay to fit the bike. Most shops claim to be experts, but I have had bad experiences with some shops. It doesn't show until you've ridden a great many miles.
Re: Bicycle Geometry Terms
#28Odd how it does not give the weight of bicycles in the specs.
Re: Bicycle Geometry Terms
#29I love this site - it is very informative. I wonder if anyone has done something similar for music - i.e. "Musical Geometry terms" ..
Are you able to elaborate on what you'd hope for from a "Musical Geometry" site? I have a side project on the backburner that tries to understand the building blocks of music in order to answer questions like "What could I call this chord?" and "What notes are in the key of C?". Hence my interest!
I've seen lots of 'music explained' types of sites, but if someone were to use their mad graphics skills to explain the geometric/arithmetic relationship between various components of music, I'd pay for it. There are sites that show you the mathematical differences in scales and harmonic series - to represent this with visual geometry would be divine.
Re: Bicycle Geometry Terms
#30Odd how it does not give the weight of bicycles in the specs.
This also the first thing I checked. For many it does, actually, e.g.: https://99spokes.com/bikes/trek/2021/fx-sport-carbon-4
But I’m in no way a bike specialist -- maybe the weight of a bike is a feature that can be overlooked for gear of this level/price (expensive, I mean). Maybe a {1,2,...},000$ non-electric bike will always weight less than 10 kg (carbon and stuff) ? It depends on the bike purpose, of course.
I’m currently looking for a bike, but more in the 200$ range... ;)
This is the cheapest bike listed: https://99spokes.com/bikes/trek/2021/fx-sport-carbon-4