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Suddenly I care about Geometry


100Tours

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This is not meant to be a bike fit discussion - more I'm learning about bike handling, and trying to make good decisions about how to put together better bikes. If bike fit is what you're after have a look for the RAD method on youtube - that's my new favourite bike sizing method.

Anyway on to choosing better geometry - and this probably matters most for gravel or monstercross type builds where you're combining unmatched frames and forks, or perhaps just shopping for new toys. I haven't yet figured out how to calculate the results - I am of the school of 'fit it and see'.

The big 3 measures are seemingly rear stay length, fork trail, and BB drop - is there anything else that matters? So I did some rough measuring on a few bikes that I enjoy - as follows.

  Fork trail Stays BB drop
track 45 400 75
road 1 65 400 75
road 2 70 400 75
gravel 100 420 55
hardtail 29er 150 440 55

Which explains a lot - check that tiny trail number on the track bike (not like you ever need to turn corners). Trail on the mtb is a bit overstated 'coz I measured that without anyone sitting on the bike to compress the shock, but this makes a pretty cool series of measures. Very pleasing to an engineering eye.

Also my gravel bike is a 26" frame running 700c wheels with a 700c fork - so it's a bit of a weird one, but that's a lot of fork trail and not a lot of BB drop. Having said that it still rides really well and holds its head very confidently on bumpy gravel, and it has tons of pedal clearance - but its probably a bad idea for bunch riding, the steering is decidedly sluggish. I'm also writing off any plans to put a longer fork on the MTB - I'm already pushing those trail limits. 

Anyway an interesting exercise - I'm keen to hear if anyone else thinks about these things 🤯

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Geometry and frame material are the 1st things I look at when evaluating a bike. I like to think that I've matured past the point of looking at what bike has the best components, and rather what bike has the best frame and geometry.

I've always maintained that it is easy to change/upgrade components, but you are pretty much stuck with the frame you have. So that should always be your stating point when comparing bike A to bike B.

Steve from "Hardtail Party" has taught me a lot of what I know today. He is a constant source of knowledge and inspiration. Its worth checking his channel out:

https://www.youtube.com/c/hardtailparty

Edited by cclayford
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19 minutes ago, cclayford said:

Geometry and frame material are the 1st things I look at when evaluating a bike. I like to think that I've matured past the point of looking at what bike has the best components, and rather what bike has the best frame and geometry.

I've always maintained that it is easy to change/upgrade components, but you are pretty much stuck with the frame you have. So that should always be your stating point when comparing bike A to bike B.

Steve from "Hardtail Party" has taught me a lot of what I know today. He is a constant source of knowledge and inspiration. Its worth checking his channel out:

https://www.youtube.com/c/hardtailparty

I watch all his videos.

Edited by Super Sywurm
That is why I'm now riding a fancy steel bike.
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