Geometry Comparison
Moderator: robbosmans
Visit starbike.com Online Retailer for HighEnd cycling components
Great Prices ✓ Broad Selection ✓ Worldwide Delivery ✓
www.starbike.com
Tube lengths don't, S/R sorts all that out. Angles theoretically do - but except for on tiny bikes HTA rarely varies by any significant amount, and STA can usually be compensated for by saddle rail adjustment or seatpost setback.
“If you save your breath I feel a man like you can manage it. And if you don't manage it, you'll die. Only slowly, very slowly, old friend.”
the best site to compare geo . great database of all current road brands
https://app.velogicfit.com/frame-comparison
https://app.velogicfit.com/frame-comparison
Current Rides:
2023 Tarmac SL7 Di2 9270
ex 2019 S-works SL6
ex 2018 Trek Madone SLR Disc
ex 2016 Giant TCRAdvanced Sl
ex 2012 Trek Madone7
2023 Tarmac SL7 Di2 9270
ex 2019 S-works SL6
ex 2018 Trek Madone SLR Disc
ex 2016 Giant TCRAdvanced Sl
ex 2012 Trek Madone7
-
- Posts: 51
- Joined: Fri Apr 14, 2017 12:44 pm
This is my favourite site at the moment: https://www.bikegeocalc.com/#7Unnameda0 ... 2.5G30H30Z
Seat Tube Angle matters for fit purposes only if it is so extreme that you can't roll your saddle forward/backward enough.
Provided that your saddle fore-aft vs the bottom bracket is dialled in, then stack and reach are quite comprehensive. The only other factors you need to take into account are stem length/angle and head tube angle -unless you have a spacer tower, the latter doesn't matter a lot, but still- for which I use http://yojimg.net/bike/web_tools/stem.php, and finally the handlebar reach. Whilst most bars have 80mm reach or so, there can be wild exceptions, with some Bontrager alloy bars or the 3T Aeronova going to around and above 100mm, which could potentially make an otherwise perfectly sized bike uncomfortable.
The websites above like bikegeocalc and velogicfit are also quite valid, especially for comparing bikes.
-
- Posts: 854
- Joined: Tue Jul 18, 2006 5:18 am
- Location: Cambridge, New Zealand
- Contact:
Things that matter for matching bikes:
Hood XY - if you use the same bars and levers this can be simplified to Bar XY - this gets your hands in the same position
Seat tube angle and post offset options - as mentioned above - only matters if it stops you getting your posterior in the right place
Chainstay length and front centre - weight distribution, stability, handling behaviour
Head tube angle and fork rake - handling behaviour
Everything else is just part of filling in the dots between the important coordinates (rider contacts and road contacts)
The yojimg stem tool (and every other calc I've seen) has an an error in the formula for bar XY. Not having calcs match reality really bugged me so I spent the time to figure out why and the velogicfit tool uses the formula that resulted (note that I'm the founder of VF). It's not a lot but it does make a difference to the calculated bar Y
Hood XY - if you use the same bars and levers this can be simplified to Bar XY - this gets your hands in the same position
Seat tube angle and post offset options - as mentioned above - only matters if it stops you getting your posterior in the right place
Chainstay length and front centre - weight distribution, stability, handling behaviour
Head tube angle and fork rake - handling behaviour
Everything else is just part of filling in the dots between the important coordinates (rider contacts and road contacts)
The yojimg stem tool (and every other calc I've seen) has an an error in the formula for bar XY. Not having calcs match reality really bugged me so I spent the time to figure out why and the velogicfit tool uses the formula that resulted (note that I'm the founder of VF). It's not a lot but it does make a difference to the calculated bar Y
- wheelsONfire
- Posts: 6283
- Joined: Mon Jul 07, 2014 8:15 am
- Location: NorthEU
Well, perhaps trail/ rake should be of interest?
Possibly chainstay lenght...
Possibly chainstay lenght...
Bikes:
Ax Lightness Vial EVO Race (2019.01.03)
Open *UP* (2016.04.14)
Paduano Racing Fidia (kind of shelved)
Ex bike; Vial EVO D, Vial EVO Ultra, Scott Foil, Paduano ti bike.
Ax Lightness Vial EVO Race (2019.01.03)
Open *UP* (2016.04.14)
Paduano Racing Fidia (kind of shelved)
Ex bike; Vial EVO D, Vial EVO Ultra, Scott Foil, Paduano ti bike.
Not for bike fit, that's into handling, which is a whole new can o worms.........wheelsONfire wrote: ↑Sun Apr 21, 2019 7:14 pmWell, perhaps trail/ rake should be of interest?
Possibly chainstay lenght...
- wheelsONfire
- Posts: 6283
- Joined: Mon Jul 07, 2014 8:15 am
- Location: NorthEU
Well, ofcourse it's about handling. I just missed that it was ONLY about fit.mattr wrote: ↑Sun Apr 21, 2019 8:35 pmNot for bike fit, that's into handling, which is a whole new can o worms.........wheelsONfire wrote: ↑Sun Apr 21, 2019 7:14 pmWell, perhaps trail/ rake should be of interest?
Possibly chainstay lenght...
Bikes:
Ax Lightness Vial EVO Race (2019.01.03)
Open *UP* (2016.04.14)
Paduano Racing Fidia (kind of shelved)
Ex bike; Vial EVO D, Vial EVO Ultra, Scott Foil, Paduano ti bike.
Ax Lightness Vial EVO Race (2019.01.03)
Open *UP* (2016.04.14)
Paduano Racing Fidia (kind of shelved)
Ex bike; Vial EVO D, Vial EVO Ultra, Scott Foil, Paduano ti bike.
For trail/rake values, simple rule of thumb is that Most bike in size 52-56 are good.
Size 50 and smaller on some brands are poorly handle (generally have too much trail due to same fork but slacker head tube angle). So go up in size to 50+ and short stem make bike handle better in some certain bike model/brand.
Size 58+ sometime start to face opposite problem when manufacturer use very steep head tube angle.
Size 50 and smaller on some brands are poorly handle (generally have too much trail due to same fork but slacker head tube angle). So go up in size to 50+ and short stem make bike handle better in some certain bike model/brand.
Size 58+ sometime start to face opposite problem when manufacturer use very steep head tube angle.
Visit starbike.com Online Retailer for HighEnd cycling components
Great Prices ✓ Broad Selection ✓ Worldwide Delivery ✓
www.starbike.com
- wheelsONfire
- Posts: 6283
- Joined: Mon Jul 07, 2014 8:15 am
- Location: NorthEU
They can vary quite much actually. BMC for instance have slow steering. My Ax bike has very quick steering.Hexsense wrote: ↑Mon Apr 22, 2019 5:40 pmFor trail/rake values, simple rule of thumb is that Most bike in size 52-56 are good.
Size 50 and smaller on some brands are poorly handle (generally have too much trail due to same fork but slacker head tube angle). So go up in size to 50+ and short stem make bike handle better in some certain bike model/brand.
Size 58+ sometime start to face opposite problem when manufacturer use very steep head tube angle.
I changed model when i bought a new Ax, to use a longer stem. I have a 120mm on this bike, on the previous i had a 105mm stem.
Anyway, it's something i wouldn't leave blank if i bought a custom frameset.
I would probably oversee chainstay lenght to. Not to mention BB!!
Bikes:
Ax Lightness Vial EVO Race (2019.01.03)
Open *UP* (2016.04.14)
Paduano Racing Fidia (kind of shelved)
Ex bike; Vial EVO D, Vial EVO Ultra, Scott Foil, Paduano ti bike.
Ax Lightness Vial EVO Race (2019.01.03)
Open *UP* (2016.04.14)
Paduano Racing Fidia (kind of shelved)
Ex bike; Vial EVO D, Vial EVO Ultra, Scott Foil, Paduano ti bike.