Geometry Comparison Tool - GEOMETRYGEEKS.BIKE

[MORNE]

So whats the best way forward to determine proper sizing for a specific make/model of bike? There is no way a bike shop will let you ride try out their bikes on a trail for good feel. I struggle with this because bike manufacturers standards are all different.

Best way is to know your numbers and what reach, stack you prefer. Then if you are like us long legged versions you have your preferred saddle height (bb to saddle) handy too, since that will be the same for most bikes you’ll ever own. Mine is 860mm from bb to top or 1035mm from pedal to top assuming 175mm cranks. That mostly means im looking for bike frames with a seat tube of atleast 500mm, more if you arent running a 200mm dropper lol. Because that means there will be close to 300mm seatpost showing regardless. I then also look for maximum stack since ill be seatted in the outer atmosphere anyway ad dont want too much saddle to bar drop. This bit is difficult with the long, low, slack trend at the moment. Then...i prefer a bike with a reach around 500-520mm, ETT around 670-700mm

 

Thats why tools like these help.

[ChrisF]

 

So whats the best way forward to determine proper sizing for a specific make/model of bike? There is no way a bike shop will let you ride try out their bikes on a trail for good feel. I struggle with this because bike manufacturers standards are all different.

Adding to Morne's reply ...

 

Most dealers have test days.

 

Last week Giant Durbanville had such a day at Conties

 

Wednesday Spez was at Bloemendal.

 

 

Step 1 ... get a bike in your size ...

 

Step 2 .... they do a quick setup to make sure you get the best experience.

 

Step 3 ... 20 minute ride on the trails.

 

 

Now is your time to quickly measure those critical dimensions that Morne spoke off.

[DieselnDust]

So whats the best way forward to determine proper sizing for a specific make/model of bike? There is no way a bike shop will let you ride try out their bikes on a trail for good feel. I struggle with this because bike manufacturers standards are all different.

 

 

Best way is to know your numbers and what reach, stack you prefer. Then if you are like us long legged versions you have your preferred saddle height (bb to saddle) handy too, since that will be the same for most bikes you’ll ever own. Mine is 860mm from bb to top or 1035mm from pedal to top assuming 175mm cranks. That mostly means im looking for bike frames with a seat tube of atleast 500mm, more if you arent running a 200mm dropper lol. Because that means there will be close to 300mm seatpost showing regardless. I then also look for maximum stack since ill be seatted in the outer atmosphere anyway ad dont want too much saddle to bar drop. This bit is difficult with the long, low, slack trend at the moment. Then...i prefer a bike with a reach around 500-520mm, ETT around 670-700mm

 

Thats why tools like these help.

 

 

As Morne says, know your numbers.

 

if your current bike fits lekker and feels great then take the measurements:

 

saddle to bar

Saddle to pedal

saddle sit point to centre of bb

Once you know these points you can work out the stack and reach and set back.

last measurement is the weight on the wheels...

Why is this important? 

On a bike with a longer front centre you may not like the feel of that longer front centre so the place to start is get the weight on that new bikes wheels the same as your current great feeling and well dialled bike and then work the set up till you're happy with the new setup.

 

Us humans are highly adaptable creatures. We can adapt without injury if done correctly and not in large steps.

The tools help immensely to give you a good reference point to start from in terms of selecting the correct stem length and saddle set back to position you similarly. Once that is done the weight on the wheels is the most important interaction between you the bike and the trail since its that what reflects the ground pushing back.

Edited December 18, 2020 by DieselnDust