[MobileChernobyl]

It's a great move and I definitely agree a more accurate measure of bike size, however I think it was a bad move to tie the measurement to plumb and level. Put a longer or shorter fork on there and the numbers change, making it tough for someone to compare frames without whipping out the pythagorean theorum.

Totally agreed, I was shocked it took all that way till you responded for anyone to spot this lol, it's the first thing I thought of when I saw it.

Unfortunatly unless it's constained by some other constant on the frame, it's really just another fancy measurement that get's distorted when you err from the manufacturer's original specs.

There needs to be a "standard" where you use center of bottem bracket to center of top headset race and HA, since there both easy enough to figure out for anyone concerned.

Here's one off the top of my head -

Distance form BB to top center of head tube = X
Head angle = HA

To get some kind of "Standardized" synthetic "Top-tube'ish" measurement just use:
X*Sin(HA)


for instance -
25" BB to HT * Sin(65* head angle)
-yeilds a synthetic 22.7" TT. That doesnt seem too bad eh? and I don't even have a bike in front of me right now!

Some more examples

"Large Frame"
25X*Sin(67) = 23.01"
25X*Sin(65) = 22.7"
25X*Sin(63) = 22.27"

"Small Frame"
23X*Sin(67) = 21.17"
23X*Sin(65) = 20.84"
23X*Sin(63) = 20.5"

OK so that doesn't exactly work right lol. Some more finaggling might work out a better formula.

Ahh fvck it... just ride the dame bike... lol

 

[ohio]

Do they? I'm a bit undercaffeinated and over distracted, and leave trig to other people, but how is the measurement of ONE line defined by two endpoints the same as the measure of two lines from an intersection?

See my awesome drawing. We're using the same right triangle to measure and a right triangle can either be defined by the length of two sides or one side and either non-right angle.

By using the hypotenuse (grey measures, I called "ohio-size" and "ohio-angle" because I'm self-centered), it doesn't change when you put a 12" super monster on there, only the angle does. Rise and Reach (orange measures)would both change if you throw on the hukkxtors fork.

edit: the yellow bike contains patent-pending ohio proprietary engineering that won't be released until 2015. This is just a photo-realistic rending to build the hype.

 

[General Lee]

edit: the yellow bike contains patent-pending ohio proprietary engineering that won't be released until 2015. This is just a photo-realistic rending to build the hype.

yeah, well i want to see a close-up photo of the underside of the bottom bracket by tomorrow or STFU!

 

[SuspectDevice]

Aha. Yes, that makes more sense now

(goes back to illustrator to finish shading '09 team clothing)
So I'll leave you with a youtube link
http://www.youtube.com/watch?v=<object width="425" height="344"><param name="movie" value="http://www.youtube.com/v/JSyhDbV9wHo&hl=en&fs=1"></param><param name="allowFullScreen" value="true"></param><param name="allowscriptaccess" value="always"></param><embed src="http://www.youtube.com/v/JSyhDbV9wHo&hl=en&fs=1" type="application/x-shockwave-flash" allowscriptaccess="always" allowfullscreen="true" width="425" height="344"></embed></object>

 

[JohnnyC]

**edit. out of curiosity sake it would be interesting if people measured their own bikes this way and we could start a thread with the stack/reach of some of the more popular frames already on the market. would certainly be easier than waiting for the bike companies to do it.

I like that idea, I thought of doing it a few months ago when I was thinking about a new bike, my KHS is too small but the claimed top tube is something like 24" and the slack seat tube is what makes it really short.

 

[ohio]

So I'll leave you with a youtube link

Thank you for that

 

[punkassean]

HOLYFUKINSHIFT I'm laughing my ass of right now because I had exactly the same reaction.

 

[Sandwich]

Aha. Yes, that makes more sense now

I don't know, for me, it's a tie between the bumble bee and the chevron guy.

 

[Sam B]

See my awesome drawing. We're using the same right triangle to measure and a right triangle can either be defined by the length of two sides or one side and either non-right angle.

By using the hypotenuse (grey measures, I called "ohio-size" and "ohio-angle" because I'm self-centered), it doesn't change when you put a 12" super monster on there, only the angle does. Rise and Reach (orange measures)would both change if you throw on the hukkxtors fork.

edit: the yellow bike contains patent-pending ohio proprietary engineering that won't be released until 2015. This is just a photo-realistic rending to build the hype.

Umm... that completely misses the point. The relationship between your hands and feet has changed drastically by putting that longer fork on your bike. So you should certainly expect the bars to feel a whole lot higher and closer to you. That is in addition to the massive increase in wheelbase, slight increse in BB height and much reduced head angle.

This is more pertinent...

I am currently running my Boxxer at about a 590 axle to crown, with 430mm reach and 600mm stack. I pull up the geo on a bike that the company says is based on a 590mm axle to crown, has a 420mm reach and 590mm stack. I can expect that my bike will feel a bit shorter, but before I even build that bike up I can see that I will need to add about 10mm (yes, technically not 10mm but extremely close unless the headtube is a mile long) of additional spacers to get the bars in the same place.

Edit: For the most part a Boxxer to a Boxxer is going to be +/- a very small amount. The effect of that difference is pretty easy to understand and can be intuitively calculated by the rider. Longer fork... yes stack will grow considerably and reach will shrink slightly.

 

[General Lee]

well obviously no simple measurement is going to account for every contingency of individual bike set-up and preference. get on 4 peoples' Sundays and they probably all have slightly different stack/reach measurements but the general fit and feel of the bikes is going to be the same. and without changing the axel-crown height each could probably be made close to identical in terms of cockpit position with changes in bar height, stem length etc.

correct me if i'm way off here, but i'm thinking the point of this new standard isn't to somehow quantify the exact way a bike is going to feel when you get on it but rather to give a much better reference point from which to determine what 'size' frame you might want to buy (or what brand) based on some numbers that are actually useful; unlike tt/st measurement. besides, it' not like all the other published geometry numbers don't change depending on individual set-up (it's sort of what makes your bike, well, yours). tire size, axel/crown, and using froks from different manufacturers will all alter head angle, wheelbase,bb height, etc. at least all of those measurements along with stack/reach can give us an idea what a bike will feel like even if we don't run the exact same set-up used to get the published figures. top tube measurement on the other hand doesn't really tell us a darn thing.

in terms of comparing dh bikes to dh bikes stack/reach is good figure to go by. most everyone uses 8" forks and has an axel-crown measurement +/- probably 15mm at most? that' not going to make much of a difference. plus it's really easy to undertand

 

[Sam B]

well obviously no simple measurement is going to account for every contingency of individual bike set-up and preference. get on 4 peoples' Sundays and they probably all have slightly different stack/reach measurements but the general fit and feel of the bikes is going to be the same. and without changing the axel-crown height each could probably be made close to identical in terms of cockpit position with changes in bar height, stem length etc.

correct me if i'm way off here, but i'm thinking the point of this new standard isn't to somehow quantify the exact way a bike is going to feel when you get on it but rather to give a much better reference point from which to determine what 'size' frame you might want to buy (or what brand) based on some numbers that are actually useful; unlike tt/st measurement. besides, it' not like all the other published geometry numbers don't change depending on individual set-up (it's sort of what makes your bike, well, yours). tire size, axel/crown, and using froks from different manufacturers will all alter head angle, wheelbase,bb height, etc. at least all of those measurements along with stack/reach can give us an idea what a bike will feel like even if we don't run the exact same set-up used to get the published figures. top tube measurement on the other hand doesn't really tell us a darn thing.

in terms of comparing dh bikes to dh bikes stack/reach is good figure to go by. most everyone uses 8" forks and has an axel-crown measurement +/- probably 15mm at most? that' not going to make much of a difference. plus it's really easy to undertand

EXACTLY.

It is valuable info for a rider to have. It seems riders (DH racers in particular) are becoming more and more aware of, and knowledgeable about, bike setup; why not give them more information about their frames.

 

[General Lee]

Here's one off the top of my head -

Distance form BB to top center of head tube = X
Head angle = HA

To get some kind of "Standardized" synthetic "Top-tube'ish" measurement just use:
X*Sin(HA)


for instance -
25" BB to HT * Sin(65* head angle)
-yeilds a synthetic 22.7" TT. That doesnt seem too bad eh? and I don't even have a bike in front of me right now!

Some more examples

"Large Frame"
25X*Sin(67) = 23.01"
25X*Sin(65) = 22.7"
25X*Sin(63) = 22.27"

"Small Frame"
23X*Sin(67) = 21.17"
23X*Sin(65) = 20.84"
23X*Sin(63) = 20.5"

OK so that doesn't exactly work right lol. Some more finaggling might work out a better formula.

Ahh fvck it... just ride the dame bike... lol

And don't forget that the angle of the dangle is inversely proportional to the heat of the meat

 

[Wobbler]

I like that idea, I thought of doing it a few months ago when I was thinking about a new bike, my KHS is too small but the claimed top tube is something like 24" and the slack seat tube is what makes it really short.

I'm in the same boat, my medium shocker is a very small medium based on the feel of it. I'll be interested to compare these numbers to some of the more conventionally seat tubed frames around the place.