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Discussion Starter · #1 · (Edited)
I'm looking for a very important measurement websites don't have listed. If someone would get these 2 measurements for me I'd greatly appreciate it. This is how to measure it.
Do this on a level floor.

1. Drop a string w/ a weight from the middle of your handlebar close to the ground.
2. Measure from the center of the BB to the String.

List what frame sizes you get these measurements from too, please. I'm looking into getting a Sunday Elite myself. The measurements match up to my old bike (medium sgs), but the ETT is 1.5" longer on the small frame! The ETT doesn't mean much to me cause (I'm sure you all know) We're not sitting on the seat... But, the distance We reach while standing does make a difference. I think this should be a new way of measuring a DH and FR top tube. Thoughts? Thanks for the help, Fahn
 

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rollin
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LarryFahn said:
1. Drop a string w/ a weight from the middle of your handlebar close to the ground.
2. Measure from the center of the BB to the String.

List what frame sizes you get these measurements from too, please. I'm looking into getting a Sunday myself. The measurements match up to my old bike (medium sgs), but the ETT is 1.5" longer on the small frame! The ETT doesn't mean much to me cause (I'm sure you all know) We're not sitting on the seat... But, the distance We reach while standing does make a difference. I think this should be a new way of measuring a DH and FR top tube. Thoughts? Thanks for the help, Fahn
i agree. sorry, not a sunday owner, can't help you. but i always subtract the chainstay length from the wheelbase, and this gives you the distance from the bottom bracket to the front wheel. but, again, head angle will give you varying BB to bar variables, as will stem length and bar sweep.
 

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Equal opportunity meanie
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What you are more or less looking for is a true downtube measurement, and yes, it is an important dimension that almost all manufacturers neglect to mention in their specs.
 

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Discussion Starter · #6 ·
Not really a DT measurement, but a measurement that you can compare "Where your center-of-gravity is".

I'm very comfortable on my 03 SGS Pro. To get a bike with a 1.5" longer ETT doesn't mean squat if the Center of the BB to the center of the bar (measured paralell to the ground!) is the same. The frame height, ST angle, HT angle, travle of the fork, rake... Can all make a difference in this measurement I'm looking for. I truly don't think a 1/2 inch diff is all that much to be concerned about. But 1.5"+ I think will be.

Here's an example of what I'm talking about... Around 2000ish, Spooky made a DH frame in one size It resembled a "Y" bike frame. The upper part of the Y came out maybe 6". It had a QR on the drive side (or TT???) of it. If you opened the QR, you could slide the "teloscopic top tube" out. Cause it was at an angle, it would move back and up at the same time. This looked like an invention to solve frame sizing! The problem to me? It doesn't adjust the toptube length in any manner, but it does adjust the ETT by quite a bit. Here's a pic of what I'm talking about.



Notice the silver part on the TT just infront of the seat? That's the part that slides out.
 

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Discussion Starter · #8 ·
Yep! Jay and me were up merli today doing trail work. Since I can't upload any pics I'll try to explain it as easy as possible.

Stand the bike on both wheels and keep the wheels straight.

Put a weight at the end of a string.
Tie the un-weighted end around the handlebar between your grip and brake lever.
Let the weight hang until it stops swinging.
Measure (parallel to the ground) from the center of the Bottom Bracket to the string .
This measurement is the magic number I'm looking for!

Thanks, Fahn
 

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eci
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2005 ironhorse sunday team. Medium
front to center is 15 1/4
super short 40mm stem, bars swept back about 3 degrees

J Rogan(j2) and i went to college together. Def a good rider. We will most likely cross paths, i'm coming home in april and plan on shuttling quite a bit. Has you ridden glen park(s-burg)?

Is the sunday going to be your diablo bike?
 

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You should be taking this front-center measurement from two places on the FRAME. Although a distance to handlebar is relevant on your bike, and changes that you may make to it, there are WAY too many variables to make what you are asking for of any use when comparing different bikes.

Stem length, bar angle, bar rise, bar sweep (both up and back), headset stack height, all will effect what you are asking for......unless the 'measurer' has the exact same set up for all of these parameters, it is near useless.

I would like to see a horizontal measurement from bb to center of headtube at either the top or bottom....that would make the most sense IMO.
 

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Discussion Starter · #12 · (Edited)
They're not useless. I'm asking for this measurement because this is the measurement I want to know...
Bar heigth and sweep are minimal measurements that can change just by rolling the bar or getting a diff one. A 1/4" is a lot less significant than the 2.5" difference in TT length between a Med SGS and a Med Sunday. Therefore the measurement I want to know is usefull to me and several others.
The HTA is the same on my bike and the Sunday. I'm using an integrated Marz stem. This means, in effect the center of the bar is relitively close to where my current setup is. The flat crown on the Sunday drops the front end down approx 1". The Sundays BB height is 1.2" lower than my current setup... This about equals out.
BUT!!! If the ETT is longer but not the "parallel BB to HB center" I'm looking for then I should still be comfortable in the cockpit. The question is do I want to go shorter, stay where I'm comfortable, or go longer? So far, the Med seems to compare within reason.

Edit- This is an argument not against you, but another website.

The measurement from the BB to the center of the HT is insignifigant to me in any way realisticaly. Here's why. If you use the BB as the fulcrum, the measurement to the HT can be the same on 10 bikes. But yet the HT can be out farther on one than on another. This is where my measurement comes into play. My version (and the standard) of the TT would expand, while your measurement stays the same. In theory, the BB would be getting lower and the bar staying relativley steady because the fork/stem/bar/HTA are consistent. Get it? Example #2. My bike feels like I'm "on it". I'm not over the top, but I'm not standing behind it. My buddy's Giant DH Comp feels (to me) like the bar is up to my chest and I'm standing behind the bar. Though that doesn't happen... I like the SGS feel better than the DH Comp. This is ALL personal preference.

davep

As far as a parallel measurement to the BOTTOM of the HT, it would make sense. Not the top. Just for the reason that the bar is more aligned vertically over the bottom of the HT and pushed out more in front of the top of the HT. Ttyl, Fahn
 
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