stover
Member
Hi All,
I have a deposit down for a Vamoots frame in 54cm. I am moving from a Specialized Roubaix and need to keep my stem (8 deg) height the same on the Moots. In this case can I get to approximately 38 inches (floor to top of bars) with the 15cm HT on a 54cm Vamoots frame (with a CK headset) Should I have the head tube changed to something like a 16 or 17cm so I can get to the bar height I need without having to use lots of spacers. Thanks for your help.
-Stover
tbill
Member
Hard to say without more info. There are a number of variables that can affect the relative height of the handlebars. A big factor that a lot of folks forget to take into account is bottom bracket drop—a lower bottom bracket effectively lengthens the head tube, and vice versa. So if the bottom bracket is lower on the Vamoots than on the Roubaix, then the handlebars may be closer to the floor but, all other things being equal (which of course they generally are not), the saddle-to-bar drop will be the same. Another factor is stem length—the longer the stem, the more the rise (assuming that you have your 8º with positive rise). Other factors include the axle-to-crown height of the fork, the stack height of the headset, and the number of spacers that you are using.
Personally, if I were starting from scratch, I would try to solve for the headtube height I wanted assuming a -6º stem (just because I prefer the way it looks vs. a positively sloped stem) and approximately 2cm of spacers. To get there, I would think that you would need a slightly taller headtube, in the 16 - 17cm range that you mention. I measured two bikes, both with 8cm of bb drop and 110mm stems, but one has a 16.3cm headtube and the other a 17cm headtube (the fork and headset heights are roughly the same). They both have handlebars close to 38" from the ground. The one with the taller headtube has 2cm of spacers. If you stick with the 15cm headtube, you could probably get there with an 8º rise stem and/or more spacers, but I think that a modest headtube extension would be the better way to go.
If you want to get a more precise rendering, plug the numbers in to BikeCAD, or ask your Moots dealer to do a mock-up in BikeCAD for you (they should be able to do this easily). My recollection is that Moots didn't charge extra to extend the headtube, but Jon should be able to confirm.
stover
Member
After looking into things more. The BB drop is 2.8 mm different. Using the CK headset with a 150mm HT. It should give me a HT of 181.4. My bottom of my 8 deg stem is at 207mm ( from botttom on HT) so I should have 25.6mm (~1in) of spacers. I think this will work for me. I am going to use the 6 deg I think will meed the 16cm head tube.
stover,
On the Vamoots as you can see we run a bit longer headtube vs. the CR and RSL...more upright, less spacers etc...We extend the head tube above the top tube by 2.5cm on the stock sizes. On the others (CR & RSL) it's 1.5cm. We don't like to go more than 2.5 above the top tube for a couple reasons....first and foremost, the more extension above the top tube the harder it is to keep the head tube from warping as we weld it...second, it just plain looks bad to see so much head tube above the top tube. In the 54cm it runs the 14cm head tube with the 2.5cm above the top tube. To go to the 15cm head tube we would be at 3.5cm above the top tube....not good for welding....not good on the eyes.
So in this case we would want to bring the top tube up on the head tube, thus needed a custom cut. The top tube would also have slope to it.
Food for thought for sure. What Moots dealer are you working through?
Let me know if you have more questions..
Thanks,
Jon@Moots
stover
Member
Jon,
Thanks for the reply. I am working with Palo Alto Cycles in CA. I was told I could switch to a 15cm HT from the 14cm because it was a common upgrade/request. I know it deviates from the standard Vamoots frame geometry but my back just wont bend that much so I have to get the stem and bars up to a manageable height for me. The 15cm HT will put my bars just about where I have them on my current ride, so I think I should be ok.
-Stover
Mootsy Collins
Member
Jon,
I'm in the same boat. I just ordered a 54 cm with a 15 cm head tube, but now you have me concerned. Are you saying that if I pick this option I would have a warped head tube or are you saying that when a 15 cm head tube is requested you raise the top tube and add slope to it so that these issues are eliminated. My Moots is only 4 weeks out....so I need to understand this before it is too late to change it. If a 15cm head tube on a 54 cm is a bad idea why is it an option? This is a big purchase for me so I want to get it right. Thanks for your help.
tbill
Member
Pre 2010, it was a common request to add a cm to the headtube (and from what I undestand, it was the frequency of the requests that among other things prompted the introduction of the new Vamoots geo).
It sounds like on of the changes in the geo of the Vamoots beginning in 2010 (along with angles, bb drop, etc.) was to add extra extension to the headtube. From what Jon said above, it's possible to get a taller headtube height than the stock geo, but it would require custom cutting because the top tube needs to be raised. Jon, is that right? Would it incur a charge for custom?
P.S. MC, love the name! "Ahhhh, the name is Mootsy, baby! Diiiiig!"
We already have a Moozilla...
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