My stack is 510 and reach is 405. Deciding on a trek speed concept size. Tested on a small it was comfortable. My numbers are in between sizes. Go for the smaller frame if it’s comfortable?
What distance are you racing? short course or long course? Comfortable is a relative term.
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What distance are you racing? short course or long course? Comfortable is a relative term.
short to start with
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Generally speaking the smaller bike will be lighter / more aggressively fit if you are truly between sizes. If you intend to do longer rides though it may not be comfortable.
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Trying to wrap my head around the science. So if my stack is 510 and bike size has a stack height of 520 that doesn’t make it too big?
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It depends on what numbers your fitter is using. When you look at the stack height on a bike company’s website they are referring to the height of the actual frame (without using spacers or taking into account different arm pads etc). Some fitters use what can be referred to as “effective stack height,” which is the stack of the bike after you add spacers, arm pads etc.
Because two different brands of bikes may have identical stack heights but use different arm pads etc the “effective stack height” could be different. Does that make sense?
You could use a bike with a lower stack and higher arm pads or a bike with greater stack and lower arm pads.
Are these your bar x,y coordinates? Or your pad coordinates?
Did you come away from that fit session with anything more than frame stack and reach #s? How about armpad stack and reach? For SC purposes, the latter is the best way to start the process of choosing a size. A frame stack of 520 (or 517 for a Medium SC) may or may not be “too big” depending on whether or not your armpads can get to where you want them on that frame size. As others have noted, the frame #s by themselves aren’t of much use unless you intend to use exactly the same handlebar setup as was used in your fit session…or, put another way, a handlebar which is able to duplicate the pad position you ended up with on the fit bike. Not all bars can do this.
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Did you come away from that fit session with anything more than frame stack and reach #s? How about armpad stack and reach? For SC purposes, the latter is the best way to start the process of choosing a size. A frame stack of 520 (or 517 for a Medium SC) may or may not be “too big” depending on whether or not your armpads can get to where you want them on that frame size. As others have noted, the frame #s by themselves aren’t of much use unless you intend to use exactly the same handlebar setup as was used in your fit session…or, put another way, a handlebar which is able to duplicate the pad position you ended up with on the fit bike. Not all bars can do this.
Carl, here is what I have:
Saddle height: 69.5
Saddle height over bars: 3cm
Saddle to handlebar reach 38.5cm
seat angle -3.5
saddle fore aft(cobb V-flow plus)
Stem Length - 100
stem angle 0
I don’t have an armpad sack and reach.
I’m most interested in if a small Trek 2012 speed concept would be completely wrong for me. I have a line an a brand new old stock size small Trek.
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This is, unfortunately, a great example of what Slowman was ranting about in this thread. Please don’t take it personally…it’s not about you…it’s more about the frustration with fitters who don’t give people like you what you really need to answer this sizing question…not just for an SC, but for ANY bike. I’m going to end up with barely more than a WAG because there’s just not enough (of the right) information to run with.
But I’ll try 
Saddle height is useful, but mostly as a sanity check on the frame size that your pad coordinates would determine. In my database there are people with saddle heights within 1-2cm of yours who are on XS, S and M Speed Concepts…but the majority are on Smalls.
Handlebar height is nice to know, but it doesn’t say anything about how high your pads are above the bar. The #'s you’ve got here are tough to interpret…69.5cm saddle height minus 3.5cm saddle-bar drop is ~660mm for bar stack (assuming the fitter truly measured to the bar, not to the pad, and yes I’m neglecting the seat tube angle for ballparking purposes)…that sort of bar stack is only really possible on an XL SC with the tallest stems. Even if that’s actually a pad stack number in disguise, a Small SC tops out around 670 and a Medium would be nearly maxed out too. Do you remember looking at the fit bike afterwards and noting that there was almost no difference in saddle height and pad height just by eyeballing it?
Saddle to handlebar reach is about the same story as above…says nothing about the pad reach. No setback # listed either. Again, pretending for a moment that 38.5 is to the bar (center?) and not the pad, on a Small SC 9-series your pad center could be anywhere from 4.5cm behind the bar to almost 16cm in front of it. If it’s a pad reach # in disguise, all SC sizes except the XL can theoretically hit it…but the XS hits it in the sweet spot and the Small would be next best.
Circling back to your original post and the frame stack and reach you ended up with, my first thought was a Medium might be the better starting point…but after going thru the exercise above I’d say a Small might make more sense when it’s all said and done. Can’t say it’s completely wrong…can’t say with any confidence it’s going to be spot-on either. If you have the opportunity to spend some time with a Small before you buy, and see if it can be adjusted to where you want your pads to be, then you’re giving yourself the best chance at making an informed decision.
When you go to test ride your speed concepts do not be afraid to test ride the bike for some significant portion of time. When I first bought a bike I would test ride it for like 10 minutes max because I felt like I was overreaching if I did any more.
If I were buying a new bike I would either test ride a medium for a weekend and then a small for a weekend if the store allows it or do a 2-hour ride. 1 hour with the medium and 1 hour with the small.
Have you ever ridden a TT bike before?
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Thanks Carl!
And no, I haven’t ridden a TT bike expect for on a trainer and around a parking lot. A longer test ride would be great I’m sure.
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I would go out and ride a few brands for a bit to see what you like and what you can handle. Deciding to purchase a smaller bike because it is more aggressive, and generally thereby more aero, sounds like a good idea until you do a 2.5 hour training ride and hate your life. LOL. I am not saying this WILL happen to you I am just saying that you should take your time.
I was told to go with a bigger frame and then I decided to go with a smaller one. It was great when I started out for Olympic and Sprint triathlons but when I progressed to longer workouts I had to sell it on Craigslist and purchase a more comfortable frame.
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So I’m thinking my fit may not have been as thorough as it could have been. We never even adjusted the bars or pads.
I don’t know what the saddle to handlebar number is exactly. I’ll have to ask the fitter. Wouldn’t the saddle to handlebar measurement be more than the reach? As I understand it the reach is the distance from a vertical line of the bottom bracket to the head tube?
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Yes it would be because you can adjust where the armpads are using a few mechanisms. First, the stem obviously increases the reach. Next, the entire armpad structure may be movable forward and back. And third, some aero bar setups allow you to move the armpads forward and back. I know those two sound the same but they are different. Its hard without a picture.
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so does it make sense that my saddle to handlebar lenght is less than my reach numbers?
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I do not think that it saddle/handlebar depends on your frame reach. The handlebars could be farther or closer because of a stem change and the seat could be farther or closer to the BB depending on where the fitter put it.
What kinds of bicycles does the fitter sell?
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Trek/Felt/Cervelo
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I dunno. Its hard to say what you should do without all the details. Personally I would go and test ride the two sizes and see what you like. When you test ride though, like I said above, do it for a long ride (at least 30 minutes) not for a very short period of time. I would be comfortable on anything for 5 minutes.