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  #1  
Old 09-28-2015, 07:50 PM
Netdewt Netdewt is offline
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Cross vs Road fit

I am looking at buying a cross bike, but have never owned one. I have just this week learned that they are fit differently.

Could you guys help me determine if a size 56 CAADX 9 will fit me?

I am attaching the geo chart for the CAADX and I measured everything listed on my current road bike. The only thing I couldn't measure or calculate is trail.

Quote:
Moser geo:

A 56
B 56
C 73
D 72
F 41
E 4.1
G 27
H 99
I ?
J 80
K 7
L 59.5
M 13
N 54
O 40
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Last edited by Netdewt; 09-28-2015 at 07:58 PM.
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  #2  
Old 09-28-2015, 07:54 PM
Netdewt Netdewt is offline
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Attached is a pic of the bike I took measurements from. I used Photoshop for angles.

I also have an All-City Space Horse size 55 that fits but has a considerable number of spacers. Geo: http://allcitycycles.com/bikes/space_horse
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Last edited by Netdewt; 09-28-2015 at 08:00 PM.
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  #3  
Old 09-28-2015, 09:24 PM
ultraman6970 ultraman6970 is online now
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IMO if the moser in 56 is ok for you then 56 caad is almost the same than the moser. Did you test it already?

Last edited by ultraman6970; 09-29-2015 at 08:07 AM.
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  #4  
Old 09-28-2015, 09:32 PM
Netdewt Netdewt is offline
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I'm sorry if my posts are confusing.

The Moser 56 is good. But I was told that cross bikes should be downsized?

I can't try the CAADX it's in Maine and not built. I don't know anyone local with one.
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  #5  
Old 09-29-2015, 08:19 AM
ultraman6970 ultraman6970 is online now
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Not sure , 1st time I heard about that, but there is a reason you mount and dismount CX style too.
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  #6  
Old 09-29-2015, 09:56 AM
sandyrs sandyrs is offline
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Don't listen to that stuff about cross bikes being downsized, it may have been true once but certainly no longer is with the geometry of many modern cross bikes. Unless your road bike is sized old school with a fistful of seat post (yours isn't) you don't need to worry about sizing down.

That 56 caadx will have a much taller front end that the Moser (when you look at the headtube length, consider that it's effectively 3cm taller than a road bike's because of the extra fork length) but it looks like with the quill stem where it is, the bars will be at roughly the same place on the two bikes since the bottom bracket drops are within 3mm. A bit of extra bar height on a cross bike can be nice for shifting your weight to the rear of the bike when the course calls for it too.

Last edited by sandyrs; 09-29-2015 at 10:13 AM.
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  #7  
Old 09-30-2015, 07:42 PM
TBLS TBLS is offline
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Pay attention to the standover, especially with Cannondale. Sizing is of course highly personal; I have a 56 caadx, works great for me even with a 1.5cm shorter top tube and 1cm shorter stem vs my 'racier' set up road.
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  #8  
Old 09-30-2015, 10:07 PM
Netdewt Netdewt is offline
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Thanks for the input. I went for it. This was a good exercise for me in comparing geometry.

There's no certainty that I'll actually be riding cross. I don't know how you get into it honestly. But I should have a few cm to spare on standover, and the geo was so similar, I decided to just do it.
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  #9  
Old 10-01-2015, 01:33 PM
Oregonic Oregonic is offline
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With the exact same seat tube angle, and the exact same eff top tube measurement (assuming the Moser numbers are totally accurate) you can get your saddle in the same spot, which is most important. And you can (theoretically) set your bars up for the same reach, or at least close.

Then play with your bar position. You might find higher (and perhaps shorter, accomplished by changing the stem) more practical for cross racing. It reduces your front end weight, and can help keep you from washing out.

As for standover, I find most of these charts to be pretty inaccurate, as tire model and size can make a big difference.

And in terms of rake, etc. - I'd just trust that Cannondale has done their homework and set the bike up correctly.

Hope it works out!
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  #10  
Old 10-08-2015, 08:17 PM
gjc985 gjc985 is offline
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I have the same size cross bike as my road bike, but my saddle is a tad lower on the cx bike. I don't think you can really go wrong if you go same size or one size lower. Stay away from getting a larger frame.
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  #11  
Old 10-18-2015, 11:59 PM
DFABob DFABob is offline
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Back when cyclocross racers were still using toe cages bikes were made with high bottom brackets to avoid pedal strike while remounting.

Here are some bike manufacturers making bikes with high bb drop, that will fit and ride more like a road bike. Bianchi, Stevens, Santa Cruz, Trek, Gary Fisher.

Source: http://www.cxmagazine.com/bottom-bra...ike-geometries
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  #12  
Old 10-29-2015, 10:51 PM
11.4 11.4 is offline
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Here's a broader way to think about it:

1. To race cross, you have a couple matters to consider with regards to the top tube. First, you want enough room at the front of the front triangle to stick your shoulder when you pick up the frame. And if the top tube has serious slope, it wants to slide off your shoulder. Second, if you want to do a rapid dismount, you want to have the top tube convenient enough (i.e., right height) so you can grab it with one hand and do a running dismount. When you do that, many/most riders like to just pick up the frame at that point of the top tube and carry the bike -- they've gotten a lot lighter than when you really needed your shoulder to haul them up a hill. Now if you have too much top tube slope, or your frame is so small that your top tube is way below you as you dismount, you aren't going to be able to reach it and dismount effectively.

2. All of this means you don't really want to go to a really small frame or not necessarily one with a lot of top tube slope. This is why Belgian cross frames tend to be big with horizontal top tubes. Or you need to train without the full range of rapid dismount options.

3. If you have a smaller frame size, things like sloping top tubes limit the room for bottle cages, and actually constrains both seat tube and down tube cages. If getting it built for you, have the seat tube bosses installed so the bottle is right down at the bottom of the seat tube (under the down tube cage rather than on top of it). Sure, there are side-entry water bottle cages, but they are just that much easier to pop out when you don't want them to, and whether in cross or in general use, you really want access from either side with either hand.

4. Also in smaller frames, if you get the frame with a 44 mm head tube and a tapered fork steer, remember that you can't make the head tube shorter than the length of the taper, which for Enve is about 8 cm or so. You already have a head tube that's effectively long because of the greater hub to crown distance in a cross fork, so if you want a low position or are on a small frame, you don't necessarily want a particularly tall head tube. This then means you have to raise the seat tube to keep the saddle to bar drop a constant measure. And that in turn means you are raising the bottom bracket.

5. Don't worry about standover height. I hear people still complaining about it, even when they already tilt the bike over a bit to put a foot down.

6. Don't worry about toe overlap at the front wheel. It's the last measurement to give priority to when planning a custom geometry. More bad bikes are designed around toe clearance and in truth, I have a good 3 cm overlap on all of my bikes and I occasionally brush the front tire as I dismount but not while riding.

In short, recommendations to downsize frames are irrelevant. Depending on your frame size, you may have some extraneous constraints, but generally, fitters and even builders often don't take into consideration issues like reaching for your top tube for a running dismount, or getting a low enough position on a small frame without running out of head tube, or using a sloping top tube to lower standover height but losing a frame that shoulders well. You basically want to shoulder the bike or you want to carry it with a hand in the middle of the top tube. Shouldering is the traditional way, but it evolved for bikes that were really heavy and somewhat bigger than we need today (thanks to nothreadset headsets in large part). If you watch the fastest riders, they tend to do a running dismount. If you can do this you want to pay attention to having the top tube high enough so you are grasping it as you swing off the saddle. Everyone does this a little differently, but it comes down to a need in designing a cross frame to consider exactly how you'll race and dismount. If you're doing a gravel frame, I really like to be able to do a rapid dismount because it's an escape route if you start to slide in the gravel or lose traction on a steep uphill. And on a gravel frame I want enough room inside the main triangle to accommodate water bottles plus the option of a small frame bag. Add a frame pump if so desired on the gravel bike and that's even more room needed inside the triangle. Even on a big frame, it goes pretty fast, and you have to remember that that tall cross fork basically reduces your main triangle size pretty rapidly. If you want a nice low bottom bracket on your gravel bike, you are shrinking the triangle (and your head tube) even further.

So anyway, these are just a few observations that might help your geometry planning. It's always fun to be told what you can't do, isn't it?
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  #13  
Old 10-31-2015, 05:59 AM
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BdaGhisallo BdaGhisallo is offline
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Lane,

You always offer excellent advice and thorough input on this and every forum you frequent. Thank you for your contributions.

Geoff
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"Progress is made by lazy men looking for easier ways to do things." - Robert Heinlein
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  #14  
Old 03-22-2016, 03:56 PM
Powerfibers Powerfibers is offline
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Many people might ride the same cross and road sized frame. However, Cannondale (OP mentions the CAADX) runs big. I ride a 54cm Trek Madone but a 52cm CAAD10 and a 51cm CAADX. They are seem the same size to me. The 51cm CAADX has a much taller head tube and sits taller that all three.
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  #15  
Old 05-18-2016, 02:42 AM
Vera J. Hogue Vera J. Hogue is offline
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A lot of hype concerning the difference between fitting a road bike and a cyclocross bike could be cleared up if we all agree on two simple things: put the engine in the right place, and then adjust for handling and comfort. Let’s break this down.
Saddle position
Your pedals are driven by large muscles surrounding the trunk, hips and knees. In fact, about 98.8% of the force you deliver to the pedals comes from your hips and knees.
Handling and comfort
‘Cross bikes typically have a higher bottom bracket. If you were smart, you’d kept your saddle in the same place as your (properly fitted) road bike. This means that your saddle is higher in the air than your road bike. Since your saddle is higher, your handlebars also need to be higher.
It’s simple really; the goal is to get the bars a bit “closer” to you. And you can do this in three different ways. You can run a shorter stem to move the bars closer, you can run your bars higher (by putting a few spacers under the stem or by using a stem with more rise), or a combination of both.
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