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So I'm contemplating building a cross bike, it seems you can get a better equipped bike for about the same money. Having never ridden cross / or up a bike before I've got some totally noob questions.

First off, when it comes to cranks, what length is recommended, is it just personal preference?
I see most of the cross specific bikes come with a smaller chain rings as well (39/48T) when I'm looking at cranks, most seem road cranks come with larger rings, 53/39, should I be looking for cross specific cranks? Are all front derailleurs compatible with these closer chain rings?

I think that's it for my first round of question... thanks,
AO

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Crank size - mostly preference, somewhat tied to height. If you have other bikes, use them as a guide. I'm 5-10 or so and usually ride 172.5 or 175 mm.

You should be able to get the right chainrings for any road crank. But it's usually cheaper to buy something like FSA's Gossamer cross that's already setup.

And other potentially moving the front derailleur down a little it should be fine.

Good luck with the build. Post if you have any more questions.
Thanks for the nearly immediate response. I've been trying to do my research first, as to not buy incompatible parts. Preparing to do ebay & craigslist shopping. I'm sure I will have a ton more questions, but for now, I'm just trying to sort out all the bits I need so I can make some sense of it all.
Here's another noob question, I also see most bikes are using brifters, how do the top mounted brakes work? do you have to have brake cables under the tape?
AO
The top mounted levers meet the cables where they come out of the tape. And usually your brake cables will be under the bar tape. You would need a break in the housing where it meets the lever, just the inner cable goes through. But keep in mind that those levers are optional, personally I don't use them.

Keep the questions coming. Happy to help.
hey AO,
JMack's right on with the crank recommendations. You can always swap rings if you have something around or buy something cheap, but you'll never need something like a 43. If you can find a cheap 46 or 48, you can throw that on a road crankset. Shifting may be a bit funky though depending on whether the ring was made for 8,9,10 speeds and has ramps or not. Keep in mind, you can't go lower than a 38 on a shimano/130 BCD (bolt circle diameter) crank, or a 39 on a campy crank (135 BCD). That's why many folks like compact cranks (110 bcd except for Campy) so you can go lower. But you'll still prob need to replace at least one ring. If you can find one with a 36 small, then you can just replace the big one. 34 is quite small for most folks. But as Jmack said, often cheaper to find a 'cross crank than buying a ring - fsa, truvativ, ritchey have them.

if you go old skool square taper cranks, or even octalink/isis, keep BB length in mind - some cross frames are a good deal wider than road for mud/tire clearance, so you may need a longer BB.

have fun with it. building a bike from scratch isn't always cheaper, but you probably will learn a lot more and end up with a unique bike that you'll feel attached to...(or hate...if it doesn't go well) :-)

What's your target budget I'm curious? We have a cheapo bike project coming together, but the rule for that is that every part has to be new. It gets quite expensive!
"(110 bcd except for Campy)" is COMPLETELY wrong. Campy's compact is 110mm just like everyone else. Their standard cranks have a BCD of 135mm. I know because I have Campy CT cranks on 3 of my bikes.

I just finished my CX build project last night. But mine is geared to be a commuter first. I'm not a big fan of the Gossemer cranks, simply because I've seen and heard of too many of them falling a part. Nothing serious, the bolts just lossen up and plop. To me the ultra torque system on Campy and Fulcrum cranks just make more sense than anyone else's. Specialized has copied the design now. You can get a Compact crankset with 50/34 rings and it will give you a broad range to start with. But you can always get 46/38 rings from TA for FSA if you want a traditional set up. I bought my frame off Ebay for $200 and after all is said and done with I spent $700-$725. But the wheel are off my road bike, so $925-$950 is more accurate. But I have a full Campy drivetrain. If I lived in Europe, it might not have cost me so much. Oh well.
Rich, you're right, I oversimplified things. But it's not completely wrong though. Sorry, I should have been more clear. For the older square taper alum cranks, you're prob fine. For the newer carbon compact cranks, and I think, all ultra-torque compacts (carbon or alum), there is a proprietary BCD which is 110mm/112mm. What does that mean? One bolt is at a strange 112mm BCD, so unless you wanna modify one hole of a normal chainring with dremel tool or drill, normal 110mm chainrings won't fit. You can tell if this will be a problem if there is the hidden chainring bolt. You can buy Specialties TA rings for these cranks, however.
Nope, you were right and I owe you an apology. I have a set of square taper Centuar alloy cranks I put an aftermarket SS chainring on. I did not know about the 1 offset bolt hole. I check my '07 Centuar CT UTcrank, and my new '08 Mirage CT UT, and they have the one offset bolt hole. Appearently this is referred to as "Campy compact". I am very use to people being ignorant of Campgnolo's line and saying just stuff because it's what they heard. My apologies, and thank you,

Rich
So basically, there are road cranks, 'cross cranks, and compact road cranks. Are there limitations for compact cranks? As in, I can't go over a certain size? I did see a local guy selling a set of truvia elita cross cranks for $50, but I'm not sure it's a deal. (If he tosses in the bottom bracket maybe)
As for the rest of the components, I'd like to stay shimano or sram to simplify my garage, my road bike is a specialized allez comp, w/ 105's, and it might be nice to have a usable parts bin for both bikes, but I'd settle for cassettes / wheels being compatible for the time being.
I don't have any budget currently, would you like to buy a motorcycle? I'm planning on selling my motorcycle to fund this adventure, all said and done it is between 1250/1750. It really depends on how much I get for it, and how good a deal I can find on some of the major components. I could buy a decent bike for that price off the shelf. The LBS has a 2009 Redline Conquest for 1199, But I'm not terribly impressed with the components at the low end. at the 1750+ price point the bikes are _much_ nicer equipt. However that's stretching my non existent budget as is.
I know, but being a gear geek (computer, car, motorcycle, etc) makes me really interested in knowing the ins and outs of what components there are, and getting the best bang for the buck.
What is the budget for the 'cheapo' bike project? Where are you starting for a frame?
Thanks for all the feedback.
AO
There aren't so much different cranks as there are different bolt circle diameters and chainring sizes. Chainrings in the correct ranges for cross are available for most road setups. Both standard and compact road cranks are fine for cross with the right rings. "Cross" cranks, are simply road cranks with the standard cross size chainrings already installed.

Redlines are good bikes, good values and are some of the more common cross rides. Personally I ride a Van Dessel Holeshot, and I have been very happy with it.

Component wise I have Ultegra drivetrain with Mavic Ksyrium Elite wheels. I don't think I would go lower than 105 with Shimano. But 105 could be a good starting group, upgrade as you go.
If you're a techie, then your like me, and maybe this will be of interest. I'd stay with the Shimano/SRAM route too, if I were you. I'm a Campy guy and I started with a blank frame so it was logical choice for me. You can get CX sized rings (39/46ish) through TA for standard Campy easy enough. "Campy Campact" you can too, but no one is stocking it. Miche makes rings for campy too, but no one carries their road rings in those sizes in the US. But I was told they could get them by a distributor. The advantage is I have more than enough confidence that my Xenon/Mirage parts will hold up, where as I don't feel anything under 105 would, but for cheaper than 105. And remember most big name after market wheels can be converted between the 2 standards. But Campy Khamsin wheels are going cheap in some places right now, and they are comfy and tough as nails.

Either way it took me year to get my build done so no hurry.
Have fun!

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