What is difference between these two? I'm not an MTB'er or a CX'er but these two appeal to me a an all arounder. I'm a roadie that occasionally will ride a dirt trail or tame single track. My goal isn't to come back from a ride covered in mud. But, I'm not opposed to it either.

A '29er wheels are just that 29 inch in diameter and the cross wheels are 28 inch. Having built a semi-cross bike myself go with the cross bike. It is hard enough to turn a 28 inch tire going uphill than a 26 inch mtb tire; think about that.

Cross man.

Ah, not exactly. First, a 29er mountain bike actually is running the same size 700c wheels as most road/cross bikes today. In fact, many of my buddies who run 29er mountain bikes run high end road racing wheels, no problem. So, don't get confused betweein 29 and 700, we are talking the same thing here.

Second, its not necessarily harder to ride a larger tire up a hill (that seems what rmwun54 is saying). If that were the case, we'd see all the guys in the TDF running 12" wheels like our kids run. Now, it is harder to overcome the starting resistance etc of a larger wheel, but once you have the wheel rolling, its faster and in fact, a larger wheel has a different angle of attack on offroad obstacles so it in fact rolls over obstacles like rocks, logs etc more easily than a traditional 26" wheeled mountain bike.

Don't believe me, go ride them if you can. I've ridden mountain bikes, 29ers and cross bikes, all off road. Trust me on this.

Now, given your desire to ride a dirt trail or tame singletrack, likely I'd get the cross bike. Otherwise, you'll have a bike that is slower on the road due to being heavier, larger rolling resistance with bigger tires etc. Now, if you end up getting into the offroad thing, riding more trails, riding in the mud a lot etc, I'd go with the moutain bike setup--as a 29er.

One option is to buy a Surly Karate Monkey frame--you could set it up as a mountain bike with suspension fork etc or set it up as a cross bike--it take 700c/29er wheels/tires just fine.

check out www.surlybikes.com

have fun

Thanks for the info. As a side note this. What are some good CX frames that accomodate disc brakes?

I know Redline and Cannondale have disc spec'd models, beyond that, not sure to be honest. I'm fairly new to CX as a long time mountain biker. Good luck.

This is mine - 2004 Salsa Las Cruces:

On a side note off the side note about Surlys. How much do they cost? I've yet to see any price list anywhere. (Info on the Crosscheck in particular.)
Thanks,
scott

do some searches here, I think I recall seeing discussion about pricing in the 800-900 range or if you go full 105 maybe a couple hundred more? They are a very cost effective route to get a good cross rig.

https://www.sheldonbrown.com/harris/s...oss-check.html