Mike552

Can I do it?

I don't know anything about cross bikes except for what I was able to pick up in this forum.
Perhaps if I state the current build sheet of my rig, then you guys can tell me what is need to be changed??

My bike is a heavily modified 2007 Jamis Aurora built our of Reynolds 520 steel
Fork: Stock chromoly
Headset: Crane Creek threadless
Shifters: Ultegra 9 brifters
Crankset: Truvativ Roleur Compact Double, 34/50
FD: Ultegra
RD: An old 7spd RSX long cage out of my parts box
Brakes: Tektro Oryx Cantilever
Wheel, front: Mavic MA3, 32h, laced to 105 hub
Wheel, rear: Campagnolo Omega 19, 32h, laced to Ultegra hub
Tires: Bontrager Select 700x28
Saddle: Brooks B17, chopped
Cassette1: 12-25 9spd
Cassette2: 11-34 9spd (I use this one when I am towing the kid trailer... I live on a street with a substantial incline so the 34T is mainly to avoid the humiliation of walking up the hill after a long ride)


Besides some beefer tires, is there anything else I need?

knobster

Change the tires out to some cross tires and ride the hell out of it.

Mike552

And what about gearing? Should I use the 12-25 or 11-34 with my compact?
(the 11-34's second larges cog is a 28T)

justinb

If you're racing, you'll appreciate the closer ratios of your 12-25, and won't need a gear bigger than 34/25 anyway. If you intend only to make it more dirt worthy, than maybe the 11-34 would be useful for some steeper offroad climbs.

Also... if you end up racing and running the 12-25, but have enough chain for the larger cassette and big front chainring, you may find that it drops. In this case, you'll want to shorten your chain. You may also find that 50 is a touch too large and 34 is a touch too small for cross racing. At this point, you can spend a couple bucks on a 110bcd ring in the 40ish range, and a couple bucks for an inexpensive chainguard, and then stop worrying about shifting in the front.

Mike552

gotcha. so you guys are big fans of single chainrings from what i can gather. eh?

knobster

Yeah, if racing I would want a single up front. Put a bash guard on it and you're good to go. I like the 12-25 cassette. Depending on your course, you may want something like a 38/39 up front, or a 42/44. Those are really easy to change also.

justinb

I am. I ran my first season of cross with a 46-38 combo... by the second race, I don't think I shifted out of the 38 for the rest of the season. My next setup was a single ring 42... worked better, but I found I preferred a 40, just based on where in the cassette that placed me for most situations. We have dry fast 'cross here, but I was still never spun out in 40-12.

The main reason I would encourage you to go to single ring for racing is that you'll almost never have a use for a 50t ring. You'll probably find 34-12 too small a weapon for long fast straights or sprints, and you'll also be massively crosschained, and probably rubbing on your 50t if it's still on there. With the 110bcd, you've got all kinds of options in rings. bbg bashguard is a good source for inexpensive chainguards. To prevent chaindrop on the inside, buy a jumpstop or 3rd eye, or just limit your existing front derailleur.

Mike552

Thanks, all great advice thus far...

I have a spare DA7700 crank that I will modify to accept the single 39 ring and go from there...

Any more advice for a newbie???

justinb

Get ready for you upcoming addiction. 'cross racing is the crack-cocaine of the bicycle world.

M_S

Do your first race on it as-is, with the 12-25 cassette. My first couple races were on a 2007 Aurora with bar-end shifters, stock gearing, and obviously different tires.

If you really get into it you'll want a different frame. For example, the Aurora has pretty measly chainstay clearance. Test the tire before buying if you go wider than a 32.

But with a tire change it's 90% there to being a cross bike. Ride it and see if you liek the sport. I liekd it enough to buy a real cross bike a month or two later.

sfcrossrider

Is that why my teeth are falling out?