single speed front

[rokmnky]

Im building my first track bike on a budget and I was wondering what the disadvantages were of running a track single speed 42t crank. I would probably run an 11-32 9spd rear cassette to help make up the difference. This is my first cross season so Im not up to riding as hard as the big guys. Probably stick to cat 4 all season.

This would save me a bit of money not having to buy a deraileur and the crank being 1/3 the price of comparable doubles.

Also how would this affect my chain choice? Would I still run a normal 9spd chain? Is there something Im looking over?

I'm also looking for a fork to fit a K2 enemy frame if anyone has a cheaper(under $50) laying around. 1 1/8 headset and it has a rather long headtube.

[Hein]

Using a trackring is possible, done so myself with a 10 speed chain. Even 11 speed seems to be possible.
However, the chain won't stick to your ring in bumpy terrain, or when the chain is on the inner or outer cogs, when you don't use a frontderailler or chainguide or chainwatch of some sort to keep the chain in place.
Search the forum for these solutions. And yes, they cost money, but you can't ride CX without some sort of chainguidance in the front.

Have fun building and riding a CX!

[Taocat]

I'm building up a cross bike on a budget this winter too and was considering the same thing - going with a 1x9. My xc race bike is a 2x9 with 44t big ring (29 small) and an 11-28 cassette (although I think I'm going to go with 11-32 for next year). I did 2 cross races on that bike and never needed the small ring. I was considering a 48t chainring with a 11-32 cassette for racing cross (in Nebraska). My main concern is with clearance on the frame I'm considering (Nashbar X found cheap on ebay) but I figure that's a frame-specific issue.

[lancejohnson]

I see no reason that the 42T wouldn't work, but then you need to sort out what you're going to do for chain retention on the chainrings - if you don't have a guard of some sort plan on stopping a lot to put your chain back on. I use the K-Edge outer guard and their clever single ring cx inner catcher which has a finger that goes over the top of the chain to keep it virtually as secure as double guards. There is a faux front derailleur setup from Paul and some other similar things, but I tend to prefer the guard solution.

A quick thought is that the Rotor 3D crankset may be a good solution for you - you can change the spider to a 144 track bcd when you want and use a regular 130 road setup for cross. Our team has been using them all season and they are a fantastic crankset...

As for your cassette - probably overkill in the range and more likely than not you'll have a hard time finding the 'right' gear. Try something like a 12-27 or 12-28 for starters. On my single ring I have a 40 or 42T and an 11-26 usually.

[nitropowered]

42t with a 11-28 or 12-28 is more than plenty.

48t is way too big. Pro's generally run 46/38 with a 12-25. But with a 32, you might be ok

[Taocat]

42t with a 11-28 or 12-28 is more than plenty.

48t is way too big. Pro's generally run 46/38 with a 12-25. But with a 32, you might be ok

You're probably right. A 46 is probably sufficient. I raced my xc mountain bike with a 44 and it's not like I was topping out. Even with a cross bike I doubt I'll be under-geared!

[vcnz]

My main concern would be the rear derailleur.
I think the cage of a rear derrailleur for road bikes is too short for a 32t, perhaps it works but if you have to buy one, I would go for the mtb version.

[lancejohnson]

Seriously, no need for anything bigger than a 28 in the rear. If you can't fit it with a road derailleur, you shouldn't put it on a cross bike - it'll probably be faster to run...

Most of the single-ring racers I know change out their chainring when they want a lower end rather than messing with a wide cassette where they can't find a gear that they feel comfortable in.

[vcnz]

Seriously, no need for anything bigger than a 28 in the rear.....

I totally agree, I've a single 42T and the sprocket with 27t is more than enough

[megman]

Seriously, no need for anything bigger than a 28 in the rear.....

I totally agree, I've a single 42T and the sprocket with 27t is more than enough

don't know what your courses are like but I am on 42T with a 26 largest sprokets and need smaller gears. Most people over here appear to be using compact chainsets so a 34 or 36 smallest at the front.

[Colin]

a 32t cassette will fit with a road derailleur, but you might need 10t pulleys. Either that, or I've heard that putting the 'b' screw in backwards works.

[XCProMD]

To avoid chain from jumping off the chainring I'm currently using this:



54 grams, works great, looks gorgeous