Cross Gearing: Just curious

[Possegal]

It is threads like these that remind me how very little I know about biking.

[anakiwa]

I put a 46-34 and 11-34 on my new bike and love the gearing. I don't race so my needs may be a little different, but I love the wide range this gives me.

[Andrea]

It is threads like these that remind me how very little I know about biking.

I used to get confused about the same thing! Maybe this will help...

The bigger numbers we are talking about are the size of the front chainrings (how many teeth they've got):
-A standard road bike usually has a 39 tooth small ring and a 53 tooth large ring.
-A road bike with "compact" gearing will usually have either a 34 or 36 tooth small ring and a 50 tooth large ring.
-On a bike that goes off-road, you usually want lower (or "easier") gears that allow you to spin faster to get through tough spots (mud and/or hills), so a lot of people go with compact cranks that have fewer teeth than what you'd use on a road bike- like a 34 tooth small ring and a 46 tooth large ring (it's still got a 34 like a standard road-going compact, but the 46 tooth large ring is more useful for riding off road because it's "easier" than a 50 or 53, and it gives you added ground clearance over a 50 or 53).
-Some CX racers find that they don't use the large ring very often, so they opt to change to a single front ring- no big or small to switch between... just one front chainring of their choice. Usually they go for something a little larger than a 34 but smaller than a 46 (a "medium" sized ring ).

The other numbers are the sizes of the rear cogs. They are also measured by how many teeth each one has, and you tell someone the size of your rear gears by giving the range from smallest cog to largest cog:
- A very common road bike gearing would be 11-23 (the smallest cog has 11 teeth, the largest one has 23). This can vary a LOT, though! Other popular ones include 11-25 and 12-27.
-CX gearing usually errs on the side of larger-toothed gears because, once again, they make it easier to climb hills & get through mud & grass, and you are not likely to need an 11 tooth cog when riding off-road (on road, you only need it for sprinting, descending, or other times when you want to really haul a**)
- When you hear of someone running a "singlespeed" setup (like mine & shefly's), that means that they've only got one gear in the back (and one chainring in the front). Singlespeeds are all about finding the right gearing that you can tolerate on hills/rough spots, but NOT be left spinning out when you get to a faster section of the course.
Mine has a 42 tooth front chainring and a 17 tooth gear in the back. I chose it because I can spin on easy, flat sections at about 19 mph, and I can still make it up most hills. I used to have a 20 tooth gear in the back, which made hills much easier, but did not allow me to go fast enough on the easy sections of course.

Hope this helps you out! I was confused for the longest time about what all those crazy numbers meant, so don't feel bad!

[Voodoo Sally]

45/39 and an 11-28 8-speed. I almost never use the small ring, and it's been racing great.

[Possegal]

Thank you Andrea!!! Yes, that did help, and I'm slightly less dumb today. Though only slightly.

[Lifesgreat]

Andrea: Thank you for your explanation, it was helpful for me.

Sorta OT, now the gearing part that confuses me is when riders start talking about the different combinations within the gears they have. For example, on a triple, they talk about how much they may like the largest front and the 3rd smallest rear gear as opposed to the medium front and smallest rear gear. Hope that makes sense. I just find the combo that feels good.

[Andrea]

Andrea: Thank you for your explanation, it was helpful for me.

Sorta OT, now the gearing part that confuses me is when riders start talking about the different combinations within the gears they have. For example, on a triple, they talk about how much they may like the largest front and the 3rd smallest rear gear as opposed to the medium front and smallest rear gear. Hope that makes sense. I just find the combo that feels good.

Thanks! Glad I could help.

Don't sweat the in-between gears thing. A lot of people make a big deal about certain combos, but I think along the same lines as you... just ride what feels right... who cares what the number is!
I ride an 11/26 set of rear gears (on my road bike), which doesn't include a 16t cog. I've never felt at a disadvantage without it, but some people won't buy the 11/26 cassette because they want the 16t!!! Madness!

[SpeedyChix]

34*46 up front, most often a 12-27 cassette. I like to be able to spin so opted for the 'easy' gear.