newbie question re. gearing.

[morsecode]

When a ride says that it requires a minimum gearing of 39/27 to participate, what exactly does that mean?

From what I gather the gearing has something to do with the number of spokes on your gears and ratios, but I'm still confused

Can anyone give me a simple explanation?
It would be greatly appreciated

[DebW]

The first number (39) is the number of teeth in the smallest chainring (the smaller the number the lower the gear). The 2nd number is the number of teeth in the largest freewheel cog (the larger the number the lower the gear). Typical double cranksets come with 39-42 teeth in the smaller chainring and 50-54 teeth in the larger one. Triple cranksets would have an additional granny ring of 30-36. Cassettes can come with a smallest cog of 11, 12, or 13, and the largest cog can vary widely, from 20 to 27 or even 32. The gears you need depend on the bike, your fitness, and the terrain. To compare gear ratios, calculate this number:

(#teeth in chainring)/(#teeth in rear cog)*(diameter of wheel)

If wheel diameter is in inches, you'll get numbers from ~30 to ~110. That number, after you multiply by pi, give the number of inches the bike will travel per revolution of the cranks. This lets you compare gear ratios from different bikes with different wheel sizes and different cranksets and clusters.

[mimitabby]

you have to know THAT just go to on the ride????

sheesh.
We go on rides with fixed gear riders all the time and they DO NOT slow us down. (Fixed gear bikes don't shift; they are always in the same gear, just like the bike you had as a lttle kid.)
seems like there's a bit of a snob component to that ride!

[kelownagirl]

I am curious about this as well. I have tried counting the teeth but have a hard time. The spec page on the Giant website says my bike has the following:

cassette: SRAM PG-950 12-26T, 9 speed
cranks: TruVativ Elita, 30/42/52T

Does that mean:

My smallest crankset chainring has 30 teeth?
My largest cog has 26 teeth?

So it would be 30/26?

Would I have the minimum gearing to ride in Morsecode's ride?

As for the diameter of the wheel, is that what the number "700" refers to?

Hope you don't mind my jumping in with additional related questions MC...

barb

[morsecode]

Well, it's a ride that focuses on climbing, so maybe that's why?
http://www.highlandercycletour.com/

We've been done a charity ride the past two years (the Ride for Roswell) and I know they don't have any minimum gearing requirements

We were thinking about doing the "Wanderer" ride, which is the easiest one (30 miles with 2 moderate climbs) and actually requires a slightly lower minimum gearing (39/25)

I showed this thread to my hubby and apparently he gets it (it's still all Greek to me :blush: ) so he's going to figuring out our gearing later.

[morsecode]

CRANKSET: Shimano MC08 42/32/22
CASSETTE: SRAM 850 11-32, 8 speed
this is my bike: http://www.trekbikes.com/bikes/2004/mountain/4500.jsp
ETA: try this link instead http://www2.trekbikes.com/bikes/bike...d=1022603&f=19

My first number would be 22? That means I definitely can't ride?
I'm so confused

[Trek420]

I've never heard of this

I've seen organised rides/tours where it's reccomended you have a road bike with a "granny gear". But never specific gearing.

Unless it's a race I don't think they can tell you what to ride.

On group rides it's common for the pace to be listed, distance, avg mph, difficulty/terrain. If you can keep pace with the group who cares what you ride.

People complete centuries on mountain bikes, recumbents, "comfort bikes"...ride what you like. This sounds kinda exclusive to me.

[madisongrrl]

Well, it's a ride that focuses on climbing, so maybe that's why?
http://www.highlandercycletour.com/

We've been done a charity ride the past two years (the Ride for Roswell) and I know they don't have any minimum gearing requirements

We were thinking about doing the "Wanderer" ride, which is the easiest one (30 miles with 2 moderate climbs) and actually requires a slightly lower minimum gearing (39/25)

I showed this thread to my hubby and apparently he gets it (it's still all Greek to me :blush: ) so he's going to figuring out our gearing later.

39/25 minimum gearing is really high. You will be fine with the gearing on your bike. I would guess there are probably very few (or maybe zero) TE women who would have 39/25 as the lowest gearing on their road bike.

Looks like a really neat ride. It should be a fun time!

[DebW]

I would guess there are probably very few (or maybe zero) TE women who would have 39/25 as the lowest gearing on their road bike.

There is at least one. I have 42/52 front and 13/24 rear. But I live in southern New England where there are hills but no mountains. I wouldn't try riding in California on these gears. However, I do like hills and tend to seek them out on my rides. I can do steep hills, but they are always less than 1/2 mile long. And BTW, my 24 rear cog is almost never used after my first month of spring riding. And my climbing cadence is generally near or above 70, cadence on the flats around 90. I use a 6 speed freewheel, and my 1970 Campy derailleur can't handle anything bigger than 24 (23 would be better for it and that's what I've usually had til the latest freewheel swap when I couldn't find one).