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.

[mimitabby]

yeah, even on our hilly rides here you can see fixed geared bikes and other strange conveyances..
How many speeds on your bike? if it's a 21 speed you can do the wanderer. I looked. That one hill, maybe you might have to walk a little? and maybe not!
I just compared it to the 70 mile ride we did a few weeks ago. I think you'll be just fine and you probably WON'T have to walk.. and if you do, so what?
mimi

[morsecode]

How many speeds on your bike?

24
Hubby's convinced we'll be fine, but I am a worrywart. I don't want to get there and then not be allowed to ride

[maillotpois]

I have never seen a ride actually require a certain gear ratio - that is really odd, and I don't expect them to go around checking cassettes before they let you go. They typically just want people to be prepared and get as many to finish as they can.

That being said, it appears you have a mountain bike? It looks like you've got a 22 in front? I can only imagine that's a MTB, though I could not get the link to open. A 22 is WAY small, and well within the "requirement" for the ride, so you should be fine.

The smaller your front ring is and the larger your rear cassette cog is the "easier" gears you have, generally. Your 22 in front is smaller than the requirement, and you have a big juicy 32 in rear, so you're fine.

However, if this is a mountain bike, and you are doing the road century, I recommend putting slick tires on your bike for rolling resistance, quiet and comfort.

[DebW]

Your lowest gear is way lower than the requirement for that ride. You have a 19 inch low gear, and they are requiring a 39 inch low gear, so you quality (if they are really going to be snobbish enough to check). But if you have a mountain bike that weighs more than a road bike, you may need lower gears than they mention. Or maybe you are such a good hill climber that you don't need anything that low.

[morsecode]

I have never seen a ride actually require a certain gear ratio - that is really odd, and I don't expect them to go around checking cassettes before they let you go. They typically just want people to be prepared and get as many to finish as they can.

That being said, it appears you have a mountain bike? It looks like you've got a 22 in front? I can only imagine that's a MTB, though I could not get the link to open. A 22 is WAY small, and well within the "requirement" for the ride, so you should be fine.

The smaller your front ring is and the larger your rear cassette cog is the "easier" gears you have, generally. Your 22 in front is smaller than the requirement, and you have a big juicy 32 in rear, so you're fine.

However, if this is a mountain bike, and you are doing the road century, I recommend putting slick tires on your bike for rolling resistance, quiet and comfort.

Yeah, I have a mountain bike. So strange that that link went bad on me... it was to the exact version I have.
Anyway, here's this year's model of my bike: http://www2.trekbikes.com/bikes/bike...d=1022603&f=19
Mine is 2 years old, but I don't think there have been any drastic changes

[morsecode]

Your lowest gear is way lower than the requirement for that ride. You have a 19 inch low gear, and they are requiring a 39 inch low gear, so you quality (if they are really going to be snobbish enough to check). But if you have a mountain bike that weighs more than a road bike, you may need lower gears than they mention. Or maybe you are such a good hill climber that you don't need anything that low.

I wish
If we do this, we'll definitely do the easiest ride

I'm so glad you guys are here b/c I'm still completely confused
but then again, I'm a real newbie.
I got my bike 2 years ago, but we've been really lackadaisical about riding. Each season riding enough to be able to survive whichever route we decide to take on the Ride for Roswell (the big fundraising ride in these parts) and then petering out. This year I really want to change that and start riding regularly and get into shape properly.

Thanks so much for your help, everyone!

[Kano]

However, if this is a mountain bike, and you are doing the road century, I recommend putting slick tires on your bike for rolling resistance, quiet and comfort.

I know we're talking about gears, but: is this why when DH comes cruising up behind me on the road, I think I'm hearing a car??????

And another question, maillotpois -- maillot=shirt, pois?????

Karen in Boise

[madisongrrl]

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

I don't think it is the Race Director's intention to be exclusive.... (I've seen this before on hilly century rides.) I think that the RD is trying to emphasize that the course very difficult (hilly) and that people won't be able to complete the ride with any "harder" gearing than 54/39 front and 12/27 rear. Mountain bikes and comfort bikes generally have an "easier" gearing ratio than 54/39-12/27, so it would be much more reasonable to climb massive hills on them.


I'm a relatively strong rider/racer. My road bike has a double up front (54/39) and a 12/27 in back. I've been on some pretty hilly rides and I've had to grind up some super steep hills in my 39-27 gear (easiest). Could I do that for 100 miles and 11,000 vertical feet? Probably not with that gearing ratio.