Double Chain Ring...yikes

[Andrea]

I checked this morning; on the big ring, it says 53-39 and on the small ring, it says 39. Is this bad ???

In my (humble) opinion, it's not necessarily bad. Before you go out & spend money on a compact or triple, check your rear cassette. For help on the hills, the cog with the most teeth should have 26 or 27 (or even more, but that can leave you missing a few gears in the middle that you'd want on the flats). Buying a cassette with that gearing will cost less than a new crankset.

Give it a chance. Yes, it's going to seem harder at times, but chances are, if you keep pushing yourself, you'll get better at using the slightly harder gearing to climb hills. To quote something that another TE-er said to me once: "No self-doubt, please!"

[OakLeaf]

I think if it's 53/39 it's already a compact? Would a standard double accommodate a 14-tooth difference?

And no, it's not "bad," there's no good or bad gearing, there's just whether it's appropriate to the rider's strength and the terrain where the bike will be ridden.

Andrea, I do hear ya, but I think we can also agree that if the strength demands are too high, then someone won't be able to progress, and will just get frustrated or even injured. It's no different from a deconditioned person trying to learn to bench press with no options but a 45-lb bar. And, not everyone here is even trying to build strength. Or has the joints to support very high strength demands. For a lot of us, increasing or just maintaining endurance is enough.

Violette, do you know what your largest cog is on the freewheel? (if you can't see where it's stamped, you can count the teeth)

I might change out the chainrings before replacing the cassette - five teeth in front will make MUCH more difference than two in back.

Does anyone know what's the maximum differential in a compact? Can she do 53/34, or would that result in poor shifting and/or a lot of cross-chaining?

[violette]

Do you mean change my small front chainring? Do you know how much that would cost. I don't think it would be a big job.

[violette]

I just checked, it says 12-25.

[Andrea]

Usually compact chainrings are 34-50 or 36-50. There are a couple of other combos out there, but those are the most common.

[VeloVT]

Originally posted by Oakleaf:
I might change out the chainrings before replacing the cassette - five teeth in front will make MUCH more difference than two in back.

Does anyone know what's the maximum differential in a compact? Can she do 53/34, or would that result in poor shifting and/or a lot of cross-chaining?


Whether or not you can go down to a super-small inner ring depends on the Bolt Circle Diameter of your crankset.

I believe standard road doubles (53/39) have 130mm BCD's -- if this is the case with your cranks, you are limited to a 38 small ring.

Most compact doubles have a 110mm BCD; if somehow you ended up with a 110 mm BCD, you can go down to like a 33.

Sheldon Brown has a little information about this on his website, and you will get more if you google some combination of "BCD" and "chainrings".

[motochick]

If I was in your shoes, I would change my rear cassette to a 12-28. That would be a good place to start...and the cheapest. If that isn't enough, then come back and tell us and we can make another suggestion.

Brenda

[rij73]

Violette, you have standard gearing. If you are hurting, first thing to try is a 12-28 cassette in the rear. If you are still hurting after riding that for a while, you can look into getting a 50/34 compact crankset. That's my 2 cents from thinking about gears a lot.

[motochick]

If I was in your shoes, I would change my rear cassette to a 12-28. That would be a good place to start...and the cheapest. If that isn't enough, then come back and tell us and we can make another suggestion.

Brenda

Not to sound like a broken record, but......
If the new cassette isn't easy enough, go to ebay and yourself a new sram rival compact set for $140 shipped. I use a 50/34 in the front and a 12-28 in the rear. I do not climb hills, I climb mountains. And I am NOT a very strong or powerful rider, but I like to go uphill without suffering. Just my $.02
Brenda

[aicabsolut]

Originally posted by Oakleaf:
I might change out the chainrings before replacing the cassette - five teeth in front will make MUCH more difference than two in back.

Does anyone know what's the maximum differential in a compact? Can she do 53/34, or would that result in poor shifting and/or a lot of cross-chaining?


Whether or not you can go down to a super-small inner ring depends on the Bolt Circle Diameter of your crankset.

I believe standard road doubles (53/39) have 130mm BCD's -- if this is the case with your cranks, you are limited to a 38 small ring.

Most compact doubles have a 110mm BCD; if somehow you ended up with a 110 mm BCD, you can go down to like a 33.

Sheldon Brown has a little information about this on his website, and you will get more if you google some combination of "BCD" and "chainrings".

Correct. She probably cannot change her rings without changing the entire crankset, which will cost mega $$. It would be much much cheaper to go with a cassette change if the rear derailleur can handle it (she needs to look at what's on there now). A good Ultegra cassette costs under $100. A new crankset can run well over $300.

Plus, even if she could change the rings, she's going to have to change both of them to get a compact inner ring, because the front derailleur won't be able to handle more than about a 16T difference.

Also, don't underestimate how big of a difference the rear cassette can make. Example: a 50/11 is a bigger gear than a 53/12. So say she's only got a 12-25 on there now. Moving to a 27 or 28 will be a big jump. She'll sacrifice some of the range towards the top end with such a large spread, but that's not necessarily a bad thing. It could get a little annoying on flat roads or in groups, but I think that's a better trade off than having gears that are too hard all the time.

[ginny]

Hi guys - okay, so this is the first thread I have read here that is pretty much greek to me. Can you provide me with a web site with a good tutorial on gearing ratios? Or maybe if I provide you with the specs from my bike you can explain the math to me? Alrighty... my bike hs a sugino crankset (triple) 30.42.52 and the cassette is campy 13/26 9 spd. So, how are you arriving at inches from teeth? Somewhere on the internet it looked like you need tire ratios too to calculate gearing ratios, but aren't all road tires the same unless you are a really small framed woman with smaller tires. For what it's worth, my tires are 700x23c (does the c mean cm?)

Thanks!