Galico

Brett 12, Sidney, Lectron. BTW and all} Thanks for the discussions and very compelling arguments. I understand the concept of the gear inch, but I looked around for definitions of redundancy. What difference in gear inch's would you consider a gear non redundant (or am I preserving it to simply)? When you look at the total non-redundant gears and seek an optimum does extreme cross chaining work into the thought process? You also equate these arguments down to a final argument of “speed clusters”, could you define “speed cluster” and “progressions” . Is a tight cassette considered one that is physically narrow or is it a function of the relative diameter of one ring to its adjoining rings (ie: less of a jump).
I looked at Sheldon’s site for these answers and did not really glean them. I get the concepts you are presenting but I am weak on the nomenclature. Thanks for your patience I can only learn by asking.

ggg300

Most agree that there is a narrow power range for us humans. The more gears that fit this range the better or at least that is what they sell us. So a cluster that is tight will not have big jumps and keep you in the zone. It gets technical but the triple should do the trick and I really like the idea of 52/39/28.

I use a compact with an 11-23 most of the time and will use the 11-27 this summer as I will make it a point to do hills that call for it. The only reason that I don’t have a triple…cost of conversion from a double…

But what ever works …I have tested a 53/39 and 11-32 and had a good time with it.

Last…the big jump…I think any shift over 9 gi difference is a big jump…what do you all think is a big jump and why?

pilotpat

My decision (just ordered a bike with DA9 + FSA SL-K compact) really came around to simplicity and versatility. Just a lot easier to swap cassettes than a crankset/chainwheel.

With the compact, I can use the 11-23 cassette that's coming on the bike for all-around fast rec riding, and racing if I get into it. Hills (like the mtns around here) - no problem, 30 minutes-ish to throw on the 12-25 cassette I've been riding for the past few years, or just swap wheels. Real mtn rides (possibly doing the Etape du Tour this Summer, plus a really awesome mtn metric century) - I've got a 12-27, giving me a 109 to 33-inch gear range!

Never been able to spin a 53x11 well except on downhills. On a long, lightly loaded, and mountainous tour, I found that a 39x27 wasn't enough.

A triple would be nice, especially on a bike for loaded touring, and we really enjoy it on our Santana Tandem - which has a huge 34 tooth plate on the back (XTR rear derailleur) that makes pulling a trailer with kids no worries. But for my road machine, I'll stick with a compact for now and see how I like it.

Avalanche325

Galico, A "tight" cassette is one that the gears have a smaller differance between. Shifting up one gear will require a little more effort. A looser cassette has a bigger jump between gears. Out on the road you can sometimes get at a speed where one gear is just a little too hard to push, but the next one down makes you spin too fast. A tight cassette helps eliminate this.

Cross chaining. According to Shimano, with a triple, you can use the following:
Big chain ring - all gears except the largest.
Middle chain ring - all gears
Small chain ring - a gears excpt the smallest.

Here is something from another thread: https://www.bikeforums.net/showthread...ange+gear+inch
The idea of three chain rings up front is to give you three different speed RANGES. It is not intended to give you 27 seperate sequential gears. Lots of people on this forum calculate all of the gear - inch ratios and shift a million times trying to shift up and down through all of the gears. That is not how it was designed to work. You generally select a range (Hi, med or low) with the front chain rings. Then you have the gears on the rear to move up and down in within that range.

Looking at the chart above and trying to shift sequentially you would go, 32/23, 44/30, 22/14, 32/20, 44/26, 32/18, 44/23, and 32/16. This is nonsense. You would simply stay on the middle chainring and use the rear cogs and go 32/23, 32/20, 32/18, 32/16. A nice speed RANGE which your legs can handle. (Khuon, I know YOU weren't saying to do this. But some people here think that is the way to do it. I am just trying to show that if you think "3 speed ranges" instead of "27 gears", the gears are not very complicated. And, you don't need to shift a million times.)

This gives you, eight gears in low range, nine gears in the middle range, and eight gears in the high range.

Brett 12

Well you really should not be using 8 cogs in each chain ring for a 9 speed casette. That just results in too much cross chaining. Shimano says you can do it, but I'd do it only if I was in a position where I didn't want to shift the front deraillleur under load.

You could do that but really you should be shifting the front rather than trying to use all those cogs with every ring. 9 speed triple has only 15 non-redundant gears anyway.

Lectron

Can you folks please read this. That what it's all about. SPEED RANGES.
You also have to think 'bout the chainline, meaning you don't use 34/11,12(&13)
What kind of speedrange is that ?
That's why I would never recomend compact crank.

JoeOxfordCT

That's not exactly a rave review of the compact.....
..is it ?

Matt Gaunt

I went for the new triple Ultegra 10s for that reason too. That, and also because if you're on a steep climb, with that leafy grease on the road, you need there to be much less power coming down in your pedal stroke than if you stand on the lowest gear on a double. Otherwise you just lose all traction and enter crashville, population: you!

Galico

I asked : . What difference in gear inch's would you consider a gear non redundant (or am I preserving it to simply)?
Could I get that explained.
I am leaving to ride to work, 18 Degrees this AM, I will look at the thread this PM.

alanbikehouston

There is a difference between "can" and "should". The chainline that has the least friction, and produces the least wear is a straight chainline. The notion that someone is going to be using every cog on their cassette from the middle chain ring might help sell replacement cassettes, but is not the best way to ride a bike.

Most of the problems with "modern" drivetrains are the result of trying to provide a "gear" for any possible situation. I saw a gear chart for a "Joe Average" sort of bike that had a range from 30 gear inches to 120 gear inches. Maybe, someday, somewhere, "Joe" was gonna need those gears. But, on a given day, he was more likely to be riding in a range of about 50 inches to 80 inches.

Let's look at "real life". Eddie Merckx set the "one hour" speed record using a 97 inch gear. The maximum gear allowed in the UK for a top "junior", age 15, in supervised racing is a 76. When training, Sean Kelly used a 67 inch gear. When Greg LeMond was 15, the "Junior" race rules limited him to a maximum of a 52 x 15. As a Pro, he rarely used anything higher than a 53 x 14 maximum.

So, why in 2005, are bikes are being sold to schoolteachers, plumbers, and shoe salesmen with 53 x11 set-ups? Why do some bikes have four gear combinations between 95 inches and 130 inches? This may be good marketing - "Get 30 speeds - including speeds the Pros of the '80's never knew existed !!", but it ignores human biology. The average schoolteacher of 2005 is not stronger than Eddie Merckx in his prime.

Most riders would be more efficient if they learned to spin at high rates, between 90 RPM and 100 RPM. If a road bike (not a touring bike) is geared from about 40 inches to 95 inches, a rider can easily access any gear between 40 iches and 95 inches with just 10 well-aligned gears.

A 2 x 8 system can easily produce 10 distinctly different gear combinations that have a straight chainline. And, if those 10 combinations are carefully matched to the needs of the individual rider, they are all that he will need in the course of any single day of riding. (For "sprints" a different cassette would be used, for loaded touring in the mountains, a different cassette would be used).

Mr. Shimano admitted in a recent interview that the gearing on a average road bike has no relationship to the acual needs of the riders. However, he says people who buly a road bike insist on buying a bike that is EXACTLY identical to what they think Pros ride. So, Mr. Shimano thinks "silly" gearing sells bikes.

terrymorse 

I climb a lot (and I do mean a lot) and I'm 47. I have a triple (53-42-30) on my touring/rain bike and a compact double (50/34) on my climbing/race bike. Both have 12-27 9-speed cassettes. They both have more than enough gearing for my needs. Personally, I don't see the need to run a tighter cassette. The jumps between gears are small enough.

The triple: I do 99% of my climbing in the middle (42) ring. I rarely use the 30 ring, only on the steepest grades over 15%, or on really long climbs like the ones in the Eastern Sierra. I have little use for the two lowest gears, so they're just along for the ride.

The double: Big ring (50) up to about 6% grades. Above that I drop to the small (34) ring. I still have little use for the bottom two gears, but it's nice to know they're there. I occasionally spin out in the top gear, so I'm thinking of building up an 11-27 cassette.

What sort of cadence do I use on the hills? About 70-75. My climbing rates:

endurance: 2500-3000 ft/hr
tempo: 3500-4000
max. effort: 4500-5300

My wife doesn't climb that fast, so I put a 50-34 double and an 11-34 cassette with an XTR derailleur on her bike. She likes those lower gears.

Brett 12

Lectron, just becasue you have a 34 doesn't mean the speed range is slower. One thing you need to understand is that the cogs are smaller too.

I just plugged in the chainrings and cogs for 53/39 (12-25) and 50/34 (11-23).

If you are using 100 rpm, the speed range for both in the smallest chaings in roughly the same (withinin 1 mph)

Go plug it in for yourself https://www.sheldonbrown.com/gears/ , Just because the 34 is phyically smaller doesn't mean that it will act like a granny ring...the cogs matter too.

Avalanche325

Well, I have 3500 miles on my chain and it is fine, checked by a Park chain tool. The cassette is fine too. No, I don't ride all day in the more extreme chainlines, but it does not cause significant wear to use your gears in the manner that they were designed for.

Avalanche325

OK, now plug in the following: 52/42/30 (11-23) and see what you get. Higher AND lower with tight spacing in between.

Brett 12

maybe you have long chainstays.....that helps a lot. Personally I would never use any extreme angles on my chain unless I had a long chain stay bike. But really is.....Is front shifting in a triple as bad as everysays says around here.

Lectron

Brett 12, believe me. As an engineer I do understand the elementary laws of physics.
This is not hard. That’s why I’m recommending Galico to go for a triple crank.
And yes. I’ve looked at the link, and since I have already done the math my selves,
I can tell Sheldonbrowns calculator is right too.

Best regards

Lectron

Avalanche325

My chain stays are not long (Litespeed Firenze). Front shifting on a triple is not bad at all. The small to middle is a big climb, but mine (Ultegra) is simply, hit the shifter, and up she goes. The middle to big is lightning quick. People that say they don't shift right need a better mechanic. I have had my bike for 1 year and I have made 1 or two minor adjustments to my deraileurs.

You are correct, you should not be riding in the middle ring and on the top or bottom cog for long periods. If you are doing this, you have not selected the correct speed range for your riding conditions. The idea is that you can be in the middle for a suprisingly large variance in terrain (and speed). Most of this will be in the middle section of the cassette. It is OK to go to the outer ones for a short period. Of course a straighter chain angle is better. But, shifting your front der less is also better.

Brett 12

That's why I like designs like the DA 9 speed triple and the new Ultegra 10 speed triple (which I recommended to Galico).....I'd rather shift from granny up to a 39T than a 42T. the gear % change is smaller this way.

In fact a 28T to 39T upshift is slightly better than a 30 to 42T up shift in both teeth count and % change.

55/Rad

On the contrary - it works perfectly and it looks beautiful. If anything, I don't have it set up to maximize it's potential capabilities. This is a function of me, not the system.

My point is, if all you are going to do is replace your standard 53/39 + 12/27 combo with a 50/34 + 11/23, you won't noticeably gain anything. I'm thinking a custom 11/25 or 11/27 cassette would give me the benefit but I'm not sure I need it at this time. I am happy knowing I could go there if needed.

55/Rad

JoeOxfordCT

Rad, I believe you got 10sp with your new compact setup right ?
What are your thoughts on a custom 10sp cassette ?
I am actually going to finally pick up my Felt tomorrow
I ended up returning the FSA Energy compact and ordering the FSA Gossamer MegaExo compact....
Other than that the bike is Ultegra 10sp w/11-23. I am hoping that should give me plenty of gearing for training in (rather) hilly western CT. But I am harboring thoughts of getting a custom "hilly century" cassette should I actually find enough time to train for one . However, I'd like to hang onto the 50-11 gear should I look for a cassette with a 27 or even 30 cog. Sheldon Brown hasn't really updated his entire site with 10sp cassette info. I am assuming he could make a 10sp "high & wide" 11-30 or something similar....

I suppose I should actually ride the bike first before I worry about stuff like this huh ??
Oh well

alanbikehouston

"Cross-chaining" is sorta, kinda possible, but not good, on a bike with a long chainstays. Cross-chaining on the short chainstays typical of today's "pretend" racing bikes puts tremendous wear on the cogs, and greatly increasing the level of friction in the drivetrain.

I don't "cross-chain", and some of my cogsets are twenty years old, and in good shape. A "cross-chainer" is gonna be needing a new cassette every year or two.

I knew a kid learning to shift a car who drove all the way to campus in first gear. Don't confuse what is possible "possible" with what a device is designed for. Richard Ballantine has written that he suspects that the only reason "cross-chaining" is even "doable" is for legal liability reasons: bike makers have to assume that someone is gonna try it, so must design their drivetrains to allow it to be done safely.

A properly designed drivetrain does not require "cross-chaining" to select gears that are actually needed by most riders. If you must "cross chain" to get to a gear that you need, you need a different cassette, or different chainrings.

gabiker

Check out www.interlocracing.com they have an 11/28 for 10 speed and there coming out with a compact specific front der.

JoeOxfordCT

Wow ! Thanks for the link. Exactly what I was looking for.
I have it bookmarked already.
What do you think about their compact specific FD ?
...Or what are your thoughts on Compact specific FD derailleurs in general ??

Thanks again for the info

gabiker

I am not sure what to think. I really don't have a problem with the Ultegra front der, however it is very close on the compact so I may try one. The one thing I don't like is all they have is braze on and you have to buy an adapter. My 11/28 should be here Monday so I''' know more then.

JoeOxfordCT

Yeah I saw that about the braze on with the FD.
I like the 11-28 though. I plugged in it's numbers into Sheldon Brown's calculator. Looks like I have my "hilly century" cassette...
You'll have to give me some feedback on the cassette when you get it
BTW How long have you been riding the compact ? What were you riding prior ? Feedback ??