HiYoSilver

Ok I have a bunch of numbers but not sure how to interpret them.
Here are 3 different shifting patterns. How would do I interpret these
numbers and decide which to use as the base pattern? I used Pattern
B yesterday, but don't have a clue when it would be best to use
Pattern A or Pattern B or Pattern C. Interesting that there are these
different patterns of shifting. Just annoying that I can't figure out
how to apply this data. Insights anyone?

PATTERN A - 17 gears, Low ring most frequent
=================================================
Gear#__Gear__%Change__GearInch
01_____Low9___12.5%___28.0
02_____Low8___14.3%___31.5
03_____Low7___10.5%___36.0
04_____Low6___11.8%___39.8
05_____Low5___13.3%___44.5

06_____Low4___07.1%___50.4
07_____Low3___07.7%___54.0
08_____Low2___08.3%___58.2
09_____Low1___05.9%___63.0
10_____Mid5___13.3%___66.7

11_____Mid4___07.1%___75.6
12_____Mid3___07.7%___81.0
13_____Mid2___11.4%___87.2
14_____High4__07.1%___97.2
15_____High3__07.7%___104.1
16_____High2__08.3%___112.2
17_____High1__xx.xx___121.5

PATTERN B - 16 gears, Middle ring most frequent
=================================================
Gear#__Gear__%Change__GearInch
01_____Low9___12.5%___28.0
02_____Low8___14.3%___31.5
03_____Low7___10.5%___36.0
04_____Low6___11.8%___39.8
05_____Mid9___05.6%___42.0

06_____Mid8___12.5%___47.3
07_____Mid7___10.5%___54.0
08_____Mid6___11.8%___59.7
09_____Mid5___13.3%___66.7
10_____Mid4___07.1%___75.6

11_____Mid3___07.7%___81.0
12_____Mid2___11.4%___87.2
13_____High4__07.1%___97.2
14_____High3__07.7%___104.1
15_____High2__08.3%___112.2

15_____High1__xx.xx___121.5


PATTERN C - 15 gears, High Chainring most frequent
=================================================
Gear#__Gear__%Change__GearInch
01_____Low9___12.5%___28.0
02_____Low8___14.3%___31.5
03_____Low7___10.5%___36.0
04_____Low6___05.6%___39.8
05_____Mid9___12.5%___42.0

06_____Mid8___14.3%___47.3
07_____High9__12.5%___54.0
08_____High8__14.3%___60.8
09_____High7__10.5%___69.4
10_____High6__11.8%___76.7

11_____High5__13.3%___85.8
12_____High4__07.1%___97.2
13_____High3__07.7%___104.1
14_____High2__08.3%___112.1
15_____High1__xxxxx___121.5


Here is a Gear Inch only summary of the patterns
LOW MID HIGH
028.0___028.0___028.0 same
031.5___031.5___031.5 same
036.0___036.0___036.0 same
039.8___039.8___039.8 same
044.5___042.0___042.0

050.4___047.3___047.3
054.0___054.0___054.0
058.2___059.7___060.8
063.0___----___----
066.7___066.7___069.4

075.6___075.6___076.7
081.0___081.0___----
087.2___087.2___085.8
097.2___097.2___097.2 same
104.1___104.1___104.1 same

112.2___112.2___112.1 same
121.5___121.5___121.5 same

same time

This is one reason why I commute on a fixed gear :-)

What, in the physical world, are you trying to do?

markhr

Looks like half stepping, i.e., changing gears by gear inches rather than consecutive gears? Anyway, too m uch like hard work I just use whichever gear lets me maintain a cadence of 95-105 rpm at any given time.

HiYoSilver

You appear to have misread the data. It's not shifting by gear inches but by ring sets.

Pattern A
Low chainring, progressive from cog #9, 27teeth, to cog#1, 12 teeth
Middle chainring, progressive from cog#5, 17teeth, to cog#2, 13 teeth
High chainring, progressive from cog#4, 15 teeth, to cog#1, 12 teeth.

So only 2 double shifts when change chainring.

Pattern B
Low chainring, from cog #9 to cog #6, 27 teeth to 19 teeth
Middle, from cog #9 to cog #2, 27 teeth to 13 teeth
High, from cog #4 to cog#1, 15 teeth to 12 teeth

Pattern C
Low crainring, from cog #9 to cog #6, 27 teeth to 19 teeth
Middle, from cog #9 to cog #8, 27 teeth to 24 teeth
High, from cog #9 to cog #1, 27 teeth to 12 teeth.


So the difference is which chainring is used as primary: low, middle or high. The shifts between gears is not excessive and shifting of chainrings is minimized.

Currently I'm using the middle chainring as primary as I think it would put less stress on chain and might be best for default shifting.

Sigurdd50

someone has too much time on their hands

oh wait, is this a script from that new TV show?

Randymac

I use to keep all the ratios in mind while I would change gears. Now, I pay far more attention to my cadence.

HiYoSilver

Does this make sense?

Desired cadence range is 80 to 100, so shift pattern

A: low, for 7-19 mph
B: mid, for 10-26 mph
C: hi, for 13-36 mph

Thus use B as default, and if hit hills where can't use B, switch to A until can generate more than 19mph. If hit downhills or tail winds, switch to C?

va_cyclist

Do people really think this much when they're riding? I just keep it in the small ring, shifting up or down as necessary to keep cadence in a good range.

Do you actually "run through" all your gears in this way, starting with 1 from a standing stop? I spend about 90% of my time riding in about 4 gears (low-3/4/5/6), and only hit the granny gear for hills.

phidauex

What are you trying to accomplish? I'm not sure if this level of analysis is necessary. Like mentioned, think more about your cadence, and shift to hold cadence.

That said, based on your data, I don't like pattern A or C, because they put your chain on the large front ring, and the large rear ring, or the small front ring and the small rear ring, neither of which are good ratios to be in, because you are running the chain at a high angle, which lowers efficiency, speeds wear, and can cause skipping or accidental deraillement under load. The B pattern avoids these 'crosschain' ratios.

Peace,
Sam

PS My fixed gear rocks the block party.

MichaelW

I use different shifting patterns going up the gears and going down the ratios.

HiYoSilver

Dumb small desktops and extra button mouse. Lost my reply.

On my 5 mile commute, 1/8 is level. There are 16 elevation changes. To route is generally uphill, and naturally the From route is generally downhill. So to keep cadence, I'm reducing number of gears used to about 10. I used to use about 13, but now trying to keep that number smaller so I can focus more on riding and less on shifting.

I don't start with low-9 or mid-9 from start. I just big shift from say mid-2/3 and guess end up about mid-7/8 but I haven't really looked. Often the big shift is a partical shift. I just want to drop about 4 gears and don't care where I end up as I'll change at least by the middle of the intersection.

Robert Gardner

People who worry about gear ratios and other numeric aspects of their bike don't bike long because they are missing all of the joys of biking.

HiYoSilver

1. understanding the potential long term results of making a choice between the 3 patterns
2. make riding more fun.

All 3 patterns have the same range and acceptable % changes between gears. I'm guessing pattern A would be used when need to work on upping cadence and pattern C would be used when need to work on upping power.




You're right pattern A does have one cross chain, from gear 9 to gear 10, low1 to mid5. Low 1 is 28x27. I just listed this gear for completion in the table. I've noticed I tend to skip from gear 7 to gear 10ish just to avoid this cross chaining.

Gear 7 in pattern C is cross chaining. Again, I don't generally use this, but you're right I need to redo series A and series C so I have shifting without the cross chaining. Thanks for catching this.

nitropowered

I commute with two bikes. One is my race bike, Standard Double, 10-speed cassette. The other is a single-speed mountain bike.

Its a no brainer for the single-speed.

For the roadie, I just choose whatever gear I am comfortable with in the conditions I am riding in. Flat is around 53- 17 or 19. If the grade goes up, I'll pop it up a gear or two. I try to maintain a steady cadance. On the major hills, I'm in the 39-19, 21, 23. I rarely use my 25. The 53-25 cross often derails so I avoid it at all costs, and the 39-25 is too low. I still wouldn't give it up because there are some hills (20-25%) that I need it on (training rides) and for when I am really tired.

amahana1

You took the words right out of my mouth!

michaelnel

I figure my bike is geared right for *my* needs when I can do 95% of my riding on the middle ring. That gives the best chainline (and best efficiency), and I only make very occasional forays to the large or granny rings. I also like the gearing that way because it's a relative PITA shifting the front.

HiYoSilver

Original for Patterns A and C were:

Revised for philanex.
PATTERN A - 16 gears instead of 17
=================================================
Gear#__Gear__%Change__GearInch
08_____Mid6___11.8%___59.7 =--> inbetween previous 2 low gears

PATTERN C - 15 gears, High Chainring most frequent
=================================================
Gear#__Gear__%Change__GearInch
07_____Mid7___12.5%___54.0 =--> same GI just eliminate cross chaining

Thus the shifting sequences [lowest speed to highest] for A pattern was [lower numbers are higher gears opposite of auto stick shifts]
L9 -> L8 -> L7 -> L6 -> L5 -> L4 -> L3 -> L2 -> L1
M5 -> M4 -> M3 -> M2
H4 -> H3 -> H2 -> H1

New A [low chainring] pattern is:
~~~~~~~~~~~~~~~~~~~~~~~~~~~~
L9 -> L8 -> L7 -> L6 -> L5 -> L4 -> L3
M6 -> M5 -> M4 -> M3 -> M2
H4 -> H3 -> H2 -> H1

Shifting sequence for C pattern was
L9 -> L8 -> L7 -> L6
M9 -> M8
H9 -> H8 -> H7 -> H6 -> H5 -> H4 -> H3 -> H2 -> H1

New C [high chainring] pattern is:
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
L9 -> L8 -> L7 -> L6
M9 -> M8 -> M7
H8 -> H7 -> H6 -> H5 -> H4 -> H3 -> H2 -> H1


[ Yes I know opposite numbers may be confusing, but it's too hard to edit all the posts. I forgot about auto gearing and made gear #1 the highest gear instead of the lowest. ]

Again, thanks for the great recommendation of removing cross chaining from the gear change progression table.

SoonerBent

Couldn't have said it better. No offense HiYo but even as an engineer myself I have to say that you're thinking about this way too much.

SS

steel_is_real

I use the following 9 gears out of a possible 21
Front-Rear When used
Low-1 Going up my driveway!
Low-2 Rarely
Low-3 Very steep hills
Med-3 Mod steep hills
Med-4 Rarely
Med-5 Slight inclines
High-5 Slight inclines, Head wind
High-6 Head wind
High-7 Flat

This is based on Sheldon Brown's recommendation to use gears that stretch the chain the least i.e. don't have chains in extreme diagonal positions

phidauex

I have to take a little issue with this... I think its true that many people get hung up on details and hence miss out on some of biking's pleasure, but I think there are some people that just truly and honestly enjoy the analysis of bicycling. That is what I love about biking, it satisfies nearly all of my interests, being environmentally friendly, exercising, sight seeing, building things, taking things apart, analyzing efficiency, problem solving, competing against others, competing against myself, buying stuff, etc. Some people love only certain parts of that list, which is fine, but that is what is great about cycling, so much to love! I get a real kick out of analysis, though I usually have a goal in mind, which is what I'm uncertain about with this current analysis. But he seems to be getting something out of it, so thats OK with me!

peace,
sam

P.S. psst, last night I used my HP engineering calculator to figure out the maximum turning speed of my fixed gear based on pedal strike angle for various crank lengths, bottom bracket drops, and tread widths. And you know what? I loved it. I just loved calculating that! Just so you know, 5mm less crank length earns you an additional .5mph of turning speed without striking.

HiYoSilver

No offense taken. I'm just trying to setup the right habits, I returned to cycling last Oct and it's been a big hurdle to understand both the new terminology and the value of newer concepts. I expect it will be about another year until I can just ride and enjoy the ride without focusing on the riding mechanics. Hopefully by then, my muscles will have been rebuilt enough that I can just use the middle chainring and float up and down the cassette as needed.

Until I looked at this issue this week, I didn't realize there even were three different series of shifts that would work with triples and cassettes.

After going thru all this, I sure can't see the value of a "10 speed" cassette where an inbetween gear is stuffed in the middle of a cassette. The cassette range itself is not extended at all. When you put the "30 gears" into a shift progression table, you're still going to end up with 16 to 17 usable gears. I would have rather the engineering effort would have gone into derailers that can handle larger gaps in cassettes and chainrings or reducing the costs of Carbon fibre frames.

Thanks for listening and making comments.

roadfix

I'm sure most of these well intended comments are falling on deaf ears....

As for my geared bikes, I simply pick the lowest and the highest ratios I think I'll ever need and assemble everything in-between without crunching numbers.......I'm happy if my cassette laid on its side resembles a profile of Mt. Fuji......

HiYoSilver

Talk to Shamino. They are the ones who decided not to extend the mountain by adding a 11tooth cog to the
12-27 9 speed cassette. Instead they kept the mountain the same size and added another switch back in the middle.

Real happiness would be to forget all this junk and have one chainring and a monster cassette that could handle all needs from low to high with smooth transitions between each shift. This would have to be lighter than current doubles and triples.

This would be a real Mt Fuji cassette with 17 cogs:

10 11 12 13 15 17 19 22 25 27 30 34 38 44 50 56 62


Marriage that with a 46tooth chainring and you would able to handle the steppest hill with a low GI of 20 and a high GI of 126. You could eliminate the front shifter, the front derailer, and 1 or 2 chainrings. Obviously you'ld need a new design for the rear derailer and the rear shifter and this would make it easier to get people who have trouble understanding shifting used to a bike.

Only disadvantage I can see is 17 cogs might weight too much. I am not an engineer, but I would think there would be a pulley type of solution that would be able to reduce the number of cogs needed and still keep each shift between 5% and 15%.

Camel

The value comes from closing the gaps without having to double shift. No change in cadence results. If you double shift wrong, you can end up too high or too low-not good for racing folks. Particularly for recreational folks using compact doubles I'd imagine.

Mind you, I don't have 10 speed cassettes on any of my bikes-just pointing it out.

Roody

Anybody have a couple Motrin I can borrow?