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Calling all Gear heads !! Attention !! Gear Calculator Problem.....

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Calling all Gear heads !! Attention !! Gear Calculator Problem.....

Old 06-19-10, 08:08 PM
  #1  
Unknown Cyclist
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Calling all Gear heads !! Attention !! Gear Calculator Problem.....

Ok...for all the nitpicking rabbits of this world - first let me say "I HAVE USED GOOGLE".

For everyone else, I've been putting numbers in Sheldon's Gear Calculator and I can't get any results that I like.



I'm putting together a lightweight 700C tourer and I have:

Chainset = Ultegra C/set 52/42/30 FC6503 9spd
Cassette = LX M580 11,12,14,16,18,21,24,28,32

Results:

52 42 30
11 126.5 102.2 73.0
12 116.0 93.7 66.9
14 99.4 80.3 57.3
16 87.0 70.2 50.2
18 77.3 62.4 44.6
21 66.3 53.5 38.2
24 58.0 46.8 33.5
28 49.7 40.1 28.7
32 43.5 35.1 25.1

This gives me the following useful gears:

1) 25.1
2) 28.7
3) 33.5
4) 38.2
5) 46.8
6) 53.5
7) 62.4
8) 70.2
9) 87.0
10) 99.4 and possibly 116

While I don't want to seem ungrateful for having 10 unique gears to choose from, there seems to be a lot of dead wood and no clear and simple gear change pattern, other than perhaps hogging the middle ring for as long as possible and chain line be damned (at 35" to 102" I could probably nearly live there).

As such, the outer ring is nearly redundant and the inner doesn't fare much better.

I've tried other combinations of chainsets and cassettes, but I can't find anything that is a measurable improvement.

A smaller outer ring simply pushes the two ranges closer together.

When I started touring I had a 14 - 34 5 speed freewheel and a 52/36 chainset.

This gave a clear and easy change pattern, reasonable chainline and well spaced gears.

1) 28.7"
2) 34.8"
3) 44.3" - change to outer ring
8) 64"
9) 82.8"
10) 100.6"

Ok, some of the steps are a little on the large side, but why can't I find cassettes or chainsets that will combine to give a modern equivalent ?

Ideally I'd like to use the cassette I've got and/or the chainset - however for the right results I'd start over.

Is there any way to get a range of about 20/25" to 100/105" with a reasonable number of even steps and - most importantly - a simple gear change pattern ?

I don't want to have to play gear lever gymnastics just to get to the next gear

Any ideas anyone ?

(please stick to inches)

Last edited by Unknown Cyclist; 06-19-10 at 08:12 PM.
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Old 06-19-10, 08:15 PM
  #2  
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You're over-analyzing it.

Small chainring: climbs and hellacious headwinds.
Large chainring: descents and tailwinds.
Middle chainring: normal conditions.

The FD is for choosing the gear *range* for the current conditions.
The RD is for 90% of your gear changes.
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Old 06-19-10, 08:19 PM
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You're overthinking it, dude. There's NOTHING ANYWHERE that says you have to go numerically up the gears.

Most of us have areas where we feel the need for front shifting due to terrain, but most of the time it's one ring and an assortment of gears.

If THIS is that important to you, you need to get an SS and ride more.
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Old 06-19-10, 08:32 PM
  #4  
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Originally Posted by Shimagnolo View Post
You're over-analyzing it.

Small chainring: climbs and hellacious headwinds.
Large chainring: descents and tailwinds.
Middle chainring: normal conditions.

The FD is for choosing the gear *range* for the current conditions.
The RD is for 90% of your gear changes.


Do you have NO respect for chainline ??

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Old 06-19-10, 09:45 PM
  #5  
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Originally Posted by Shimagnolo View Post
You're over-analyzing it.

Small chainring: climbs and hellacious headwinds.
Large chainring: descents and tailwinds.
Middle chainring: normal conditions.

The FD is for choosing the gear *range* for the current conditions.
The RD is for 90% of your gear changes.
This is a very good generalization. Out of the 30 possible gear combinations there are only two that you should definitely try to avoid, big to big and small to small.

Choose the gears that let you keep a high cadence, easy enough that you can turn the cranks pretty fast. Avoid having to push the pedals too hard.
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Old 06-20-10, 05:03 AM
  #6  
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Originally Posted by DX-MAN View Post
You're overthinking it, dude. There's NOTHING ANYWHERE that says you have to go numerically up the gears.

Most of us have areas where we feel the need for front shifting due to terrain, but most of the time it's one ring and an assortment of gears.

If THIS is that important to you, you need to get an SS and ride more.
Well, perhaps - but I'm not sure 'overthinking' is correct. People used to put some thought into what gear ranges they wanted and what change patterns.

I guess times change and now people are content to be handed a plethora of repeated and useless gears and to say thank you for it.

Maybe there is 'NOTHING ANYWHERE' that says I should have a logical progression where the next evenly spaced gear is actually easily obtainable, but equally there is 'NOTHING ANYWHERE' that says I shouldn't have this.



I have considered trying a fixed gear, I've just finished assembling a folding tourer with a 5 spd geared hub from 32" to 80" and having made a few trips on it, I'm not sure I'd what to try anything with a more restrictive gear range.

But who knows what the future holds.....
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Old 06-20-10, 06:44 AM
  #7  
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If "a logical progression where the next evenly spaced gear is actually easily obtainable" is what you want, it does exist. You just need to get one of these:

http://www.rohloff.de/en/products/sp...son/index.html

Be prepared to pay dearly for it, however.

I wouldn't say we all are "content" with the duplicate gears on our multiple sprocket and derailleur-equipped bicycles, but most of us are somewhat pragmatic about the cost-to-benefit ratio.
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Old 06-20-10, 07:17 AM
  #8  
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you've crunched the no.s for what gearing you have. that's good. you have the widest stock cassette available. not good for touring. probably never
use 52x11,12. try crunching the no.s for 12-28 9 sp cassette and a 26-38-48 crank. 24 to 108" with about 16 close ratio gears. you'll have assemble
the cassette, but you can get what ever gearing you want. or you could make a 13-32 out of your present cassette by
getting a 13 1st position cog and a 15 mid position cog. this would give you 100 to 22" with a 48-38-26 crank.

Last edited by roberth33tiger; 06-20-10 at 07:43 AM. Reason: spelling, added 13-32
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Old 06-20-10, 08:26 AM
  #9  
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Originally Posted by Unknown Cyclist View Post
Well, perhaps - but I'm not sure 'overthinking' is correct. People used to put some thought into what gear ranges they wanted and what change patterns.

I guess times change and now people are content to be handed a plethora of repeated and useless gears and to say thank you for it.

Maybe there is 'NOTHING ANYWHERE' that says I should have a logical progression where the next evenly spaced gear is actually easily obtainable, but equally there is 'NOTHING ANYWHERE' that says I shouldn't have this.
Modern cassettes have enough cogs that a reasonable gearing progression can be had by just switching to the next cog. No need to change chainrings too. Doesn't that seem like an improvement? I realize that you seem offended by the un-complication of gear shifting but I think you'll quickly get over it when you try the "new" way.

As for repeated gears, you need to actually go out and ride a bike with the set up you are considering. When you do, you'll find using each one of the chainrings provides you with a gear range suited to certain terrain (as already mentioned). When you shift from one chainring to the next, that gear repetition prevents having to make a large number of shifts at the rear to get to the next logical gear or to a similar gear that you were using (in anticipation of a terrain change).

I would agree with post #8 though that the crank and cassette you are considering are not ideal for touring. Way too much high end (unless you like to really bomb those descents) and too little low end. A touring crank with a road cassette would make a lot more sense. You could run something like a 46/36/24 with a 12/27 cassette or even 12/30.

You will also quickly find out how tolerant newer systems are of cross-chaining. I use every cassette cog when in my middle ring without issues (though I do need to trim the FD to avoid noise). In the big and small rings, every combination is usable without noise though in practice I never go anywhere near the big/big or small/small combo. I shift to the outer or inner chainring solely for descending or climbing then get right back in my middle ring and simply shift at the rear.
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Old 06-20-10, 08:39 AM
  #10  
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front-Nr-rear-Nr-i (sorted by i) where i=cinematic ratio of the gears.
39-II-26-1-1.5
39-II-24-2-1.625
39-II-22-3-1.772727
39-II-20-4-1.95
53-I--26-1-2.038462
39-II-18-5-2.166667
53-I--24-2-2.208333
53-I--22-3-2.409091
39-II-16-6-2.4375
53-I--20-4-2.65
39-II-14-7-2.785714
53-I--18-5-2.944444
39-II-13-8-3
53-I--16-6-3.3125
53-I--14-7-3.785714
53-I--13-8-4.076923

dura-ace 7400 cassette (8speed 13-26) and dura-ace 7400 chainrings (53-39)

But that's irrelevant. I usually go with the big ring and 3rd-4th gear (counting from the biggest) speeding up to 7th gear (8th is just for descends, on flats only at massive sprints to 50km/h I drop to the 8th gear)
The small chainring (not exactly a granny ring at 39tooth) I use it on climbs (in combination with the the largest gears 26-24-22-20).
But I'm a slow cadence rider so the big chainring is almost worn out while the small chainring is brand new (21years old, but not worn out)

On cars is another story. It can be intercalated steps like 1low 1high 2low 2high.. or in sequence 1low 2low 3 low.. 1high 2high or neither (but those that are neither have automatized transmission, not manual, not with planetary gears). For a fact smart for two has 2x3speeds (3 in the gearbox, 2 on the final drive - but it's an automatized mechanical transmission), also it's common on trucks with 2x5 2x6 speeds that are either range or half step.- different things, cars do not have chains but they have helical gears and spur gears (for reverse usually) so it's not comparable.

Last edited by Asi; 06-20-10 at 10:36 AM.
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Old 06-20-10, 08:52 AM
  #11  
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If you want to simplify your gearing Unknown Cyclist, you're not going to find it using 9 speed cassettes. Are you friction or indexed shifting?

My favorite bike to ride has 26/44/48 rings and a 7sp 13-15-17-20-24-28-32 FW. I get 17 distinct gears out of it, it shifts wonderfully in friction. I mostly ride between the 44 and 48, saving the granny for steep hills. I've tried more than 7 cogs,and hated the extra right hand shifting. I''ve got two hands, two shifters and I prefer to use them both. Even six speeds is good BTW. I know there' no more 7 sp. cassette hubs, so I stick to using 7sp Phil Wood FW hubs. There's plenty of 7sp FW's to be found, 13-28 are the most common, but IRD makes them in 13-32 also.
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Old 06-20-10, 08:55 AM
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Gathr: there are also shimano tourney megarange 14-36 6-7sp freewheels But that is kind of crap quality.
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Old 06-20-10, 09:09 AM
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Asi ...... Yes ....It's too bad Shimano doesn't make good FW's anymore. I know some people buy various versions of their FW's and make their own custom cogsets though.

I keep buying vintage used and NOS Sachs FW's from people that don't want them anymore. A few weeks ago a guy sold me a box of barely used bodies and all the cogs/spacers (enough for 6 FW's) for $25 shipped! He was about to throw them in the trash.
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Old 06-20-10, 10:18 AM
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Originally Posted by Unknown Cyclist View Post
I'm putting together a lightweight 700C tourer and I have:

Chainset = Ultegra C/set 52/42/30 FC6503 9spd
Cassette = LX M580 11,12,14,16,18,21,24,28,32

Results:

52 42 30
11 126.5 102.2 73.0
12 116.0 93.7 66.9
14 99.4 80.3 57.3
16 87.0 70.2 50.2
18 77.3 62.4 44.6
21 66.3 53.5 38.2
24 58.0 46.8 33.5
28 49.7 40.1 28.7
32 43.5 35.1 25.1

This gives me the following useful gears:

1) 25.1
2) 28.7
3) 33.5
4) 38.2
5) 46.8
6) 53.5
7) 62.4
8) 70.2
9) 87.0
10) 99.4 and possibly 116
I generally don't look for an exact sequence when I ride my 30sp touring bike. THere are just too many useful combinations to actually get it wrong. I don't ride my bike like a car where you start out in '1st,' bring the revs up and shift to '2nd,' '3rd,' etc. I usually start in the middle ring, middle or slightly larger cog; when I get moving I can decide if I need to shift up or down, and the terrain dictates what chainring I use.

Trying to simplify the sequence through 30 gears is very difficult, and this is (IMHO) one of the primary disadvantages of multi-chainring derailleur systems.

But since you asked, I think the following might be an acceptable sequence:

52 42 30
11 (126.5-13th) 102.2 73.0
12 (116.0-12th) 93.7 66.9
14 (99.4-11th) 80.3 57.3
16 (87.0-10th) (70.2 - 8th) 50.2
18 (77.3- 9th) (62.4 - 7th) 44.6
21 66.3 (53.5 - 6th) 38.2
24 58.0 (46.8 - 5th) (33.5 - 3rd)
28 49.7 (40.1 - 4th) (28.7 - 2nd)
32 43.5 35.1 (25.1 - 1st)

Edit: Added a JPG to help with formatting:


This gives you 13 unigue ratios with no significant cross chaining, and a relatively simple sequence to follow:

biggest three cogs in the small ring, then downshift one cog and upshift the middle ring; 5 cogs in middle ring, then downshift one cog and upshift to big ring; use big ring for alll small cogs.

I defy anyone to come up with a better solution!
(except maybe a Rohloff Speedhub with a chain tensioner with a FD and 24 and 38 tooth chainrings).

Good luck!
Attached Images
File Type: jpg
GearChart..JPG (15.3 KB, 8 views)

Last edited by LarDasse74; 06-20-10 at 10:24 AM. Reason: Added JPG
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Old 06-20-10, 06:33 PM
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Originally Posted by dperreno View Post
If "a logical progression where the next evenly spaced gear is actually easily obtainable" is what you want, it does exist. You just need to get one of these:

http://www.rohloff.de/en/products/sp...son/index.html

Be prepared to pay dearly for it, however.

I wouldn't say we all are "content" with the duplicate gears on our multiple sprocket and derailleur-equipped bicycles, but most of us are somewhat pragmatic about the cost-to-benefit ratio.
Yeah, I've got a Rohloff on my Thorn Raven Tour and am still somewhat in two minds about it tbh.

Not because of the cost, just because the claimed benefits don't seem so beneficial in real world situations.

I'm not discounting the Rohloff entirely, I'll persevere with it when I'm not in a hurry and I think I'd be happy to have one on my recumbent or on a tandem (because it's simpler) - but - as far as the Raven Tour goes, atm I can't really see it being a keeper.

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Old 06-20-10, 08:17 PM
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Just ride your fricking bike! Stop thinking it is a car.
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Old 06-20-10, 09:40 PM
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Originally Posted by Unknown Cyclist View Post
Well, perhaps - but I'm not sure 'overthinking' is correct. People used to put some thought into what gear ranges they wanted and what change patterns.
People used to put som thought into their gear ranges when they had only 10 possible combinations. You have 27. Of course there's going to be some dead wood.

Besides, the objective is not to have a single possible combination for every possible condition. It's to have a useful range for steep hills on your small ring, moderate hills and flats on your middle ring, and moderate hills, flats, and downhills on you large ring.
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Old 06-20-10, 09:50 PM
  #18  
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personally, I'd go with something like 13-30 mixed cassette with a 26-36-46 touring triple.
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Old 06-20-10, 09:54 PM
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Originally Posted by AEO View Post
personally, I'd go with something like 13-30 mixed cassette with a 26-36-46 touring triple.
Nice choice - biggest issue is finding a 13t that will take a lockring. After that, it's a mix-n-match proposition.
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Old 06-20-10, 10:14 PM
  #20  
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Originally Posted by TomT74 View Post
Nice choice - biggest issue is finding a 13t that will take a lockring. After that, it's a mix-n-match proposition.
just buy a 13-25 cassette.

not too hard to find tiagra/HG50 9sp 13-25 cassettes.
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Old 06-21-10, 03:14 AM
  #21  
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Originally Posted by LarDasse74 View Post
I defy anyone to come up with a better solution!
I've toyed with the idea of running a quad front(38-41-44-47) against a normal 3-speed IGH rear hub(75%-100%-133%). That would give you 12 separate gears spaced 5.5 - 8.5% apart, no repeats.

I cancelled the idea for two reasons:
1) thinking about how to get it to work from a pair of Campy brifters just gave me a headache (besides, which'd be "front"? Mechanically it's obvious of course, but in keeping with the "left sets range" philosophy it'd require a switch)
2) it still didn't give me quite the range I needed for an all-season commuter.
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Old 06-21-10, 03:20 AM
  #22  
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Originally Posted by Unknown Cyclist View Post
....Maybe there is 'NOTHING ANYWHERE' that says I should have a logical progression where the next evenly spaced gear is actually easily obtainable.....
I think Shimano missed out a bit on their "electronic shifting", Di2 or whatever the name is. I'd like to se such a system working like paddle shifts on race cars. Toggle a switch one direction and you have an upshift, toggle the other way and you have a downshift, with a small electronic brain keeping track of it's a FD or a RD shift. Could be programmed to ignore ratios that are too close to each other.
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Old 06-21-10, 05:14 AM
  #23  
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Originally Posted by roberth33tiger View Post
you've crunched the no.s for what gearing you have. that's good. you have the widest stock cassette available. not good for touring. probably never
use 52x11,12. try crunching the no.s for 12-28 9 sp cassette and a 26-38-48 crank. 24 to 108" with about 16 close ratio gears. you'll have assemble
the cassette, but you can get what ever gearing you want. or you could make a 13-32 out of your present cassette by
getting a 13 1st position cog and a 15 mid position cog. this would give you 100 to 22" with a 48-38-26 crank.
I'm considering a 48/36/26 or possibly changing the outer ring on my 52/42/30.

Then again, the SRAM APEX 46/38 looks interesting.

SRAM also do a 50/34 - I wonder if the 34 inner would go on 46/38 ?

A 46/34 might be the answer....
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Old 06-21-10, 06:28 AM
  #24  
Shimagnolo
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Originally Posted by dabac View Post
I think Shimano missed out a bit on their "electronic shifting", Di2 or whatever the name is. I'd like to se such a system working like paddle shifts on race cars. Toggle a switch one direction and you have an upshift, toggle the other way and you have a downshift, with a small electronic brain keeping track of it's a FD or a RD shift. Could be programmed to ignore ratios that are too close to each other.
I've been thinking the same thing.
I'm sure it is only a matter of time until someone does it.
Once good mechanical parts exist for electronic shifting, reprogramming the logic is trivial.
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Old 06-21-10, 06:50 AM
  #25  
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Originally Posted by TomT74 View Post
Nice choice - biggest issue is finding a 13t that will take a lockring. After that, it's a mix-n-match proposition.
Lots of places sell them , choose Miche or Shimano ....
The Shimano ones are XT/XTR, but you can get Ultegra ones too. They all fit the same. All it takes is the time to find them.

http://www.ebikestop.com/miche_shima...eed-FW1732.php

http://www.jensonusa.com/store/produ...M760+Cogs.aspx

http://www.universalcycles.com/shopp...&category=1569
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