The timeless appeal of 7-speed gearing

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bigjim
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Re: The timeless appeal of 7-speed gearing

Postby bigjim » 9 Jan 2019, 7:44pm

maybe friction front shifting with indexed rear is the final solution!

Recently done that to one of my bikes. Shimano Sora STIs with only the rear cassette indexing. The front is operated by a DT shifter. It all works very well. I generally spend most of my time in the middle ring anyway.
Nothing left to prove.

Bmblbzzz
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Re: The timeless appeal of 7-speed gearing

Postby Bmblbzzz » 9 Jan 2019, 9:43pm

bgnukem wrote:Am currently building up a Spa Aubisque-based bike !

Totally OT but this struck me from when it was announced as a really bad name. Or maybe deliberately sarcastic at the expense of the mamils who will buy it. I mean, why not just call it the Fat [rude word removed]?
:D

Bmblbzzz
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Re: The timeless appeal of 7-speed gearing

Postby Bmblbzzz » 9 Jan 2019, 9:45pm

Ooh, I've fallen foul of the automatic censor! First time that's happened. It wasn't a word I consider terribly rude (else I wouldn't have used it). In fact, it's still official terminology at the Home Office. Seven letters, FTR. Definitely not four....

thelawnet
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Re: The timeless appeal of 7-speed gearing

Postby thelawnet » 9 Jan 2019, 11:20pm

Annoying Twit wrote:In hindsight, I think that the main advantage of the Claris is that it has proper brifters. The A070 brifters that work with Tourney have that small side button like the old Claris. Not that I'm ever likely to buy any bike with them on, but out of curiosity how well do the A070s work? How good is the 'user interface'?


I believe that Sora was originally 3300 8-speed, 2200 was introduced the next year as 7-speed, and was effectively Sora 2200.

In 2008/2009 Sora became 3400 9-speed and 2200 became 2300 8-speed.

In 2012/2013 Sora removed the thumb lever to match the higher groupsets, as Sora 3500, and the new 2400 was given the Claris name.

Tourney A070 was launched the same year as Sora 3500, so the year before 2400, hence A070 was a 7-speed version of 2300, and was further differentiated when 2300 was discontinued. I think that 2200, 2300, 3300, 3400 & A070 shifters are pretty similar.

slowster
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Re: The timeless appeal of 7-speed gearing

Postby slowster » 10 Jan 2019, 1:15am

This thread has certainly given me pause for thought, especially SamuelD's original point about the optimal nature of many of the 7 speed cassettes, i.e. no 11 or 12 tooth sprockets and nice 2 tooth jumps from 13 to 21 on the 13-28 cassette for example (something which I think is not available on Shimano's 8 or 9 speed cassettes).

Comparing the 12-36 9 speed cassette with the 13-28 7 speed cassette, and assuming for example a 44/34/24 triple chainset, the only significant advantage for me of the 9 speed cassette would be the two ultra low bottom gears - http://www.ritzelrechner.de/?GR=DERS&KB=24,34,44&RZ=12,14,16,18,21,24,28,32,36&UF=2220&TF=90&SL=2.6&UN=MPH&DV=gearInches&GR2=DERS&KB2=24,34,44&RZ2=13,15,17,19,21,24,28&UF2=2220. In most other respects for me the spread of the gears with the 7 speed cassette would be as good or better than the 9 speed cassette.

Moreover if friction shifting were used, then if those two extra lower gears were required for cyclecamping or a holiday in the Alps, it would be a relatively simple matter to switch to 9 speed: just change the cassette and chain.

The possibility of using a 7 speed to reduce wheel dish in a frame with 135mm OLN spacing is also very appealing, but I presume that requires a (no longer available?) 7 speed freehub compatible with a modern Shimano hub shell.

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hujev
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Re: The timeless appeal of 7-speed gearing

Postby hujev » 10 Jan 2019, 3:09am

Glad this tread was resurrected, as I'd missed it before (hoping I did at least; if I didn't, I probably already replied with 87% the same thing I'm about to write here...)

5, 6, or 7 speed freewheels (er, blocks) for me! I'm finally getting around to building up two Woodrup frames; one a custom touring I took delivery of going on 3 years ago (!), and another, an 86 Giro Touring I bought used in .. 2008(!!).

I've never used more than 7, and (save on short-owned interim bike 15 years or so ago), never had a 'freehub', finding freewheels 100% adequate for me.

Another thing that's adequate is 21 gears! (I'm always a 3x up front which apparently is also an anti-fad now)... Never found it that difficult to vary cadence despite what the gear-hucksters would lead one to believe, that you should constantly shift to keep a dingle, clockwork cadence... After all, we can walk and run, dance (not me) or stagger, even kick, so why is it made to be such an impossibility to pedal at a variable speed?

Maybe if I weren't too old I'd try a single-spped, fixed gear, or penny farthing.

So I've always been a 'crossover' shifter, as they used to call them, using the small chainwheel for the steep hills or especially hellish headwinds, the large for tailwinds and downhill, and middle for everything (95%) else (see again this in Tony Oliver's book: http://hujev.net/image/velo/screen/czrP4183308.jpg). I guess that's more common now with 10 or 12 or whatever on back but I guess I was getting to saying I never fell for the much-discussed 'half step' and similar schemes (which received as much letters to the editor and so forth, period-corrected, as a 'hot button forum topic' would nowadays).

Anyway, all I wanted to say before going off on the above is that for the 2016 Woodrup I'm using my first-ever 'custom' block (gear freaking! .. of sorts .. because factory spec blocks have always been good enough, but I have to justify my chain whips finally!).

So thought I'd try a nice increasing cog size since I seem to notice differences in the smaller cogs more than the higher. Luckily I have an absurdly plush stash of NOS Suntours, Winner Pros in large part, so was able to do 13,14,15,17,21,26,34.

Let's see if copying this gear chart from the St. Sheldon website works:

24 50.00% 36 27.80% 46
13 50.4 75.7 96.7
7.70%
14 46.8 70.3 89.8
7.10%
15 43.7 65.6 83.8
13.30%
17 38.6 57.9 73.9
23.50%
21 31.2 46.8 59.8
23.80%
26 25.2 37.8 48.3
30.80%
34 19.3 28.9 37


... well not so well, but anyway... too bad I can't specify monospaced type. At least I can change the colours... Chainrings on top line, with percent (in gear inches!) between, and cogs down the left side and gear inches to the right of each, etc.

24,36,46 up front. All this on a 135-spaced rear hub (Phil Wood), so plenty of room for my preferred dork disc (spoke protector) too!

And I'll hear nothing of '.. weak axles.. mm .. blablabla .. hmmm .. .. 135 spacing .. blabla bearings further out, freehubbs, mmblabla' with a Phil Wood Hub!!

On the 85 I happen to have a 13-30 7 sp. Sachs I haven't used much since buying ca. 1998, so may try that (a better match, I think, with the Campag 1034 record hubs & Mod. 58 rims with my Ofmega/Avocet triple chainset; the 144 BCD sadly allows me a smallest 41t middle and I'll probably swap-down the 50 to a 48).

Here's another hard to read table:

30 36.70% 41 22.00% 50
13 60.6 82.9 101
15.40%
15 52.5 71.8 87.6
13.30%
17 46.4 63.4 77.3
17.60%
20 39.4 53.9 65.7
15.00%
23 34.3 46.8 57.1
13.00%
26 30.3 41.4 50.5
15.40%
30 26.3 35.9 43.8


I'm also a fan of 5-speed, esp. as the Winner Pro which has a nice flat, 'no-soak-in' outer body in 5-speed (the 6&7s, like most freewheels, have an outer cog that acts as a sort of 'dish' to feed water into the bearings; illustrated also in Oliver's book on the page near the above link, but I didn't scan that part). So good on muddier bikes (like my 84 Trek or Kibo). But I'll be honest - even if I rusted out a freewheel I year I believe I am covered for life... A recent Winner7 freewheel I had on since 2005 still spun like new when I removed it tho, even after four long, sometimes wet, heavy tours and other 'weather'.

Lately I've developed a fetish for 'normal' 6-speeds, too (and have a small stash). Why go 'ultra 7' when you can go 'straight six'? Who knows, I like both! I may yet change my mind on the Giro touring (126mm spaced) and instead of the Sachs use a Winner Pro-6000 (the non 'ultra' spacing model) with whatever combination I can dream up that requires switching at least one cog.

All these 5, 6, & 7-speed freewheels, at least (know nothing of freehubs) also allow me to use my favo(u)rite Sram PC-8x0 chains, too. I think I saw somewhere that the narrower and narrower chains for those 9,10, 12, 15 or whatever freehubs use chains more akin to (and expensive as, and maybe as fragile as?) jewellery chains, eh? A nice PC-870 will cost me about $20, but did I see 10-speed chains at like $80 or something?? I may be wrong as I wasn't looking, but seem to recall some shock in the background of my chain listing.

So the timeless appeal of 5,6,7 for me is:
1) I have a good stash,
1.5) I need a 1.5 for the colour blend - how about freewheels are, well, just Cool, and they're mostly 5, 6, & &7!
2) they've always been 100% adequate technologically and in number of gears provided,
3) a Phil freewheel hub costs me $175, but a Phil freehub-hub os about 400...
3.5) Nice wide, easy to shift spacing (especially with Manly Friction Shifting!)
4) they're (mostly, for me) Suntour!

//robert, going crazy with the colours to make up for my table formatting inadequacies

Greystoke
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Re: The timeless appeal of 7-speed gearing

Postby Greystoke » 10 Jan 2019, 6:39am

My most used bike has 3x5, my old tourer had 2x6 which I've upgraded to 3x6....both screw on freewheels.
I've never risen a bike with a cassette.
Both bikes are super reliable, parts are cheap and still readily available.
What's chain rub? :D I can use all the gears without silly chain angles (I don't, but I can)

Brucey
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Re: The timeless appeal of 7-speed gearing

Postby Brucey » 10 Jan 2019, 10:00am

Hujev's gears in another (hopefully more easily digestible) format here

http://ritzelrechner.de/?GR=DERS&KB=30,41,50&RZ=13,15,17,20,23,26,30&UF=2185&TF=90&SL=2.6&UN=MPH&DV=gearInches&GR2=DERS&KB2=24,36,46&RZ2=13,14,15,17,21,26,30&UF2=2185

The one built round the suntour freewheel (with the 46-36-24 chainset) looks like a 13-30 6s to which a 14T sprocket has been added; I'd have probably chosen to do something different to that (in fact I did, see below).

The SunTour winner pro is a great freewheel (I used to use those to the exclusion of almost everything else) but it has a few weaknesses;

- the shift quality isn't that good (not the best BITD, pretty dismal by modern standards)
- getting hold of sprockets now is both difficult and expensive. Folk want silly money for new ones on e-bay.
- for touring duties the 21t sprocket being the largest that will fit in the #3 position is a limitation; BITD there were converters so that larger sprockets could be fitted in this position.

I used to use a 13-28 7s freewheel with a 50-44-30 chainset; this is a bit like an alpine double but with an extra chainring that suits fast work. Freewheel could be built as 13-26 instead or the 30T chainring swapped for a 28T one if a different gear range was more appropriate.

http://ritzelrechner.de/?GR=DERS&KB=30,44,50&RZ=13,15,17,19,21,23,26&UF=2185&TF=90&SL=2.6&UN=MPH&DV=gearInches&GR2=DERS&KB2=28,44,50&RZ2=13,15,17,19,21,24,28&UF2=2185

eventually I swapped the freewheel arrangement for a 7s cassette hub; no more limitations concerning sprocket availability/position, no more worries about broken axles, excellent shifting and bulletproof reliability from something that cost very little. However whilst I have never managed to destroy one, given that 7s freehub bodies are now getting difficult to source I may have to come up with another plan in the future.

cheers
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mig
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Re: The timeless appeal of 7-speed gearing

Postby mig » 10 Jan 2019, 10:11am

"Maybe if I weren't too old I'd try a single-speed, fixed gear, or penny farthing"

i've never quite understood this. when is this age? and what's so demanding? or is it from that TdF quote about the use of derailleurs from years ago?

in reading the thread yesterday i realised that i've never ridden a bike with a 7 speed gear. went straight from 5 to 8. seems that i've missed out.

iandusud
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Re: The timeless appeal of 7-speed gearing

Postby iandusud » 10 Jan 2019, 10:27am

Here's my experience. I have two modern road bikes, one for winter with 12-32 10 speed cassette and my summer bike with an 11 speed 11-32 cassette. There is no advantage of the 11 speed over the 10 speed because I don't need an 11t sprocket. I also regularly use my Moulton which has a 7 speed freewheel. Where I need closer ratios my first two bikes give me gear ratios of 48, 54, 61, 68, 75 and 84 inches. My Moulton gives me 48, 55, 59, 68, 79. Gears higher than this are only used downhill where being able to hold a high cadence isn't need. The first two bikes have 29" bottom gear, the Moulton has a 26" bottom gear. In practice the Moulton has an equally useful and usable set of gear ratios as the other two bikes. The jump from 68 to 81" might seem a bit big but in practice it isn't. Where I like to have close ratios is in the 50-70" range. Below 50" I'm going slowly enough to warrant bigger gaps. Once I'm spinning out on a 70" gear I'm moving along very nicely and easily push an 80" gear. If you use a half step and granny set up you'd probably get even closer ratios on a 7 speed set up than a 10/11 speed with a double chainset.

I like all my bikes but I'm not convinced by the need for so many sprockets at the rear.

Ian

Brucey
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Re: The timeless appeal of 7-speed gearing

Postby Brucey » 10 Jan 2019, 11:20am

mig wrote: ...in reading the thread yesterday i realised that i've never ridden a bike with a 7 speed gear. went straight from 5 to 8. seems that i've missed out.


maybe. Where I grew up there were plenty of hills (some very steep; the closest one is/was used as a hill climb course...) so having a 21 or 24 sprocket was useful (these days I'd want at least 30T ahem....) and having one bike which would get you to a local TT and then let you ride it meant that having a few closely spaced sprockets was a good idea too. Pretty much as soon as I could, I ditched 5s freewheels and bought compact 6s ones and then converted them to 7s ones. It must have been about 1979 or maybe 1980 when I first used c6s/7s; it meant that I could ride TTs and not kill myself riding out them, all on the same freewheel.

I quickly realised that 126mm OLN 7s meant that I couldn't use the lightest wheel compenents without the wheels suffering; the dish was very slightly worse than 5s 120mm OLN and plenty worse than 5s 126mm OLN was of course. By fiddling around I managed to make the 7s wheels work at ~128mm OLN and with clearances optimised (the chain wore the paint off the inside of the dropout and my wheels didn't even work in my friend's frames) the dish on the wheel was about the same as 7s 130mm OLN would be with less carefully chosen parts. I changed from freewheels to 7s cassette hubs shortly after SunTour revised their freewheel range and my favourite sprockets went NLA in the LBS. When 8s 130mm OLN came along, and furthermore you couldn't modify/improve the dish/spacing (eg on a campag freehub, because of the daft design of the thing), I not only didn't see the point, it would have meant a lot of expense and it'd be a significant step backwards, wheel strength-wise.

So I've owned plenty of 8s/9s/10s etc bikes, but I've only ended up with this gearing by accident; it happened to be attached to a bike that I would gladly have bought with different gearing on. In most cases when I have built a bike up from scratch I have built less dished wheels with one or two sprockets less than is fashionable and used those; for example an 8-from-9 cassette on a 7s freehub body means you can ditch the (nearly useless) 11T sprocket from a typical 9s cassette and have reasonable gearing without a lot of faff/expense, all in a wheel that is quite a bit stronger (and/or lighter) than it would be otherwise.

I note with interest that a 2x7 system can give you more, better gears than a 1x11 system and that a 3x7 system usually gives you as many or more, better gears than a 2x11 system. So arguably a 7s based system is 'enough' for most purposes and could (if it were properly developed) be built a fair bit lighter and stronger than alternatives.

The point that most people miss is that less wheel dish means stronger and/or lighter wheels (and not by a small amount). The approach that is presently used to give some form of backwards compatibility is to fit spacers when using a 7s cassette on a 8s freehub and similarly spacers when fitting other cassettes to an 11s freehub; however a more asinine approach would be hard to imagine, since this means you have all the disadvantages of both systems wrapped up in one hopeless package..... :roll:

cheers
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gxaustin
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Re: The timeless appeal of 7-speed gearing

Postby gxaustin » 12 Jan 2019, 6:39pm

The point that most people miss is that less wheel dish means stronger and/or lighter wheels (and not by a small amount).


Interesting points as ever but while I get stronger (and stiffer?) I don't fully understand why they would be lighter; unless you mean because the freehub would be a bit shorter and that would mean a bit lighter?

I've never experienced a wheel collapse but I have been amazed at the dishing used for 11 speed. Mind you my 1999 Mavic Cosmos wheels accepted an 11 speed cassette without modification, much to my surprise.

yostumpy
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Re: The timeless appeal of 7-speed gearing

Postby yostumpy » 12 Jan 2019, 6:57pm

Olive will be in need of TLC in about a month (after the winter hosteling rough stuff weekend ) so I have bought a 13-28 7 speed to try, on my 10 sp hub. I don't have the 4.5 mm spacer but have a Shimano and a campag cassette spacer, that come out at just over 5mm together, so I'm sure a little bit of sanding and they will work. If I like it, then I'll hunt them down! (working with friction bar cons btw)

mattsccm
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Re: The timeless appeal of 7-speed gearing

Postby mattsccm » 12 Jan 2019, 8:27pm

Scope here for my rough stuff bike. (Well nowadays they call it a gravel bike as that's all it does.) Got a pile of 7 speed Shimano free hubs. 5mm spacing perfect for my 8 speed Campag Record Ergos. Unless i have this all wrong.
Now what about doing this with a 135 spaced frame?

Brucey
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Re: The timeless appeal of 7-speed gearing

Postby Brucey » 12 Jan 2019, 9:15pm

no problem, 7s/135 was a thing and 7s/130 can be converted easily enough.

cheers
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