shimano cassettes - 7-speed good : 8-speed not so good

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Graham
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shimano cassettes - 7-speed good : 8-speed not so good

Postby Graham » 3 Feb 2019, 4:39pm

I recently bought a 7-speed cassette with a useful spread 14 - 32.

Even more recently I bought a 8-speed 11 - 32, gradually realising that the 7-speed had the better spread of gears.

I can usefully use a 13 tooth sprocket, but anything starting with 11 or 12 are a wasted opportunity.

Looking around the usual websites I could only find 8-speed cassettes with 32t, starting with the ( unwanted ) 11 tooth sprocket.

This lack of choice seems to be something new.
Last edited by Graham on 3 Feb 2019, 6:22pm, edited 1 time in total.

reohn2
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Re: shimano cassettes - 7-speed good : 8-speed no so good

Postby reohn2 » 3 Feb 2019, 5:01pm

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Brucey
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Re: shimano cassettes - 7-speed good : 8-speed no so good

Postby Brucey » 3 Feb 2019, 5:04pm

six different 7s ratios (starting with 12,13, or 14T) in four different types here

https://www.sjscycles.co.uk/cassettes-7-speed/?ratio=13%2D28&ratio=12%2D24&ratio=12%2D28&ratio=12%2D32&ratio=13%2D26&ratio=14%2D32

and eight different ones in 8s (starting with 13 or 12T here

https://www.sjscycles.co.uk/cassettes-8-speed/?ratio=12%2D21&ratio=12%2D23&ratio=12%2D25&ratio=12%2D34&ratio=13%2D23&ratio=13%2D26&ratio=13%2D38&ratio=13%2D40

inevitably shimano will stop doing a full range of cassettes in the future but other manufacturers will fill any real niche I would imagine.

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cycleruk
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Re: shimano cassettes - 7-speed good : 8-speed no so good

Postby cycleruk » 3 Feb 2019, 5:27pm

I used to get 8 speed 13/26 cassettes and exchange the 23 & 26T sprockets for 24 & 28T from other redundant MTB cassettes..
28T being the largest sprocket available at that time.
Perhaps you could do something similar for yourself.
Leave getting old to others.

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Graham
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Re: shimano cassettes - 7-speed good : 8-speed no so good

Postby Graham » 3 Feb 2019, 6:28pm

Thanks for your researches. I'm sorry that I didn't make the critical factor clearer i.e. biggest sprocket must be 32t.

I think I'll just have to live with the 11t ring on the new 8-speed cassette. Although there may be some limited cannibalisation possibilities despite my ruthless uncluttering.

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Re: shimano cassettes - 7-speed good : 8-speed no so good

Postby kylecycler » 3 Feb 2019, 6:45pm

I've got the same problem as Graham, and although I'd settle for a 30T lowest cog on my triple chainset bikes, all their cassettes start at 11T.

I think I tried fitting a 13T smallest cog to an 11-32 Shimano cassette (I think the next cog up on the cassette body might have been a 14T) but the 13T cog was off a SRAM 13-26 cassette and I don't think it worked, even though it fitted perfectly well. If it had been off a Shimano cassette it might have worked ok, but tbh my memory of doing it is a bit hazy.

I think I tried the above on a Carrera TdF road bike which came with a 52/42 chainset and the 13-26 cassette referred to above; I now run it with 52/38 at the front and 11-32 at the back, which is ok except it still gives a stupid-high highest gear. My two hybrids run 48/38/28 chainsets but still with 11-30 or 11-32 cassettes.

Would it make any sense to work at the other end and fit a smaller biggest chainring, still with the seemingly obligatory 11T highest cog at the back?

NickJP
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Re: shimano cassettes - 7-speed good : 8-speed no so good

Postby NickJP » 3 Feb 2019, 8:54pm

Just fit a smaller chainring. Except for our tandem, I haven't used a chainring bigger than 42t in years.

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Re: shimano cassettes - 7-speed good : 8-speed no so good

Postby roger » 3 Feb 2019, 9:12pm

BBB sell 13 up 8 speed cassettes. They also sell 14 and 16 up 9 speed.
As has already been said cannibalisation seems the answer. Get a "used" 14 up and mate with your 11. It is odds that the 14 will have a lot less use than the mid range sprockets. I have some 15 Marchisio shimano fit sprockets if anyone is interested.


Roger.

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Re: shimano cassettes - 7-speed good : 8-speed no so good

Postby Brucey » 3 Feb 2019, 9:35pm

kylecycler wrote:....Would it make any sense to work at the other end and fit a smaller biggest chainring, still with the seemingly obligatory 11T highest cog at the back?


that's just giving in to the blighters, and it results in a less efficient, faster-wearing transmission too. There is usually a way of building what you want if you can't actually buy it.

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Re: shimano cassettes - 7-speed good : 8-speed no so good

Postby Samuel D » 3 Feb 2019, 10:04pm

I don’t think this lack of Shimano 13T–[large] cassettes in 8-speed is new. The 11–34T model is relatively new but, as you note, not ideal. A 13–32T would be better for most people but doesn’t exist. The 11-34T stretches eight ratios too thinly and can ill-afford to waste one on an 11T sprocket as it does.

Shimano made more sensible cassettes for 7-speed than 8-speed and above. You’ve seen my thread on this. The mystery is why Shimano and the market moved in this unfortunate direction.

Anyway, several of the nice 7-speed cassettes are disappearing, likely having gone out of production. There are signs that some 8-speeds cassettes are going the same way, so a few days ago I bought a stash of 13–26T cassettes while they’re still cheap and available.

This post on another forum describes a method for making a suitable 8-speed cassette. Unfortunately it costs a lot more than buying one off the shelf. Since low running costs are half the point of 8-speed for me, that somewhat defeats the purpose. Your motivation may differ.

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Re: shimano cassettes - 7-speed good : 8-speed no so good

Postby zenitb » 3 Feb 2019, 10:32pm

Graham wrote:I recently bought a 7-speed cassette with a useful spread 14 - 32.

Even more recently I bought a 8-speed 11 - 32, gradually realising that the 7-speed had the better spread of gears.
.


Yes..I have the same problem..compounded by the fact that my "classic" Shimano 105 hubs (FH-1056) will not take 11 top cogs anyway..only 12 minimum.

So I have just bought the Decathlon (actually Sunrace) alternative - a12-32 tooth 8-speed block - see link and pics below

https://www.decathlon.co.uk/12x32-8-spe ... 28485.html

I think this will give you the same gaps as your 7 speed 14-32, plus an extra fast downhill gear?

On eBay you can get single 13 tooth sprockets for £2.27..see third picture. Swap the 12 tooth Decathlon/Sunrace top cog for this one and you are sorted...your original seven 14-32 ratios plus a new 13 tooth 8th gear top - what do you think?

(NB I have just ordered the single 13 tooth sprocket myself to check it fits)
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Re: shimano cassettes - 7-speed good : 8-speed no so good

Postby LuckyLuke » 4 Feb 2019, 9:06am

I've done something similar ish to zenitb above. (After being inspired by the great forum threads on splitting cassettes over the years Thanks all.)
I've brought 9 spd 11-32 & 11-34 cassettes. I've drilled & punched out the pins & reassembled with used 8spd spacers. I discard the 11T & 13T sprockets for a used threaded 13T one, from an 8spd 13-26 cassette.
Another I like is to split an 8 SPD 13-26, remove the 14T & add a 30T 8 or 9 spd sprocket, (new or used), on the end. This gives 8 SPD 13-15-17-19-21-23-26-30.
Or use 9 SPD spacers and make a 9 spd 13-15-17-19-21-23-26-30-34.
Best wishes,
Luke

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Graham
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Re: shimano cassettes - 7-speed good : 8-speed no so good

Postby Graham » 4 Feb 2019, 10:17am

SamuelD : thanks for drawing my attention to your 7-speed topic. That is a very good analysis.

It was only because I bought the 7-sp & 8-sp cassettes around the same time that I realised that something counter-intuitive was going on.

I suspect that I have using 11t-32t cassettes on the 8-speed Dawes, without really noticing. This is probably due to the small chainrings 40t & 28t. It is possibly that I do occasionally use the 11t sprocket. ( But I'd still prefer 12t or 13t as the smallest. )

ZenitB : thanks this is very useful to know that the Sunrace cassettes 12t-32t : 8 speed, are available.

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Re: shimano cassettes - 7-speed good : 8-speed no so good

Postby hondated » 4 Feb 2019, 10:43am

Given all that's been written it's got me wondering why on earth touring bikes were ever fitted with 9 speed. Particularly if my understanding is correct the 7/8 chains last so much longer. Was just a fashion thing ? :?

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Re: shimano cassettes - 7-speed good : 8-speed no so good

Postby Samuel D » 4 Feb 2019, 1:10pm

hondated wrote:Given all that's been written it's got me wondering why on earth touring bikes were ever fitted with 9 speed. Particularly if my understanding is correct the 7/8 chains last so much longer.

They don’t last much longer, only fractionally longer if at all for a given construction and material quality. They can be made a little cheaper due to less elaborate pin-retention methods, although often they’re made in the same way. It’s the even narrower chains that have required expensive manufacturing procedures such as counterbored plates to reliably keep the pin in thinner and thinner plates without the end of the pin overhanging the plate face where it would interfere with the very close adjacent sprocket.

Touring bicycles are a small niche and Shimano essentially ignores them. Besides, their buyers are like the buyers of other bicycles, not necessarily technically savvy people who think critically and independently about these things. More = better as it does elsewhere in cycling and consumer culture.