8 speed chain with 9 speed chainring and front and rear mechs?

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Sweep
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8 speed chain with 9 speed chainring and front and rear mechs?

Postby Sweep » 7 Sep 2019, 10:01am

I think this question has been asked in bits before, but this is a kind of 3 in one question.
And I treat this place as the source of the last word on such matters.
So, before I start tinkering ......


I have an 8 speed set up on a self built tourer.

Front chainset is 22/32/42 (Alivio)I think only ever came in that format.

Am thinking of putting a 44T big ring on which I think will fit.
But it's 9 speed. Likely to be a problem?
If I do fit it, a scouring of shimano's techsheets seems to indicate that I will also have to fit new front and rear mechs to handle the increased capacity and the front's change from a 20 to 22 spread and a 12 rather than 10 jump from middle to big ring.
But these mechs are 9 speed.
Will the 8 speed chain run OK through these?
Sourcing of these bits no issue as I already have them.
The bike and cassette will remain as an 8 speed set up - I like it.
It's an 11 to 34 on the back. Won't be changing that either.
Sweep

reohn2
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Re: 8 speed chain with 9 speed chainring and front and rear mechs?

Postby reohn2 » 7 Sep 2019, 10:27am

Fit the 44t chainring,it'll work,Mr Shimano is a bit elastic in his specs :wink:

I've just gone the opposite way on my Vaya,are you ready for this?
I had and Alpine double 24/39 on a custom assembled 9sp 14/32t,but wanting to go back to 8sp but to avoid a bigger gap than I wanted somewhere in the cassette had make it an 8sp 14/30,which didn't have a low enough bottom gear with the 24t c/ring,so I went back to a MTB triple.
I had an Alivio 22/32/44t one but the 44t was juussstttt a leettle too high for my liking so I bought a 42t ring from Wiggle and fitted that.

So I now have an 8sp 14-30t(made from a Sram 8sp 12-26t,disgarded the 12 and 13t cogs replaced with a Shimano 9sp 14t top,and a 30t behind the 26t),an 8sp 22/32/42t Alivio chainset,run on a Deore M590 9sp rear mech, a 10sp Tiagra front mech,KMC X9 9sp chain,operated by Shimano 8sp 1055 d/t levers in Kelly's on drops.
Everthing runs and changes perfectly :D

Don't you love it when a plan comes together :mrgreen:
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I cycle therefore I am.

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Sweep
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Re: 8 speed chain with 9 speed chainring and front and rear mechs?

Postby Sweep » 7 Sep 2019, 10:45am

reohn2 wrote:Fit the 44t chainring,it'll work,Mr Shimano is a bit elastic in his specs :wink:

I've just gone the opposite way on my Vaya,are you ready for this?
I had and Alpine double 24/39 on a custom assembled 9sp 14/32t,but wanting to go back to 8sp but to avoid a bigger gap than I wanted somewhere in the cassette had make it an 8sp 14/30,which didn't have a low enough bottom gear with the 24t c/ring,so I went back to a MTB triple.
I had an Alivio 22/32/44t one but the 44t was juussstttt a leettle too high for my liking so I bought a 42t ring from Wiggle and fitted that.

So I now have an 8sp 14-30t(made from a Sram 8sp 12-26t,disgarded the 12 and 13t cogs replaced with a Shimano 9sp 14t top,and a 30t behind the 26t),an 8sp 22/32/42t Alivio chainset,run on a Deore M590 9sp rear mech, a 10sp Tiagra front mech,KMC X9 9sp chain,operated by Shimano 8sp 1055 d/t levers in Kelly's on drops.
Everthing runs and changes perfectly :D

Don't you love it when a plan comes together :mrgreen:


Thanks for the reply reohn.
I take it you mean my plan to change the chain ring will, thanks to shimano flexibility, work with those 9 speed mechs passing an 8 speed chain, not that I can keep the 8 speed mechs which seem to have capacity issues.
Re your dazzling bodging, if I have it right, you are running a 9 speed chain? I have massive stocks if 8 speed chains and want to use them. Also i understand they may be tougher.
Surprised that you found the 44T too much. I can't see any downside. Can use it with some pretty large cogs on the back, and if that offers no relief, or causes bad chainline, just drop to middle front ring.
And overall I anticipate less stressed components as the 44T will hopefully mean I spend less time in the smaller rear sprockets, especially the despised 11T
Interested of course in other answers to my initial question.
Sweep

NetworkMan
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Re: 8 speed chain with 9 speed chainring and front and rear mechs?

Postby NetworkMan » 7 Sep 2019, 3:11pm

Hello Sweep,
There is a possibility that after going from 42 to 44 T that the shift from middle ring to little ring won't be quite as good. That's because you'll have to raise the FD by about 4 mm and so the outer cage plate will be 4 mm further from the middle ring which in turn will make it less able to knock the chain off. I just don't know if this will be important but generally this may be in 'panic mode' - under load as you start off up the hill and find you've run out of gears.
That happened to me once on my 3x8 speed tourer when the FD was out of adjustment. It wouldn't shift and I ground to a standstill. I managed to shift it when stopped but wasn't able to get enough momentum to restart and had to push up a long hill on a cycle path. That bike has the interval between middle and big 1 T less than designed risking the chain interfering with the FD inner plate on the upshift from middle to big, but I got away with it and after adjustment it works well.

Unlikely you'll have any other trouble, though if it were me I'd think the change from 42 to 44 was too small to bother. YMMV of course!

Edit: I meant keep your 8 speed mechs. 2T too little capacity on the rear mech just isn't an issue. At the very worst the chain will go slack when you run little to little but you probably wouldn't anyway.
At the front you might just find that when you run little to little the chain rubs on the bottom of the cage. To check using your present setup, engage little to little. Now measure the gap between the bottom of the FD cage and the chain. You need a clearance of 2 mm per tooth so if you have 4 mm you'll be fine. If not then you won't be able to use that gear, Shift down at the rear until you have that 4 mm clearance. This gear will be the one you will be able to use. Chances are it won't be an issue anyway - as R2 says these things are usually OK. You'll need a little more chain of course.
Last edited by NetworkMan on 7 Sep 2019, 3:39pm, edited 1 time in total.

NetworkMan
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Re: 8 speed chain with 9 speed chainring and front and rear mechs?

Postby NetworkMan » 7 Sep 2019, 3:23pm

reohn2 wrote:So I now have an 8sp 14-30t(made from a Sram 8sp 12-26t,disgarded the 12 and 13t cogs replaced with a Shimano 9sp 14t top,and a 30t behind the 26t),an 8sp 22/32/42t Alivio chainset,run on a Deore M590 9sp rear mech, a 10sp Tiagra front mech,KMC X9 9sp chain,operated by Shimano 8sp 1055 d/t levers in Kelly's on drops.
Everthing runs and changes perfectly :D

Don't you love it when a plan comes together :mrgreen:

In principle you ought to get a touch of chain rub due to the cage plates on the FD being a shade too close together for a 9 speed chain but then I expect that Vaya has longer chainstays than Mr. Shimano expected which will help!

Of course a person less charitable than myself might say that lot was mix and match to the point of deliberate perversity! :wink: :)

reohn2
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Re: 8 speed chain with 9 speed chainring and front and rear mechs?

Postby reohn2 » 7 Sep 2019, 4:30pm

NetworkMan wrote:
reohn2 wrote:So I now have an 8sp 14-30t(made from a Sram 8sp 12-26t,disgarded the 12 and 13t cogs replaced with a Shimano 9sp 14t top,and a 30t behind the 26t),an 8sp 22/32/42t Alivio chainset,run on a Deore M590 9sp rear mech, a 10sp Tiagra front mech,KMC X9 9sp chain,operated by Shimano 8sp 1055 d/t levers in Kelly's on drops.
Everthing runs and changes perfectly :D

Don't you love it when a plan comes together :mrgreen:

In principle you ought to get a touch of chain rub due to the cage plates on the FD being a shade too close together for a 9 speed chain but then I expect that Vaya has longer chainstays than Mr. Shimano expected which will help!

Of course a person less charitable than myself might say that lot was mix and match to the point of deliberate perversity! :wink: :)
Yes,I'm very perverse :shock: ,and also have a friction lever on the front mech :D
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Sweep
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Re: 8 speed chain with 9 speed chainring and front and rear mechs?

Postby Sweep » 7 Sep 2019, 4:34pm

Thanks for your thoughts on that network man.
Won't the porential front mech issue be solved by installing the deore 9 speed front?
Unlike the 8 speed one on there at the moment it is specced for a 22T difference overall and a 12T gap between middle and top.
You have given me pause for thought though. Maybe it's not worth me tinkering. I have other bikes I can go faster on. Maybe I should chill when on this. The 44T rings (obtained cheap) will doubtless find a use eventually, even if only to take up the load when I wear out my 42Ts.
Sweep

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531colin
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Re: 8 speed chain with 9 speed chainring and front and rear mechs?

Postby 531colin » 7 Sep 2019, 4:50pm

Just bung the 44T ring on and try it, with all the existing sprockets/mechs.
Theres a fair chance it'll all work anyway.
2 extra teeth "capacity" is most unlikely to be a problem....whats the worst that can happen? Chain slack in small chainring/small sprocket?...you won't be using that anyway. Chain might foul the bottom of the front mech. cage in small chainring/small sprocket? ....you can look at present clearance, and see what will happen if you move the front mech. up a couple of millimeters.
Is your existing front mech. designed for 10 tooth difference middle to big chainring, or a 12 tooth difference?

Most of my bikes are 8 speed, just one is 9 speed. For convenience, I run 8 speed chains throughout; no problems.
However, I do run friction front shift, I'm not messing about with indexing and trim shifts.
The 9 speed bike has 9 speed mechs. front and back, running 8 sp. chain ; a couple of 8 speed bikes have 9 speed F. mechs at least, but again all friction front change. The rear mechs on those bikes are old and not marked for number of speeds. (The marked ones are "Mega 9 speed" Deore MTB stuff.)

reohn2
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Re: 8 speed chain with 9 speed chainring and front and rear mechs?

Postby reohn2 » 7 Sep 2019, 5:03pm

Sweep wrote:Thanks for the reply reohn.
I take it you mean my plan to change the chain ring will, thanks to shimano flexibility, work with those 9 speed mechs passing an 8 speed chain, not that I can keep the 8 speed mechs which seem to have capacity issues.
Re your dazzling bodging, if I have it right, you are running a 9 speed chain? I have massive stocks if 8 speed chains and want to use them. Also i understand they may be tougher.

Interested of course in other answers to my initial question

I can't see any reason why an 8sp chain won't work just as well as a 9,8sp and 9sp sprockets are the same thickness as are 8sp and 9sp chains.
The external width difference between 8sp and 9sp chains is 0.5mm max with some makes of 9sp chains being as wide as 8sp.

Surprised that you found the 44T too much. I can't see any downside. Can use it with some pretty large cogs on the back, and if that offers no relief, or causes bad chainline, just drop to middle front ring.
And overall I anticipate less stressed components as the 44T will hopefully mean I spend less time in the smaller rear sprockets, especially the despised 11T.

44x14 = 86.5inch on 37mm Hypers.
42x14 = 82.5inch,which I can occasionally spin upto 25mph with a 100rpm cadence,tailwinds downhills,etc,in my favour,but crucially and more to the point,the cruising ratios are one sprocket higher on the cassette on the 42 than the 44 which keeps a straighter chainline :D
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pwu
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Re: 8 speed chain with 9 speed chainring and front and rear mechs?

Postby pwu » 7 Sep 2019, 5:13pm

The Deore M511, LX M571, Xt M751 and XTR M953 front derailleurs were sold as 8 and 9 speed compatible. The downside is specific size band clamps and top/bottom pull specific. The M511 is dual pull and 34.9 and can use adapter bands. There are loads of LX on ebay, I recently got a new old stock one for £5.

fdm571.jpg

NetworkMan
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Re: 8 speed chain with 9 speed chainring and front and rear mechs?

Postby NetworkMan » 7 Sep 2019, 5:24pm

Yes, yes don't buy any more kit until you've tried. Perhaps wind a bit of tape around seat tube under the FD before you move it up so you can easily revert if needed.

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Sweep
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Re: 8 speed chain with 9 speed chainring and front and rear mechs?

Postby Sweep » 7 Sep 2019, 7:15pm

531colin wrote:Just bung the 44T ring on and try it, with all the existing sprockets/mechs.
Theres a fair chance it'll all work anyway.
2 extra teeth "capacity" is most unlikely to be a problem....whats the worst that can happen? Chain slack in small chainring/small sprocket?...you won't be using that anyway. Chain might foul the bottom of the front mech. cage in small chainring/small sprocket? ....you can look at present clearance, and see what will happen if you move the front mech. up a couple of millimeters.
Is your existing front mech. designed for 10 tooth difference middle to big chainring, or a 12 tooth difference?

Most of my bikes are 8 speed, just one is 9 speed. For convenience, I run 8 speed chains throughout; no problems.
However, I do run friction front shift, I'm not messing about with indexing and trim shifts.
The 9 speed bike has 9 speed mechs. front and back, running 8 sp. chain ; a couple of 8 speed bikes have 9 speed F. mechs at least, but again all friction front change. The rear mechs on those bikes are old and not marked for number of speeds. (The marked ones are "Mega 9 speed" Deore MTB stuff.)

Thanks for the reply Colin.
Will keep it as a reference on the 8/9 speed issue - have a habit of forgetting stuff.
To answer your question, my existing 7/8 speed front mech is, according to shimano, for a chainset with a 20T difference (this would become 22) and a difference between middle and top ring of 10 (this would become 12)
Last edited by Sweep on 7 Sep 2019, 7:53pm, edited 1 time in total.
Sweep

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Sweep
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Re: 8 speed chain with 9 speed chainring and front and rear mechs?

Postby Sweep » 7 Sep 2019, 7:18pm

pwu wrote:The Deore M511, LX M571, Xt M751 and XTR M953 front derailleurs were sold as 8 and 9 speed compatible. The downside is specific size band clamps and top/bottom pull specific. The M511 is dual pull and 34.9 and can use adapter bands. There are loads of LX on ebay, I recently got a new old stock one for £5.

fdm571.jpg


Thanks pwu - will look out for the M511.
Am building up stocks of bits and like to minimise the range of bits I have so that they can be swapped across bikes if need be - this strategy is helped by the fact that I will be staying a flatbar rider and I have no intention of going above 9 speed. My spares buying also means that I have good stocks of adaptor bands :)
Sweep