8 speed chainset with 9 speed everything else?

[531colin]

……..The 8s chain on 9s cassette thing has the best chance of working if the cassette has 2T intervals or larger throughout, and may be sensitive to the exact brand/model of cassette too......

The cassette I'm using is this one here....https://forum.cyclinguk.org/viewtopic.php?f=5&t=54328&hilit=nightmare&start=30
13, 15, 17, 19, 21, 23 ,26, 30, 34. Made from 2 Shimano (9sp.) cassettes, a 13 - 25 Tiagra "junior racing" one and a 11 - 34 HG50.
Incidentally, the same cassette that I made in 2011 is still in use; I change the chain before it wears enough to damage the cassette.

[horizon]

(Correction: my Suntour chainset is 7/8 speed (it doesn't say so on the box but further research proved it.)

I run a number of bikes, all 7/8/9 speed. I've kept them fairly strictly in their speed zones up till now, on the (correct) assumption that there would be problems if I didn't but still benefitting from lots of commonality. This is the first time I've waded into compatibility. It happened because I was looking to build a nine speed system and was trying to find this:

Deore or Alivio triple chainset
22 32 42
9 speed
Square taper
170 mm
Colour not important but preferably black
Located in the UK
Reasonable NOS price
New
Preferably with chainguard as this uses a 122 BB that I already had (new)

I struggled to find this (still cannot even with further looking). So I went for the 7/8 (fits the bill perfectly apart from the speed). I think I must have had a blind spot as I didn't think the 9 speed was an issue (the Suntour doesn't even have speeds marked on the box).

However, not only has this presented an issue this time, it has thrown my whole strategy as it seems as though 9 speed is unsustainable. There has been discussion on here about future availability but I got the impression that there would be plenty of NOS around for a long time to come. It looks as though a better plan is to ditch 9 speed and go for 8 which does seem better supported. I have a feeling that others have been here before me.

[Brucey]

just to clarify; when I have seen the jamming problems with 9s chain on 8s chainrings, it has normally been the joggled/ramped parts of the chainrings which have caused the jamming, because these parts of the chainring are slightly wider. Annoyingly things can look fine on the workstand and yet can still catch you out on a test ride, with consequent risk of damage to the RH chainstay. As I mentioned upthread, you can file these areas to a thinner size quite easily and this normally results in acceptable performance (on the road; offroad might be a different kettle of fish).

8s chainrings that have seen much use (NB but have not acquired burrs that make the teeth wider than usual) normally work OK with 9s chain but there can be a secondary problem which is that downshifts (esp the shift from the middle ring to the little ring) can become reluctant too.

cheers

[horizon]

Thanks for that Brucey. What I am looking for is off-the-shelf compatibility partly because of my own limited metallurgical ability, partly due to convenience but also to a sense that this is going to work across the board.

I wouldn't really have entertained the idea of using a 7/8 chainset on this bike were it not for (a) limited availability of what I wanted and (b) some opinions on-line that it would work (the view out there is very mixed, not just on here).

My dilemma therefore is whether to go for 8 or 9 on this bike. I want to use my existing stock of parts as far as possible but I'm also prepared to buy new if needs be.

[slowster]

With regard to your list of specifications, have you identified a Shimano model number for a chainset which meets your criteria (and which would allow you to search for webshops selling that particular model)?

For example, it looks like Deore and Alivio 9 speed chainset (at least those currently availalble) are Octalink, not square taper, and square taper was only used for lower spec Shimano chainsets, e.g. like this one.

[531colin]

……... it seems as though 9 speed is unsustainable. ....

I used to worry about the future availability of spares. As a result, I have a box of unused cassettes and mechs. which I bought in 2011; the originals are still working.

……….I wouldn't really have entertained the idea of using a 7/8 chainset on this bike were it not for (a) limited availability of what I wanted .......

I imagine you are talking about 4-bolt chainsets to get a 22T inner ring? If you are able to use a 24T inner ring, then there is a choice of Stronglight/Spa square taper 74/110 BCD (5 bolt) chainsets which will suit 8 and 9 speed chains. There are lots of these chainsets in use, I imagine chainrings will be available for some time. (I am probably using some chainrings which are old enough to vote.)

[bgnukem]

To add my experiences here, I tried to use the Spa Cycles triple, Sugino XD-derived which I believe was originally designed for use with 7- or 8-speed, with a 9-speed chain and had issues with the chain getting stuck between 'rings and slipping - loss of drive.

I guess this was due to the gaps between 'rings being too wide for the narrower chain. It was one of the cheaper versions of the chainset with the two outer 'rings in steel, so perhaps slightly thinner than the alloy 'rings. The chain didn't jam on the teeth of the 'rings though. Not sure how compatible Shimano 8- and 9-speed chainsets are though.

[531colin]

To add my experiences here, I tried to use the Spa Cycles triple, Sugino XD-derived which I believe was originally designed for use with 7- or 8-speed, with a 9-speed chain and had issues with the chain getting stuck between 'rings and slipping - loss of drive.

I guess this was due to the gaps between 'rings being too wide for the narrower chain. It was one of the cheaper versions of the chainset with the two outer 'rings in steel, so perhaps slightly thinner than the alloy 'rings. The chain didn't jam on the teeth of the 'rings though. Not sure how compatible Shimano 8- and 9-speed chainsets are though.

I always wonder why I can't call all this stuff to mind as easily as I think I should be able to....then I remember I've been retired 7 years.
So, yeah, Sugino XD2 originally (thanks for the memory jog!) Subsequently branded "Stronglight Impact" and much later sold as "Spa".
The original tooling was not accurate, so every XD2 triple chainset had thin washers between the middle ring and the spider....omit these at your peril, because the middle ring will be too close to the big ring and too far away from the small ring. (Memory letting me down again here....it might not be all of them, it might vary depending on whether you can see all 5 chainring bolts, or there is one hidden behind the crank.)
I have no personal experience of the cheaper chainsets with steel/alloy rings, but we sold a lot! Isn't it the 2 inner rings in steel, and alloy big ring?
Mine are all Stronglight rings apart from a single Spa ring bought because I changed the ring size.

[pwa]

My 9 speed chains go over an XD2 triple without the chain disappearing down gaps. It is the one with one bolt hidden behind the crank. No washers on bolts. Non-indexed front lever. 26/36/46. I think the rings are TA.

[Sweep]

I always wonder why I can't call all this stuff to mind as easily as I think I should be able to....then I remember I've been retired 7 years.
So, yeah, Sugino XD2 originally (thanks for the memory jog!) Subsequently branded "Stronglight Impact" and much later sold as "Spa".
The original tooling was not accurate, so every XD2 triple chainset had thin washers between the middle ring and the spider....omit these at your peril, because the middle ring will be too close to the big ring and too far away from the small ring. (Memory letting me down again here....it might not be all of them, it might vary depending on whether you can see all 5 chainring bolts, or there is one hidden behind the crank.)
I have no personal experience of the cheaper chainsets with steel/alloy rings, but we sold a lot! Isn't it the 2 inner rings in steel, and alloy big ring?
Mine are all Stronglight rings apart from a single Spa ring bought because I changed the ring size.

cripes colin - thanks for tossing that in! I have one - have taken it apart at least once - knowing me will have possibly mislaid/not refitted these mysterious washers. I use it as a 9 speed. Mine is the one with one bolt hidden behind the crank.

I use a rapidfire for the front shift which has a trimming function which possibly helps.

[horizon]

I imagine you are talking about 4-bolt chainsets to get a 22T inner ring? If you are able to use a 24T inner ring, then there is a choice of Stronglight/Spa square taper 74/110 BCD (5 bolt) chainsets which will suit 8 and 9 speed chains.

The 24T is probably OK but they're a little out of my price range at £125.00 (though It's reassuring to see that they are available).

The one that caught my eye is this one:

https://spacycles.co.uk/m2b0s109p2000/S ... e-Chainset

It's a 28T but the price and quality is what I'm looking for. I would snap one up if it had a 22T small chainring (needs 64 BCD I presume but could take a 24T?). Another option is to buy the crank/spider and build it up but Spa are limited AFAICS to 74 BCD.

However all this is academic if it isn't clear if all the Spa chainsets are really OK for 9 speed:

bgnukem wrote:
To add my experiences here, I tried to use the Spa Cycles triple, Sugino XD-derived which I believe was originally designed for use with 7- or 8-speed, with a 9-speed chain and had issues with the chain getting stuck between 'rings and slipping - loss of drive

I really like the idea of Spa carrying on with these chainsets while everyone disappears into outer space with ten and eleven speed, octalink and Lord knows what. But this has left me a bit unsure now.

[horizon]

With regard to your list of specifications, have you identified a Shimano model number for a chainset which meets your criteria (and which would allow you to search for webshops selling that particular model)?

For example, it looks like Deore and Alivio 9 speed chainset (at least those currently availalble) are Octalink, not square taper, and square taper was only used for lower spec Shimano chainsets, e.g. like this one.

I'm going to check it out. I'm pretty sure that the early Deore etc were square taper but they've now gone and yes, octalink are still around as (cheap) NOS. The one you linked to is fine but I was hoping to go a bit better quality. I had thought that Acera would provide the answer but it seems impossible to find square taper with 22 32 42 and 9 speed (and not every retailer even says what they are).

[slowster]

To add another data point, I'm running an XD2 46/36/26 triple with TA rings and a Campag 10 speed chain and derailleurs. Front shifting is OK (not as slick as with components all from the same groupset, but OK), and I cannot recall the chain skipping on the middle chainring.

That's not to say it has never happened, but if it did it evidently did not register with me as a (serious/recurring) problem that needed investigation (whereas the chain does frequently skip on the 3rd smallest sprocket of the 13-29 10 speed Campag cassette, and I've yet to properly investigate and fix it).

[horizon]

Thanks for that. I've landed somewhere where I never expected to, this no-man's-land between 7/8 and nine speed. I thought it would be easy to find what I wanted (see spec list above) but it isn't the case. And I'm a bit worried now about Spa's blurring of the lines between 7/8/9. Hmmm.

[Tompsk]

My 9 speed chains go over an XD2 triple without the chain disappearing down gaps. It is the one with one bolt hidden behind the crank. No washers on bolts. Non-indexed front lever. 26/36/46. I think the rings are TA.

+1 with original rings as supplied from spa, my 9 speed chain appears to have no issues changing up or down with non indexed front shifter.