spacing between chainrings

[J Schwartz]

weird question...but here goes

I disassembled a Silver triple and had it apart for awhile and recently put it back together as a double with a bashguard.

So, it's Guard>40t>30t.

I think I may have used the incorrect spacers between the 74bcd 30t and the 110bcd 40t...they were in my box of parts.  I'm not sure.  I think there is too much space between those two chainrings ...a few times riding recently, the chain wants to go down between them

Can someone tell me what size this spacers should be and how much space, in general should be between two chainrings on a triple, 9 speed?

thanks

[Will Boericke]

I've never had to use spacers on chainrings, but I've also never disassembled the aforementioned crank.  To my mind, if you need spacers on a crankset, you've designed something wrong.

[RichS]

Joel,

If this helps, my 8 speed setup is: Guard/44/30 — but with a Sugino crank (if that makes a difference). Shifted with a Claris triple. No spacers involved and works fine.

Perhaps try without the spacers and /or play with the adjustment on the derailer.

Best,

Rich in ATL

On Saturday, May 13, 2023 at 8:50:06 AM UTC-4 J Schwartz wrote:

[Joe Bernard]

I search of the webs produced 3.5mm as a common spacer for the granny ring on triples, and this matches the set I have.

[Joe Bernard]

The other possibility here is you're using a narrow 10-speed chain, it might hang up a bit between the middle and small rings on a Silver crank if the shift is a little lazy. 

[Garth]

Somewhere between 3.5-3.6mm should work as that's what I measure the spacing between the large arms on every crank I own. I measured the thickness of the arm "shelves" up which the rings sit. So if the inner ring mounting holes are flush with the middle ring, it's obvious a 3.5-3.6mm spacer will do. I give a range because there are always slight variations of these things. If the rings are not flush with where you place the spacers, well then you must add/subtract the distance that the middle ring sticks to that. A digital caliber can measure that distance, if there is any, using the "other end" of the caliper, whatever that thingy is called.

[Garth]

Oh sheesh, how about  "If the rings are not flush with where you place the spacers, well then you must add/subtract that distance from each other". Some chainrings are thicker than others. that said, it doesn't have to be exact, you simply don't want to use something much too thick, like a 5mm spacer !

[aeroperf]

Typical spacing between chainrings is 5mm.

However, it is all about the chainline.

https://www.sheldonbrown.com/chainline.html

[Patrick Moore]

I've not used the Silvers but some square taper triples used spacers between middle and granny; I just looked at the spacers between the 42 t ring and the 28 t granny on my Logic 110 triple (guard/42/28).

[Patrick Moore]

Oh, and my spacers are AFAIK from the 7 speed or 8 speed era -- they've been in my little drawer for decades -- and I'm using them with an 11 ("eleven") speed chain (42/28 X 10-25 10 sp cassette); it never occurred to me that I might have spacing problems and in fact I never have had any.

--

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Patrick Moore

Alburquerque, Nuevo Mexico, Etats Unis d'Amerique, Orbis Terrarum

[J Schwartz]

thanks for all the input

very helpful....and for the article on chainline...something I always avoid getting too detailed about, but should.

I believe the Silver crank requires spacers between granny and middle, but I could be wrong.

Here's a pic from above 

I'll measure the spacers and see if they are closer to 5mm or 3.5mm

Also, the chain is a 9 speed.

I may need to do a little dialing-in on chainline in general.  The BB is a Phil and I can move the 113 spindle left or right as needed.

[Joe Bernard]

Judging from a photo is basically impossible but I'm going to do it anyway, your spacers look wider than my 3.5. I'll betcha 3.5 is the ticket for you. 

[Joe Bernard]

Btw needing spacers on a Silver crank instead of having the spacing built in is useful. You can use really thin ones to get the rings closer for a double-ring-plus-guard 11- or 12-speed drivetrain. 

[John Hawrylak, Woodstown NJ]

Suggest calling/writing RBW.

I recall a Grant write up a few years ago comparing the Silver to the XD2 2 and I remember something about spacers on the 74mm BCD posts.

 If the crank is on the bike, you can measure the distance form the end of the seat tube to the teeth of the Middle and Inner rings using paper cut to size, and then the difference is the middle to Inner ring spacing and verify if > 5mm.

For reference, my XD-2 with Sugino Rings have ring spacing > thr 5mm Shimano standard:
Outer to Middle,   7mm

Middle to Inner,  8mm

John Hawrylak

Woodstown NJ

On Saturday, May 13, 2023 at 8:50:06 AM UTC-4 J Schwartz wrote:

[J Schwartz]

Well I already took the crank off

The spacers I used, which I really thought were the ones that came with the Silver crank, are indeed 5mm

But they very well may not be the ones that came with

I also have a set of each of these two below.  One is obviously larger around than the other

-The larger diameter spacer measures 3mm tall 

-The small diameter spacer measures 4mm tall

Which would be advisable to put on?

Crazy to think that 1mm here or there would cause the issue of the chain slipping down between the rings.

Also, as all this pertains to chainline....

I should be referencing the middle chainring in my case to the middle of the seat tube to get the appropriate chainline, correct?  (Even though this isn't really a triple, but a double with a bashguard in the large spot)

thanks

JS

[Joe Bernard]

I would guess on 4mm. The worst that happens is you change em again! 😁

[Steve]

Joel, for purposes of chaining I'd suggest ignoring the bash guard and reference your chainline as you would for a conventional double (the bash guard is irrelevant to tchainline considerations. If you happen to have a long enough meter/yardstick (or something like it) you can lay one end between the two chainrings and check which cog on the cassette the other end.of stick rests on. For a nine speed the "ideal" would be a right on the 5th cog, i.e., the middle of the cassette. Anything fairly close to that is good. (Apologies if I'm belaboring what you already know).  

[J Schwartz]

Thanks for the feedback

I ended up changing the 5mm spacers to 4mm spacers, replaced the Phil 113mm BB to a UN50 110mm BB I had laying around, made some front derailleur limit adjustments and cleaned the drivetrain... Quick ride around and things seems to be shifting very well.

Haven't had the chain try to dive in between the rings either