Thomas: If you look closely at most chainrings, you'll notice a slight bevel on the inside, with the outside being flat. This is not universal but is fairly common. The intended position location is evident in the countersinking of the bolt holes. An outer ring will have the mounting holes countersunk for the chainring bolts on the outer (non-beveled) face. A middle or inner ring will have countersinking detail on the inner face.
I have successfully used middle rings on the outside. The bolt heads just stick up a bit but everything works fine. One time I even (mistakenly) installed a middle backwards (bevel out), taking my cue from the countersinking rather than the bevel. It also worked fine. The above is experience with plain, flat rings with no shift assist ramps'n'pins. IMHO, if a 44T works for you in the middle, a 46T has a high probability of also working. The nuts won't be flush with the ring but if you look at the countersinking it's quite shallow. dougP On Wednesday, June 17, 2015 at 1:27:38 PM UTC-7, Thomas Lynn Skean wrote: > > Hi! > > Has anyone used the 46T Origin-8 chainring sold by RBW (or one like it) in > the middle position on the RBW-sold Sugino crank (or one like it)? Any > comments on how well it works or worked? If you got it to work "well > enough" for you, was there anything non-obvious that you had to do to make > that happen? > > So here's the deal: I have three bikes, two Hillbornes and a Bike Friday > (406BSD wheels). The Hillbornes have the triple Sugino cranks sold by RBW. > The Bike Friday came with a 130BCD triple crank, 52T/42T/30T. I got rid of > the 52T chainring because I never used it; higher than I want in general. > Replacing the 42T middle chainring with a 44T was an improvement in the > overall gearing on the Bike Friday and leads me to want to try a 46T. > > However, as another goal I'd like to have the same Sugino 110BCD crank on > all three bikes. My question above arises because I don't see any > 46T-or-greater 110BCD chainring on the web sold as a "middle" ring. Some, > including the 46T 110BCD Origin-8 chainring sold by RBW, are not described > as being either explicitly inner, middle, or outer. I note that RBW's > web-site says that its 44T chainring can be used as either a middle or an > outer; it does *not* say that for the 46T. > > With respect to a given 110BCD chainring that is sold as a middle vs outer > ring for a triple crank, what about the chainring makes it that way > (instead of being position-agnostic)? > > In case it matters to potential respondents... the Hillbornes have 7-speed > clusters in the back and the Bike Friday has an 8-speed cluster. Also, I'm > uninterested in 9-speed unless I'm forced by product availability to go > that way. Fortunately I have predicted the demise of less-than-9-speed > drivetrains, thus making it very likely that they'll stay around. I wonder > if that principle works when predicting one's own demise? > > Yours, > Thomas Lynn Skean > P.S. > Just so you know I've considered it... the shifting between the 30T inner > and the 44T middle chainring on the current Bike Friday setup works "well > enough" for me. I've literally had zero problems, but I've done it rarely > enough that it's a very limited sample size. I suspect the 30T-46T would be > good enough for me also, though I do have a 32T 74BCD chainring waiting in > the wings, which I presume would have a decent chance of shifting much like > the 30T-44T combination. With the overall gearing on the Bike Friday, > goodness knows I'd be happy enough with a 36T inner ring if they are > available. > -- You received this message because you are subscribed to the Google Groups "RBW Owners Bunch" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To post to this group, send email to [email protected]. Visit this group at http://groups.google.com/group/rbw-owners-bunch. For more options, visit https://groups.google.com/d/optout.
