Shimano 105 crankset mods: A vs. B chainrings
Peter
Am attempting to shorten the cranks and lower the gearing on my ride,
currently setup w/ a 105 triple 54/42/30 w/ 175mm crankarms. Want to drop
down to 165's and 52/39/26. One solution I thought of was to buy an
entirely new 105 triple 165mm 52/42/30 crankset for $110 and swap out the
middle and granny chainring for another 50 bucks or so. Would like if
possible to use a Shimano 105 39T to minimize compatibility issues.
In looking at the Shimano website, I notice that they specify the 52/42/30
chainrings for the triple. In the same document, they specify the
chainrings for the double in pairs as:
- A-53/42T
- B-53/39T
- B-52/39T
- B-50/39T
the bottom line being that if you want to use their 39T ring, you need to
match it with a "B"-type large ring (50/52/53). My questions are:
1) Is it OK in general to use the 105 39T ring in a triple setup?
2) Is it OK specifically to use the 52 from the triple crankset with the
39T from the double, since it appears you need to match the 39T with the
"B" 52, and I have no idea whether the triple 52 is a "B"
3) I'm going to have to go non-Shimano for the 26, since they don't make
one. If the 105 39T is not compatible with my triple's 52, does it really
matter if I substitute someone else's 39T (e.g., Sugino)?
Thanks.
--
Peter
Anti-spam =
a) Remove NS_
b) Change the 2 zeroes to alpha O's
c) Change com to net
Qui si parla Campagnolo
middle and granny chainring for another 50 bucks or so. Would like if
possible to use a Shimano 105 39T to minimize compatibility issues.
>><BR><BR>
<< 1) Is it OK in general to use the 105 39T ring in a triple setup? >><BR><BR>
No because shimano shifters need a middle ring with pick up pins/ramps and
other things that will get the chain to the middle ring. Look at a TA 130mm BCD
for 39t designed as a middle ring.
You can use any 74mm BCD 26t.
Peter Chisholm
Vecchio's Bicicletteria
1833 Pearl St.
Boulder, CO, 80302
(303)440-3535
http://www.vecchios.com
"Ruote convenzionali costruite eccezionalmente bene"
Peter
news:20040723091113...@mb-m29.aol.com:
> NS-<< entirely new 105 triple 165mm 52/42/30 crankset for $110 and
> swap out the
>
> middle and granny chainring for another 50 bucks or so. Would like if
> possible to use a Shimano 105 39T to minimize compatibility issues.
>>><BR><BR>
> << 1) Is it OK in general to use the 105 39T ring in a triple setup?
> >><BR><BR>
>
> No because shimano shifters need a middle ring with pick up pins/ramps
> and other things that will get the chain to the middle ring. Look at a
> TA 130mm BCD for 39t designed as a middle ring.
>
> You can use any 74mm BCD 26t.
>
And would the combination of, say,
a) a Shimano 52t (52-A triple, to be exact)
b) TA 130mm BCD 39t
c) and, say, a Sugino 74mm BCD 26t
work? (The underlying question being Is it OK to mix brands, if all other
requirements are met?)
And finally, what does "ramped and pinned" mean?
Jeff Wills
> NS-<< entirely new 105 triple 165mm 52/42/30 crankset for $110 and swap out the
>
> middle and granny chainring for another 50 bucks or so. Would like if
> possible to use a Shimano 105 39T to minimize compatibility issues.
> >><BR><BR>
> << 1) Is it OK in general to use the 105 39T ring in a triple setup? >><BR><BR>
>
> No because shimano shifters need a middle ring with pick up pins/ramps and
> other things that will get the chain to the middle ring. Look at a TA 130mm BCD
> for 39t designed as a middle ring.
>
> You can use any 74mm BCD 26t.
>
Beg to differ, Peter. A couple friends of mine installed
un-pinned&ramped 39 tooth Shimano chainrings as the middle of their
triples. None of them mentioned problems with shifting. They weren't
particularly worried about having the ultimate in snappy shifts,
however.
NS- If you want to have pinned & ramped chainrings, the TA's are one
possibility. FSA also makes pinned & ramped chainrings in a variety of
sizes that will fit your 105 crankset. I have them on an Ultegra
crank and they work fine:
FSA Road Chain Ring, 39t, 8/9sp, 130mm BCD, Black, Middle Ring on Road
Triple. Item #FS-RR39M
FSA Road Chain Ring, 42t, 8/9sp, 130mm BCD, Black, Middle Ring on Road
Triple. Item #FS-RR42M
FSA Road Chain Ring, 44t, 8/9sp, 130mm BCD, Black, Middle Ring on Road
Triple. Item #FS-RR44M
FSA Road Chain Ring, 48t, 8/9sp, 130mm BCD Item #FS-RR48AG
FSA Road Chain Ring, 50t, 8/9sp, 130mm BCD Item #FS-RR50AG
FSA Road Chain Ring, 52t, 8/9sp, 130mm BCD Item #FS-RR52AG
FSA Road Chain Ring, 53t, 8/9sp, 130mm BCD Item #FS-RR53AG
FSA Road Chain Ring, 54t, 8/9sp, 130mm BCD Item #FS-RR54AG
FSA Road Chain Ring, 55t, 8/9sp, 130mm BCD Item #FS-RR55AG
(from the Bike Tools Etc. catalog http://www.biketoolsetc.com/ )
Jeff
Jeff Wills
<snip>
>
> a) a Shimano 52t (52-A triple, to be exact)
> b) TA 130mm BCD 39t
> c) and, say, a Sugino 74mm BCD 26t
>
> work? (The underlying question being Is it OK to mix brands, if all other
> requirements are met?)
>
> And finally, what does "ramped and pinned" mean?
Yes, this combination should work fine. The differences between "A"
series and "B" series are minor and probably not noticeable unless you
do all your upshifts under full pedal pressure.
FWIW: I had a Shimano crank with Willow outer, Vuelta middle, and SR
Ninja inner chainrings. It worked fine- but that was on a
friction-shifted setup. Indexed front shifting (i.e. STI) can be more
finicky.
"Ramped" means that the back side of the chainring is contoured to
allow the chain to transition from inner to middle (and middle to
outer) more easily. "Pinned" means there are projections (usually
steel) riveted to the back side of the chainring to pick up the chain
during the shift.
Jeff
Qui si parla Campagnolo
b) TA 130mm BCD 39t
c) and, say, a Sugino 74mm BCD 26t
work? >><BR><BR>
Yep, altho a 'A' type ring is not essential.
Pinned and ramped means they have chainring additons, pinned on doodads and
such to 'encourage' the chan to get to the middle and big ring, particularly
with shimano's 'positional' type left STI shifter. Not as big a deal with
friction, barcons or Campagnolo where you can essentially 'overshift' to get
the chain up there, and then recenter the front der.
Qui si parla Campagnolo
un-pinned&ramped 39 tooth Shimano chainrings as the middle of their
triples. None of them mentioned problems with shifting. They weren't
particularly worried about having the ultimate in snappy shifts,
As a bicicletteria, I guess the shifts have to be on par with the stuff taken
off..customers are always right!!!
;-o
Jeff Wills
> jwills-<< Beg to differ, Peter. A couple friends of mine installed
> un-pinned&ramped 39 tooth Shimano chainrings as the middle of their
> triples. None of them mentioned problems with shifting. They weren't
> particularly worried about having the ultimate in snappy shifts,
> however. >><BR><BR>
>
> As a bicicletteria, I guess the shifts have to be on par with the stuff taken
> off..customers are always right!!!
>
> ;-o
And the parts always work perfectly on the stand, don't they? :-P
Jeff
Peter
news:a13b2743.04072...@posting.google.com:
>
> FSA Road Chain Ring, 39t, 8/9sp, 130mm BCD, Black, Middle Ring on Road
.
.
.
> FSA Road Chain Ring, 55t, 8/9sp, 130mm BCD Item #FS-RR55AG
>
> (from the Bike Tools Etc. catalog http://www.biketoolsetc.com/ )
>
> Jeff
And the questions keep spawning!
a) On a number of sites I've seen descriptions which distinguish betw.
"mountain" and "road" chainrings. Is this simply the difference between a
110 and 130mm BCD or is there something more I should know?
b) I hear tell that Shimano 105/Ultegra triple FD's prefer (require?) a 10-
tooth gap between large and middle ring for STI to work properly. I don't
have STI; I have SRAM grip shifts (this is a recumbent, BTW, not that it
matters). Is this requirement irrelevant, then? I mean, I don't intend to
get wacky here, but would like to know I can go 12-14 teeth on either side
of the middle ring without angering the Gods of Smooth Shifting. Also, now
that I know I can mix brands without wreaking havoc, I may go 50-38-26 or
48-38-24
c) Any comment on brand quality betw. FSA, Salsa, Sugino, and Shimano,
Vuelta or hell, even Nashbar's house brand? FSA's appear priciest,
followed by Shimano, Salsa, and Sugino. I put in about 75 miles a week
over varied terrain. No races or competitions. What's the consensus for a
sweet spot on price/performance? Rumors, anecdotal evidence and slandering
a competitor's product are all welcome!
Qui si parla Campagnolo
>><BR><BR>
Sometimes, sometimes they work better on the road when we ride them.....
Jeff Wills
> jwi...@pacifier.com (Jeff Wills) wrote in
> news:a13b2743.04072...@posting.google.com:
>
> >
> > FSA Road Chain Ring, 39t, 8/9sp, 130mm BCD, Black, Middle Ring on Road
> .
> .
> .
> > FSA Road Chain Ring, 55t, 8/9sp, 130mm BCD Item #FS-RR55AG
> >
> > (from the Bike Tools Etc. catalog http://www.biketoolsetc.com/ )
> >
> > Jeff
>
> And the questions keep spawning!
> a) On a number of sites I've seen descriptions which distinguish betw.
> "mountain" and "road" chainrings. Is this simply the difference between a
> 110 and 130mm BCD or is there something more I should know?
In general, "mountain" chainrings are either 94mm or 110mm bolt
circle. "Road" chainrings are 110mm, 130mm, 135mm. *I've* seen no
other distinction of any consequence- and I've been working on bikes
for 25 years.
> b) I hear tell that Shimano 105/Ultegra triple FD's prefer (require?) a 10-
> tooth gap between large and middle ring for STI to work properly. I don't
> have STI; I have SRAM grip shifts (this is a recumbent, BTW, not that it
> matters). Is this requirement irrelevant, then? I mean, I don't intend to
> get wacky here, but would like to know I can go 12-14 teeth on either side
> of the middle ring without angering the Gods of Smooth Shifting. Also, now
> that I know I can mix brands without wreaking havoc, I may go 50-38-26 or
> 48-38-24
The requirement is largely irrelevant, particularly with Grip Shifts.
STI can be more finicky, but Grip Shifts have many of the same
advantages as friction shifters- among them, the possibility of
overshifting and then backing up a notch to center the chain in the
derailleur cage.
BTW: My wife's bike has 24-38-48 chainrings (no pins or ramps) and she
has Grip Shifts too. I've never heard her complain about the shifting.
My 24-39-53 setup works fine with my elderly XTR brake/shifters,
thanks largely to Sheldon's page on "Front Derailers To Solve Special
Problems": http://www.sheldonbrown.com/harris/derailers-front.html . A
FD-R443 works perfectly on my weird combination.
(Don't let it get around, but we're both riding Tour Easy recumbents.)
> c) Any comment on brand quality betw. FSA, Salsa, Sugino, and Shimano,
> Vuelta or hell, even Nashbar's house brand? FSA's appear priciest,
> followed by Shimano, Salsa, and Sugino. I put in about 75 miles a week
> over varied terrain. No races or competitions. What's the consensus for a
> sweet spot on price/performance? Rumors, anecdotal evidence and slandering
> a competitor's product are all welcome!
I've used most of those brands (hell, I've got a bin full right now).
I've had Sugino chainrings last for several years, along with FSA and
Shimano. The Vuelta chainrings that I've had wore very quickly and
occasionally required deburring with a flat file. Buy good parts-
they're ultimately less frustrating.
Jeff