chainring spacing question
Nate Nagel
have come to the conclusion that I might as well just go 9-speed on my
new bike. Won't take a whole lot, and my 700c wheels fit in and I can
make my brakes work.
One question that may make or break this though - did the spacing
*between* the chainrings change at any point in time? e.g. if I wanted
to go with all modern drivetrain stuff can I reuse my old cranks and
spiders, or do I need to go *all* new?
thanks
nate
--
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Tom Kunich
"Nate Nagel" <njn...@roosters.net> wrote in message
news:h843v...@news1.newsguy.com...
> OK, after actually playing with all the stuff I have laying around I have
> come to the conclusion that I might as well just go 9-speed on my new
> bike. Won't take a whole lot, and my 700c wheels fit in and I can make my
> brakes work.
>
> One question that may make or break this though - did the spacing
> *between* the chainrings change at any point in time? e.g. if I wanted to
> go with all modern drivetrain stuff can I reuse my old cranks and spiders,
> or do I need to go *all* new?
Going from 7 to 8 speed the spacing between the crank chain rings narrowed.
Same going from 8 to 9 and 9 to 10. I don't know about the 11 but probably.
Also as the chain narrowed and the spacing between gears narrowed the front
derailer was modified to work properly. While you can get most of the
nearly-the-same-speed stuff to work most of the time there are times you
need to get new derailers.
Johnny Twelve-Point presented by JFT
wrote:
>OK, after actually playing with all the stuff I have laying around I
>have come to the conclusion that I might as well just go 9-speed on my
>new bike. Won't take a whole lot, and my 700c wheels fit in and I can
>make my brakes work.
>
>One question that may make or break this though - did the spacing
>*between* the chainrings change at any point in time? e.g. if I wanted
>to go with all modern drivetrain stuff can I reuse my old cranks and
>spiders, or do I need to go *all* new?
With Shimano, the rings from 9- and 10-speed goups are closer together
than previous stuff, I think via the shape the rings -- I'm not sure.
That said, I ride with 9 speeds chain, cassette and shifters on a bike
with cranks and rings from an 8-speed group and it works OK. On rare
occassions the chain skids on top of the inner ring on a downshift,
rather than settline in. Have to reshift when that happens. Or do a
little bunnyhop to shake the thing down.
AMuzi
> OK, after actually playing with all the stuff I have laying around I
> have come to the conclusion that I might as well just go 9-speed on my
> new bike. Won't take a whole lot, and my 700c wheels fit in and I can
> make my brakes work.
>
> One question that may make or break this though - did the spacing
> *between* the chainrings change at any point in time? e.g. if I wanted
> to go with all modern drivetrain stuff can I reuse my old cranks and
> spiders, or do I need to go *all* new?
Your bike was born at 125mm, Nine wants to be 130mm. A
measurement is in order, perhaps an alignment. Nine requires
shifters with cables, hub, cassette, rear changer and chain.
Crank can stay as it is. Most classic double fronts will
shift with an STi lever, most classic triples won't.
--
Andrew Muzi
<www.yellowjersey.org/>
Open every day since 1 April, 1971
Nate Nagel
right, I have all of that stuff laying around (well except for the
cables, but those are cheap and needed anyway) I was just curious if I
could keep my old crank/spiders because they're in good shape and decent
looking, and I don't have another square taper triple crank laying around.
Come to think of it, I have two extra 9-speed chainrings (came with my
other bike because the PO changed the gearing at some point) although
it'd be a miracle if they happened to be the same BCD as the larger two
rings on this one.
(checks)
nope, they're not...
but I'm actually doing pretty well... because I bought a cheap used
wheelset which turned out to be really decent, 105 hubs, I didn't even
replace the balls in them and they're smooth. I have everything but the
cassette there, and new SRAM cassettes are cheap... yes, it's 130mm but
I fit it into the frame just by springing the stays slightly and letting
it drop in. I know that's not "right" but it works. If I make this
permanent I can probably manage to cold set it myself. For some
packratted reason I kept the old chain off my other bike when I replaced
it, so I can use it for fitting/test riding. I figure a pair of ders
and I'm most of the way there. everything else (cables etc.) I would
have had to buy anyway. only thing up in the air is the cranks and
chainrings, worst case I can try it when I get it all back together and
if it doesn't work, then start looking for new stuff.
I just checked the spiders on both of my bikes (one is new 9/2, other is
old Shimano 600 triple) the thickness of the metal between the two
largest chainrings is just a shade over 1/8" on both, so it appears that
I *can* use my old spider, worst case I just buy new rings... yes?
Michael Press
Nate Nagel <njn...@roosters.net> wrote:
> OK, after actually playing with all the stuff I have laying around I
> have come to the conclusion that I might as well just go 9-speed on my
> new bike. Won't take a whole lot, and my 700c wheels fit in and I can
> make my brakes work.
>
> One question that may make or break this though - did the spacing
> *between* the chainrings change at any point in time? e.g. if I wanted
> to go with all modern drivetrain stuff can I reuse my old cranks and
> spiders, or do I need to go *all* new?
Really? The current set up sounded very good with a couple
parts replacements. Now you are going down to a frame set
an building up again.
--
Michael Press
Hank
> "Nate Nagel" <njna...@roosters.net> wrote in message
Center-to-center spacing did not change. The rings became thicker
below the teeth, in a ramped shape, to leave less room for narrower
chains to fall between and skate.
This skating is so infrequent, that it's generally OK to use a 7 or 8
speed crank for a 9 or 10-speed system.
I used a Sugino XD300 with 8-speed rings on an otherwise Campy 10-
speed setup, with a 5.9mm chain, with no ill effects. Not once did the
chain skate between rings.
P. Chisholm
Yes reuse the old crank and use some shifting finesse when shifting to
the small ring from the big(take pressure off the pedals) and it will
work fine.
N8N
> In article <h843vf02...@news1.newsguy.com>,
I was going to do that anyway - scrub out the seat tube and steerer
with kerosene, repack bearings, etc. (would have started that
yesterday but it was raining, and in the interest of domestic
tranquility I'm not going to do that inside) this actually is a
shortcut since I have a good set of wheels with a Shimano 9-speed hub
and new tires just serviced a couple hundred miles ago (and stainless
spokes, which just makes it look nice.) The other thing, which I
didn't post, was that when I slapped a chain gauge on it despite the
fact that it works really well, it's apparently slap wore out (fell
all the way through,) so who knows if the rings are good. So $20-
something for a new cassette vs. $20-something for a new freewheel is
a wash. I'll stop by the LBS down the street next time I get home
from work early and see if they have some "good used" chainrings that
they'll sell me (they're the kind of place that would have that kind
of thing) might as well go ramped and pinned if I'm going nuts. BB
doesn't feel all that bad so I'll just put some new balls in it unless
I find something awful when I get in there (need to pick up a lockring
tool and pin spanner) and I kind of like the vintage look of the old
cranks.
Now, of course, I'm wondering if I shouldn't repaint the frame (decals
are available, even!) but I will reserve that decision until I have it
built up again and riding. And, of course, if this works I might
treat it to a set of Dura-Ace indexed shifters.
The other advantage would be that I've been considering building or
having built a wheel with a dynohub, if I go 700c then I could use it
on either of my bikes. Seems that the only time I really have to ride
is when it's likely going to get dark if I go more than 20 miles or
so.
nate