Cassette change

I have a 50/34 crank and run an 11-28 11 speed drivetrain. I am thinking of going to an 11-30 or and 11-32 cassette. I have not looked and am generally competent mechanic but what are my chances the chain will not need to be resized with theh 30 or 32. My thinking is the 30 will be ok but not 32. Any way to know just checking my present set up?
Deacon mark

On 5/7/2021 6:37 PM, Mark cleary wrote:
I have a 50/34 crank and run an 11-28 11 speed drivetrain. I am thinking of going to an 11-30 or and 11-32 cassette. I have not looked and am generally competent mechanic but what are my chances the chain will not need to be resized with theh 30 or 32. My thinking is the 30 will be ok but not 32. Any way to know just checking my present set up?
Deacon mark

No way to know that with certainty but changing to a new
chain with a new cassette is generally best practice.

That said you, could (and should) easily check the length
before actually riding it:

http://www.yellowjersey.org/CHNLENGT.JPG

Drop the lower pulley and slip your chain out of the rear
changer. Wrap it on the largest sprockets front and rear.
Ensure there are at least three rivets extra length. If so,
pass it back through the changer and go ride. If not, new chain.

Do that test before riding. A too-short chain shifted to
big-big is an expensive error.

--
Andrew Muzi
www.yellowjersey.org/
Open every day since 1 April, 1971

On 5/7/2021 4:37 PM, Mark cleary wrote:
I have a 50/34 crank and run an 11-28 11 speed drivetrain. I am thinking of going to an 11-30 or and 11-32 cassette. I have not looked and am generally competent mechanic but what are my chances the chain will not need to be resized with theh 30 or 32. My thinking is the 30 will be ok but not 32. Any way to know just checking my present set up?
Deacon mark

Adding 2T to the rear cog will essentially require one more link in the
chain (I'm calling the distance between two rivets "one link", i.e. you
can only remove/add even numbers of links).

Reasoning: The chain only wraps around half the cog. The runs from the
top of the cog to the top of the chainring will be essentially the same
length, similarly for the bottom (there are differences, but they'll be
negligible. So 2T more on the cog means 1T more that the chain has to
"wrap."

So to do a quick-and-dirty rough test: Put chain on big ring, big cog.
Maybe put on some disposable gloves if you care. Grab the lower chain
run and see if you have enough extra chain on the bottom run to "fold"
it to be effectively one [or two] links shorter. Does that pull the
derailleur lower pulley unacceptably far forward for your taste? If
not, you're probably going to have enough chain for 2 [or 4] more teeth
on the largest cog.

In deciding if the lower pulley is pulled too far forward, note: You
don't want it pulled taut, that's asking for chain-busting trouble.
Quite a bit shy of that will still make for a lot of chain noise, and
shifting will probably suffer. If you can religiously avoid the big-big
and similar combinations, shy of taut will avert explosions. I prefer
to not pull the lower pulley very much far forward at all.

It's a separate issue whether the upper pulley will clear a larger cog,
but for small size increases, you can usually fudge the B-limit screw to
make it work.

Mark J.

On Friday, May 7, 2021 at 9:59:43 PM UTC-7, Mark J. wrote:
On 5/7/2021 4:37 PM, Mark cleary wrote:
I have a 50/34 crank and run an 11-28 11 speed drivetrain. I am thinking of going to an 11-30 or and 11-32 cassette. I have not looked and am generally competent mechanic but what are my chances the chain will not need to be resized with theh 30 or 32. My thinking is the 30 will be ok but not 32.. Any way to know just checking my present set up?
Deacon mark

Adding 2T to the rear cog will essentially require one more link in the
chain (I'm calling the distance between two rivets "one link", i.e. you
can only remove/add even numbers of links).

Reasoning: The chain only wraps around half the cog. The runs from the
top of the cog to the top of the chainring will be essentially the same
length, similarly for the bottom (there are differences, but they'll be
negligible. So 2T more on the cog means 1T more that the chain has to
"wrap."

So to do a quick-and-dirty rough test: Put chain on big ring, big cog.
Maybe put on some disposable gloves if you care. Grab the lower chain
run and see if you have enough extra chain on the bottom run to "fold"
it to be effectively one [or two] links shorter. Does that pull the
derailleur lower pulley unacceptably far forward for your taste? If
not, you're probably going to have enough chain for 2 [or 4] more teeth
on the largest cog.

In deciding if the lower pulley is pulled too far forward, note: You
don't want it pulled taut, that's asking for chain-busting trouble.
Quite a bit shy of that will still make for a lot of chain noise, and
shifting will probably suffer. If you can religiously avoid the big-big
and similar combinations, shy of taut will avert explosions. I prefer
to not pull the lower pulley very much far forward at all.

It's a separate issue whether the upper pulley will clear a larger cog,
but for small size increases, you can usually fudge the B-limit screw to
make it work.
You cannot tell the arm length of the rear derailleur nor how much slack the person who installed the chain left. These are all variables. But I agree with Andrew that if you are going to install a new cassette unless you have a perfectly new chain it is best to install a new chain. I am changing my position on buying cheap chains because you can replace 4 of them for the cost of one good one. Using my special hot wax and teflon combination, the chain is so slippery that it is difficult to hold to install the quick link.. I have not managed to wear out a medium end KMC. So I bought a Connex for the Ti.

On 5/8/2021 9:51 AM, Tom Kunich wrote:
Using my special hot wax and teflon combination, the chain is so slippery that it is difficult to hold to install the quick link.

I've got a little special tool that hooks links near the end of a
separated chain to keep them close together and allow inserting another
link or two. It's just two short stamped steel arms hinged at one end,
with a thumbscrew to control the open distance.

Like many of my tools, I got it used, so I don't know what it's called.
But I suppose a long twist tie could do pretty much the same job.


--
- Frank Krygowski

Op zaterdag 8 mei 2021 om 18:56:13 UTC+2 schreef Frank Krygowski:
On 5/8/2021 9:51 AM, Tom Kunich wrote:
Using my special hot wax and teflon combination, the chain is so slippery that it is difficult to hold to install the quick link.
I've got a little special tool that hooks links near the end of a
separated chain to keep them close together and allow inserting another
link or two. It's just two short stamped steel arms hinged at one end,
with a thumbscrew to control the open distance.

Like many of my tools, I got it used, so I don't know what it's called.
But I suppose a long twist tie could do pretty much the same job.


--
- Frank Krygowski

You can make one yourself with a spare spoke. Very handy.

Lou

On Saturday, May 8, 2021 at 1:53:29 p.m. UTC-4, wrote:
Op zaterdag 8 mei 2021 om 18:56:13 UTC+2 schreef Frank Krygowski:
On 5/8/2021 9:51 AM, Tom Kunich wrote:
Using my special hot wax and teflon combination, the chain is so slippery that it is difficult to hold to install the quick link.
I've got a little special tool that hooks links near the end of a
separated chain to keep them close together and allow inserting another
link or two. It's just two short stamped steel arms hinged at one end,
with a thumbscrew to control the open distance.

Like many of my tools, I got it used, so I don't know what it's called.
But I suppose a long twist tie could do pretty much the same job.


--
- Frank Krygowski
You can make one yourself with a spare spoke. Very handy.

Lou

Or you can use a piece of metal coat hanger or other stiff metal that's thin enough to fit between the side plates of the chain links.

Cheers

On Saturday, May 8, 2021 at 10:53:29 AM UTC-7, wrote:
Op zaterdag 8 mei 2021 om 18:56:13 UTC+2 schreef Frank Krygowski:
On 5/8/2021 9:51 AM, Tom Kunich wrote:
Using my special hot wax and teflon combination, the chain is so slippery that it is difficult to hold to install the quick link.
I've got a little special tool that hooks links near the end of a
separated chain to keep them close together and allow inserting another
link or two. It's just two short stamped steel arms hinged at one end,
with a thumbscrew to control the open distance.

Like many of my tools, I got it used, so I don't know what it's called.
But I suppose a long twist tie could do pretty much the same job.


--
- Frank Krygowski
You can make one yourself with a spare spoke. Very handy.

That's a good idea. I have a lot of spokes laying around from when I would spoke up those old Campy flat rims.

On 5/8/2021 11:56 AM, Frank Krygowski wrote:
On 5/8/2021 9:51 AM, Tom Kunich wrote:
Using my special hot wax and teflon combination, the
chain is so slippery that it is difficult to hold to
install the quick link.

I've got a little special tool that hooks links near the end
of a separated chain to keep them close together and allow
inserting another link or two. It's just two short stamped
steel arms hinged at one end, with a thumbscrew to control
the open distance.

Like many of my tools, I got it used, so I don't know what
it's called. But I suppose a long twist tie could do pretty
much the same job.



I've seen those.

Mechanics normally drop the chain off the front so it hangs
without tension.

--
Andrew Muzi
www.yellowjersey.org/
Open every day since 1 April, 1971

On Sunday, May 9, 2021 at 11:21:44 AM UTC-7, AMuzi wrote:
On 5/8/2021 11:56 AM, Frank Krygowski wrote:
On 5/8/2021 9:51 AM, Tom Kunich wrote:
Using my special hot wax and teflon combination, the
chain is so slippery that it is difficult to hold to
install the quick link.

I've got a little special tool that hooks links near the end
of a separated chain to keep them close together and allow
inserting another link or two. It's just two short stamped
steel arms hinged at one end, with a thumbscrew to control
the open distance.

Like many of my tools, I got it used, so I don't know what
it's called. But I suppose a long twist tie could do pretty
much the same job.


I've seen those.

Mechanics normally drop the chain off the front so it hangs
without tension.
--
Andrew Muzi
www.yellowjersey.org/
Open every day since 1 April, 1971
I can't do that since I have a dog fang to keep from dropping the chain.

And since we're talking about tech for a change. I have those ceramic bearing'd rear idler pullies, I use those rather than the stock idler pullies because the stock ones gum up and start dragging and tear all of the teeth off of the idler pullies. This doesn't happen with either steel or ceramic bearings. But it is easier to get the ceramic bearing models.

I did a ride today that included some climbing to see if i have healed yet from falling down those stairs, Other than my sheer exhaustion for reasons I can't figure out, I seemed OK. 3/4's of the way back one of the rear idlers exploded and jammed everything up. I happened to be in a place where I could move off of the road and sit on a high spot. It took me a couple of minutes to figure out what had happened and finally work everything loose again. Though the aluminum idler had shattered it had left the bearing behind. in small and small I was able to ride the bike home again though at frightfully low speed. I think I have one of the steel bearing models around that has a more robustly built idler