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7 Speed Issue

Old 04-27-20, 07:48 PM
  #1  
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7 Speed Issue

Hi folks!

Currently having an issue with a 7 speed cassette swap.

On my Miyata 1000 I orginally had a 7 speed 12-28 cassette (silver) and wanted to switch to a 12-32 cassette (black) for better range. I had no issues swapping out the cassette. When I tried fine-tuning the rear derailleur, I noticed the clanking sounds with the drive train and more noticeable vibrations when turning the crank. I had no issues with the previous cassette. My RD is a M760 XT, so I figured it would have no problem with the range. What do you think could be the problem? Any solutions?
Should I just switch back to the original cassette?
I'm still a newbie with cycling, so pardon my lack of knowledge! Thanks for taking a look.

I'll post some pictures below for.

12-28

12-32
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Old 04-27-20, 07:54 PM
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Did you re-measure the chain for correct kength when installing the new cassette? Larger rear cog means more chain tension.
Make sure to check the clearance between the upper pulley wheel and the cassette in small/big. Might need to adjust the B screw or pull the wheel back a tad in the dropouts.

As an aside, have never seen a cassette with those little ’buttons’ on the cogs. Are they supposed to aid in shifting?
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Old 04-27-20, 07:57 PM
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I believe that when you looped the new(?) chain through the derailer cage that you may have positioned the chain on the wrong side of the retainer bridge that gaps between the two cage plates. This would leave the chain to rub and rumble quite noisily on the bridge. Not visible from your photo angle.
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Old 04-27-20, 07:58 PM
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First: how is Cowtown? Still snow on the ground? Too bad about the Stampede.

Anyway, I assume you replaced your chain. Chains are 3,000 mile (max.) throwaway consumables, and you may be experiencing a new cassette not playing well with an old chain. The old chain is probably too short - that is if it was sized correctly with the old 28-tooth cassette. Expect that when you shift into the big cog at the front, and the largest cog at the back that this will tear off your rear derailleur, and carry the fragments into the front derailleur. Which will destroy that and perhaps a couple of the chainrings as well.
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Old 04-27-20, 08:10 PM
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Originally Posted by Dave Mayer View Post
First: how is Cowtown? Still snow on the ground? Too bad about the Stampede.

Anyway, I assume you replaced your chain. Chains are 3,000 mile (max.) throwaway consumables, and you may be experiencing a new cassette not playing well with an old chain. The old chain is probably too short - that is if it was sized correctly with the old 28-tooth cassette. Expect that when you shift into the big cog at the front, and the largest cog at the back that this will tear off your rear derailleur, and carry the fragments into the front derailleur. Which will destroy that and perhaps a couple of the chainrings as well.
Calgary is great, aside from the oil slump and pandemic itself!
I'm seeing a lot of activity in the local parks with runners and cyclists, which is nice to see, but also somewhat worrisome!

The chain has roughly 2500km on them. I believe they may have extra wear since it's the same chain I used from my Calgary-Vancouver trip last summer. It could also be that I'm missing a chain link.
I'll head over to my LBS to pick up a new chain if it's something I need.
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Old 04-27-20, 08:13 PM
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Originally Posted by dddd View Post
I believe that when you looped the new(?) chain through the derailer cage that you may have positioned the chain on the wrong side of the retainer bridge that gaps between the two cage plates. This would leave the chain to rub and rumble quite noisily on the bridge. Not visible from your photo angle.

Here you go.

it could also be that I may need a new chain or extra link since this one has 2500km on it with heavy touring use for the first 1100km of its life out of the box.
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Old 04-27-20, 09:45 PM
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I went through a similar thing recently although with fewer teeth on the cogs. Had the same thing happen though. Turns out the upper pulley wheel was just touching the teeth on the largest cog. It made the same noise and vibrations you described. Fortunately, I found this problem on the stand before riding. As rccardr said you might need to adjust the b-screw.
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Old 04-27-20, 09:50 PM
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Originally Posted by ltokuno View Post
I went through a similar thing recently although with fewer teeth on the cogs. Had the same thing happen though. Turns out the upper pulley wheel was just touching the teeth on the largest cog. It made the same noise and vibrations you described. Fortunately, I found this problem on the stand before riding. As rccardr said you might need to adjust the b-screw.
I did adjust the B-screw but it didn't help the situation, unfortunately.
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Old 04-27-20, 11:30 PM
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Thank you for the clear pictures. Nice bike from what I can see and you have fenders on it. It looks like the derailleur will handle the extra wrap and if you have things properly adjusted when on the small chainring in the front and the large or second largest cog in the back, that it should be working good even if the chain is short. Your chain is nice and clean, however, that could be because you are careful about maintenance.

One of the things that I do when setting up a derailleur is not even use the shifter. Perhaps some of you might not like this, however, I move the derailleur with my left hand thumb, no indexing, while my right hand turns the crank. I do this to verify that the chain is shifting properly. It helps to feel what is happening. I can also twist the derailleur body into a different position to see if that improves shifting.

Is this happening in all gears or only the largest cogs? If it is only the large cogs then perhaps the guide pulley is too close to the cassette cogs. If it happens in all gears, then perhaps it is the chain. It is always good to get a new chain with a new cassette.

Are those rivets or round things magnets? Do they help with shifting.

So, we are with you, this combination should work. A new chain with the extra links might be the key. Let us know how this works out. Then post a picture of the complete bike.
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Old 04-28-20, 01:39 AM
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Chain wear check.

Select the bigger chain ring - the one at the pedal end. Pinch the chain at the he 3 o'clock position and pull it away from the chain ring teeth. A new chain and new chainring won't allow you to see much under the chain. If you can see half a tooth your chain needs replacing. If you can see most of the tooth when pull on the chain, the chain is kaput and will be damaging the rest of the gear train hardware, don't ride it until you replace it.
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Old 04-28-20, 02:28 AM
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I'm also jumping on the chain train and guessing that's the problem. I recently replaced a 12-32 7 speed cassette with 12-28, adjusted the original chain length to match, but still had issues with it shifting properly. I then installed a new chain and presto! silky smooth shifting.
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Old 04-28-20, 12:01 PM
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Update!

I bought a new chain for 7 speed and added a few more links from the original one. I'm still confused because there is vibration on the smallest cog but the other ones seem to be fine.
I might consider just sending it to the LBS to solve the headache for me.

I did compare the two chains side by side and the old one showed significant wear, so it was a good call to replace it. The clanking sound is gone, but I still feel the vibrations on the smallest cog.

As requested, a few pics of my bike after a somewhat thorough clean.


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Old 04-28-20, 12:06 PM
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Take the same pic as you did in post # 6, but with the chain on the largest cog. That will be more illustrative.
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Old 04-28-20, 12:19 PM
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That is a good looking bike. Planet bike fenders, Brooks leather seat and matching handlebar wrap. Tan brake hoods, bar end shifters, fatter tires, cantilever calipers. A nice touring machine, nicely set up.

"Super Nice" and you don't have to have you valves in the right position or a pretty background here. That is a reference to GCN Nice or Super Nice segment.

Perhaps since it is only vibrating only in the smallest gear, perhaps the derailleur needs a slight adjustment on the H screw. I know you probably tried this already, but it is worth a try again maybe. The other idea that I have is that perhaps the guide pulley on the derailleur si a bit dirty and not free to move side to side as it should. I am just guessing here, but I am hoping you can solve this on your own.
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Old 04-28-20, 12:25 PM
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Might the chain be riding along the tip of the fender's mounting bolt?

Look from behind and view the chain clearance there, and also the clearance to the next-larger "second position" cog.

I am confused as to why the new chain wasn't long enough(???).

Does the lower run of the chain feed smoothly onto the lower pulley? No contact with the cage plates, right?

The KMC "Z" series chains are a good value, but the X-series chain is far, far better for only a few dollars more. I have measured a good deal of link-to-link pitch difference on several Z-series chains, although this is almost certainly not your problem here.
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Old 04-28-20, 12:32 PM
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Because it is only happening in the high (smallest cog) and you're in not in the granny with a chain that is too long, have you tried to adjust the high limit screw to see if you can get rid of the vibration. I'm only assuming that there is a adjustment issue since you had no vibration on your old 12t and you have already changed out the cassette and chain. I recently did a similar swap with a couple of freewheels and even though things shifted well, I needed to tweak the limit screws to really get things dialed in.

John

Edit Added: Didn't see Velo Mule's post above recommending the same thing.
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Old 04-28-20, 12:50 PM
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Originally Posted by dddd View Post
Might the chain be riding along the tip of the fender's mounting bolt?

Look from behind and view the chain clearance there, and also the clearance to the next-larger "second position" cog.
+1, or maybe even rubbing on the inside of the dropout. Looks like very little clearance in the photo from post number 6. If that's the problem, you may need to re-position the hub locknuts/axle slightly to the drive-side and re-dish the wheel.
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Old 04-28-20, 12:56 PM
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I had no issue with the hub before so I'm not sure what's going on.
The limit screw helped a bit.
The lower ones are the ones that seem to cause slight vibration. I tried lubricating the drive train a bit, which did help. It shifts fine. The chain is not rubbing against the dropout and is aligned with the smallest cog.
Here are some additional pictures


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Old 04-28-20, 03:49 PM
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Someone has probably already said this, but it's usually best to start with a new chain for a new cassette or freewheel.

And rather than exceeding a 13-28 cog range for a 7-speed cassette or freewheel, sometimes it's better to swap the original small chainring to something smaller. For example, for a typical 130 BCD crankset (space between bolts), switching from a 42T small chainring to a 38 or 39 makes a huge difference on climbs. Generally works better than trying to make a 7-speed cassette or freewheel handle a range of 12-32 cogs.

(This doesn't apply to your bike, which has a long cage rear derailleur, but another factor is trying to make a short cage rear derailleur handle that spread, since most short cage RDs were designed for a range of around 13-24 for all around sporty riding, 13-21 for crits and 13-26 for mountain stages. Long cage RDs are a bit heavier but they run really smoothly with larger cogs, with less drivetrain drag, so they're often better for many of us recreational cyclists.)

Those Shimano "mega-range" type cassettes and freewheels are the low end of their lineup and feel a bit crude compared with either better Shimano or comparably priced third party cassettes and freewheels -- especially SunRace and MicroShift, which provide excellent values compared with Shimano's entry level stuff. (Shimano's high end stuff is still in an elite class and priced like it.)

One problem with Shimano's "mega-range" type freewheels and cassettes is the lack of clearance between the smaller cogs and the hub. These work best with chains marked "narrow" (narrow across the pivot point on any single figure-of-eight shaped link plate, not narrow between link plates). With other chains the pivot points of the links will try to climb out of the freewheel/cassette in the smaller cogs. I picked up that tip from an Amazon reviewer, of all things, who included a photo illustrating the problem. Helped fix a pesky problem I'd had with shifting and running -- basically because the Shimana Mega-Range freewheels/cassettes are cheaply made and poorly spec'd compared with their better stuff.

Another problem is trying to cram 12-32 cogs into a 7-speed cassette or freewheel. The gear jumps are huge, especially between the two largest cogs, and will feel really awkward when shifting on climbs. It helps to anticipate and shift earlier, rather than waiting until our legs are dead and we're mashing 40 rpm.

When the original 7-speed wheel on my Univega was pretzeled by a car, I experimented for awhile to find a suitable replacement cassette or freewheel for an old but good wheel a friend gave me to replace the damaged wheel. The coin finally dropped that the new-to-me wheel was built for an 8-speed. Switching from a 14-32 Shimano 7-speed MegaRange to a MicroShift 8-speed 11-32 was much smoother shifting and running. There are still a couple of slightly awkward shifts but spreading the large cog range across 8 rather than 7 speeds really helped.

When I was recovering from injuries and needed a bit of help on my 7-speed road bike, I knew I didn't want to exceed a reliable 13-28 cog range. But I also needed an easier climbing gear than the original 42T small chainring and a 28T big cog. So I bought a couple of Vuelta 130 BCD chainrings, in 38T and 39T. These are just as well made as my original Suntour chainrings, shift and run just as well. Currently I'm running that 7-speed bike with a SunRace 13-28 chromed freewheel (excellent quality for less than $20) and 52T Suntour big chainring and 39T Vuelta small chainring. I keep the 38T Vuelta in case I decide to switch back to the 13-25 freewheel, for a little help on steeper climbs into headwinds when my legs are cooked.
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Old 04-28-20, 04:07 PM
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Is it just chordal action on the small cog? That would be normal.
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Old 04-28-20, 04:33 PM
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Solved!

I replaced the smallest cog with the original one (same tooth size and very little wear) and I tightened the lock nut for the cassette a bit more. I immediately noticed a difference. The vibrations went away.
I'll keep everyone posted if things go bad again or just take it to the LBS to not spam the thread anymore. Cheers!
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Old 04-28-20, 05:01 PM
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Originally Posted by BikeWonder View Post
I replaced the smallest cog with the original one (same tooth size and very little wear) and I tightened the lock nut for the cassette a bit more. I immediately noticed a difference. The vibrations went away.
I'll keep everyone posted if things go bad again or just take it to the LBS to not spam the thread anymore. Cheers!
That's XLNT diagnostics!
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Old 04-28-20, 05:28 PM
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Originally Posted by canklecat View Post
Someone has probably already said this, but it's usually best to start with a new chain for a new cassette or freewheel.

And rather than exceeding a 13-28 cog range for a 7-speed cassette or freewheel, sometimes it's better to swap the original small chainring to something smaller. For example, for a typical 130 BCD crankset (space between bolts), switching from a 42T small chainring to a 38 or 39 makes a huge difference on climbs. Generally works better than trying to make a 7-speed cassette or freewheel handle a range of 12-32 cogs.

(This doesn't apply to your bike, which has a long cage rear derailleur, but another factor is trying to make a short cage rear derailleur handle that spread, since most short cage RDs were designed for a range of around 13-24 for all around sporty riding, 13-21 for crits and 13-26 for mountain stages. Long cage RDs are a bit heavier but they run really smoothly with larger cogs, with less drivetrain drag, so they're often better for many of us recreational cyclists.)

Those Shimano "mega-range" type cassettes and freewheels are the low end of their lineup and feel a bit crude compared with either better Shimano or comparably priced third party cassettes and freewheels -- especially SunRace and MicroShift, which provide excellent values compared with Shimano's entry level stuff. (Shimano's high end stuff is still in an elite class and priced like it.)

One problem with Shimano's "mega-range" type freewheels and cassettes is the lack of clearance between the smaller cogs and the hub. These work best with chains marked "narrow" (narrow across the pivot point on any single figure-of-eight shaped link plate, not narrow between link plates). With other chains the pivot points of the links will try to climb out of the freewheel/cassette in the smaller cogs. I picked up that tip from an Amazon reviewer, of all things, who included a photo illustrating the problem. Helped fix a pesky problem I'd had with shifting and running -- basically because the Shimana Mega-Range freewheels/cassettes are cheaply made and poorly spec'd compared with their better stuff.

Another problem is trying to cram 12-32 cogs into a 7-speed cassette or freewheel. The gear jumps are huge, especially between the two largest cogs, and will feel really awkward when shifting on climbs. It helps to anticipate and shift earlier, rather than waiting until our legs are dead and we're mashing 40 rpm.

When the original 7-speed wheel on my Univega was pretzeled by a car, I experimented for awhile to find a suitable replacement cassette or freewheel for an old but good wheel a friend gave me to replace the damaged wheel. The coin finally dropped that the new-to-me wheel was built for an 8-speed. Switching from a 14-32 Shimano 7-speed MegaRange to a MicroShift 8-speed 11-32 was much smoother shifting and running. There are still a couple of slightly awkward shifts but spreading the large cog range across 8 rather than 7 speeds really helped.

When I was recovering from injuries and needed a bit of help on my 7-speed road bike, I knew I didn't want to exceed a reliable 13-28 cog range. But I also needed an easier climbing gear than the original 42T small chainring and a 28T big cog. So I bought a couple of Vuelta 130 BCD chainrings, in 38T and 39T. These are just as well made as my original Suntour chainrings, shift and run just as well. Currently I'm running that 7-speed bike with a SunRace 13-28 chromed freewheel (excellent quality for less than $20) and 52T Suntour big chainring and 39T Vuelta small chainring. I keep the 38T Vuelta in case I decide to switch back to the 13-25 freewheel, for a little help on steeper climbs into headwinds when my legs are cooked.
your analysis is fine but i always rile at being called a recreational cyclist. I use wide gears because i schlep groceries and camping gear as well as pull a trailer when hauling big stuff. Now when touring i guess you could say i was recreating but honestly people who race their bikes are participating in recreation. I am just using a terrific mode of transportation.
I'll get off my dopey soapbox now.
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Old 04-28-20, 06:24 PM
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I felt that the 7s 12-32t cassettes were long overdue, and much superior to the MegaRange Approach.

Too bad though that no one offers a freewheel with this range.

I have to credit SRAM with coming up with the 12-14-16-18-21-26-32 spread.
Shimano has now copied that 7s cassette number-for-number, so perhaps they might someday offer a freewheel with that range?
In the mean time, I am going to be experimenting with shortening SunRace's 10s freewheel. Plan is to take off the 11t cog and shorten the body. This would create a 7s-width freewheel with nine ratios from 13-36t.
Here's hoping that the (albeit expensive and rather heavy) 10s freewheel's internal lockring threads extend just a few extra mm into the body! Still waiting for it to arrive.
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Old 04-28-20, 07:44 PM
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ramzilla
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You're doing pretty good with the Deore RD on that big cog set. But, when stuff gets all stretched out like that it starts making noise. You might want to try a newer Deore RD like this:

https://www.universalcycles.com/shop...hoCblkQAvD_BwE

Much longer cage for bigger diameter cogs. Plus, you probably need an extra link or two in your chain. Be good. Have fun.
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