Freewheel / Casette Wobble

[cyberknight]

Nowt wrong with subways , definitely not BSO territory
I had one with a 7 speed cassette a long time ago but as @Drago says worth checking just in case

 

[DRM]

40Nm (marked on lockring) is 20kg force with a 12" spanner (effective lever 8"). "Strong arm bar" definitely not required. A 70kg person will push about 20kg with one arm when doing a press-up (offered for calibration purposes).

I did say tighten it up, not swing on it like an angry gorilla, many DIYers have no idea how much torque they are applying, hence i suggested a torque wrench and 40nm equals 4.079 kg-m

 

[Ajax Bay]

SRAM 7 speed! No wonder I felt a pretty massive jump between some gears. I think SRAM casettes are great . .
I had 8 speed on a Claris roadie and got good results with a small range.
13-26 would be very sweet [on the bike].

AASSIA
Here's what you need to do:
1) Take the wheel out and look at the sprockets. Is there a lockring there (beside the smallest sprocket) - it will have 12T (say) and 40Nm on it - you have a freehub and cassette. Otherwise it's a freewheel block.
2) If freewheel, you are restricted to 7sp on that wheel.
3) If freehub, you might be able to fit an 8sp cassette, but the width of the cassette is 5mm wider than a 7sp cassette, so it may not fit. So you'd need a new wheel (freehub for 8sp).
Frankly, aspiring to converting to 8sp is a diversion.
You say you felt 'a pretty massive jump between some gears' but we don't know what sprocket range you have - eg 12-28.
13t smallest sprocket freewheel - https://www.tweekscycles.com/sunrace-7-speed-freewheel-2008183/
7sp cassettes with a 13t outer sprocket tend to also have a relatively small largest sprocket.
13-26 cassette: https://www.merlincycles.com/shimano-hg50-7-speed-cassette-13-26-55124.html (OOS)

 

[GoatBeard]

Pretty sure it's a freewheel as the cogs seem to be attached as a single unit with only a removable lock ring as the smallest cog. But any way, I've taken a chainwhip at it and tried to tighten. Won't budget and still wobbles. Can't remove it until my socket arrives, is there anything I can do? Hope the splines haven't worn out. I can remount the wheel but my god it's so out of true setting the brakes is impossible.

 

[Sharky]

Well you've confused me.

Your last sentence - unable to set the brakes, because the wheel is out of true. I can't think of anything to do with a cassette, freehub or "block" that would cause issues with the brakes (presume rim brakes?). Sounds more like wheel bearings or wheel axle, if the rim itself is true.

Whatever, I hope you find the fault.

 

[sleuthey]

If the freewheel is built into the cassette it will tighten it self on the hub with pedalling thus tightening with a chain whip will not achieve much. When you have it removed when you get the tool rotate the hub and if it still wobbles then the issue is a buckled hub so replace hub and keep cassette or vice versa if the hub is straight

 

[Fab Foodie]

Old worn Freewheels often had a slight wobble in them. As long as they shift cleanly, they’ll go on for ages.

 

[Cycleops]

If the wobble is so bad it’s affecting the true running of the rim as your post suggests a serious problem somewhere, probably with the freehub (which sounds you have as opposed to a freewheel), but you won’t know until you remove the cassette. Could also be wheel bearings.

 

[GoatBeard]

On my rear wheel, there's a through-bolt. Taking the through bolt off is a bad idea as I've discovered as ball bearings from either end of the wheel can come spilling out! Now, for reassembling the wheel and putting it back on the bike I'm slightly miffed. On the through-bolt, there's a nut on one end that I can't budge or reposition. On the other end, there's a (A) ring washer that goes inside (protects the ball bearings) and then a large washer (B) that holds that in. A rubber boot (C) goes over that, at a final washer sits behind the boot. A nut threads on after that.

I'm having problems reassembling it all. (A) only goes in so far, and if I overrighten (B) the wheel no longer spins when re-attached to the bike. If I loosen B it does spin freely, but C doesn't cover the whole assembly leaving a gap which water could get in. Bad for the bearings potentially. Are there any videos or demos explaining how to put it all back together again the correct way? If this isn't a BSO I don't know what is.

 

[Ajax Bay]

It's not a (blameless) BSO, it's a wheel, taken apart.

 

[Ajax Bay]

Pretty sure it's a freewheel as the cogs seem to be attached as a single unit with only a removable lock ring as the smallest cog. But any way, I've taken a chainwhip at it and tried to tighten. Won't budget and still wobbles. Can't remove it until my socket arrives,

If there's a removable lockring (which is not a sprocket (cog)) then it is NOT a freewheel, it's a freehub and cassette. One cannot 'tighten' a cassette with a chain-whip (as the OP has discovered).
I'd observe that if the OP keeps making new threads then all the background is lost and makes decent advice harder to offer.
Connect the SNAFU with the thru-axle reassembly.

 

[GoatBeard]

It's not a (blameless) BSO, it's wheel, taken apart.

I figured it's a wheel. But hey I'm getting somewhere at least.

 

[Ajax Bay]

I'm getting somewhere

Where?

 

[Dogtrousers]

Pictures might help - or anything that may be written on the hub like a model number.

Does it looks something like this? https://si.shimano.com/pdfs/ev/EV-FH-5800-3719A.pdf

Google for "bike rear hub service". Tons of tutorials and videos, but without knowing what you are dealing with hard to know which is right / wrong.

 

[Hugh Manatee]

Take a picture or two of what you have. The basic (old) setup is quite easy once you see how it works.