12

From looking up the specs I presume your crank is FC-M8000-2. If you're saying that the crank arms are moving while the big ring and chain remain stationary in space, and the rear cog didn't move, the only possible explanations are that either the interface between the spider and the right crank has failed, or the metal toothy part of the composite XT big ...


9

I expect that after 10,000 km your chainring also needs to be replaced (frankly, I find it astonishing that you made it that far without replacing anything else. That's amazing.). Am I correct in guessing that you spend most of your time in your middle chainring? If so, it will be significantly more worn than your large or small rings, which would explain ...


9

The comments above are probably correct; if your chain is new, then the issue is likely a worn cassette. Because they wear out as a pair, chains and cassettes are often replaced simultaneously. A new chain on an old cassette can lead to skipping, just like an old chain on a new cassette can lead to skipping. Another possible cause of "losing grip" could be ...


8

Only 500 km from new? Sounds like cable stretch where the inner cable increases in length from new as it beds in. Did you use up your free service? Most new bikes from shops come with a 2-8 week "tweakup" to fix minor things like this. If you bought the bike off the web, then its up you to fix it. Firstly check out your brake line - there should be some ...


8

Cogs and chains "wear together" (regardless of whether they are front rings or rear sprockets). The old chain does not slip on the ring, because the old chain's rollers are worn down. They have an overall smaller diameter than the rollers of a new chain, and also a different shape: new rollers are cylinders, but worn ones look like small pulleys, they have ...


7

If everything is shifting smoothly and the hanger is aligned, it's very likely the freehub body slipping intermittently, which feels much like the chain slipping. Usually it takes a visual to be sure it's the freehub and not the chain. Different freehub designs call for different procedures to fix and investigate this. The root cause could either be overly ...


6

If you just want to go with something basic that's close to what you have, it's easy to get a replacement repair type crankset for this sort of bike. Check your tooth count, but it's probably 42/32/22, and then check the length, which is usually stamped on the inside of the arms. It will probably be either 170mm or 175mm. The other distinguishing factor is ...


5

sounds like your chainrings are worn. Look at the rings and see if they are "shark fin" shaped rather than symmetrical - a google image search for "worn out chainring" will show examples including some really, really worn out rings. The old worn out chain likely wore out the rings as well. I've had exactly what you're describing on a couple bikes and it ...


5

The only ''quick fix'' is to find a gear combination that works and hope for the best. Spending a few pounds on a chain wear checker will save you ever having to be in this position as you can check once a month or whatever and change the chain before it starts eating the rest of your drivetrain.


4

The chain will typically slip under the following conditions: 1. the chain is worn out (this can be measured with a cheap tool, or by your LBS). 2. the cassette is worn out 3. one or more of the chainrings (the cogs on the crankset) is worn out 4. the chain and/or cassette/cogs/pulley wheel are dirty and full of oil/road-grit/gunk. These can occur ...


4

I presume all the new drivetrain parts were replaced close enough together that they were all new or new-ish at the same time. If on the other hand just the chain was replaced, the cassette or rings were highly worn, you rode anyway for some time (say a few hundred miles), and then replaced those too, it's possible you could have put enough wear on the chain ...


4

The freehub was the issue. As it turns out, the bicycle manufacturer (Pinnacle) have issued a recall on the rear wheels of a small number of units of both my bike model (Arkose 4, 2016) as well as another model sharing the same rear wheel (Arkose 4, 2017). It seems there were manufacturing defects in a batch of rear hubs/freehubs, causing the pawls to fail ...


3

It's possible that during cleaning a grain of sand, for example, has become stuck in the chain causing a stiff link which does not travel cleanly over the cogs. Cleaning chains and cogs often involves a significant amount of moving dirt around before extracting it. A simple test for this is to move the chain through both hands bending every link. You'll ...


3

Regarding your second question about exactly how worn a chain has to be before it skips on sprockets that are also worn, I don't believe that a nice clean engineering analysis is possible, because you would need a specific wear model for both the sprocket and the chain. There are far too many variables: alloy composition, heat treatment, and surface finish ...


3

According to Park Tools: A worn chain shifts poorly and wears sprockets at an accelerated rate. The CC-3.2 is a go/no-go gauge designed to accurately indicate when a chain reaches .5% and .75%, the points at which most chain manufacturers suggest replacement. For 9 and 10-speed chains, replace chain just as the gauge fits the 0.75% side fits flat ...


3

Yes a new chain can skip in either an old chain ring or old cassette. The length between chain lengths needs to match. So the old chain matched up to the old ring. The new chain does not match up with the old chain ring. I suspect the middle chain ring looks worn. If so for sure time to replace it. What do I need to know to buy new chainrings for ...


3

Assuming that the cabling is clean, that the derailleur is nicely indexed and well alligned, the derailleur hanger not bent, and the chain correctly moves lateraly +/- 4mm for each gear up or down, then I would have a look at the distance between the upper jockey pulley and the sprockets. The distance should be on all sprockets less than 25 mm and more than ...


3

There could be several possible reasons for this behaviour - Derailleur could be out of adjustment - can be fixed by barrel adjuster/adjusting the tautness of the shifter cable. You can shift into a cog in the middle of range and visually inspect if derailleur is in line vertically under the cog that chain rests on. When derailleur is properly adjusted, ...


3

I have experience with DNP freewheels (7 speed, 11-28) and KMC 6-7 speed chains. I had exactly the same chain slip problem (literally word for word) with chain slipping and managed to fix it with great deal of attention to the derailleur setup. You might think that your rear derailleur setup is good because of the evidence provided by good shifting. That ...


3

Your lock ring is loose. Normally the cog is quite tight from pedaling and you can do some braking with it. When you brake harder it breaks loose and unscrews until it hits the lock ring. This is what you feel as sliding. The lock ring has left hand thread to keep the cog from unscrewing completely. Now that the cog has tightened against lock ring, the ...


3

Downtube shifters are usually called "friction shifters" and friction is key when fixing the issue you describe. I own and periodically use an old Cannondale with such system. Every now and then I find myself with the same problem as yours. How to fix it? Easy, just tighten the lever of the shifter. Mine came with an integrated metal triangle handle (...


3

What is likely happening (which David and Daniel describe the fix to) is that your rear derailleur has become maladjusted and is moving the chain further outboard--and off the sprocket cluster--than is necessary for your particular cassette or freewheel. In a sense it does "think" there is one more gear since the current adjustment is allowing the derailleur ...


3

By far you have to replace the big chainring. This is waaaaay abused right now.


3

Some ideas that might have helped, some Degrease/wipe the chain and chainring and cassette. By removing grease/lube off the outside, it might be a little less slippery. Remove a link of chain to increase the derailleur's tension. You'd need a chain tool and a master link. Risk here is that in larger toothcount gears, you may run out of chain and bust ...


2

A comment by @user10512 diagnosed the problem and provided the right solution exactly (see below). It was a shot rear wheel hub causing the chain to slip on front chainrings. I didn’t think to troubleshoot the rear wheel hub until after I’d already swapped out the bottom bracket, chain, cassette and front chain rings. Now that I have everything new and a ...


2

I had this trouble, and after checking the usual suspects (Replaced chain, cassette, cables, housing, and derailleur), it turned out my frame was failing near the bottom bracket. Although it's the most expensive to fix: before you start replacing components, do a quick visual inspection of the frame. Look for cracks/separations around the rear triangle. ...


2

It is likely that your cassette is worn. A new chain on a worn cassette will skip, because of the mismatch of the shape of the teeth on the cassette with the chain's spacing (which is shorter than what the cassette expects due to wear). You can visually inspect your cassette for wear by either looking for gaps in how the chain meshes with the cassette, ...


2

If chain us not slipping then id say you have a busted freehub by the sound of it. Take the cassette off, remove the freehub inspect the paws check for excess grease or lack of. Otherwise look at a new freehub body. I had the same issue you describe last week.


2

There are a few possibilities here: 1) Cleaning the cassette took away the gunk keeping a slightly worn cassette from showing. If you use the middle gears most, they may be more worn than the rest. Unlikely, but not impossible. 2) You bent the derailleur hanger or derailleur cage when removing or cleaning. More likely than #1, and easy to test. 3) Check ...


2

a theory: you might have too much friction between the derailleur cable and its housing. such friction could prevent the chain from going to the intended place when you shift; when the friction subsides, the cable would move and the chain would slip into place. apply some lube to the cable and slide the housing back and forth to spread the lube along. ...


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