Chain Jump

[Surgeseouk]

Hi all,

self admitted complete newbie here. I have a https://archiv.cube.eu/en/2022/533101 and after 2009 miles I’ve just changed the chain and pads. Cycled the first time today since servicing and it was a dream except for some chain jump in gears 6/7 under load. To clarify the bike is not slipping in to other gears, just jumping but remaining in the correct gear. I think it’s probably the cassette ( I definitely waited too long to replace the chain) but wondered if I should try anything first?
Thanks in advance!
danny

 

[flash]

Hi all,

self admitted complete newbie here. I have a https://archiv.cube.eu/en/2022/533101 and after 2009 miles I’ve just changed the chain and pads. Cycled the first time today since servicing and it was a dream except for some chain jump in gears 6/7 under load. To clarify the bike is not slipping in to other gears, just jumping but remaining in the correct gear. I think it’s probably the cassette ( I definitely waited too long to replace the chain) but wondered if I should try anything first?
Thanks in advance!
danny

I think you are probably right, but first check you haven't any stiff links.

 

[saneagle]

Hi all,

self admitted complete newbie here. I have a https://archiv.cube.eu/en/2022/533101 and after 2009 miles I’ve just changed the chain and pads. Cycled the first time today since servicing and it was a dream except for some chain jump in gears 6/7 under load. To clarify the bike is not slipping in to other gears, just jumping but remaining in the correct gear. I think it’s probably the cassette ( I definitely waited too long to replace the chain) but wondered if I should try anything first?
Thanks in advance!
danny

That's not unusual. New chains are much stiffer along their length, so you can get problems when the back sprocket is fairly far out of line with the front one (chain-line). It'll go away after a couple of days as soon as it wears in. You can check it by looking at the alignment of the derailleur, chain and sprocket when you've selected the problem gears. It's possible that you might need a bit more derailleur adjustment to line it up properly while there's more resistance to the chain reaching those sprockets.

becareful about judging the sprocket, especially if you get it looked at by a bike shop. Decent cassettes have a lot of weird teeth that makes them look worn when they're new. They have long oval gaps between the teeth and some teeth like dog's canines. If you want to check the cassette, check it against a new one of exactly the same type.

Look at all the different shapes of the teeth on this one. Many people that don't know better would replace it, even though it's new:

 

[Surgeseouk]

Cheers guys, really appreciate the comments. Will have a look tomorrow

 

[guerney]

I experienced weird chain jumping under load on gears 5, 6 and very occasionally 7 (of 8) for awhile, after I'd changed cassette and chain to brand new ones recently, and really couldn't make sense of it... but after liberal application of Hypoid 90 (@Nealh's and @saneagle's chain lubricant of choice) on chain and cassette, matters improved, but only completely went away after about 80 miles of riding plus lubrication of the rear derailleur. Until then, I worried I'd been palmed off with a second hand or factory second/reject/fake SRAM cassette, or that I should have removed the wax my brand new chain had arrived coated with, or that my chainwheel had worn. If there had been chain jumping on gear 8/8 aswell, I would have worried about a bent rear derailleur.

 

[matthewslack]

2000 miles is low but not unfeasibly low for cassette lifetime, depending on riding conditions, riding style etc.. Mud, hills and high assist levels could do this.

Assuming same number of links in new chain,
I would fit new cassette of proper quality and if problem goes away consider that the cause. If not put old cassette back on and try further diagnosis.

My first cassette lasted 6,000 km, these days I use multiple chains, swapped every 1000 or so km, and I'm at 8,500km with enough life left to get through a winter of muddy but low mileage commuting.

I mistakenly tried an Airbike cassette once, it was trashed after 1,000 miles. Shimano, usually bought in a sale, is my normal now.

If you do a lot of off road or steep hills, you might consider 10 or 11 speed upgrade when a cassette change is due. Shimano M5100 is robust, reliable and components often turn up at good prices.

 

[Peter.Bridge]

I had exactly the same ! I didn't realise it was normal with a new chain, it's all ok now.
I found loosening off the 'B' screw on the rear derailleur helped (so the chain wrapped round more of the rear cog)
I am going to order some hypoid 90 too, my Halfords gt85 is running out !

 

[sjpt]

Chains and cassettes work best together when they are about equally worn. But chains generally wear faster than cassettes. It's quite common that putting a new chain with an old cassette doesn't work very well.

For best life I have seen it suggested to buy a new cassette and three chains and change the chains round every now and then (500 miles???) Then when all four are pretty worn repeat. I've never bothered.

 

[Saracen]

I had a similar problem

Shop said new chain on OLD cassette.

Changed the cassette.

Perfect.

 

[saneagle]

I had a similar problem

Shop said new chain on OLD cassette.

Changed the cassette.

Perfect.

The shop always says that because it gives them a chance to sell something. As I said above, they'll even point out the strange shaped teeth on the cassette and tell you it worn.

 

[Nealh]

In all the years I have owned a bike, I have never changed a cassette because of jumping or teeth issues. I recall buying a coupe of cassettes simply because of wanting a larger top gear like a 36t or a 42t.
Chains are seldomly changed bar really old worn ones several years old, in the most part I will swap out an out a pair of chains in rotation.

 

[flash]

In all the years I have owned a bike, I have never changed a cassette because of jumping or teeth issues. I recall buying a coupe of cassettes simply because of wanting a larger top gear like a 36t or a 42t.
Chains are seldomly changed bar really old worn ones several years old, in the most part I will swap out an out a pair of chains in rotation.

Back in the mists of time with 5, 6 ,7 speed blocks / cassettes they used to last for ever. When I was younger I did 10,000 miles a year. I had 2 chains which I changed each week, so I had 1 on the bike and one soaking in a tray of diesel. With this system my drive train would last a couple of years. Back to the present with 10, 11,12 speed chains and cheap chinese cassettes that are made out of cheese. I change at around 1000 miles. In winter on my road bike I ride 68 inch fixed with a single speed wide chain, lasts for ever.

 

[saneagle]

Back in the mists of time with 5, 6 ,7 speed blocks / cassettes they used to last for ever. When I was younger I did 10,000 miles a year. I had 2 chains which I changed each week, so I had 1 on the bike and one soaking in a tray of diesel. With this system my drive train would last a couple of years. Back to the present with 10, 11,12 speed chains and cheap chinese cassettes that are made out of cheese. I change at around 1000 miles. In winter on my road bike I ride 68 inch fixed with a single speed wide chain, lasts for ever.

I think you're mistaken about cheap Chinese cassettes. They're made of steel, the same as your old cassettes, so they last forever. It's the expensive ones that wear out quickly because they're lightweight and made of aluminium alloy, and they're much thinner to take 10 and 12 speed chains.

 

[Surgeseouk]

Thanks for all your advice guys, genuinely appreciate it. I’ve checked the chain cycling it backwards and there is jump at all so does that rule out a stiff link? I’ve taken some images but I’m not exactly sure what would be helpful so if the answer is none of them I can definitely take more.
Thanks again,

danny

 

[Surgeseouk]

Should say no jump!

 

[saneagle]

Thanks for all your advice guys, genuinely appreciate it. I’ve checked the chain cycling it backwards and there is jump at all so does that rule out a stiff link? I’ve taken some images but I’m not exactly sure what would be helpful so if the answer is none of them I can definitely take more.
Thanks again,

danny

Absolutely no wear on the gears, so you can cross that one off. The only thing you can see is a bit of damage to the corners of the teeth from slipping. I'm going to say you need to adjust your derailleur to get better alignment on those two.

 

[Surgeseouk]

Awesome! Thank you!

 

[Sturmey]

It can sometimes be very difficult to see the wear on the sprocket. What you need to look out for is wear at the three to five o clock position on the contact face of the 'U' parts of the relevant sprocket teeth. This causes the chain to ride up on the sprocket tooth. Sheldon Brown explains it in the link below. I have successfully repaired/redressed the worn sprocket when they can be dismantled by using a round chainsaw sharpening file and filing as shown in diagram below. It works great and is a very useful skill, especially with a mid mounted motor.

Bicycle Chain and Sprocket Engagement and Wear

Maintenance of bicycle chains.

www.sheldonbrown.com

Technical FAQ: Chain hops and grinding cogs

A reader is wondering why his chain comes off the biggest cog on a 1x mountain bike cog, and how to refurbish cassettes.

velo.outsideonline.com

 

[Surgeseouk]

That’s brill thank you. I’ll have a look

 

[RichardKMS]

This will probably sound daft, but nobody has mentioned it, so here goes:
Sometimes, when in top gear (9th), and riding up an incline, using the second level of assistance, the chain seems to slip momentarily, but then recover. Not a major problem unless you are standing on the pedals (which I don't usually do). Doesn't seem to do it on any of the other gears. It is just possible that I am working it a little too hard, and need to change down a gear, but this happens even when I have a fair bit of momentum built up. I'm not trying to climb a hill in top gear from a standing start.
Before I had an e-bike I'm sure I have been told that chains will stretch over time. I think it's more that the holes in the links get worn down, which makes the chain a bit sloppy. I thought (wrongly?) that one solution was to simply remove a couple of links from the chain. Is this a good idea?
I'm talking about a bike with a rear derailleur. Probably not a good idea on a bike with hub gears.
My bike is a Trek Allant +5, a hard tail hybrid with mountain bike aspirations.