June 5, 2019 at 8:15 am #263626
I tried to convert my bike from 3×7 to 1×8 because I trashed the rear wheel. I kept my rear derailleur (7/8 speed compatible) and bought a new shifter, new cranks and put a Sunrace 11-40 8-speed cassette on the new rear wheel. The cassette came with a derailleur hanger extension. Here are the problems I am having (counting cogs from inside to out / biggest to smallest).
1) Doesn’t want to shift into fourth cog. Will not even start to shift when downshifting from 5 to 4. Either have to give shifter a bit more pressure or go down to 3 and back to 4. I have tried adjusting the derailleur and even took the cassette off to make sure I had everything together correctly. It is as if there is a bigger space between those two cogs. Of course these are the two most useful cogs.
2) Chain skipping on 6th and 7th cogs. I was chalking this up to lack of chain tension because I can’t see anything else wrong and 8th cog works fine. Chain can’t be shorter or would rip off the derailleur in 1st cog. I am considering either a longer b-screw but leaning toward new derailleur because there was some damage at the very bottom. I will also get a new chain. Is there anything else it could be? Like not enough chain wrap?
I wish I would have dragged my feet more because the Microshift Advent group set has finally hit the market. Would have been a bit more but 1×9 with clutch and slightly more range.
July 7, 2019 at 7:53 pm #265447
Still having problems and could use help. I checked my chain and it was stretched so I replaced it. Initially put on new chain with 2 extra links to account for the stretching but that didn’t work so I ended up taking out 4 (so I am 2 less than previous chain). No issues when on the work stand but on road/trail 5 plus still skipping.
Derailleur definitely needs replaced. If the answer is “clearly it’s just the derailleur” great! But wondering if all the trouble I had and using a stretched chain has damaged the cassette. But to be honest, I don’t use those gears much.
If that is case, will probably spring for Microshift Advent.
I need a bike that I can hammer on the climbs. Right now I will not pedal out of the saddle for fear of slipping and getting a chest full of bars. This is not how I ride.
Anyone experienced similar issues?
July 8, 2019 at 9:12 am #265453
If I were to guess, its one of two things; you chain length or your B-screw adjustment (you didn’t mention if you are using the hanger extension/longer B-screw). If I were to guess, your chain length is probably to blame. Your chain length doesn’t refer to the actual physical length of the chain (you mentioned adding 2 links to account for strech) but it doesn’t work that way. Chain length refers to the number of links in the chain. Try following this for sizing your chain: https://www.youtube.com/watch?v=O0YibMDWBAw
July 8, 2019 at 9:18 am #265454
I am using a 22mm extender. I’m fairly certain the hanger is straight. I am now two links shorter than the previous chain and lost one gear that was working (i.e. not slipping) in the process.
July 8, 2019 at 7:33 pm #265585
Checked chain against instructions in video (thank you for that btw). Exactly right length.
Could it be the derailleur?
July 8, 2019 at 10:15 pm #265587
I know you said you checked, but are you positive you didn’t miss a spacer between your gears? I’m only asking because it looks like the meat of your problems is at the transition from the spider-mounted gears to the loose gears…
Barring that, maybe try removing the extender. I know it may sound counter-intuitive, but I put a Sunrace 11-46 11spd on my fatbike and couldn’t get it to work with the extender (11spd NX mech FYI). Without the extended it works great. The extender might be causing a problem with your B-screw adjustment. Before going Eagle, I always had my best luck adjusting the upper pulley as close to the cassette as possible without them touching. Good luck!
P.S. the Park Tools YouTube page is a great resource to see demonstrations on repairs. They do an amazing job describing how things work and what the different adjustments do, way better than I or most people ever could.
July 8, 2019 at 11:58 pm #265589
I would second the advice to remove the derailleur hanger extender. If it does not sit flat on the hanger (with such a small contact patch it would be easy to miss) it will actually put your derailleur in misalignment. I figured it out after a lot of fooling around. The SRAM 8 speed x3 and x4 both accepted a 40 tooth cassette without the extender. I don’t know about Shimano.
Eventually I bought a derailleur alignment tool which would have diagnosed the issue in minutes.
July 9, 2019 at 8:35 am #265611
Thank you for the advice so far. It is helping me triage but no solution yet.
I removed the extender and still having same issues on ride to work, which is scary when crossing a busy street and gears are popping. I adjusted the derailleur a bit so hopefully the ride home will be better.
I don’t see any spacers in the cassette and all cogs are on the right way. I might try tightening again though.
I think next step is new derailleur and checking that hanger is not bent.
July 22, 2019 at 9:36 am #266461
Update: Put new derailleur on (more on that later) but didn’t solve problem. Though there was no obvious wear the problem was the cassette. I decided to stick within the parameters of the new derailleur (max 34t) and give up on the wide ratio cassette and put on a brand new chain. First ride was excellent (other than a slow speed OTB from a stump hiding in the weeds).
I had demoed a $5,800 bike earlier in the day. Everything on that bike was effortless and was worried riding my bike after would be a bummer. But with working gears I had a blast (much better terrain on my local trails compared to the trails for the demo).
The only issue I am having with the new derailleur is removing the rear wheel. All other derailleurs the wheel dropped straight down and then pop the chain off. This one, Microshift MarvoLT, doesn’t do that. As I pull the wheel straight down the derailleur extends into the larger cogs. The plastic jockey wheel jabs right in the gears. Can’t push the wheel forward because it hits frame. Anyone have a similar experience? Tricks you can share?
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