New 10 speed drive train always skips a gear
 

I've got a Shimano 10 speed cassette 11-36, a SRAM 1051 chain, and a Tiagra flat-bar 10 speed road shifter. The derailleur is a medium cage Deore LX Rapid Rise model, made for the 9 speed drive train. Now I know these derailleurs can work on 10 speed drive trains because I used one on a 3x10 mountain bike some years back in combo with the same model Tiagra flat bar shifter, and it worked perfect (although I had a long cage model). But on my current 1x10, no matter how I adjust the derailleur, I can't get it to catch all gears. Either the cable is too loose and the first shift won't jump a cog, or the derailleur makes it all the way to the small cog before the last shift, or the thing skips from 4 to 6 or 5 to 7...I've fiddled with it for 3 hours now and only quit from exhaustion cause it's after midnight here.

I checked the derailleur alignment with my Park DAG 2.2 and it's perfect. I swapped in a different but identical Deore LX Rapid Rise derailleur, same problem. I tried a wolf tooth derailleur extender just in case the 36T was just a little too much for the medium cage, but really it shouldn't be an issue. It didn't help, so I took it back off. My adjustment screws are set perfect. The only thing that's off some is my chain line, but the chainline would never be perfect anyways in a 3x10 setup, so it shouldn't matter on this 1x10. Regardless of my rationale there, I ordered a different bottom bracket so I'll give it a try when it arrives, but I'm not expecting chain line to fix the problem. I'm starting to wonder if I got a bad shifter that pulls just a little too much cable...I don't know. I'm at my wits end and will probably just take the loss and go back to 1x8 if I can't get this to work soon.

Open to ideas.

The first step to diagnose indexing issues is to check the overall span or travel from end to end.

Shift to low gear and back the limit out of the way while you adjust the trim to be perfect. Now shift to the 2nd high gear and see if the trim is spot on. If it isn't then you have a lever/RD mismatch.

Note that this test must be done on low and 2nd high because many systems depend on the cable being slack in high and trim set by the limit screw.

The above assumes you've eliminated the obvious like cable friction, and the wire is correctly routed at the pinch bolt.

Tried your test, and sure enough it is not lined up in 2nd to high gear. In fact, 8 clicks instead of 9 on the shifter pretty much perfectly traverses all 10 cogs. I decided to take a closer look at the box on the cassette and noticed it has the Dynasys logo, and says HG-X. I'm wondering now if I'm an idiot and just bought an incompatible cassette. The cassette model is CS-HG50-10.

Tiagra 4700 10 speed shifter uses 11 speed pull ratio over 10 speeds and your RD doesn't.

​​​​​​https://www.cyclabo.com/topics/n8s6n3o8ge/

Were there multiple models of Tiagra flat bar shifters? Because I definitely had a Tiagra 10 speed flat bar shifter that worked perfect with a 3x10 mountain bike back in the day.

In any case, I found an extra 9 speed cassette 11-34. Shifts great now using the 10 speed shifter as a 9 speed shifter.

Looks like there was a 4600 and 4700 model of Tiagra 10 speed flat bar shifter. I'll have to see what I have...I actually have a couple of them, maybe they're different. But that's for another time...it works with the 9sp cassette now so I'll leave it alone.

Edit: So I have a pair of 4700 model 10 speed shifters. I must have had the 4600 back in the day, because it was before the 4700 was released.

Thanks for the help everyone in helping me shed some light on the mystery.

Basically your RD options to run those shifters (4700) on 10 speed are a 4700 RD or 11 speed road RD but still using a 10 speed cassette

I'm so used to rapid rise now, I think I'd have a hard time going back to high normal. Thankfully the 4700 shifter does seem to work perfect with the 9sp cassette.

I went ahead and bought a 4600 shifter on ebay, though. I'll either swap it out and put the 10 sp cassette back on, or I'll save the combo for a future bike and keep using this bike as a 9 spd.

I bought those 4700 shifters on ebay a while back, figuring they'd be good to have in the future for moving to 10spd because it was getting harder to find quality 8sp and 9sp parts. Never would have guessed Shimano made two different flat bar Tiagra 10 spd shifters with different pull ratios. But I guess this is what happens when I make bad assumptions.

Tiagra 4700 is a total outlier that you have to wonder "What were they thinking?" at Shimano, especially since they now have 2 "Tiagra" 10 speed that don't mix & match

It's not a 'total outlier'. It's more like 'the first of a new series'. The 4700 FD and RD use the same ratio as the 11 speed road groupsets. The newer Sora R3000 and Claris R2000 also use the same new FD pull ratio as the 4700 and 11s drivetrains.

Sadly, i hear the new GRX group uses the much maligned "4700" pull ratios too... sigh.

Not aware of that, but it's just plain stupid to not have these backward compatible with existing 8-9-10 stuff when everything in those speeds had been cross compatible.
What have they gained beyond making people buy all new stuff when a shifter is replaced.

That is interesting to know that the 4700 shifters work with 9 speed traditional 1.7:1 actuation ratio RDs.

It was my understanding that the new road (10, 11 speed) RD actuation ratio was 1.4:1. When I did the math 3.95mm (10 speed cassettes ctc) / 1.4 it equaled 2.82mm of cable, which is the old 8 speed shifter cable pull. 9 speed shifter pull is 2.55mm of cable.

John

There is a very good reason why Tiagra 4600 and 4700 groups use a different pull ratio and it mostly has to do with shift cable routing under the bar tape. When Shimano first introduced this type of cable routing with the 5700/6700, and 7900 series there were numerous complaints about shifting issues. Simply put, those shifters pulled too little cable per shift for precise shifting and also with cable friction. The previous 5600,6600, and 7800 series drivetrains worked better. Shimano solved that when they went to 11 speed with its revised shifters and derailleurs. They also used the same pull ratio as 11 speed when they introduced Tiagra 4700 so as not to repeat their error. I would not be surprised to see Tiagra move to 11 speed in the near future and it would be fully compatible with current 11 speed groups

I think my standard for perfect was lower after messing with that impossible 4700/rapid rise/10 speed cassette combo for hours. I've done a couple rides now with the 4700 and the 9 speed cassette, and it does shift nice and smooth on the middle cogs, but seems rougher at the edge cogs. That's good to know that an 8 speed cassette might work perfect, though.

Link didn't paste correctly, see below.

Since the time Shimano decided that the first modern index system should have a different pull/actuation ratio (Dura Ace 74xx), and Campagnolo released one of the best early shifters in their Ergo, people have been trying to mix-n-match shifters, derailleurs, mfg's.

But there is some good news. To make the early 74xx shifters and RD's play with non-74xx shifters and RD's, alternate cable routing started to be employed. By routing the cable differently on the RD, it is possible to change the actuation ratio by around 10%. You could probably use the Alternate C routing and get less RD lateral movement to match up better with your 9 speed cassette. I used DA 7401 levers with alternate routing (B). Here is a link to the concept:

https://www.sheldonbrown.com/drivetrain-mixing.shtml

I am pretty familiar with Rapid Rise setups; many people call them Rapid Demise. I have a couple bikes with them. It came about when my wife started to ride a mountain bike and was having issues with the opposite shifter function between front and rear. She had mastered the opposite (upshift/downshift) downtube shifters, but the triggers made it too frustrating. I installed a RR RD on my mtb's and over time just stuck with them.

The one major flaw with Rapid Rise is the mechanical advantage of the return spring is nowhere near the mechanical advantage of pulling cable to shift into the largest cogs. Climbing under heavy load, and even backing off momentarily to shift into the lowest gear, that spring just could not move the chain fast enough. On a mtb, with sudden terrain changes, it required just too much anticipation or perfect technique not to pull the drivetrain apart.

John

I put an 8 speed cassette on temporarily, seems to shift well under tests, but I haven't had a chance to ride it yet. Still has the 9 speed chain because I didn't want to sacrifice one of my new 8 speed chains for just messing around. I may actually end up moving things back to 10 speed before I get the chance to ride it again anyways.

Cable pull article looks interesting, although they casually mention tabbed washers, but no reference on what ones specifically to use or where to get them. Not sure if that's a normal hardware store thing, but don't remember ever seeing tabbed washers before. In any case, probably not something I'd ever try, but it's interesting to know it's a possibility.

I think tabbed washers started in the 90’s, maybe late 80’s. My guess is the tab prevents the washer on the clamping bolt from turning when the bolt is tightened.

The entire alternate tuning is based on changing the distance from the RD pivot to the attach point. Closer the the pivot moves the RD more, further away moved it less. When you run the cable around the tab it is further away and moves the RD less.

Going from 10 speed to 8 speed is quite a downgrade. Especially since Shimano publishes no current RD actuation ratios or work arounds.

The Tiagra 4700 with 8 speed is basically an internet theory since the real Tiagra 4700 actuation ratio is an educated guess and cable pull is a calculation off that guess.

At some point, it might be worth it to find a set of 4600 shifters that will work with a 9 speed RD and 10 speed cassette. Maybe even Microshift, although others will have to chime in.

John

The 4600 I ordered arrived early (today). So I never did take the bike on a ride with the 8 speed cassette. But I'm happy to announce it shifts right as a 10 speed now.

I don't remember exactly what I paid for the 4700 shifters, but whatever it was, I'm sure it was too much considering they're of limited use to me. I threw one in my Goodwill donation bag. The other I re-labeled as an 8 speed shifter, just in case I need one one day.

That was an adventure. Thanks, Shimano.

https://cimg1.ibsrv.net/gimg/bikefor...4eb9bc9f99.jpg

Good job!

Keep your eyes open for a backup set of 4600’s and if you are set on Rapid Rise, look for a backup.

Of the ones I’ve used, the M760 has been the best. In some ways better than an M960.

The M580 B spring seems to fade over time, I’ve had to use a longer B screw just to keep running a 32t.

John