nycphotography

I searched around a bit, but didn't find anything really on point for this...

I have a SRAM red 10 group (11-28), originally built on a 2008 SL2 Team frame w/ a 53/39 Quarq (that required the Force crankset).

Anyhow, everything shifted perfect, worked perfect.... except the frame was cracking at the headset and I had to replace it.

So I picked up a SWorks SL4 frameset, a new set of jagwire cables and housings, a new PC 1091 chain, a Praxis GXP bottom bracket, and moved everything to the new (used) frameset.

I took it to an LBS to press the bottom bracket, throw on the chain, and adjust the derailleurs. It worked well for a few weeks, and as the cables stretched in, I got the expected rear shifting issues, which I trimmed out using the adjuster at the rear derailleur. easy peasy.

But the problem has persisted / resurfaced in a really weird way... it only ghost shifts on the small ring, NOT the big ring, and it doesn't show any symptoms on the stand.

It only screws me when I'm climbing the tough stuff, hard on the power on the small ring, usually at the top of the cassette. It manifests as dropping from the big cog down one on it's own, or taking two gears instead of one and then clicking until I tell it to take the second gear at which point it takes one more and keeps clicking. It seems to really only affect the 3 or 4 biggest cogs.

But it's maddening when I'm standing to attack on a climb and suddenly I get that slip-lurch-bang as it jumps a gear, and then I don't have the smallest cog available.

10 minutes later, over the top, and it's smiling and acting right, pretending nothing happened lol

And I get home and throw it on the stand and it's working perfect!!!

ANY IDEAS here?

cyclezen

OK,

under pressure, chain jumps because the:
1. the upper drive length is coming off the top of the cog at an angle enough to jump to next lower
2. chain is coming from slack lower run and being diverted by the orientation of the RD cage.

so for 1, check the chainline, make sure it is set properly for the type drivetrain. check to make sure that the wheel is preperly centered and dished (frame may be off if the wheel is truely centered and properly dished?)

for 2, check the RD for a twisted, out of spec RD/RD cage.

but very likely, check the dropout hanger, if it's twisted even a tiny bit, this will happen, with contribution from the RD.
not a 'new' sworks frame, right? check or replace the dropout with 'new' and report back.
the assumption is that you or whomever knows how to properly adjust the RD shifting...
lettuce no...

woodcraft

Check RD hanger alignment, check that cassette is tight,

& if it's a new chain w/ old cassette get a new cassette.

nycphotography

OK So I'll try swapping the hanger between my SL2 and the "new" SL4 and see if the problem persists.

Next up, the cassette... but that's a $$$ fix just to try and see. Maybe I have an extra 10sp cassette I can try and see what happens.

Thanks for the ideas.

velociraptor

A. RD hanger may be out of alignment. The only way to be sure is to have it realigned with the tool by a pro. Your old hanger would likely be slightly bent from general use as well, so I wouldn't use that.

AND/OR...

B. RD upper limit needs to be backed off a little bit (derailleur top jockey wheel should sit 0.5-1mm inboard of the biggest cog). In addition to smooth shifting, this makes sure that load-induced flex from the BB to the chain stay doesn't move the derailleur enough to pull the chain off the top cog.

woodcraft

You could also try putting the old chain back on.

I wouldn't count on either a new or swapped RD hanger being aligned,

but it doesn't take a pro to check/adjust- just need the tool.


I have the same SL2/ red setup. Any noticeable difference (aside from the skipping) with the new frame?

nycphotography

The old chain was... way past due, and I just broke it in half with pliers to remove it. lol

But yeah... other than the setup / adjustment issues.

I expected the frame to just be a swap out replacement and not really an upgrade.

HOWEVER, when I originally got the SL2, the first half season or so I would frequently feel like I had a flat back tire... the back was just... spongy... compared to the stiff a$$-splitting frames I had been riding before it (early 2000's carbon frames).

NOW with the SL4, I find I'm getting that "flat tire" feeling again... this time both front and back. It seems like its more comfy / cushy than the SL2. And the first time I stood to sprint up a short hill (columbia hospital off riverside) it just snapped to attention. I was definitely smiling.

Now, about a month later, I don't still feel that difference in crispness climbing, though I do still notice the "flat tire" cushy feeling. Overall, I'm pleasantly surprised that it is, in fact, an upgrade.

rpenmanparker 

Speaking of the alignment tool, I have a brand new, never used one I would let go for $60 delivered. Or maybe less. Park, of course. PM me if interested.

woodcraft

If the chain was way past, it could have easily taken the cassette with it.

This is a Tarmac that feels/felt spongy? Huh. Tried different wheelsets?

nycphotography

The SWorks SL4 frame only feels spongy relative to the other older SWorks SL2 Team frame. The same DV46 wheelset made the move from the SL2 to the SL4.

To me, it's just my ass adjusting to a less harsh ride, which I expect to stop noticing after a few more weeks. It was the same "hmmm" adjustment with the SL2, but only for the first few months. Then it just felt normal. In handling and power delivery it's crisper than the SL2. I think it's an improvement in both directions.

I said the old chain was "way past it" meaning I knew it was "due" and didn't bother to save it. Having raced motorcycles I learned (the expensive way) that if you replace the chain before it is so stretched that it eats up the sprockets, you can make the sprockets last a lot longer. It wasn't past that point, but approaching it.

However the cassette does have at least 5000 miles on it across probably 4 or 5 chains. So maybe it's just time.

I swapped it for a barely used Rival cassette off another bike and tweaked the adjustment. It seemed better on a 5 mile test ride (pushing against the brakes to simulate climbing strain).

Of course that's meaningless... everyone knows it will wait patiently to screw me on a real climb when I'm trying to hold someone's wheel. lol

nycphotography

Here's an interesting tidbit: the SL4 has a different hanger than the SL2. Who knew?

woodcraft

Thanks for the clarification.

Similar issue:
https://www.bikeforums.net/bicycle-me...ly-granny.html

nycphotography

thx for the link. I was initially thinking chain too long myself.

Maybe it was just time for a cassette.

nycphotography

Update: I rode it a while, tweaked it a bit more, and things settled down.

So I put the old red cassette back on this morning, tweaked the rd alignment a little again, and took it out for a 50 miler. Seems to be better at this point. I think it really needed for the derailleur to be aligned and I had just not looked close enough to notice it was off.

Chi_Z

trust me just buy the parktool DAG2, it will save you so much money and time. 1 trip to LBS is about the same the cost of the tool. A new hangers does not mean it is aligned to your frame.