- This topic has 36 replies, 16 voices, and was last updated 11 years, 4 months ago by
allanj.
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December 4, 2014 at 6:16 pm #22823
Mother Theresa
This is driving me berserk. On my spangly new Park stand the gears are perfect and shift seamlessly (one year old Forme Ax Edge Pro with Ultegra 10 sp cassette). Mount up and pedal away and I miss changes up and down – not always on the same shift – and only 1:20 probably go awry. What might be wrong?
I’m new to bikes (after 30 years away) but have been known to strip and rebuild an engine with impunity so not a complete novice.
MT
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Charles_Hunter
Cheap chain checker, will
Cheap chain checker, will also help you fit a new chain but you’ll also need a chain breaker for that. Measuring with a ruler will work too.http://pages.ebay.com/link/?nav=item.view&alt=web&id=181571902176
massspike
Cable (imho). You could try
Cable (imho). You could try adjusting the tension ref. Shimanos instructions or Index Setting here http://www.parktool.com/blog/repair-help/rear-derailler-adjustments-derailleurMother Theresa wrote:
UnlessMother Theresa wrote:
Unless any further suggestions I will do the chain 1st. I don’t have a checker but Christmas is coming…You can use a tape measure. When new the links align on 12″. If they are stretched over 1/8″, replace the chain.
Given the bike is 1 year old, I seriously doubt chain wear will have caused any other damage. A rule of thumb: 10 chains = 2 cassettes = 1 chain ring.
Update.
Hanger straight (see
Update.Hanger straight (see what I did there?)
Most gear change failures were from 8th to 7th and 7th to 6th. It usually failed when changing direction of shift except in 1st and 10th (so that is my poor testing technique whilst on the stand because when mindlessly going from 1-10-1 it was fine but even on the stand going from 4-3-4 for example it required two clicks to make it come back to 4) and
this was case whether going up or down.Does this refine the diagnosis?
As a brewer’s son I definitely agree with the last comment. =D>
Unless any further suggestions I will do the chain 1st. I don’t have a checker but Christmas is coming…
antigee
a very comprehensive list up
a very comprehensive list up there – I’ll save a link for next time indexing is driving me crazy and I think I’ve checked everything!My 2 cents worth – I’d swop the chain – my experience and dogmatic opinion is that 10 speed chains don’t last that long and depends a bit on riding style and what sort of weather but 3000kms is a fair distance depending on weather and road grit/lubrication/cleaning (I know some people will get more)
A chain checker is a cheap investmentSo swop the chain? but bike shops will usually tell you if the chain is worn it will have worn the cassette/chainrings as well – some truth in that but at 1yr / 3000km I’d be a little less concerned – I understand that bike shops don’t want bikes back and so replacing the cassette sort of “guarantees” it isn’t going to come back (likwise overtightening pedals Grrrrrrrrrrrrrrrrrrrrrrr)
Pretty sure on a 1year old bike it won’t be the lever, last for years – could be the cable, again if ridden a lot in rain and especially on winter (salt gritted) roads
I’d vote to do the chain first (or at least get a tool and check it) and then do the cable check all the ends and for dents and give the rear mech a good clean – only thing about changing the cable is that stretch will be your enemy on indexing good luck and beer will help 😉
wellcoordinated
I think this is a chain
I think this is a chain issue. As sad previously if it is worn, as well as stretching it also loses its lateral stiffness. With no resistance on the stand this doesn’t matter, but on the road with the riders weight it does
matthewn5
I had it with a brand new
I had it with a brand new Ultegra 6700 setup. Tried everything, eventually changed groupsets. It just never shifted cleanly. Was worst from about the 21 to the 17, that part of the cassette, noisy, always trying to shift up or down again all the time.There’s too much friction in the cable under the bars, I reckon, and the derailleur spring isn’t strong enough to pull it across against that friction. That’s the only explanation I could find, having done everything, even straightened the (straight) hanger.
By comparison the Ultegra 6600 setup with exposed cables on my winter bike worked straight off and is still working perfectly thousands of km later despite all kinds of weather. As is the Campag setup that replaced the 6700.
Boo. This lasts one sounds
Boo. This lasts one sounds expensive.I will keep you informed.
glynr36
massspike wrote:It could also
massspike wrote:It could also be the ratchet in the shifter itself. My Ultegra 6600 behaves a bit like yours (not all shifts work) but it has 30,000 kms on it so I put it down to slough in the mechanism. As I understand it the Shimano shifter ratchet moves 1/1.3 the distance the rear derailleur is supposed to move. If it isn’t quite moving ‘1’ unit (due to wear) the rear won’t shift. As far as I know there is no way to fix/overhaul the shifter.I had this with a Chorus shifter as well, turns out it was on the way out and failed.
Warranty replaced, but sounds very similar to symptoms I was having.If the previous owner rode it
If the previous owner rode it heavily for 9 months, then the chain could be due for a change (3000kms is a reasonable lifetime for one). This usually makes everything run roughly (noisier) before it disrupts shifting but if you want to avoid #2 and #6 Tjuice’s list check/change the chain.FSA cranks work fine with
FSA cranks work fine with Ultegra rear mechs.Strewth, lots of info there.
Strewth, lots of info there. I never knew bikes were so complicated.I have only had the bike three months but the guy who owned it before I suspect put a lot of miles on it though it is in great nick.
The crank is FSA and the rear end ultegra, will the chain have a makers mark on it somewhere to see if there is a mismatch? That said the chap said he hadn’t changed anything except tyres and brake blocks and I would hope that Forme would engineer the cables/runs etc correctly.
I’ll brave the cold weather tomorrow and look very carefully at the positioning of the derailleur, or else go to Leisure lakes when my fingers freeze up.
It could also be the ratchet
It could also be the ratchet in the shifter itself. My Ultegra 6600 behaves a bit like yours (not all shifts work) but it has 30,000 kms on it so I put it down to slough in the mechanism. As I understand it the Shimano shifter ratchet moves 1/1.3 the distance the rear derailleur is supposed to move. If it isn’t quite moving ‘1’ unit (due to wear) the rear won’t shift. As far as I know there is no way to fix/overhaul the shifter.Tjuice
Sounds like something is only
Sounds like something is only very subtly wrong, so you’re probably not far off getting it right. Over the years, I have encountered a number of potential causes of similar problems. Each manifests itself in a subtly different way, so you may need a bit of trial and error. And it’s not surprising that things work okay on the stand because nothing is under any real load. Applying the much bigger forces when you pedal tend to amplify the impact of any slight misalignments.
Anyhow, here are some ideas, not in any particular order:1) Slightly bent derailleur hanger. If you find you can adjust your indexing so that it works perfectly for most of your gears but you have problems at the very top, or at the very bottom, this could well be the cause. Took me a long time to work that one out when I came across this issue (bent hanger was not at all obvious)
2) Derailleur jockey wheels overly worn (look like pointy shark teeth). Can be dangerous and cause chain to jump, especially under load. I’ve spread myself across the road as a result of this in the past.
3) Using brake sheaths instead of gear sheaths around the gear cables. They are different and will compress in different ways
4) Gear cables being forced around some overly tight corners. Can cause gear cables not to move freely within the sheaths and get a bit stuck.
5) Slightly sticky chain links in one point. Make sure every chain link can flex freely
6) Deformed chain rings (or cogs on the cassette). If the chain is getting a little stuck on the ring/cog it will cause problems. Check that all teeth of cogs and chainrings look to be in good condition
7) Mis-matching chain and cassette (i.e., not formally compatible)
8) Sticky shifters. Only like to be an issue with very old shifters, but if the grease internally has got a bit old and sticky this can cause problems. Unfortunately, shifters tend not officially to be user serviceable. But I managed to open up a pair of very old RSX shifters, clean them out and re-grease them and then they worked perfectly again…
9) Bedding in. If you’ve just put new cassette, chainrings and chain together, very occasionally, they just need to bed in a little over a few more miles. I went spare with an old bike of mine when I replaced these three components, and had exactly the kind of symptoms you describe. After having checked all the above and found nothing, I discovered that the problem went away after some more days riding as the interfaces between all these new components wore down slightly to suit each other
[Edit: Appreciate some of the above may not be relevant to your specific problem, but may be helpful to the broader community]
Good luck!
Mother Theresa wrote:Cables
Mother Theresa wrote:Cables appear to be OK on the outside, is there a test to see?It would be tension issue (e.g. cable stretch) so just visually check the indexing when it is on your stand….shift through all the gears and make sure everything lines up vertically. If you need a new cable, the derailleur won’t be moving the correct distance for each shift. This assumes you have followed Shimano’s instructions for indexing it first.
You could then try this while sitting on the bike to see if your weight is causing deflection — you can usually see the rear mech from the saddle if you can’t backpedaling should be smooth. If everything looks good statically then you’d have to ride the bike (since that is where the problem shows up). Ideally you’d have a friend behind you to see if he sees something odd.
The infrequent nature of the problem doesn’t seem like cable stretch although it wouldn’t hurt to replace it. Something is randomly causing the derailleur not to move the correct distance.
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