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Hi All,
I've been riding a Planet X road bike for years and it has a 10 speed Tiagra drivetrain.
I know it's offensive to the cycling Gods but I very often ride with a crossed chain- i.e biggest ring on the front and probably the second biggest sprocket on the back, definitely the third. I know it's not great practice but it's definitely a habit now rightly or wrongly and it never seems to do too much harm.
In any case I was cycling in Yorkshire a few weeks ago and my rear mech (felt like) it exploded behind me- mech was in the spokes, mech hangar was bent and so on. I took it to a local bike shop who confirmed it was f***ed. They put a new 105 rear mech on but couldn't get it running smoothly so I limped home rather than hold my riding buddies up all day.
I took the bike to a local bike shop when I got home proper and they have now replaced the mech hangar as it was bent and also fitted a new chain as the previous one had two quick links in and has been the subject of an accident. All seems fair enough.
The drivetrain is running smooth now but if I am in the big ring on the front it is totally un-rideable in the largest 3 sprockets on the back.
My question is, is there something I can do to try and attain the full range? What could be the difference?
Of course I could just suck it up and avoid crossing the chain when riding but it seems to me like it should at least be possible to *sort of* use these ratios?
The limit screws seem correct and I've tried increasing the cable tension which doesn't seem to change anything.
Could the chain be a link short I wonder?
Is the cage on the new rear mech the same length as the old one?
That or just learn to use your gears properly. This setup will help.
Cross chaining may not be ideal, but it shouldn't have left the second shop unable to shift into three sprockets.
Pretty sure the cage is correct length as the guy in the second LBS verified this (there was a slightly tense moment when we thought the wrong one had been fitted in the first LBS).
I take the point about not crossing the chain but I'd rather have the option and sometimes it happens by accident when very tired or racing mates etc. It's never been a problem to do before, so I'm wondering what the difference could be.
I should say, the chain does shift into the three large rear sprockets (from big ring on front) but sounds like a bag of spanners and is in no way rideable.
The chain should always be long enough to allow a big / big combo even if it makes you a terrible bicyclist 😉 . Is the arm on the mech fully extended on the largest sprocket that you can shift into?
Just read your last comment. Check if the noise is the chain is jumping or snagging on the lower jockey wheel. If it is then there is a solution
Did the shop check the hanger alignment?? New hangers aren't always straight
Was the front mech cable retensioned? Perhaps it’s the chain rubbing against the FD cage?
Check if the noise is the chain is jumping or snagging on the lower jockey wheel. If it is then there is a solution
Bike is in the shed now but I do feel like this could have been the noise?
Did the shop check the hanger alignment?? New hangers aren’t always straight
Yeah no idea- I will bear this in mind if I can't diagnose anything else.
Was the front mech cable retensioned? Perhaps it’s the chain rubbing against the FD cage?
Hmmm...not sure but I definitely don't think this was the noise/problem. I think I would have honed in on this- I'm sure it was something related to the rear mech.
Cheers for all replies!
If it's the jockey wheel then I had a similar issue on a 1x10 setup on the larger sprockets. Basically the chain angle is causing it to catch on the teeth. I got these
https://www.merlincycles.com/shimano-105-5800-11-speed-jockey-wheel-set-103056.html
And fitted the longer toothed upper jockey in the lower position. The longer teeth seem to mesh better with the chain and it runs smoothly.
Thanks Joe.
Okay, last question. Could it somehow be the frame being bent/warped? The bike is a very cheap alloy one and has spent years going on and off a couple of turbo trainers. Never been properly crashed though.
I feel like it probably isn’t the frame as it’s always been used on turbo trainers and was never an issue before but I’m wondering if hypothetically there’s a point where this would preclude me from ever getting the indexing right?
Really hope not as the plan was to buy a new bike and stick this one on the turbo trainer!
Shimano always used to advise that you should be able to ride all gear combinations (including with triples) but did advise against riding the bail out gears excessively due to increased wear; I still ride them at times.
I'd check the chain length first and recheck the limit screws; if the limit screws were properly adjusted in the shop they'd have picked up this problem!
Current 105 mechs. are 11 speed although I've no idea whether an 11 speed mech. on a 10 speed drivetrain would cause these symptoms.
The only other thing that springs to mind is whether the new mech. might have a lower total tooth capacity which your setup now exceeds (not very likely though).
Failing that, take it back to the shop; they shouldn't have let it go if it wasn't working correctly.
Cheers. At work now but yeah will try and stArt from scratch with the limit screws later and take a look at the chain length, fingers crossed.
Hmmm, I've just had a quick look at the Tiagra page on the Shimano Europe website and there's a triple option; are you riding a double or triple?
On the current 105 page there's only a double and short or medium cage mechs. It looks like the medium cage mech. is meant to work with the double. I get a bit confused with all of the 'total capacity' figures but I'd guess that if you now have a medium cage 105 mech. on the back and are riding a triple there's going to be a problem with the 'front difference' capacity.
No, riding a double on the front. 50 teeth on the big ring and 12-28 on the back I think.
Can the OP clarify what they mean by unrideable in the 3 largest sprockets?
If the chain is skipping about then it could be the sprockets are too worn to play nicely with the new chain?