"lost" gears

Tashman

Hi all, please excuse my newbie ignorance but i've only just started in the world of "proper" bikes.

I have a 2010 Giant Defy 1 with Shimano 105 set up on it, but i seem to not be able to moce onto the 2 biggest gears (smallest cogs). The shifter doesn't make any click or sign that it's trying to select. Any advce will be much appreciated as i'm sure those of you ITK will have a simple solution.

CiB

The shifters are a ratchet that release enough cable to allow the mech to change one gear at a time. Sounds like the ratchet has reached its end before the mech has, so you need to release the cable at the mech, pull on it whilst changing down the last few clicks on the shifter then reattach it and tweak it to get the indexing right.

If not that, it might be that the limit screws are in too far. Don't play with these until you're sure you know what you're doing - check Youtube first.

Or the cables are sticking in the outers and aren't releasing to allow the last couple of stops. Another chance to undo the cables and lube the inners & outers properly.

Tashman

Thanks, i'll check it later this evening. Was all good a couple of weeks ago when i took delivery. Had a couple of chain jumps on my last ride tho so could i have upset something putting it back on?

arlowood

Tashman wrote:

Hi all, please excuse my newbie ignorance but i've only just started in the world of "proper" bikes.

I have a 2010 Giant Defy 1 with Shimano 105 set up on it, but i seem to not be able to moce onto the 2 biggest gears (smallest cogs). The shifter doesn't make any click or sign that it's trying to select. Any advce will be much appreciated as i'm sure those of you ITK will have a simple solution.

Did the gears work fully before and you have now noticed the problem with the 2 smallest cogs not able to be selected?

If that is the case then the problem could be down to your inner cable being jammed or frayed so that the return spring on the derailleur is not able to pull the chain over far enough to reach the two smallest cogs. I would try releasing the cable clamping bolt on the derailleur and check that it is pulling the chain over onto the smallest cog. That is the default position of the tension spring on the derailleur.

As you change across the cassette block (small to larger cog) you are pushing against that spring and the derailleur is held in place by the ratchet system in your shifter. When you flick the paddle to change up a gear (larger to smaller cog) the ratchet is released momentarily and the spring tension in the derailleur pulls the chain across to make that change. For this all to work well then your inner cable must be snag free and running smoothly otherwise it will prevent the derailleur spring from doing its job.

If yours is missing out on the top two gears then I suspect cable fouling is the problem and you may need to remove and lubricate the inner cable or install a new one if it is frayed.

On the other hand if the bike is new to you and you've only just spotted the missing gears then it could be that it has been set up incorrectly from the start and you may need to re-index the gears from scratch. This video will help if that is the case

https://www.youtube.com/watch?v=SkzvfCaIbyQ

drlodge

Try changing gear until you're on the smallest sprocket...can you then click the shifter some more (one or two clicks) as though it wants to shift onto even smaller sprockets? If yes, the cable as slipped and will be slack when in the lowest gear. If no then something is sticking or preventing the rear derailleur from moving to the largest sprockets.

svetty

Agreed cable fraying most likely - or perhaps bent hanger? Unless you are confident to fit a new cable and check hanger alignment yourself I'd suggest buying a bike-savvy mate a beer and getting him to sort it whilst you assist and learn the ropes.

Tashman

Thanks for the advice guys, turns out my 9 year old had spotted the adjuster screws and so adjusted them! I guess it was a cycle maintenance lesson for the pair of us At least he'll be able to sort out his own in future

CiB

That was lucky - if it had been the lower limit screw in the other direction you'd have had the mech round the spokes and a bent hanger by now. You might want to impress on him the consequence of altering things.

keef66

I'd park it with the drivetrain facing the wall in future.

But check he hasn't loosened the QR levers or the pinch bolts on the crank before you ride...

Tashman

I did give it a once over before heading out, nothing obvious that i could see, and he swears it was only those screws. (The lower limit needed tweaking too). We'll chalk it to experience as no harm done and we both now know how those effect the running.
As an added bonus i also knocked 50 secs off my Strava on a nearby climb! Joys of being a newbie i guess, big gains to be had