1st gear ?

hairy_boy

Hi,

My 1st proper mountain bike - a Giant Terrago is now around 6 weeks old, I had a Scott hybrid prior.

Anyway, since new the Terrago has been a bit temperemental about changing from 2nd down into 1st gear on the front chainrings - ie. moving the chain onto the smallest chainring. I only have this issue when pedalling uphill and then wanting to change mid-ascent into 1st gear !

The gear change works perfectly at all other times - only have the issue pedalling uphill and wanting to change mid ascent - is this normal ? do I just have to change gear on a flat section, prior to starting a hill ?

Also, if on a larger sprocket (lower gear) on the back the change to 1st on the front seems less problematic. So what I'm saying is when the rear mech is in middle to higher gears the change on the front from 2nd down to 1st when pedalling uphill just doesn't work !

Any advice would be appreciated, not sure if I'm expecting too much from Deore front mech !

nicklouse

if you are loading the drive train when changing down on the front all that happens is a tick tick noise. you must unload the drive train to allow shifts. Like wise forcing an upshift is bad and can cause breakages.

hairy_boy

Wow, thanks for the quick response nicklouse.

As I suspected, its just me then :oops:

Thanks again !

nicklouse

it may not be you, but have a think about your gear changes and try lifting off on the pressure when you are changing gear.

europeandy

Personally i dont use the smaller sprockets of the back in conjunction with the small one at the front, it makes the chain run diagonally which cant be good, plus with the overlap in gears it shouldn't be neccesary.
Try changing to small cog on the front earlier and using middle gears on back till you need the really low gearing.

xtremedash

The extra tension in the chain, when under load, is stronger than the spring in the front mech, so it won't push the chain of the ring. Also you may find that as the equipment has worn in over the last few months it may need a little tweak to get optimum shifting performance.

I've recently had to sort a couple of mate's front mech's. The usual steps I take:

Shift rear gears to a middle sprocket

shift front mech to smallest

Undo front cable

Check bottom limit screw, adjust if necessary

Screw barrel adjuster on the shifter all the way in, then back out 1 turn.

Ensure cable is clean and kink free

Pull taught and tighten to front mech

Check shifting between small and middle chainring

Then shift to outer ring,

Check upper limit screw

If the chain does not want to lift onto outer ring try adding tension with the barrel adjuster

justresting

I have also got a terrago (about 2 months) and I dont use the 2 smallest rear cogs with the smallest front or the two largest rear with largest front as I believe it distorts the chain too much.

hairy_boy

I don't use the opposite extremes of the gears as I'm aware of the issues around the chain not running straight.

My issue was around running in say 5th gear (out of 9) on the back and having issues changing down to 1st gear on the front.

I'm still not convinced about the change to 1st on the front being right - even when not under what I'd call load the change to 1st is still problematic - I find that 'double' changing down makes the chain move across onto the smallest sprocket - what I mean by that is I push the gear lever from 2nd to 1st and on the gear indicator the red indicator moves into 1st position - the chain doesn't move onto the smallest chainring but click-click-clicks on the middle chainring, I then press the gear lever again (more into 1st gear) and the chain then moves onto the smallest chainring correctly. Any advice around this guys ?

This problem is still very much more present when changing down mid hill but I am very much aware now of not changing under 'load' so I'm getting a bit of speed in 2nd then trying a quick change down to 1st - hope this makes sense.

I have lowered the position of the front mech (only by 2mm) as it looked a little high and will see how I get on - any advice from more experienced people around this 'double shift' indicating how to fix this would be appreciated.

nicklouse

too much cable tension.

hairy_boy

nicklouse wrote:

too much cable tension.

Thanks Nicklouse, so when tightening the cable into place (with the front gears in 1st gear) how tight should the cable be - ie. just pulled a bit with my fingers and tighten the bolt, pulled a little with a pair of pliers or really given quite a bit of tension before tightening the bolt ?

Also, once in 1st gear - the front mech hanger currently looks correctly placed - ie fairly even space both sides of the chain - and when changing onto the largest sprocket on the rear (ie lowest gear possible) the chain doesn't rub at all on the inside edge of the front mech hanger.

nicklouse

as tight as it needs to be to shift up the gears and slack enough to allow it to get to the bottom gear.

just set it to as you think and then adjust with the barrel adjuster on the shifter.

sc999cs

Click on Parktools in nicklouse's signature to get full instructions on adjusting gears and lots of other good stuff.

Steve C