Tiagra Front Levers
therichieboy
Posts: 58
So Halfords replaced my front Tiagra STI lever. They are triple shifters but for a compact double chainwheel.
I've had this in the past and never had to click twice to move up and down between my chainwheels. I have to now on this new one.
Is this normal?
I've had this in the past and never had to click twice to move up and down between my chainwheels. I have to now on this new one.
Is this normal?
0
Posts
FCN 4 Roadie
I've got Tiagra on my Boardman and it only takes one click for me.
Don't quote me on this but when they are set up the lever should be clicked as if to move to the smallest chainring.
Tiagra levers are only made for triples.
Shimano's tech docs section has pdfs of how of this works. Quick quote from one: "When lever b is operated, there is one click where trimming (the noise prevention mechanism) engages, and second stronger click when the gear shift stroke is completed. After trimming, the next push will complete the gear shift stroke".
All it does is to provide two front derailleur positions for each chainring - one best placed to avoid chain rub for the outermost gears and one best placed for the innermost ones.
Edit:
With the large lever fully clicked on the outer chainring, a single small click on the small lever should move the front derailleur slightly towards the frame but still leave it on the outer chainring. A second click should drop to the next chain ring. This is then trimmed by a small movement and click on the large lever.
if the front deraillleur cable tension is incorrect, the highest position using the large lever is never reached and it drops to the inner on one click.
The sight guides are handy for checking this - the red bar shouldn't be central in each segment but at the left or right of it.
John
I have to give it a fair bit of force to change.
FCN 4 Roadie
It aint dura ace........
But it works!!
This kind of ties in with the trimming issue - two small clicks when in the highest trimming point and it shifts easily to the next ring. If you want to go straight down to the next ring when you're in the highest trimming position then it's one big movement of the small black lever.
I don't have to push mine very hard at all - just move the lever further than the movement needed for one shift.
Same principle as the rear derailleur - shift one gear\position with a small click and two with a bigger one.
http://tinyurl.com/mcso4y has the lever positions.
John
I don't really know how I should be setting them up. Should I be adjusting the lower limit screw with the shifter clicked all the way down, as if I was on the smallest chainring of a triple, or as if I was on the middle ring?
That way, when you change up, you can't force the lever past its highest chainring position and damage it when it's stopped by the limit screw of the front deraillleur. When you change down, this doesn't matter as all you're doing is releasing the cable tension - you can't damage the shift lever by somehow forcing it against the lower limit screw.
Hope this makes sense.
John
yes that will stop you over shifting, but it is slightly less fiddly to set up if you put big ring on the middle setting.-there isn't really the potential to overshift if you have it set up right.
...but that said I did the lever jamming thing myself when I first got my bike - I reckon that it had been set up middle click to big ring but cable tension was was ever so slightly too loose so when it didn't change up on the first big click I wrenched it over a click too far pushing the mech against the high limiter (which was probably a little too loose as well) thus jamming the sti ratchet.
if it does jam don't force it back, just release the cable at the mech, then use the shimano tech doc (or park tools guide etc) to set up from scratch to stop it happening again
That's what I did. Well, I released the cable at the mech, then arsed about with it in exasperated ignorance until I somehow got it shifting again, which I'm sure constitutes the same thing, more or less.