Tips for increasing gear cable tension on setup?

Hi all,

Setting up front mech on Shimano 105. Leaving aside already having the barrel adjuster screwed right in, any tips for helping me get the gear cable super tight for when tensionining it for screwing it into the front mech?

Hope that makes sense.

Cheers for any help.

Pull it as tight as you can by hand, then tighten the bolt just enough to hold it. Then pull the mech cage away from the frame a bit with your left hand, slacken the bolt slightly with your right hand, slide the cable up a bit, and retighten the bolt.

If you struggle and feel like you need a third hand, you can either find something to wedge behind the cage or you can screw the inner stop screw in, then wind it back out by the same amount once you’ve tensioned the cable.

Don’t cut it too short to start with. Leave enough to wrap round a finger so you can pull it tight. Or buy the tool, as above.

Set the inner stop-screw too far outboard then unscrew afterwards.

That last one is really quite cunning, and I wish I’d thought of it. I usually just grab the end with some grips and push the cage very slightly outwards to create some slack.

Edit: scratch reply, misread OP.

Is it 105 5800 11 speed? If so the low limit screw is wound in until the outer plate is parallel to the big chain ring, clamp the cable, then wind the L limit screw back out to the correct position and in theory the cable tension is correct. Stupid procedure.

Cheers for the tips.

@bigyan..it is. I’ve followed the Shimano tech docs to get it setup properly and it’s working fine, but that is with the cable tensioner screwed back out alot – leaving me little room for re-tensioning when the new cable stretches. I want to tighten it a bit more at the start to allow me to retightem later.

Do gear cables actually stretch more than the barrel adjuster can cope with?

As others have said I just swing the mech out a little bit, pull the cable tight and tighten the clamp bolt again.

Wind the L limit screw in a touch more prior to clamping, and you will get a bit more cable tension.

I take the it the convertor is the right way around?

Also the first time I clamp it I will hold the mech and shift to settle the cable ends (assuming internal gear cable, if its external just pull on an exposed section of inner as normal)(you will normally get quite a bit of “cable stretch” as the outer seats in the cable ends/compresses slightly)

The washer can also rotate when you tighten the bolt which slackens the cable, a drop of oil or grease between the bolt head and washer can sometimes help with that, if not just wind the L limit screw in so the outer plate is further out than the big ring.

You can’t, the tension in the cable is equal to the force exerted by the spring in the derailleur. I have no idea why we talk about increasing tension. The barrel adjusters merely change the length of the cable. So all you actually have to do is remove any slack. And then either increase or decrease the cable length to get the indexing bang on.

Stuck an inline barrel adjuster in my 105 with fine thread so can tune with both frame and barrel adjusters. In my experience 11 speed is quite sensitive to very small adjustments so coarse thread on frame adjuster and fine on in line works well.

Or as above wedge the mech out and set frame adjuster in middle to give wiggle room

I have no idea why we talk about increasing tension.

Excellent pedantry.  This talk of adjusting tension has always bothered me too, although even more so because it’s not completely wrong.  You’re right that what matters is adjusting the cable length, but doing so will change the cable tension as one end of the cable is fixed to the shifter and the other is attached to a spring, and the force exerted by a spring increases with extension.

To answer the OP, my trick is to put the chain on the big ring then without turning the pedals, shift onto the small ring.  The chain will stop the mech moving all the way to the inner position and you can make small adjustments to where the cable is clamped with no tension on the cable.

Cheers everyone – some good suggestions which I’ll use. 😀

I just pull the cable through the clamp, then use a pair of needle nose pliers to give it a bit of a yank, while tightening the clamp up. If you are a bit too ‘grippy’ with the pliers it can crush the cable a bit, but it’ll probably only be the mechanical fairies that get antsy about that….