Shimano 105 R7000 Front Derailleur Setup - New Bike

Question

Just got a new bike with Shimano 105-7000 series, previously rode a bike with older style Shimano 105-5700. So the overall adjustment is different.

So on the new bike i'm finding that the setup doesn't seem right. Symptoms and observations are:

• The high limit screw has been set all the way in
• Chain rub when on largest chainring and smallest sprocket (aka top gear)
• Cable tension on derailleur alignment marks when in position 3 (1 trim spot down from highest setting) don't align. If I align the marks using the small cable tension screw on the unit then the up/down shift does nothing.
• Barrel adjuster near the handlebars is wound fully clockwise

I'm wondering if this all means that the original cable tension is not correct and thus all the settings are out of whack. The fact that can't get the alignment of the marks on the derailleur, nor having to wind the barrel adjust completely makes me think the cable tension is not correct.

Overall for a supposed better system than the 5700 series i'm not seeing the benefit yet.

Any suggestions ?

Answer 1

The Shimano 'toggle' FDs function well when adjusted correctly, but they are frequently misadjusted. Despite not being new anymore, it's still possible to find mechanics that set them up like other front derailleurs, which has no chance of working.

Setting them up is quite simple once one knows the steps.

Check the height (clears the big ring by 1-3mm when directly over it), then check that the back support screw (if present - braze-on models only) is properly engaged, which means it's contacting the frame/back-plate appropritely and if you were to loosen it, the tail of the derailleur will angle in slightly (1-2mm). Using either the back support screw or the band clamp, make the outer cage flat with the big ring.

In the "L-trim" shifter position (slackest), with the chain on the small ring and biggest cog, adjust the L screw so that there's 0.5mm or less gap between the inner FD cage and the chain.

In the "T-trim" shifter position (second from all the way out), with the chain on the big ring and biggest cog, adjust the H screw so that there's 0.5mm or less gap between the inner FD cage and the chain.

Also while in the T-trim position, adjust the cable tension using either cable tension adjuster so that the adjustment marks align.

When all 5 parameters are right at the same time, everything should work. (Height, angle/back-screw, L, H, tension).

Never at any point in a normal setup do you check the gap between the chain and the outer cage, nor do you take the chain off the biggest rear cog.

The above steps are a paraphrasing of the dealer manual available at si.shimano.com, which is also a step-by-step guide you can use to get good results, but it's a little more drawn out.