I have a Shimano 105 derailleur system with 105 shifters. Shifting on the front derailleur from the top to the bottom ring is very stiff and sometimes takes two attempts with quite a loud poping sound and not a smooth shift. Shifting from the bottom to the top ring is smooth and a joy to use. I would be grateful for your advice on how to make this shift easier. Regards CP

Can't tell what's wrong without knowing everything you've done. Try just going through the Park Tool procedure from start to finish, skipping no steps. http://www.parktool.com/blog/repair-help/front-derailleur-adjustment Front Derailleur Adjustment

I’m happy to help further over the phone at https://www.6ya.com/expert/donald_f2ed37026a3ac881

Which brand of shifters are you using? A SRAM derailleur won't work with Shimano shifters and vice-versa.

So - first; if you are using SRAM shifters with the Red derailleur - then changing to Shimano will not solve your issue but only make it worse.

If however you have Shimano shifters - then this is a good solution.
The Red derailleur should not shift that poorly with SRAM shifters. It is not the best - but it's not bad. If I had the bike in a repair stand I would be looking carefully at the following after affirming that the shifting system was indeed all SRAM:

• Derailleur cage height relative to the large chanring - should be a maximum of 2 mm
• Derailleur cage should be aligned as close to parallel to the rings as possible
• Derailleur upper and lower limit screws should be adjusted within spec and in order to allow the derailleur to travel the correct amount for ideal shifting
• Derailleur cable tension should be correct.

Hope this helps... Let me know if you need more.

Derailleurs have a return spring in them that will always return them to the smaller cog (whether it is front or rear). The derailleur cable resists this spring tension. If your front der. is on the large ring and will not shift to a smaller ring then it could be a couple things. First, too much cable tension preventing the spring from returning the derailleur to a smaller cog. Second, you low limit screw is set too far in so the derailleur cannot travel back to a lower gear. This will be evident if you shift to a smaller cog, the derailleur does not move and the cable becomes slack. Third, something else is preventing the derailleur from moving, perhaps the derailleur was moved when installing the new crankset and it is getting hung up on a tooth of the large chainring, there could be some foreign matter lodged in the derailleur spring preventing it from operating, the spring could have broken so there is no longer enough tension to move the derailleur back to it's "home" position. Good luck.

Try flushing out the shifter(s) with WD-40, use plenty. The next step will be replacing the shift cables and cable housings.

• Take the bicycle in an area free of cars and obstacles, such as an open parking lot. Concentration is required when learning to use Ultegra shifters or any other type of bicycle shifter.
  
• 2 Mount the bicycle and rest both hands on the proper Ultegra hand control. The left-hand control operates the front derailleur. The right-hand control operates the rear derailleur.
  
• 3 Start pedaling, smoothly and evenly. While pedaling is crucial to propelling the bicycle forward, it is also necessary when shifting the derailleur. Pedaling forces the chain to rotate. The chain must rotate before it can transfer to another gear.
  
• 4 Push the outside right Shimano Ultegra lever in toward the bicycle. The rear derailleur will shift the chain to a smaller rear gear.
  
• 5 Push the inside right Shimano Ultegra lever in toward the bicycle. The rear derailleur will shift the chain to a larger rear gear.
  

Rear Ultegra Derailleur Control

• 1 Push the outside left Shimano Ultegra lever in toward the bicycle. The front derailleur will shift the chain to larger front gear.
  
• 2 Push the inside left Shimano Ultegra lever in toward the bicycle. The front derailleur will shift the chain to a smaller front gear.
  
• 3 Use the front and rear Ultregra hand controls interchangeably. For small changes in gearing, using the rear control. For larger changes, choose the front control. A smaller gear causes the bicycle to travel a shorter distance per pedal stroke but also requires less energy to use. A larger gear requires greater effort but in turn causes the bicycle to travel farther per pedal stroke.
  

Look for excess friction in the shifter cable or maladjustment. Spring tension in the rear derailleur is all that drives it to the smaller cogs.

http://www.parktool.com/blog/repair-help/rear-derailler-adjustments-derailleur

There will be adjustment, check the front derailleur. There is a wire which is held by a pinch bolt, undo the bolt pull the wire out a little, tighten up and check the gears again. Do this until it works.

Hope this helps

If you learn to shift correctly this won't happen..

Google bicycle shifting technique, for example:

http://coachlevi.com/cycling/complete-beginner-guide-to-bicycle-gears-shifting/

You should NEVER run cross-chained (big-big or small-small). The drive train performs best when the chainline is as close to straight as possible. Excess sideways stress on the chain will wear it out prematurely and increase its normal efficiency.

To demonstrate this for yourself, put the bike in the same combination of gears you're having a problem with. Get behind the bike and look staright along the top of the chain. As you can see the line of the chain is a mild zig-zag where it is parallel to the bike at each gear but needs to angle across the drivetrain in between. On some bikes the chain might even come in contact with the next larger chainring when used this way.


If you can shift to the big-big combination without snapping the rear derailleur off, you're lucky. The big-big combo uses up all available chain length and the rear derailleur will be pulled toward the front of the bike, sometimes so far that it is in danger of being snapped off.

THERE IS NO UPSIDE TO CROSS-CHAINING.

As you can see, the rear derailleur is not long enough to **** up all the slack this gear combination creates. There are other combinations that would yield the equivalent gear ratio without either stressing the drivetrain or dropping the chain.

The basics of shifting are these:
1) The big ring and right side of the cassette in back are for speed.
2) The small ring and the left side of the cassette are for high torque, lower speed

This is somewhere between solution and clarification request: if you disconnect the cable from the derailleur and shift up and down, does the shifter click as it should? If not, you need to disassemble and clean your shifter.

It sounds like you could have two different problems. Your derailleur has become contaminated or your shifter may need to be lubed. Either way, the likely solution is the same. The best solution to get the derailleur operating again is to spray it with GT-85 or PB blaster and manually move in back and furth until it is working again. The same goes for the 105 shifter, spray GT-85 inside the shifter by compressing the brake lever and spraying towards the head of the shift cable. This will solve a non-functioning shifter many times.

The only other problem that fits is the limit screws could be wrong or the deraileur is in the wrong position. This would not be the case unless someone adjusted your derailleur before the ride you started have that problem. Or if the derailleur has moved. Both of which require the derailleur to be fully readjusted.

Hope this helps. Thank you

H sets the outer limit (for the big ring) and L sets the inner limit (for the small ring).