My 10-year old son is racing a Guerciotti E-740 Disc.
The frame is equiped for a direct mount front derailleur. Because of the form of the seat tube, it is not possible to use a front derailleur with a collar.
I have installed a 46T chainring in the front (because of the max. gear they can run during races in their age category).
Problem is that the lowest position for the chainring that is possible with the standard direct mount adapter of the frame is for 50T. With this front derailleur height, shifting works but the chain often goes off when shifting from the small chainring to the big chainring.
Does anyone know about a sort of adapter to lower the front derailleur on a direct mount frame?
I can only find this on AliExpress, but the dimensions are the same. I would need something similar, but with a couple mm more tolerance to lower the front derailleur:
Would it be easier to keep the original chainrings and limit the rear derailleur instead? You can just use the limit screw to block off the top couple of sprockets, then adjust the cable tension to eliminate the slack.
If you just need a couple millimeters, I suggest simply filing the slot. The more difficult way to do it would be to slot the frame mounting holes, as the recesses designed to clear the heads of the frame’s rivet nuts would need to be lengthened too.
Lastly, you might want to search for a Time front derailleur mount. It has three holes, giving two options of mounting height.
Might be a stretch, but if the chain is falling off the inside edge of the chainrings (closer to the seat tube, instead of the outside of the bike), then would a chain catch help?
Unfortunately that is not allowed by the officials here in Belgium. If you do that, you have to grind off the teeth of the smallest cogs of the cassette, so they are sure the limits of the derailleur will not be changed between the bike check and the start of the race.
For this season (U11), max. gear is 5.52m. Current setup is a 46T chainring in the front and a 18-32 cassette at the rear. 46-18 with 30mm tires is spot on that max. gear.
Next season (U12) max. gear changes to 5.76m, which means that I can switch the front chainring to a 48T next year.
I already considered that, but when the chain comes of (which is certainly not the always the case) it goes over the big chainring and falls off on the outside.
