Fine Tune your rear derailleur with new Linientreu precision laser tool

Let’s create a problem that doesn’t exist and create an expensive tool to fix it!

I can have the derailleur adjusted by the time you get that tool mounted using my Mark I eyeballs.

Misguided concept. It will only work for its intended purpose if the hanger is perfectly straight – and this tool can’t help with hanger alignment. And that would be a better purpose.

It would need to mount to the plane of the wheel to function for its stated use.

Want perfect….perfect…..perfect RD setup.

Step 1: Check frame alignment-on a table.
Step 2: Make sure that rear wheel is perfectly true.
Step 3: Check derailleur hanger alignment against that perfect wheel.
Step 5: Set high limit screw with cable detached.
Step 6: Attach that cable and turn the barrel adjuster out past correct. Shift to the low cog and set the low limiter screw.
Step 7: If the b tension screw is off, turn it in or out as needed and run the chain up and down the cogs 2-3 times. readjust as needed.
Step 8: Fine tune cable tension.
Step 9: Ride the bike around the block….just to make sure that under load everything is still just right.

What’s the problem with this silly laser tool? It doesn’t check frame alignment, or that the bb is faced in line with the dropouts, or that the hanger is straight. It also only works on bikes in the stand, with no torque flexing the bike and its drivetrain parts oh so slightly (let alone the effect that suspension compression has on the drivetrain).

I don’t bother putting frames on an alignment table and only check hanger position if the derailleur looks off……and I get perfect rear shifting on the bikes I assemble or service. If you can straighten a sub-2mm disc brake rotor by sighting it through the pads on a bike, you can see if a 5.5 mm wide chain isn’t aligned right. It’s well within the bounds of human perception.

This is a flawed tool which provides one very precise metric for getting good shifting, but on a straight frame that’s an easy job. On a frame that has an alignment issue somewhere, this thing is useless. On a full suspension bike that’s adjusted in the stand without factoring in sag or travel, this thing is useless.

Having worked at bike shops for a few decades, I’ve found that some customers like the idea of wrenching on their own bikes more than the reality of doing so. They think that with the right tools, they can rival the work that guy with the greasy apron and a few thousand hours of wrenching time does. And they buy exotic stuff, from (so, so choice) Var and Campy toolsets of yore to spoke tension measuring tools to titanium hammers (the worst use of titanium…..EVER!!!!). This tool will appeal to these people, and then it will sit, unused and dusty on an unused, dusty workbench. And when the tool wanker who bought this silly tool tries to sell it to his local mechanic (who will GLADLY pay for a Var or Campy tool kit, which is useful) it won’t sell. And then it will either go back to bike tool purgatory on the bench (or maybe in the toolbox) of unused stuff…..or get thrown away.