How To Straighten A Bent Mech Hanger

Gently apply a little bit of force and then take another measure using the gauge. When its just a small bend in one direction I usually straighten it out on the bicycle sometimes even with a derailleur on.

Check And Align Rear Derailleur Hanger Youtube

Using a hex wrench unscrew the derailleur mounting bolt from the derailleur hanger.

How to straighten a bent mech hanger. Mech hangers are designed to bend and absorb impact so as you adjust them you will find they bend easily. If the hanger has bent inwards then start horizontally with the gauge at the 3 oclock position. An alternative is to remove the derailleur with a 5mm Allen wrench and then use an adjustable crescent wrench to apply leverage to the hanger.

The amount of error is actually one-half the gap between gauge and rim. If you feel the hanger is straight enough you can perform the following checks. Avoid over-correcting the bend because this will weaken the hanger.

Frame is a 2009 trek top fuel 98. But most of us dont have one in the toolbox. I show how to fix a bent derailleur hanger without expensive tools like Park Tools DAG-2 Derailleur Hanger Alignment Gauge.

The problem with the crescent wrench is that you just need to be careful that you tighten the wrench down tight on the hanger and make sure that the jaws of the wrench extend past the mounting hole for the derailleur. The bracket axle is unlikely to be bent but the B-link bracket itself can bend which will chuck it out of whack but the out-of-whackness will tend to be more consistent similar to the effect of a bent hanger. Most of the time it is not visible to the eye if a hanger is bent or not.

When bending hanger it is best to bend small in amounts and recheck. Grab the derailleur body not the pulley wheels and apply firm constant pressure to bend it in the required direction. The Expensive Hanger Adjustment Tool Another less accurate option is to use a crescent wrench to straighten the bent hanger.

I like to use Olympia Tools Adjustable Wrench 15 Inches but other tools might work as well. Telltale symptoms of a misaligned hanger - the rear derailleur will shift fine at one end of the cassette but will lose its ability to shift and hold a gear as it moves from one side of the gear cluster to the other. Bend a bit recheck both side and then re-bend a bit more.

I have access to the park tool straightener but before I try to straighten it I wanted to check if its ok to put those forces on a carbon frame. The length of the rod will guide you in knowing how far you need to bend and if the hanger is relatively straight again. Leave the chain in place on the derailleur letting the derailleur fall away from the hanger.

If its a bit twisted then you really need to take it off the bike and place it on a straight surface. If your hanger is straight the gauge arm should sit in the same position relative to the rim. You can either cannibalise a QR axle and have it it your toolbox screw it on to the mech hanger and that way you should see which way it is out bent in bent out and then use spanner to bend up.

I think I may have a bent rear derailleur hanger. The chain stays are aluminum seat stays are carbon joined together at the rear axle. Rotate the arm of the alignment tool to the 12 oclock position pointing straight up.

Rear derailleurs can get knocked about out on a ride. Put the bike in a mechanics workstand attach the alignment tool bend the hanger reattach the derailleur check the gears and its done in 5 minutes. This repair is meant for steel f.

The best tool for the job is a derailleur straightening wrench. Also check the derailleur body isnt bent twisted. Take a soft approach when realigning them.

Realigning the hanger is done by grabbing the rod and bending it in the direction you want to. As the gap is closed it increases at the reference point 180 degrees away. Reinstall the mech shift into the middle of the cassette and check the.

Check the hanger looks straight by eye. BUT be aware that big bends should be reduced by using pliers or a vice first as you do not want to be pulling the threads out. And screw in a spare wheel.

Be careful not to damage the threads in the hanger with the edges of the wrench. We show you how to fix the hanger in case it gets bent or brokenClick here to subscribe to GMBN. You cant sight straighten a hanger for the simple fact that it has to be aligned on 2 axes from the back looking along the length of the bike and the twist of the.

This can then be used to straight the hanger and also to align it by comparing it to the wheel in the frame.

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