2.5mm allen key too large to loosen shift


New Member
Apr 12, 2011
(hi im new didnt know where to post this) ive been trying quite sucessfully to place a broken brake lever on my mountain bike, i bought a new set and i had managed to take off the handlebar grip but as i proceeded to inset the 2.5mm allen key up into the allen bolt i realised the allen key was too big . i dont have any sizes smaller , any idea what size i need for a SCRAM GRIP SHIFTER MAX?
I've seen screws on bikes for all the main sizes of allen key: 1.5, 2, 2.5, 3, 4, 5, 6, 8, 10mm

The grub screw you're talking about is probably for either a 2mm or 2.5mm key.

For occasional use, keys can be had very cheaply. However the quality of either the key or the screw has a BIG bearing on whether it will fit properly (particularly at smaller sizes).

If you're prepared to use them over and over spend some money on a quality set of allen keys. I spent somewhere around AU$70 on a good set (all the sizes above plus a holder) a few years ago. They're made of stainless tool steel, will last me for years, and have never burred a screw yet.
I agree with Tafi keep away from the cheap low end plated allen wrenches.

Park Tool has some decent tri-wrenches that have three keys on each. They may have one that has the sizes you are missing on one tool. Husky and Craftsman both have decent sets available at reasonable prices.

Get the proper tool you need to do the job. If you dont you will end up wasting more money and time than if you had the job done at the LBS.
hi i just had another look at it maybe the hole i was focusing on due to the positioning of the bolt on the shift is just part of the grub screw and the allen key is infact too small , just measured it against a ruler and the key is 2mm so maybe 2.5mm is the correct size afterall , pity my key is 2 4 5 and 6