Bicycle Cone Wrench





Introduction: Bicycle Cone Wrench

About: I miss the days when magazines like Popular Mechanics had all sorts of DIY projects for making and repairing just about everything. I am enjoying posting things I have learned and done since I got my first ...

Make a high quality cone wrench for all of your bicycles from an adjustable wrench.

Step 1: What You Need

Buy a good quality 8 inch adjustable wrench. The jaws should be tight and move smoothly. You will also need a grinder, an oilstone, and some light oil.

Step 2: Grind the Wrench Slowly

Close the jaws tightly and place the handle of the wrench in a vise. Grind from the side with the metric scale. An angle head grinder works well. Be patient. Grind slowly. Cool often. Do not let the steel discolor from heat. Dip in water. Do your grinding forward of the openings inside the jaws so you do not cut into them. Grind the thickness of the jaws down to about 2 - 2.5 mm. in thickness. The grinding process requires about one hour.

Step 3: Finish With a Handstone

A power grinder does a good job, but you can get more precise results by finishing the ground surface with an oilstone. Use thin oil to flush grit out of the jaws so they work smoothly. Work the jaws back and forth. Repeat flushing with oil until there is no more gritty feel.

Step 4: Using the Wrench

Place the jaws around the bearing cone with the ground side up. This allows room for another adjustable wrench or a fixed wrench to loosen or tighten the locking nut. You now have a quality cone wrench that fits any bearing cone and will not distort under use because it is made from quality tool steel.



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27 Discussions

Cone wrenches should see minimal torque, and this adjustable version should work fine. The bearing cones are hardened, and unlikely to round. Plenty of cone nuts have seen needle-nosed pliers after all.

In use, you will find it handy to have two cone wrenches: When the bearings are a little too tight, it is easier to leave the locknuts alone, and turn the two cone nuts apart. This works far better than trying to loosen a lock nut, change clearance, then tighten the locknut and see how it feels. With two cone wrenches you can set the bearings in a minute or less...with only one you may fuss and cuss for 10 minutes or longer.

Awesome. I was in a bit of a jam trying to fix a bike with no cone wrench and no where to get one. I had way to many adjustable wrenches and a bench grinder, so I was able to make one in about 30 minutes! Works like a charm.

1 reply

Thank you for looking and for sharing your experience. This wrench is sturdier than those stamped out of thin steel. You will enjoy it each time you use it. And, you will never need to go and buy a new wrench because the cones on a new bicycle are a millimeter or two different from your old bicycle.

Thanks. It really works, too. I made one a couple of years ago for a guy who is starting up with his own bicycle repair business, but does not have extra money to buy tools. He loves it.

if you are designing a shifter(wrench), and dont want to damage nuts, there are two solutions which you could impliment. number one is put a spring to push the jaw outward so it dont move when you return, secondly, some shifters have this "tooth" inside of them, sort of like the one in step1 (its the 45* spot inside the moving part of the jaw, but pictured one is a little small, limiting the max nut size) overtightening may break it (not done this yet, despite using concrete anchors with a 200mm shifter), but a tool could be designed to take advantage of this trait. You push the tooth into the flat part of the nut, its highly unlikely to burr the nut - the worst it gets is a "bite" mark in the side of it. This only works in one direction, clockwise in the above image.
its probably useful to someone...

I like the Adjustable Cone Wrench. Good idea, and good photo. Walmart sells a black and yellow handled Stanley brand "crescent" wrench, that has very tight jaws and a comfortable rubber coated plastic handle, for $10.

It fits over most headset nuts even! So your idea will make a $10 wrench that also doubles as a headset lockring wrench (there are several sizes as well as the common knurled upper headset cone instead). This idea should work well on the lockrings if turned so the top wrench doesn't collide with the jaws of lower wrench.

For touring bicyclists, who carry ALL necessary gear, the $10 stanley wrench can be cut down to 4" with a simple hacksaw in a couple minutes, making a light portable tool.

stanley crescent wrench.jpg
1 reply

I have seen those wrenches at Wal-Mart. I was attracted to the thinner black part on each jaw. Some of the grinding work would already be done. I am glad to know the jaws are tight.I have not needed to work on a headset so far, but thank you for the report. Thank you for looking at this and for your comments. I hope all goes well with your bicycle touring. I rode the TOSRV in Ohio almost 40 years ago, but that is not quite the same as mapping a route and riding across most of a state or two with a group of friends.

did you know that you shouldnt really use adjustable spanners becuse when using them the jaws move outwards slightly and can round off nuts but other than that great ible,i just g to a carboot and find a spanner that will fit and just grind that down


9 replies

 Your observation about adjustable wrenches or spanners goes to the question of their fitness for use.  Here in the USA we had a well-known bicycle mechanic named Sheldon Brown.  Much of his stuff is still on-line and accessible.  He said adjustable wrenches or spanners are fine, if used carefully.  That would mean keeping the jaws tight on the flats of the nut.  I purposely bought a better wrench for this modification because I knew it would have less movement in the jaws.  It would also be possible to compensate for any looseness by grinding a slight angle into the movable jaw face so both jaws were parallel when tight.  I have never rounded corners on a nut with an adjustable wrench or spanner, but I am fairly careful with them, too.

I managed to pick up a nice adjustable spanner for a few quid,= and did your project now i can undo any locknut,thanks :)

I hope you enjoy and use your wrench as much as I do mine. Please let us know later how things are going for you with the wrench. Thanks for your comment. It is a great feeling when someone makes use of one of my ideas.

Ive used this twice already,once on my cones on my old mtb that had seized so i couldnt get enough leverage using a normal cone spanner and another time using it to uno a very thin nut holding a plate together,im sure it is a great feeling,once again thanks

 I failed to include why I spoke of Sheldon Brown in the past tense.  He died in February of 2008 from a massive heart attack.  He had previously suffered from other very serious health problems and blogged about them.  His pages on all manner of things about cycling, especially his guides to repairing various problems can still be found at:

yes spannes are fine but i have some pictures o some rounded nuts on my bike ill post them if i can find them

Phil, something is wrong in Instructables, because I just received the notice that you have posted this. But it suits me to let you know that a few days ago I had to do this with a fixed wrench, 15 mm. I do not know how it is in the USA, but here in Argentina is often preferable to do things yourself rather than trusting the "experts." Two bikers told me that my bike had no problem with the bearings, but I finally decided to disassemble it and found that the pellets were nearly all oval. Now it is as new!

not to take sides or anything, but... actually there are definite advantages to both buying cone wrenches that are ONLY for cones and making an ajdustable one for only that purpose: the reason cone wrenches are consumable tools, not a lifetime investment, is that if you strip the flats of some other nut on your bike, you can probably either use the trusty and overkillish vicegrips or a drill to get it off and replace it with a new nut. cones, being mostly inside one's bearings, have very little metal to get purchase on, and if those things strip, you are in a world of hurt, even if you are in a workroom/garage/shop with the tools to grind the axle off and at least salvage the hub. On the side of the road... cellphones would be whipped out, or thumbs would be extended, or firewood would be gathered, depending on where this happened. In short, conewrenches are made deliberately softer than the steel of the cones themselves to avoid screwage of the consumer. If you are a gorilla-fist with your bike (I have to keep an eye on my own apishness sometimes) use dedicated conewrenches. If you are going on a long, looooong exscursion and have learned beforhand the vital, crucial, lifesaving feel for how tight your nuts and bolts should be (and you check your bearings as often as you should), grind a decent crescent wrench into one of these. TMI, or just enough?