Park Tool CNW-2 Chainring Nut Wrench Tool

It's ok. Managed to get the two stuck bolts out without too much difficulty, but the tool doesn't really inspire much confidence; it's quite a loose fit and slipped a few times but did the job. That said it's only the second chain ring I've worn out in 10 years so not a job I regularly undertake. Better than a chisel!!After reading other comments I thought I'd qualify my review some more;1. If you can't get the thing to align properly, just turn the whole nut/bolt assembly until you can get some purchase and stability against the chainset with the tool. You'll have to experiment, but you want the tool to align so that the arm has as much contact with the chainset as possible. You get some purchase with it then.2. As a previous review stated, use a rag - better than your own flesh.3. If you're really struggling, try clamping it somehow. It'll work fine for a bike that's been looked after, but if the bolts are really seized, it's only going to help you so far.4. Still getting nowhere? Use a bit of heat if you can. Hard to do, but an ice cube on the allen key nut with a hot water on the bolt might work (I've managed to do sealed bearings this way!).5. When tightening back up, clean all surfaces with petrol/diesel. If you get a good contact surface the rubbishy bolts won't spin quite so easily 20,000 miles later!!6. Most important of all.... Keep your chain in good condition and don't run with a worn one... It'll only wear the chain ring faster, and you'll be back trying to free stuck bolts sooner rather than later!

You can get away with using a flat bit of some other tool but this will make things fractionally easier. The nuts tend to be self-locking so you don't need to a get a particularly strong purchase to tighten things up, you just need to hold it enough to really get a grip on the chainring and this is sufficient for that.Frankly the nut and bolt design that uses a hex key for both sides is superior in every way I can think of and if you have the choice you might want to just buy some replacement chainring bolts for about the same price as this tool.Note that the tool is not symmetrical. One end has narrower and longer 'teeth' than the other.

You may think you do not need one of these, your chainring bolts tighten up just fine by putting your finger on the back whilst you crank away with the torx and anyway you could always use a screwdriver. There’s no polite way to put this - you’re wrong. One day there’ll be a loose bolt that won’t tighten and keeps coming lose. It in no way impacts your riding but you know it is loose and it’ll drive you mad, you’ll end up taking your drive train apart just to threadlock it.I used to think that, then I got one of these cos I had creaking from swapout dropouts and it allows me to make sure the bolts are nice and tight without popping the wheel off.For such a minor investment you have smugness not usually seen outside of parliament as you know you can nip up your chainring bolts effortlessly.

Weird and cheap looking . . . YES !And with an even more odd way to hold the spanner (If I dare call it that)The best way I came up with was to place it in the Bolt Slots then force it flat against the Chain Ring, holding it there whilst using a Hex to undo / tighten the screw !I tried holding it in hand like a spanner but gave up as it cuts into my hands . . . Thus the laying flat against the Chainring method !Unconventional I know but it works for me !

Trying to get purchase on the nut with this is very difficult. There is basically about half a mm of slots in the nuts which you need to hold with the tool while turning the bolt. The result is it slips out of the slots and rounds them very easily. I managed to get two of five loose before giving up and taking it the bike shop. They also struggled and had to drill out the bolts and nuts completely. Therefore it may not be the fault of this tool but generally a stupid design. What is wrong with a std nut which you can hold fast with a spanner?

For years I have been getting by without these. Serviceing my 10 yr old road bike drove me to buy this. It is a world apart from improvising with a screwdriver.Typical park tool quality & value, well thought out and not cheap, but very good for the price.

Very difficult to use, keeps slipping off when trying to exert some pressure. Landed up scatching the back all over as it doesn't sit properly within the groove.

It looks as flimsy as anything but it did the job perfectly. Plenty of purchase on my Shimano chainset - 10 mins to thoroughly check and tighten all the bolts. One note of caution - use gloves or wrap your hand in a towel while you work. My preliminary (barehanded) attempt resulted in a nasty cut to the knuckle courtesy of the teeth in the big ring.