Is there a dedicated tool to hold this slotted `nut` from spinning while unscrewing- for removing chain rings? See photo.

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Location
Loch side.
Since a couple weeks I tried to source steel versions of those double allen key bolts (they would make it alot easier/quicker for me to flip/rotate chainrings on their mount) but wherever I found such, all aluminium.
Just apply copper compound before tightening and they won't give you trouble.
 

Jenkins

Legendary Member
Location
Felixstowe
Since a couple weeks I tried to source steel versions of those double allen key bolts (they would make it alot easier/quicker for me to flip/rotate chainrings on their mount) but wherever I found such, all aluminium.
Single chainring up front? How about...
Amazon product ASIN B001GSQO3WView: https://www.amazon.co.uk/Truvativ-Chainring-Bolt-Kit-Arm/dp/B001GSQO3W?th=1
 

12boy

Guru
Location
Casper WY USA
I've had 2 park nut wrenches one with only slotted end and one with two, the two being of different depths. Have worked well for decades, even when loaned to my buds who ascribe to the dictum....never use force, get a bigger hammer.
 

silva

Über Member
Location
Belgium
The stainless steel bolts I now have (named "Zenith") are specified:
Considering the chainring bolts we stock in our shop: in each case the rear (nut) part has a depth of: Zenith (single) = approx 4mm (double 7mm) and Stronglight = approx 4.5mm.
Therefore the combined thickness of material (taking into account the countersink in each part if applicable) of your chainring/crank spider mounting hole depth would need to ideally be around 0.5 to 1mm larger than this measurement to give the best fit. If the bolt is longer then the two parts will not tighten fully, if too short then not enough of the chainring will be supported.
The diameter of the slotted nut head is standard at 12mm. The inner bolt diameter is 10mm.
The "Product Information" on the amazon page seems to be for something else so I'm unable to verify dimensions.
I think I found these here:
https://hollandbikeshop.com/sram/tr...blad-boutjes-8-5mm-staal-singlespeed-zwart-5/
TRUVATIV kettingbladbouten
Presentatieverpakking voor 1-speed crank tandem, staal, M8,5, zwart, set à 5 stuks, draadlengte 7 mm, buslengte 9 mm, met plaatjes
It's not clear if I can use these instead of the Zenith ones I now have.
The 4 mm rear/nut part depth is nowhere mentioned and those washers don't look like being 3 mm thick.
 

silva

Über Member
Location
Belgium
Just apply copper compound before tightening and they won't give you trouble.
If you refer to corrosion/galling issues, that wasn't my reason for not wanting alu here, it was because I experienced aluminium screwthread as quite weak - easy to strip.
 
Location
Loch side.
If you refer to corrosion/galling issues, that wasn't my reason for not wanting alu here, it was because I experienced aluminium screwthread as quite weak - easy to strip.
Why would they strip? Just don't overpower the thing. I've tightened hundreds of them without stripping one that I can remember. Every single high-end crank comes with them fitted and chainrings are changed all the time. I can strip a steel nut if I want to. But I don't.
 

Jenkins

Legendary Member
Location
Felixstowe
Yet again you're over thinking things. The aluminium ones from Superstar Components only need tightning to 7nm and there's five of them so plenty secure enough. Use threadlock if you are that woried.

As for the steel ones from Amazon - to quote one of the reviews...
What I love about these is that they have Allen key sockets on both parts of the bolt assembly so are easy to do-up and undo. The included spacers were used to pack-out the bolts and give required chainline on my singlespeed.
 

silva

Über Member
Location
Belgium
High-end likely refers to professional usage meaning its to win races where every gram counts.
But that aside, less power when tightening means less tightening strength (for what this matters in a chainrings case since the force is likely dominantly exerted perpendicular on the thread), but what also matters is bolt thread wear / material detoriation due to tightening/losening. Steel is quite elastic, aluminium is poor on that. I've had alu pedal cage mounting screws and I've seen them all break after a while, a problem that was gone after I replaced with steel screws. Same story for the bolt / screw heads, tools wearing these out much faster.
 

silva

Über Member
Location
Belgium
Yet again you're over thinking things. The aluminium ones from Superstar Components only need tightning to 7nm and there's five of them so plenty secure enough. Use threadlock if you are that woried.

As for the steel ones from Amazon - to quote one of the reviews...
In the case that refers to my chainline problem, that's a goner, first along spacers between rear cog and its disc mount, now it's straight without due to a steeper angle of the right crank.
But the potential problem with the chainring bolts is that my chainrings have deep recesses for the bolt heads, meaning shorter nuts. The Truvativ set of 5 is listed as 7 / 9 mm and include 5 washers 2 mm thick. 7 - 2 = 5 and my current Zenith bolts are 4 mm, meaning that the chainring will still sit loose after tightening.
But I don't wanna hijack this thread if that is a notdone.
 
Location
Loch side.
High-end likely refers to professional usage meaning its to win races where every gram counts.
But that aside, less power when tightening means less tightening strength (for what this matters in a chainrings case since the force is likely dominantly exerted perpendicular on the thread), but what also matters is bolt thread wear / material detoriation due to tightening/losening. Steel is quite elastic, aluminium is poor on that. I've had alu pedal cage mounting screws and I've seen them all break after a while, a problem that was gone after I replaced with steel screws. Same story for the bolt / screw heads, tools wearing these out much faster.
Listen carefully: Stop overthinking things and drink a beer. If that doesn't help, repeat until the urge subsides.
 

slowmotion

Quite dreadful
Location
lost somewhere
Drill a hole in the middle of a 2p bit. Cut the 2p bit in half with a hacksaw. Make it pretty with a small file. That's your slotted bit. Grip it with a mole wrench or pliers
 

silva

Über Member
Location
Belgium
Listen carefully: Stop overthinking things and drink a beer. If that doesn't help, repeat until the urge subsides.
Based on past experience in all applications I encountered them, I don't want aluminium bolts and such short thread lengths / small as chainring bolts are even a worst case.
 

silva

Über Member
Location
Belgium
The Park tool is meh. I find Stronglight stack bolts are reliably self-tightening.
I have had a stronglight chainring mounted on a stronglight spider, and I couldn't find those bolts on the web.
FILE0139_spider_hole_recess_small.JPG
FILE0130_bolt+nut-reeds_small.JPG


I'm not sure since I got it mounted, but the ring with reeds on the nut looked like having fret out the spiders bolt holes to that larger diameter during the tensioning. I didn't have problems with it, but it would mean that mounting a chainring irreversibly "damages" the crankset spider, rather awkward I'd say.
Repeated such tensionings probably removes the remaining material that gives grip, meaning at some point it's over and the nut spins instead of fixes when tightening.
 
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