chainring bolts

[raleighnut]

If your interest is semantics then feel free to replace 'bolt' with your 'internally threaded dowel pin'.
User Stompier clearly chosed 'bolt' as a reference for the mount / being a pair (2) components. Clear enough for me since the context was too.


https://www.w8ji.com/dielectric_grease_vs_conductive_grease.htm

Galvanic corrosion (as in this case stainless steel on aluminium) requires an electrical current, which an electrical insulator decreases (alot). The galvanic voltage over these (and any) different metals is (way) too low for ionisation.
This is the GREASE I used:
https://www.nyco-group.com/site/content/uploads/TGN46-4E4a.pdf
cheap @ 3 euro per kilo, purchased 5 years ago in a metalware shop, never have had galvanic (and any) corrosion wherever I used it.
For what it matters, no electrically conducting content.
https://www.sciencedirect.com/topics/materials-science/galvanic-corrosion

That grease contains soap as do most (it says it in the initial product description) which does nothing to prevent corrosion unlike Petroleum Jelly which is waterproof. It is a better lubricant though but seeing as the 'bolts' don't rotate in service they don't need lubricating.

 

[silva]

Buy a new / used Stronglight 2000 crankset?

Do you like cranks breaking and a walk home?
I don't.
If that wasn't obvious.

 

[silva]

That grease contains soap as do most (it says it in the initial product description) which does nothing to prevent corrosion unlike Petroleum Jelly which is waterproof. It is a better lubricant though but seeing as the 'bolts' don't rotate in service they don't need lubricating.

The grease also contains mineral oil (it says it in the initial product description too, feel free to read all the ingredients of your diet coke ) which does something to prevent corrosion.
I also didn't talk about lubrication - I talked about preventing galvanic corrosion, galling, whatever that metal on metal contact may cause.
What you say about Petroleum Jelly is possible. I don't know. I also don't need, since I already possess something that proved to do the job by solving problem I tried it for, and this grease at 3 euro per kilo I also see as economical reason to not search for alternatives alike Petroleum Jelly. A grease I also find practical in use - just a needle picking abit from the canister then on the bolt/whatever. No dripping no mess.

 

[midlife]

Do you like cranks breaking and a walk home?
I don't.
If that wasn't obvious.

I thought the OP said the crank spider had broken ? If the crank has broken then one of the options is to buy an identical replacement where the OEM bolts will fit.

 

[Stompier]

Not actually sure what this thread is about anymore, so I'm out.

 

[raleighnut]

Not actually sure what this thread is about anymore, so I'm out.

And miss all the fun, 👼

 

[silva]

I thought the OP said the crank spider had broken ? If the crank has broken then one of the options is to buy an identical replacement where the OEM bolts will fit.

No, story repeat in a nutshell:
- couple months (?) ago left crank of the Stronglight set broke, luckily on the way home with 3 km to go.
- I managed to fix it by sawing the crank off and replacing it with the left crank I had from the first crankset replacement (not due to failure but due to bcd change need to find a 1/8" chainring for)
- 3 weeks after that, the right pedal broke off, quick inspection showed cracks in the right crank of the Stronglight set, causing the pedal mount to split open under force causing the pedal ejecting, luckily on the way home with 6 km to go.
- I suffered a chain tension variation whoms cause I had eliminated to the bottom bracket area, either the square taper axle either the crankset offcenter, since the crankset had to be replaced anyway I decided to try to get rid of that chain tension variation at the same time, by trying Octalink instead of square taper.

Now, in aboves story I had two times alot luck. If the failures had happened in the middle of traffic this forumuser could have been no more.
I concluded that the Stronglight Track 2000 chainset choice was a bad choice. I never have had broken cranks before on all of the bikes I had.
So I didn't and don't see a replacement with a same as an option, since they may break again in the future and my luck may have been over then.
A dealer last week mounted a Shimano Octalink crankset and an Octalink bottom bracket / axle. Only that (at delivery!) said he didn't find a 47t ring at his suppliers so I had to order and mount one from Velosolo UK, to then discover the bolts that the dealer provided were too long, aside some other discoveries, which triggered me to start this topic here.

Questions were:
1. Anyone can explain/find a source for those strange chainring bolts on the Stronglight crankset?
2. In my single chainring case, there is room for "out the box" thinking, meaning that the usage of standard (not bike specific) bolts may be, repeat, may be, an option. In meantime I discovered that bolts exist with allen key entries on both sides (5 and 6 mm) which could also make it easier to mount/unmount. But the Stronglight ones were the easiest: a tool at one side only. But apparently, both spider arms and bolts have special modifications to make that possible, modifications that I found nowhere documented on the web. Specific: a monetary coin alike reeded edge to give grip, and a conical part, in a degree comparable with a square taper crank mount. But even better would be a simple (sunk if needed but cant see why) hexagon with a simple external nut on the other side. That appears to me as the most reliable and easiest to service option.

Thank you.

 

[silva]

Some pictures say more than a thousand words.
1) the second failing Stronglight crank. Notice the crack and the ruined pedal thread inside. The force on the pedal pushed open the crack, the pedal got loose, ruined the thread in a matter of secs to then fall away.
2) the larger diameter recess (frame side) in the mount hole of the Stronglight spider.
3) the Stronglight (the name is printed on them) bolts themselves, notice the reeds on the side of the frame side "nut". Those reeds are visible inside the hole in the spider, probably the steel of the bolt pressed them in the aluminium.
So far I couldn't find any picture on the web showing these.

 

[silva]

... and the surfaces of the first crank breakage (left crank),
... and what I had to do to get the broken crank off without tool and without causing further damage.
Together, several entire days lost, while I had better things to do, with some people relying on me.
Including this entire weekend. Yesterday the mounting of the new chainring, the bolts problem, the refit of the bike due to dealer unable to get it in the car with my double bag and basket, including today.
And this afternoon in order to bring the bike more in balance when alot loaded on the back, the fitting of a small backpack under the handlebars to put the heavy small things (my tools spares etc) in it, with little room due to too short brake lines, handlebars shape, and the front light sitting in the way, which I had to unmount and move forwards, by creating a new inbetween mount fixed to fender and tube, and along a thin stainless steel plate bent to adjust the angle as required to compensate for the movement. The expensive frontlight (German brand SON) was mounted in a stupid / problematic fashion: the electrical wires sitting right in front of the hex head of the mount bolt, I had to file the aluminium of the hole in the long alu stick out in order to get the allen key on the bolt head and to be able to pull the bolt out, without damaging the insulation of the wires.

 

[silva]

Another question, the chainring bolts of the Stronglight crankset / mount didn't need a tool on the frame side, the very reason (I see it too as a benefit) for the specialties of bolt-nuts (the reeds on their side) and the recesses in the spider holes. Since the replacing Shimano crankset doesn't have these specialties, normal bolts are used.
Now, is there an alternative for the requirement of a special tool for the frame side (the sleeves at the side of the hole inside nut - alike for a big screwdriver with its center cut out if bolts are abit longer)?
As far as I can judge, there could be a chance for an allen key on the frame side too, ofcourse a smaller one than the bolt head at the pedal side.
Anyone knows if such are available and where to get them?

 

[silva]

As a followup 1 year later (now 2+ months ago):
I took out the 5 chainring-dedicated bolts and sleeved nuts.
I took 5 standard M10 bolts and nuts, steel.
I put the latter in the places of the former.
The hexagon heads *just* fitted between the position ridges, so close that after tensioning the corners of the hexagon very slightly hit the spiders alu.
Well, with 2 months 55 km/day like that, no problem.
Today for the first time losened them again (to flip and rotate the chainring on its position).
And put them back in with the nuts at the inner instead of outer side, because the exposed thread (bolts are 5 mm too long) is then also covered from rain by the chain protection.
Much easier, and always possible to flip chainring in same position with same length bolts.

Sometimes thinking "outside the box", delivers.

 

[weareHKR]

An epic read...
Can't say in all my years I've never had a problem with chainring bolts - made specifically for the purpose!
When I replace a chainring I also change the bolts too!
Don't regular nuts & bolts look rather ugly?

 

[silva]

An epic read...
Can't say in all my years I've never had a problem with chainring bolts - made specifically for the purpose!
When I replace a chainring I also change the bolts too!
Don't regular nuts & bolts look rather ugly?

Those bolts wasted my time to lose/fasten due to the reasons mentioned.
With the current regular anchored nuts & bolts, a single regular key (about everybody except burocrats has 1 in the garage) suffices.

About the cosmetical factor, look at the bikes older picture in my avatar. It's not my ferrari, it's my shopping cart. Couple years ago, before the corona nazi's banned flea markets, I stood 10 metres away from my heavily loaded bike, some youngsters passed and stopped when seeing it. One said "Geez it's a truck".

But if you really want to judge it in terms of art, think of "industrial look" haha.

 

[Ajax Bay]

took 5 standard M10 bolts and nuts, steel.

. . . . loosened them . . . and put them back in . . . the exposed thread (bolts are 5 mm too long)

Get 5 shorter bolts?

 

[silva]

Get 5 shorter bolts?

They sold these M10 bolts lengths in 5 mm increments. One shorter would therefore not meet the min 1 thread beyond nut rule. In building construction they even chose the nut height as extra.