Tuning UT cranks - alloy main bolt?

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kman
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by kman

While refitting my Chorus 11 ultra torque cranks today I thought the main fixing bolt was kinda heavy. I know SR uses a Ti bolt there but is there an aluminium one available anywhere?

I tried searching for a while (here and wider internet) but keep getting mixed results and nothing helpful. Its an unusual bolt so I'm doubtful if what I'm talking about even exists.
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uraqt
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by uraqt

I am 99% sure that the TI SR/R bolt is threaded the opposite directions so you can't change the bolt with a campy one.

C

Mackers
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by Mackers

My Fulcrum RS came with an aluminum bolt that needs an 8mm key.

Permon
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by Permon

uraqt wrote:I am 99% sure that the TI SR/R bolt is threaded the opposite directions so you can't change the bolt with a campy one.

C


I am 101% sure about the Ti bolt for Super Record being opposite direction.
The reason for the opposite direction is to avoid somebody using steel bolt in titanium super record axles. Ti and steel reacts together...so the connection could became a lifetime one :twisted:

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kman
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by kman

Thanks guys, I wasn't really considering the SR Ti bolt anyway but good to know about the reverse thread. I'll see if I can find the Fulcrum alloy bolt.
You can't be a real country unless you have a beer and an airline. It helps if you have some kind of a football team, or some nuclear weapons, but at the very least you need a beer.
-- Frank Zappa

5 8 5
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by 5 8 5

Permon wrote:I am 101% sure about the Ti bolt for Super Record being opposite direction.
The reason for the opposite direction is to avoid somebody using steel bolt in titanium super record axles. Ti and steel reacts together...so the connection could became a lifetime one :twisted:

Yes, the SR bolt is a reverse thread.

Permon, you are incorrect. If anti-seize or loctite (preferred method) is used then it won't seize.
The reason for the reverse thread is to not allow tuning of the standard SR to justify the cost of the SR TI.

I have heard of people using an Isis titanium crank bolt instead of the steel Campag one.


Mackers wrote:My Fulcrum RS came with an aluminum bolt that needs an 8mm key.

Mackers, are you sure it's aluminium? If it is definitely aluminium is it a genuine Fulcrum part?
I wouldn't of thought aluminium would be the best material for that bolt as the recommended toque is 42-60 Nm.

Permon
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by Permon

And if you do not use the correct antiseize or loctite???
It will be f...ed up.
I am running UT cranks from 2007....I assembled them 100times....never used any antiseize or loctite.
Wrong or not. Matter of fact that a lot of people dont use any antiseizes on threads.

So, how to solve such situation....? Hm, what about reverse thread? :welcome:

P.S. I am pretty much sure the -40grams of the SR cranks comes from the axles itself, not bolt.

Mackers
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by Mackers

5 8 5 wrote:
Mackers wrote:My Fulcrum RS came with an aluminum bolt that needs an 8mm key.

Mackers, are you sure it's aluminium? If it is definitely aluminium is it a genuine Fulcrum part?
I wouldn't of thought aluminium would be the best material for that bolt as the recommended toque is 42-60 Nm.


I got it new and that's what came with it, definitely aluminum.
As chance would have it I'll be replacing it with an SR crank this week, so I can take a pic and slap it on a scale for ya.

Mackers
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by Mackers

Took it off tonight, it weighs between 6 and 7 grams according to my kitchen scales.

Pic to follow.

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kman
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by kman

Sweet, thanks Mackers. I can't find any info on it on the net. The campag bolts have the part number stamped on them (FC-RE007 for the steel bolt and FC-SR*** for the Ti bolt, or something similar, I can't remember exactly).

If the Fulcrum alloy bolt has a part number stamped on it that would make it a lot easier. Alternatively, I'll go and measure up the thread and start looking for alternatives like the ISIS one suggested.
You can't be a real country unless you have a beer and an airline. It helps if you have some kind of a football team, or some nuclear weapons, but at the very least you need a beer.
-- Frank Zappa

Serge58
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by Serge58

I've replaced several Chorus and Record UT crankset bolts with Alu. bolt.
You do need to grind outside a little bit or it is not going to fit in the hollow slightly
tapered UT axle.
You also need to take off a washer and reinstall it as I remember.
These bolts were available on Ebay. We are talking about steel axle here.
The 11sp. Ti axle is left-hand thread and I've never seen replacement for those.

ferrarista
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by ferrarista

Didn`t know fulcrum had an Alu central bolt.

There is an older and newer steel central bolt for UT.

older 16grams
Image

new version 21 grams
Image


The titanium bolt for the super record is 9.8grams
██

5 8 5
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by 5 8 5

Mackers wrote:Took it off tonight, it weighs between 6 and 7 grams according to my kitchen scales.

Pic to follow.

Cheers, Mackers.

I've checked some Fulcrum docs going back a number of years and the part number for the bolt hasn't changed (CC-RS007) for any of the chainsets (R, RS and RRS). It would be interesting to see what part number is stamped on yours.

5 8 5
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by 5 8 5

Permon wrote:And if you do not use the correct antiseize or loctite???
It will be f...ed up.
Don't understand what you mean :noidea:
Permon wrote:I am running UT cranks from 2007....I assembled them 100times....never used any antiseize or loctite.
Wrong or not. Matter of fact that a lot of people dont use any antiseizes on threads.
If you mean you fit all threads dry then that's just asking for trouble..........

From the Ultra Torque manual -
"NOTE
To prevent long-term oxidation of the retaining bolt thread, use a threadlocker fluid. We recommend you use only
Loctite 222."


Image

Permon wrote:So, how to solve such situation....? Hm, what about reverse thread? :welcome:

Again :noidea:

Permon wrote:P.S. I am pretty much sure the -40grams of the SR cranks comes from the axles itself, not bolt.

Incorrect. It's a combination of the axle and the bolt. Check out ferrarista's post above.

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kman
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by kman

OK, I finally got around to doing this. The stock, steel bolt is 16g on mine - the original version as posted earlier. I purchased a pair of "15mm Hollow Titanium Crank Bolts" from Toronto Cycles for $12. Claimed weight is 11.8g (pair) which seems pretty close on my crappy kitchen scales. They thread straight in to my Chorus 11 UT cranks and work fine. Interestingly, they are claimed as lighter than the aluminium bolts on TC. I think this is because the aluminium ones use a smaller allen key and therefore have more "meat" to the bolt. The Ti ones are quite thin walled.

$6 and 30 seconds to save 10-11g. Easy choice.

Here's a link to their cranks page in case anyone is interested, the ones I got are towards the bottom on the left;
http://torontocycles.com/Selling/Chainrings_and_Cranks.html
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