Back by popular demand, the general all-things Road forum!
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TobinHatesYou
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by TobinHatesYou on Thu Jan 10, 2019 9:41 pm
TobinHatesYou wrote: ↑Mon Nov 05, 2018 7:38 pm
Not sure if direct-mount like CT claims. My bet is a really tight BCD and any loss in lateral stiffness is made up by the single-piece construction of the rings. Direct-mount would make things harder for Quarq to design around.
I wrote this over a month ago, and agree.
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parajba
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by parajba on Thu Jan 10, 2019 10:30 pm
petromyzon wrote: ↑Thu Jan 10, 2019 8:19 am
Meh. Whenever a new groupset comes out there is a chorus of voices stating that it is ugly. Fast forward 2 years and it will seem normal. How can a chain be ugly FFS?
Rear mech looks chunky which doesn't bode well for the weight, but the move to 10T and consequent smaller chainrings, now ?direct mount, should save them a decent amount of weight.
I am just talking about the hoods, they look as big/ugly as the current ones. Pity.
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torob
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by torob on Thu Jan 10, 2019 11:30 pm
TobinHatesYou wrote: ↑Thu Jan 10, 2019 9:41 pm
TobinHatesYou wrote: ↑Mon Nov 05, 2018 7:38 pm
Not sure if direct-mount like CT claims. My bet is a really tight BCD and any loss in lateral stiffness is made up by the single-piece construction of the rings. Direct-mount would make things harder for Quarq to design around.
I wrote this over a month ago, and agree.
Are we all talking about 'direct mount' in the same sense, or is there some confusion about the use of that word?
Why wouldn't SRAM stick to the current SRAM mount system for Force 22 and Red / eTap (power-meter specific versions)? In other words, crank +
removable spider + rings
Using Tapatalk
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grooveninja
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by grooveninja on Fri Jan 11, 2019 12:46 am
My vote is it will be like SRAM's 12 speed Eagle direct mount chainrings which have a spline around the BB spindle the 3 small torx screws. I would not be surprised if the double chainring is even machined from a single piece of AL for both chainrings mounted on this spline. So the crank is the same between the double and single, its just the spline/chainring that is changing. When SRAM went to this setup from late XX1 and Eagle they took weight off the cranks from having a spider with seperate crank bolts and they already have been machining single piece cassettes with 10-50t for the rear so a double chainring wouldn't be things they don't already having tooling or know how to do. I would also wager the group is also lighter, as almost everything I'm seeing is just following changes they made in XX1/Eagle and those dropped weight despite adding gears (11, then 12speed) and clutch mechanisms.
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TobinHatesYou
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by TobinHatesYou on Fri Jan 11, 2019 1:35 am
grooveninja wrote: ↑Fri Jan 11, 2019 12:46 am
My vote is it will be like SRAM's 12 speed Eagle direct mount chainrings which have a spline around the BB spindle the 3 small torx screws. I would not be surprised if the double chainring is even machined from a single piece of AL for both chainrings mounted on this spline. So the crank is the same between the double and single, its just the spline/chainring that is changing. When SRAM went to this setup from late XX1 and Eagle they took weight off the cranks from having a spider with seperate crank bolts and they already have been machining single piece cassettes with 10-50t for the rear so a double chainring wouldn't be things they don't already having tooling or know how to do. I would also wager the group is also lighter, as almost everything I'm seeing is just following changes they made in XX1/Eagle and those dropped weight despite adding gears (11, then 12speed) and clutch mechanisms.
Well no, not quite.
Modern road Quarq spiders bolt into the DS crank/spindle assembly with an 8-bolt interface. This is very likely to be the case with the new Quarq. However it would be insanely stupid for the chainrings to be integrated into the Quarq, so it's logical to assume a hidden 4-bolt pattern is being used, accessible from behind the chainrings.
And yes, the chainrings are reportedly machined out of a single piece of aluminum.
It will be interesting to see if SRAM offers non-Quarq chainrings as a direct-mount system or if they stick to a 4-bolt BCD.
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mattr
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by mattr on Fri Jan 11, 2019 8:45 am
petromyzon wrote: ↑Thu Jan 10, 2019 8:19 am
Meh. Whenever a new groupset comes out there is a chorus of voices stating that it is ugly. Fast forward 2 years and it will seem normal.
Nope, all campag 11 and 12 speed rear mechs make me feel ill. I have no idea what the individual doing the styling was smoking. Probably shredded tyre.
Shimano road mechs have become too industrial (R9000 and onwards.) and still look horrible to me ~6 years on.
I'll still use them, just avoid looking at them
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Calnago
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by Calnago on Fri Jan 11, 2019 4:20 pm
The debate was never about whether DUB was compatible with BB90. It’s not, although the slightly shy of 30mm spindle did make it possible for at least the spindle to fit. The question was whether Trek would come up with a new BB to accommodate DUB. They won’t, at least not any time soon. Although, things can always change when you start sleeping with someone.
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TobinHatesYou
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by TobinHatesYou on Fri Jan 11, 2019 8:57 pm
???
30mm spindles always fit through the 37mm bore of BB90, just as they fit through the even tighter 34mm bore of an English threaded shell.
As for Trek replacing BB90. That is unofficially official. It’s coming very soon.
And it wasn’t just you. A couple others were insistent that DUB would somehow work with Trek’s BB90 because they thought it was a variant of Shimano’s BB86 (PF41)
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Calnago
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by Calnago on Fri Jan 11, 2019 9:12 pm
TobinHatesYou wrote:30mm spindles always fit through the 37mm bore of BB90, just as they fit through the even tighter threaded bore of BSA.
As for Trek replacing BB90. That is unofficially official. It’s coming very soon.
That’s the bearing outer race dimension you’re talking about. I’m talking about the actual pass through bore of BB90 through the shell. 30mm is very very tight and rubs. 29.9 is jusssst right, well, not really but it would fit through in a pinch. I certainly hope you’ve at least had a good look at the inside dimensions of a BB90 shell at each step through point, because from what your saying it doesn’t appear that you have. The 37mm dimension is simply the diameter of the bearing seats. Go ahead. Push a 30mm spindle all the way through a Trek BB90 shell with no bearings on it. See how it goes. Now do it with a 29.9mm spindle. How much better is that? Anyway, no matter. I will look forward to Trek’s new standard for road BB’s. We can revisit and discuss it’s merits and shortcomings again at that time. Till then, it is what it is.
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TobinHatesYou
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by TobinHatesYou on Fri Jan 11, 2019 9:44 pm
Just measured with calipers. The diameter at the second stepdown is 30.5mm or .25mm clearance, so it’s pretty close. Anyone know how much 30mm spindles deflect at a distance of 5mm from the bearing?
Also you did question DUB incompatibility here:
@TobinHatesYou: I’ve seen where you’ve said something similar before but I’m just curious why you think Trek would have to change it’s BB90 spec to accommodate Srams dub? Where does the problem lie? I’ve looked at Dub only a little but didn’t see how there would be much of a problem adapting it to BB90.
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Calnago
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by Calnago on Fri Jan 11, 2019 10:44 pm
Yes, I was asking where the problem was... and it’s the bearing size, not the spindle size. Let’s just wait until Trek comes out with their DUB compatible BB to discuss further. Or, you can continue, but I’ll wait.