Living with Discs - Feedback and Opinions

[MoPho]

Don't need to, last time I rode with him he was on a rim braked Evo with EeBrakes, not the disc frame in his videos.

I don't live in LA anymore, but friends of mine posted pics of rides they've done with him and he was on disc



.

[TobinHatesYou]

I don't live in LA anymore, but friends of mine posted pics of rides they've done with him and he was on disc

He was on his disc SSEvo for both Phil's Fondo and the Saturday pre-ride.

[FishXChips]

Delete

[RyanH]

Unfortunately I see him around a lot. He's been on this bike, just without the dumb chopped bars:



His Disc Evo is custom painted with cookies on it and in sponsor colorway so it would make sense that any public appearance he's going to be on the bike.

[TonyM]

Deleted

[TonyM]

Yes just the pad alignment. Much faster procedure than with rim brakes (especially when switching aluminum wheels with carbon wheels)

[XCProMD]

Anyone experiencing such a heavy disc howl that it makes the whole bike judder? Shimano 9150, wet but not very much.

Frame is a Sarto Seta


Inviato dal mio iPhone utilizzando Tapatalk

[TobinHatesYou]

Anyone experiencing such a heavy disc howl that it makes the whole bike judder? Shimano 9150, wet but not very much.

Frame is a Sarto Seta

RT-99 or RT-900 rotors? If so, trash them and use SRAM Centerline X rotors.

[Calnago]

@TobinHatesYou: regarding your skewer/hub issue. You’ve got a few catch 22 type things going on.
To recap: your bike is coming out of your trainer. Clearly it is not clamped in well enough. You say when you have enough pressure to hold your bike properly the bearings bind. No wonder it’s falling out of the trainer or moving around in your actual bike. Part of your problem is your hub does not seem to be able to be adjusted independently of the forces being applied by a skewer, a bad design. Not good. Whether the forces are from a normal dropout skewer or a thru axle is irrelevant. A good hub will be able to be adjusted perfectly and spin the same whether it is outside of the bike/trainer or clamped very firmly in the bike/trainer. I hate hubs that do anything less.
Or perhaps you’re using a flimsy skewer. That’s an easy fix. Use a good skewer.
One final thing is that your dropouts may not be square to the axle ends.
I suspect the main issue however is the fact that your hub bearings bind if you put enough force on the wheel to hold it securely. This is simply unacceptable and forces you to try to guess just how poorly adjusted you need to set your hub/bearing adjustment off the bike for it to be acceptable when properly mounted on the bike. That’s the stuff of department store kids bikes. But it’s not a disc/non disc issue. There’s nothing simpler than a nice quick release and dropout.
Thru axles on discs are good to ensure the critically important alignment of the rotors. Not that good wheel alignment isn’t important for a rim brake bike, it’s just not quite as sensitive to it. Also, the beefier thru axle helps stabilize any twisting forces caused by the assymetrical forces that a disc brake exerts on the system.

[Mr.Gib]

Anyone experiencing such a heavy disc howl that it makes the whole bike judder? Shimano 9150, wet but not very much.

Frame is a Sarto Seta

Certain fork/rotor combinations will cause fork shudder/judder. depending on the spacing of the gaps in the rotor and the flexibility of the fork, you can end up with fork vibration. A super stiff fork will most likely prevent the problem but then the ride quality of the bike will no be as good. I had this problem and mostly solved it by using Shimano Ice Tech rotors on the front. Sram Centerline rotors are even better in this regard but provide a bit less stopping power.

[AJS914]

I had a horrible shudder that reverberated through the whole frame from the rear brake. It was an aluminum Specialized Crave hard tail with XT brakes.

I first solved the problem by taping a big hunk of metal to the seat stay near the rear brake. That dampened the oscillations. Finally, I tried sanding down the rotors with emery cloth and installed new pads and that worked. A new rotor would have also worked.

My theory is that disc rotors get pad deposits just like rotors on a car which causes the rotor to grab more in a certain spot. You can refresh the system by installing new or try sanding/cleaning.

[XCProMD]

Thanks a lot for the advices.

I swapped wheels wind put the Boras with Campag rotors. It certainly shows less judder but it's still annoying sometimes. Interestingly those wheels on a Willier Cento with Record don't make the bike rattle.

I'll try the Shimano wheels on the Campag bike and report here.


Skickat från min iPhone med Tapatalk

[TobinHatesYou]

@TobinHatesYou: regarding your skewer/hub issue. You’ve got a few catch 22 type things going on.
To recap: your bike is coming out of your trainer. Clearly it is not clamped in well enough. You say when you have enough pressure to hold your bike properly the bearings bind. No wonder it’s falling out of the trainer or moving around in your actual bike. Part of your problem is your hub does not seem to be able to be adjusted independently of the forces being applied by a skewer, a bad design. Not good. Whether the forces are from a normal dropout skewer or a thru axle is irrelevant. A good hub will be able to be adjusted perfectly and spin the same whether it is outside of the bike/trainer or clamped very firmly in the bike/trainer. I hate hubs that do anything less.
Or perhaps you’re using a flimsy skewer. That’s an easy fix. Use a good skewer.
One final thing is that your dropouts may not be square to the axle ends.
I suspect the main issue however is the fact that your hub bearings bind if you put enough force on the wheel to hold it securely. This is simply unacceptable and forces you to try to guess just how poorly adjusted you need to set your hub/bearing adjustment off the bike for it to be acceptable when properly mounted on the bike. That’s the stuff of department store kids bikes. But it’s not a disc/non disc issue. There’s nothing simpler than a nice quick release and dropout.
Thru axles on discs are good to ensure the critically important alignment of the rotors. Not that good wheel alignment isn’t important for a rim brake bike, it’s just not quite as sensitive to it. Also, the beefier thru axle helps stabilize any twisting forces caused by the assymetrical forces that a disc brake exerts on the system.

I fixed it or jury-rigged it anyway after the bike finally popped out. The end-caps were screwed-in medium finger-tight. I backed out both end-caps to be very loose, which increased the side-load on the caps and not the rest of the freehub. Anyway it very much is an issue because this situation can never occur with TA. Also the twisting forces with a 50lb indoor trainer that doesn’t twist with the bike is what popped the dropouts out anyway. So while it is partially a hub preload issue, it can be entirely avoided with TA.

I was using a steel skewer from my old trainer, and heat from the flywheel/trainer was causing it to expand just enough to become even more loose.

[Calnago]

^^
So much wrong with your response that I have to assume you're just trolling now. Apologies to other posters in this thread.

[TobinHatesYou]

^^
So much wrong with your response that I have to assume you're just trolling now. Apologies to other posters in this thread.

There's nothing wrong. I loosened the hub endcaps a slight amount to just less than medium finger-tight. You don't know what you don't know, and that's ok...just don't pretend you're the expert here. The clamping force is more than enough...and there is no play in the system. It's basically a preload adjustment. I invite you to fly out here and devise a more complicated, yet worse solution. CycleOps is a bit at fault here for designing a trainer hub that can be compressed as much as it can along the axle, but I see absolutely no case for catastrophic failure with my fix.

You insist that QRs are fine, yet you don't understand that disc brakes were not crucial change in the MTB world that brought TA about. Suspension forks were, especially upside down ones like the old Hannebrinks which couldn't make use of a bridge. TA gets rid of so many outstanding issues for the typical fast recreational rider for me, especially one that goes hard with indoor training. It's basically a value-add when you hop on the disc train.

If you're denying the fact that the tiniest bit of expansion in the pieces of a QR can have a perceivable effect, indeed the coefficient of thermal expansion for steel is quite small. However I popped the bike back in, tightened and clamped the QR down while the system was still hot. Everything spun freely, I backpedaled fine and the freehub spun backward. After I let the system cool, I tried it again, and the chain could not make the freehub spin backward, slackening the top of the chainline and tugging a bit on the RD cage. Also the QR was extremely easy to clamp and release while warm/hot.