Road Disc Brakes- Rotor Choice

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FactoryMatt
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Joined: Tue Apr 14, 2015 4:35 am

by FactoryMatt

Theres a cpl grams difference. Ti pins maybe not sure not worth it tho.

Re tobin..i wonder if he had a solid rotor.

by Weenie


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snaxez
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by snaxez

Is there any advantage between XTR internal serration and external serration?

R1Phrankey
Posts: 62
Joined: Fri Jul 31, 2020 8:39 am

by R1Phrankey

With some brands of hub, the tool for internal serration may not fit. Then you have to use the external serration locking nut (and tool).

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pdlpsher1
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by pdlpsher1

TobinHatesYou wrote:
Wed Apr 07, 2021 12:06 pm
pdlpsher1 wrote:
Wed Apr 07, 2021 3:00 am

The pad material vaporized and resulted in a complete loss of braking. The vapor prevents the pad from touching the rotor, much like a puck on an air hockey table. Yes, the tandem has a caliper front brake and a rear disk brake. On the tandem the rear wheel provides majority of the braking force, unlike on a single bike. Some older model tandems use a drum brake with a large amount of material to act as a large heatsink. They are designed as a drag brake with a control lever mounted on a bar end. They are meant to be turned 'on' and left on for the entire descent.

Mechanical or hydro disc? The extra hose length leads to slop in the brake feel / lever actuation over time.

I can assure you that you did not create some kind of gas boundary layer that could overcome the force of the pistons sandwiching the rotor. It sounds like you simply glazed the pads or experienced severe fade with a brake system that needed to be bled or flushed.
Mechanical disk. Mechanical disk offers some advantages on a tandem, namely no fluid to broil under extreme heat and ease brake line disassembly for a travel tandem that has couplings. The loss of braking is not due to the mechanical cable. It's due to the pad not making any contact with the rotor due to the vaporization of the resin pads. The loss of braking was 100%, as if the brake wasn't even there. It's quite scary. I've watched a YouTube video about a guy having the exact same thing happen to him on a descent.
Last edited by pdlpsher1 on Fri Apr 09, 2021 12:16 am, edited 1 time in total.

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pdlpsher1
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by pdlpsher1

snaxez wrote:
Thu Apr 08, 2021 9:04 am
Is there any advantage between XTR internal serration and external serration?
The ones with internal serration is lighter by 2 grams (7 grams vs. 9 grams). The XTR rotor comes with a lockring (external serration) but I didn't use it. I have 12mm axles so there's no need for a lockring with external serration. You only want to use the ones with external serration if you have a 15mm axle or a hub that will only take it (as mentioned by R1Phrankey).

szazbo
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by szazbo

pdlpsher1 wrote:
Fri Apr 09, 2021 12:12 am
snaxez wrote:
Thu Apr 08, 2021 9:04 am
Is there any advantage between XTR internal serration and external serration?
You only want to use the ones with external serration if you have a 15mm axle or a hub that will only take it (as mentioned by R1Phrankey).
Unless you have DT 240 hubs. On the front wheel using an internal splined lock ring, you can torque the lock ring on, but is almost impossible to get off without stripping the spline. No matter what tool you use, the tool bottoms out on the axle and prevents full engagement of the tool into the lock ring. The axle end tapers larger behind the lock ring. Dont ask how I know. To remove the lock ring, I had to use a quick release to keep the tool engaged. Now I have an external lock ring

FactoryMatt
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by FactoryMatt

external is the way to go, but be careful with some front forks; they rub on my Crux, i had to lap it down.

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pdlpsher1
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by pdlpsher1

I have these tools and by using the one with the handle I have no issues with the internal lockring and DT Swiss 240 hubs. The tool with the handle is a newer generation and has a wide and deep hole, and it won't interfere with any part of the hub's endcaps. I hope this helps. The internal lockring has a smaller profile and it looks better, IMHO.

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ms6073
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by ms6073

pdlpsher1 wrote:
Fri Apr 09, 2021 5:35 pm
The tool with the handle is a newer generation and has a wide and deep hole, and it won't interfere with any part of the hub's endcaps.
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Cool, Park Tool FR-5.2H. Did not know that was available.
- Michael
"People should stop expecting normal from me... seriously, we all know it's never going to happen"

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ms6073
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Location: Houston, Texas

by ms6073

Nope. While the tool may work for older 6-bolt hubs or those with QR end caps, it does not work for 12mm thru-axle! Pictured below is a spare rotor side end cap for a DT Swiss 240S Straight pull, centerlock front hub purchased in 2018. The end cap is tapered which prevents the Park Tool FR-5.2H as well as the Park thru-axle, regualr, or any applicable lockring tools from being able to maintain adequate engagement as the lock ring is tightened preventing proper torque of the lock ring. More importantly, if the lockring is already installed, the lack of full engagement of the splines prevents the tool from being able to remove the lockring and exerting more force to futher seat the tool, will score/damages the end cap and the reason why the image is of a spare end cap!

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- Michael
"People should stop expecting normal from me... seriously, we all know it's never going to happen"

carbonazza
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Joined: Wed Apr 10, 2019 9:14 am

by carbonazza

The new DT-240 EXP doesn't have this problem, both wheels can be set with an inner ring

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pdlpsher1
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by pdlpsher1

Sorry to hear that. Mine is the newer 240 EXP. Perhaps there's a trend to redesign the end caps so an internal lockring can be used.

R1Phrankey
Posts: 62
Joined: Fri Jul 31, 2020 8:39 am

by R1Phrankey

I also have the 240 EXP and am using the internal lockring. No problems.
My other bike has the old 240 hubs and at the front hub I had to use the external lockring.

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pdlpsher1
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by pdlpsher1

I received my XTR 140mm rotor today. It weighed 85g. vs. 121g. for the 160mm Ultegra it replaced. By going with 140mm I also eliminated the adaptor plate and two small screws, and those weighed 17g. So by switching from 160mm Ultegra to 140mm XTR I saved a total of 53g. My front fork can only accept 160mm or 180mm. So I have a 160mm XTR rotor on it which weighed 104g, for a saving of 17g. over the 160mm Ultegra. So total weight saved for the bike is 70g. (17g. front and 53g. rear).

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hartmannce
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Joined: Mon Sep 14, 2020 5:13 pm

by hartmannce

pdlpsher1 wrote:
Wed Apr 14, 2021 4:06 am
I received my XTR 140mm rotor today. It weighed 85g. vs. 121g. for the 160mm Ultegra it replaced. By going with 140mm I also eliminated the adaptor plate and two small screws, and those weighed 17g. So by switching from 160mm Ultegra to 140mm XTR I saved a total of 53g. My front fork can only accept 160mm or 180mm. So I have a 160mm XTR rotor on it which weighed 104g, for a saving of 17g. over the 160mm Ultegra. So total weight saved for the bike is 70g. (17g. front and 53g. rear).

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Are you sure your fork accepts only 160-180mm rotors? When I switched the front rotor from 160mm to 140mm - I used an adapted between the caliper and the body of the fork.
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by Weenie


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