shimano centerlock lockring

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cure
Posts: 155
Joined: Fri Nov 12, 2010 9:17 pm
Location: Dallas, Texas

by cure

hello, i'm getting different information on which lockring comes with the XT RT-MT800 Centerlock Disc Rotor 160mm/140mm. I got a 140mm from amazon and it looks like external lockring. i am going to get the 160mm from jensonusa, but was told it was the internal lockring - the same tool used to lock cassette. why would it be 2 different lockrings? should it be consistent or is something i'm missing? please help me understand which is correct info, need to know if i need to buy proper tool. thank you!
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pdlpsher1
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by pdlpsher1

Some older hubs can only take an external lockring. Most newer hubs can an internal lockring. The difference between the two is weight, with the external lockring being heavier. If your hub is compatible with the internal lockring then you should use it if possible in order to save a few grams. What type of lockring do you have on your wheels? You can test compatibility by using a cassette lockring. If it can be threaded on by hand then your hub is compatible with the internal lockring. You should never use a cassette lockring to subsitute a rotor lockring. Both share the same internal diameter and threading, but the cassette lockring has too small of an external diameter to hold the rotor.

ps I bought some XTR rotors and they came with external lockrings. I believe this is done since external lockrings can be used on all hubs, while internal lockrings can only fit on the newer hubs.

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cure
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Location: Dallas, Texas

by cure

pdlpsher1 wrote:
Sun Oct 31, 2021 6:28 am
Some older hubs can only take an external lockring. Most newer hubs can an internal lockring. The difference between the two is weight, with the external lockring being heavier. If your hub is compatible with the internal lockring then you should use it if possible in order to save a few grams. What type of lockring do you have on your wheels? You can test compatibility by using a cassette lockring. If it can be threaded on by hand then your hub is compatible with the internal lockring. You should never use a cassette lockring to subsitute a rotor lockring. Both share the same internal diameter and threading, but the cassette lockring has too small of an external diameter to hold the rotor.

ps I bought some XTR rotors and they came with external lockrings. I believe this is done since external lockrings can be used on all hubs, while internal lockrings can only fit on the newer hubs.
Hi I'll have the dt Swiss 240 hubs. I think those are fairly new right? It's farsports wheelset and was told it doesn't come with lockrings. I will receive them sometime later this month or later. The weight of the external lockring I have is 10g vs 8g of internal I think. My concern is the thickness, will it clear my frame whe the hubs. I saw other post here having to use 3rd party lockring. Think it was trek checkpoint with dt Swiss 240 hubs. I wish I had my frame already (March 2022......) to test clearance. Hate this long wait for everything.
i love udon.

ooo
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by ooo

cure wrote:
Sun Oct 31, 2021 5:51 am
why would it be 2 different lockrings? should it be consistent or is something i'm missing?
This rotor is offered in 2 types of packages, with internal and with external lock ring:

IRTMT800SSI - 140 mm RT-MT800 with internal lock ring
IRTMT800SSE - 140 mm RT-MT800 with external lock ring
IRTMT800SI - 160 mm RT-MT800 with internal lock ring
IRTMT800SE - 160 mm RT-MT800 with external lock ring

You can buy second matching lock ring separately, if you want
'

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cure
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Location: Dallas, Texas

by cure

ooo wrote:
Sun Oct 31, 2021 8:15 pm
cure wrote:
Sun Oct 31, 2021 5:51 am
why would it be 2 different lockrings? should it be consistent or is something i'm missing?
This rotor is offered in 2 types of packages, with internal and with external lock ring:

IRTMT800SSI - 140 mm RT-MT800 with internal lock ring
IRTMT800SSE - 140 mm RT-MT800 with external lock ring
IRTMT800SI - 160 mm RT-MT800 with internal lock ring
IRTMT800SE - 160 mm RT-MT800 with external lock ring

You can buy second matching lock ring separately, if you want
oh nice, thanks so much. i saw this post:

viewtopic.php?f=113&t=158166&sid=cefda5 ... 5&start=15

shows the internal not fitting the standard cassette tool. was there a sizing problem with tool or part? or is is a special shimano tool i'm missing?
i love udon.

TobinHatesYou
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Joined: Mon Jul 24, 2017 12:02 pm

by TobinHatesYou

cure wrote:
Sun Oct 31, 2021 10:44 pm

oh nice, thanks so much. i saw this post:

viewtopic.php?f=113&t=158166&sid=cefda5 ... 5&start=15

shows the internal not fitting the standard cassette tool. was there a sizing problem with tool or part? or is is a special shimano tool i'm missing?

Many front hubs are designed for 15mm thru-axle compatibility, then adapted/converted down to 12mm. For a while hub manufacturers overlooked this when designing their front hub endcaps, making them too big for the diameter of the cassette tool. This happened to me with my White Industries CLD front hubs. They sent me what were "prototype" axle/endcaps at the time with some extra material machined away.

This won't be an issue with rear hubs since everything is standardized on 12mm.

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cure
Posts: 155
Joined: Fri Nov 12, 2010 9:17 pm
Location: Dallas, Texas

by cure

TobinHatesYou wrote:
Sun Oct 31, 2021 10:53 pm
cure wrote:
Sun Oct 31, 2021 10:44 pm

oh nice, thanks so much. i saw this post:

viewtopic.php?f=113&t=158166&sid=cefda5 ... 5&start=15

shows the internal not fitting the standard cassette tool. was there a sizing problem with tool or part? or is is a special shimano tool i'm missing?

Many front hubs are designed for 15mm thru-axle compatibility, then adapted/converted down to 12mm. For a while hub manufacturers overlooked this when designing their front hub endcaps, making them too big for the diameter of the cassette tool. This happened to me with my White Industries CLD front hubs. They sent me what were "prototype" axle/endcaps at the time with some extra material machined away.

This won't be an issue with rear hubs since everything is standardized on 12mm.
So even though it says "DT Central lock240EXP SP 12*100mm" in my wheel specs it doesn't mean it's a true 12mm? How to determine this? Thanks
i love udon.

TobinHatesYou
Posts: 12456
Joined: Mon Jul 24, 2017 12:02 pm

by TobinHatesYou

cure wrote:
Mon Nov 01, 2021 2:22 am

So even though it says "DT Central lock240EXP SP 12*100mm" in my wheel specs it doesn't mean it's a true 12mm? How to determine this? Thanks

They're designed to be convertible, so technically they aren't true anything.

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cure
Posts: 155
Joined: Fri Nov 12, 2010 9:17 pm
Location: Dallas, Texas

by cure

TobinHatesYou wrote:
Mon Nov 01, 2021 2:43 am
cure wrote:
Mon Nov 01, 2021 2:22 am

So even though it says "DT Central lock240EXP SP 12*100mm" in my wheel specs it doesn't mean it's a true 12mm? How to determine this? Thanks

They're designed to be convertible, so technically they aren't true anything.
I see. Would you suggest me to inspect wheelset first before purchasing disc rotors, still not sure which of the 2 lockrings will work and fit in frame. Thanks
i love udon.

TobinHatesYou
Posts: 12456
Joined: Mon Jul 24, 2017 12:02 pm

by TobinHatesYou

cure wrote:
Mon Nov 01, 2021 2:55 am

I see. Would you suggest me to inspect wheelset first before purchasing disc rotors, still not sure which of the 2 lockrings will work and fit in frame. Thanks

I highly doubt this would be a problem with something as current as a 240EXP. The internally splined lockrings should work. The Shimano external ones have clearance issues with many road forks. The thinner ones have such a low profile to the splined interface, they are easy to damage.

by Weenie


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User avatar
cure
Posts: 155
Joined: Fri Nov 12, 2010 9:17 pm
Location: Dallas, Texas

by cure

TobinHatesYou wrote:
Mon Nov 01, 2021 3:15 am
cure wrote:
Mon Nov 01, 2021 2:55 am

I see. Would you suggest me to inspect wheelset first before purchasing disc rotors, still not sure which of the 2 lockrings will work and fit in frame. Thanks

I highly doubt this would be a problem with something as current as a 240EXP. The internally splined lockrings should work. The Shimano external ones have clearance issues with many road forks. The thinner ones have such a low profile to the splined interface, they are easy to damage.
thats reassuring. my wheelset will be on a gravel bike, wilier jena. so the main difference would be profile difference and a few grams savings (4g total i think). thanks for your help!
i love udon.

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