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I recently purchased the eewings mountain titanium crank, and I need to choose a chainring. The interface is sram 3 bolt direct mount.

I wanted to get a 44T/46T/48T chain ring, but seems like I can't find any for sram 3 bolt.

I noticed that cane creek sells some spiders here.

I do not manage to understand what are the differences between the spiders they are selling. What is the difference between a "1x" option and a "2x" option? Are they different in size? I do intend to use 1x drivetrain, with a sram eagle cassete, chain, and derailleur. But I am not sure which one of the spiders I should get, or perhaps I have other options without using a spider?

More details about the specs:

  1. The bottom bracket is 68mm BSA. I have a chris king threadfit 30 BB (which is intended for 73 BSA), but I will be adding 2.5 mm of spacers on each side to make it compatible with the shelll.

  2. The crank is eewings mountain.

  3. The rear end spacing is 12 x 142mm

  4. XG-1275 Eagle Cassette

Thank you very much for any assistance.

1 Answer 1

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Your choices all revolve around your intended chainline. Secondarily, you need to figure out if that chainline can be made to work on your bike with that size ring, or how bad the compromise will be if not.

Were you asking about the road version of the eewings and a normal road/gravel drivetrain, you could be choosing between the 1x and 2x spiders if you wanted (for whatever reason) to use 110mm BCD rings as opposed to DM. The 1x spider would put a normal non-offset 5-bolt 110mm ring at around the chainline a 142x12 1x road rear end expects it to be, and the 2x would in turn play nice with contemporary road double FDs and 142x12 2x rear ends. Or, you could use any of the other third party SRAM DM spiders, and the list goes on.

We know you intend to pair a 44/46/48t ring with Eagle, which is unusual and would typically cause frame clearance problems at the chainstay on any bike that came with it. If that's true you'll need to make a study of whether you can cheat the chainline out enough to clear and still have a reasonably functional drivetrain. Your tools for doing that will be using a chainring offset you wouldn't otherwise choose, tweaking the effective offset by adding chainring spacers, or potentially reshuffling or adding BB spacers. Since these cranks use a ring-type preload adjuster, they do have some ability to vary the total amount of BB spacer used. What's important is you always have full engagement of the teeth that secure the crank and can torque the bolt normally without any binding. In other words, you can add or reshuffle spacers to the drive side of the spindle as long as the preload adjuster is still the thing that brings the bearing adjustment from too loose to just right, and also as long as the spindle is still contacting the bearings on an area where it's intended to.

Assuming no clearance problems, the conversation is about how to get the chainline on a 44/46/48t ring to where you need it to go. Which offset you'd need to reach each chainline if you were running DM is listed in the documentation for the cranks below. SRAM 3-bolt DM rings in any of those sizes barely exist, and mostly as Alibaba-type off-brand products you may or may not want to commit to dealing with. If you pass on those then you're looking at doing this with one of the spiders, since that's the way to use whatever 110 5-bolt ring you want. They will typically all be flat, 0mm offset. The documentation for the spiders let us know they're all 7.5mm offset, and from the documentation for the mountain cranks you can infer that means the 1x spider takes you to 47.5mm chainline, which is likely problematic for Eagle on 142x12 since it's far enough in that involuntary pickup on the big cogs will probably occur, though that can depend on chainstay length. You could potentially buy up to around 4-5mm to get a little further out by either adding chainring spacers and/or using BB spacer tricks. Opinions differ about the limits of how much spacer you want under the chainring, but I tend to feel up to 3mm is safe. There have been cranks that always use that much. Very powerful riders may run into problems with the bolts loosening or breaking eventually. Use steel chainring bolts if you're running spacers.

B

If 47.5 is way too far in, the question then becomes what does mounting a flat 110mm NW ring in the outer position on the 2x spider get you. That isn't a spec they give; the chainring spacing they're made to output is probably in the realm of 5-7mm. Assuming 6mm, it moves the chainline 3mm out to the right, so in other words it makes the spider act like a 4.5mm offset ring, so 51.5mm-ish, which can be tuned out from there with chainring spacers to be anywhere in the realm of what a Boost frame would expect. Again, you're likely doing all this within the context of splitting hairs on frame clearance. You could get the 2x spider in hand so you can take the measurements needed to dial and sanity check it. You'll also want a range of chainring spacers and bolts to work with, since you could potentially need more bolt length than what a 1x set will tend to give.

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  • Hey Nathan. thank you so much for the detailed response, I appreciate it. I will add the specs you mentioned were missing, for my frame. 1. The bottom bracket is 68mm BSA. I have a chris king threadfit 30 BB (which is intended for 73 BSA), but I will be adding 2.5 mm of spacers on each side to make it compatible with the shelll. 2. The crank is eewings mountain. 3. The rear end spacing is 12 x 142mm. I am trying to make sense of all the information you provided, but in the meantime would be nice to hear if what I mention here changes anything. Thanks again, appreeciate it a lot.
    – yuvalon
    Dec 2, 2023 at 9:42
  • and XG-1275 Eagle Cassette.
    – yuvalon
    Dec 2, 2023 at 9:49
  • You're welcome. For 142, you're likely going to be able to make it work at least in terms of shifting by using the 1x spider but then using chainring spacers to tune the chainring out a little (which I didn't think about on the first pass, but I've added above). The 1x spider will put the ring at 7.5mm offset and 142x12 cranks typically want 6mm, were this a SRAM crank, and the base position is probably pretty close with the eewings. So seeing what adding 1.5-2mm gives you could be a starting point. But, you've still potentially got frame clearance to contend with. Dec 2, 2023 at 16:35
  • @yuvalon I noticed that Garbaruk is doing SRAM 3-bolt DM rings of these sizes. They take the unique step of making each size less offset (for a further out chainline all else equal) the bigger the ring, in prediction of chainstay clearance issues, which is kind of a messy approach unless it happens to work right for you. Dec 2, 2023 at 23:14
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    Thank you, it was very insightful. I will update my findings here in the following weeks.
    – yuvalon
    Dec 3, 2023 at 22:52

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