I’m getting a new bike that has 55mm chainline and SRAM transmission drivetrain. My old XX1 Quarq dzero won’t work with that chainline/BB, so I need to figure something out. I can get the single-sided XO crank for $400, but I’m concerned I’ll regret going w/ single sided power. The only good double sided crank-based option I’m seeing for 55mm CL and SRAM transmission is the new XX crank with the threaded chainrings. I like to switch rings pretty frequently based on course and training and want to make sure these things aren’t a pain to deal with (besides the stupid list price of $128/per ring). They also require a special $65 tool to change them. I’ve looked at the manual, swapping doesn’t look too bad other than having to remove the pedal every time. Honestly, the threaded rings seem kind of dumb to me, but maybe it will prove to be a good design. I’ve had great luck with quarq PM’s in the past and would like to go that route, but I’ve love to hear feedback from someone with experience swapping the threaded rings before I decide.
Would you consider a non-SRAM crankset and power meter spider?
I have GX Transmission on my bike, and I’m using a P2Max NGEco power meter with the Wolftooth Drop-Stop B chainrings. They have a Transmission-specific tooth profile.
That’s all on a set of Shimano XT cranks, because that’s what my bike had when I bought the power meter. Works flawlessly.
Yes, I have the tool it’s pretty easy not a big deal if you willing to invest in the tool, my current and it’s nice that my current setup t-type used the same chain size for 34/36 ring!
Thanks. I’m kind of holding that as a last resort. Besides my good history with quarq, I also have hopes that the flight attendant system might be available as an upgrade kit at some point and it integrates w/ sram pm’s. Maybe it will eventually work with any PM, but it’s not clear at this point.
I did look at the P2Max options and saw versions for boost and non-boost, but didn’t see an option for 55mm chainline. Are you running yours at 52? I’ve heard differing reports on whether shifting performance suffers with 52mm CL, so again would prefer to go with the supported 55mm if I can.
I’m pretty sure mine is running at 52, and it works great. Not trying to convince you - the flight attendant integration seems like it world be really useful if that’s the case…
I also think that the crankset has a heavy influence on chainline. I didn’t think that the spider has much of an influence….
You are not alone, lots of reports of running fine with 52. I’m honestly not even sure that’s an option on the bike I’m getting since it has a “wide” bottom bracket which I think means I have to use a crank with the wider q factor and spindle.
Yeah, I’m a bit confused by that point also and surprised all these spiders seem to have different parts for boost, nonboost, superboost (I assume due to chainline differences). I figured it would just be a function of the spindle length on the crank and the spider wouldn’t matter, but that doesn’t seem to be the case. I also found that the new threaded sram rings can be had with different offsets to run 55 or 52 with the same spider/crank, but it looks like the way they did that was designing the “wide” crank for 55 CL and moving the ring in a bit for 52. So, the cranks have the wider q factor of a 55mm cl, but actually running a “normal” 52mm chainline. It’s all pretty confusing to me.
To make it more complicated (thanks engineers!) I do know that you can run spacers between the spider and chainring to adjust chainline. But I think that only helps you go from 55mm to 52mm chainline.
Also, different chainrings have different offsets (which is probably also what the spiders have, if I’m thinking), and so I think all of that probably needs to be figured out. And not all of the manufacturers list those in the specs they publish on their sites or PDPs…
Yes, very frustrating.
The links I found helpful when researching this for myself:
the new Quarq with threaded chainring has 0 offset, so you would use a 3mm threaded chainring with a dub wide crank for a 55mm chainline or a 0mm offset chainring with a non-wide dub crank
If your current XX1 powermeter is the 8-bolt SRAM mount style on a Boost-spaced bike, it probably has a 3mm offset in which case you could still reuse it with the right SRAM crankset and a T-Type compatible chainring. The XX1 crank with a DUB Wide spindle will work with a 3mm offset powermeter to give you a 55mm chainline. Then you just need a T-Type chainring and there are a few options out there for those.
I did this recently with the 3-bolt version of that crank and a Wolf Tooth chainring, and it works perfectly. If you want an exact part number, you can also just ask SRAM Rider Support directly: https://support.sram.com/hc/en-us/requests/new?ticket_form_id=1260811300130. I asked Rider Support a very similar question recently and they were surprisingly helpful in getting me to the right answer. I couldn’t find much good documentation on available DUB Wide cranksets, so I just went straight to the source.
Unfortunately it’s an old dzero with a GXP spindle/crank, so no 8 bolt connection option and I assumed the GXP spindle isn’t long enough for the “wide” BB standard. Yeah, it’s old, but has been bullet proof. The carbon crank arms are so beat up from rock strikes that it makes me nervous on my race bike anyways, so it is probably time to replace even if I could make it work.
Thanks. I think this makes sense, but not what I was thinking. Just to make sure I understand - The dub wide crank requires the offset to push the chainring 3mm “inboard”? With a 0 offset ring on the wide crank, would that make the chainline 58mm?.
I was thinking the non-wide crank would have a 52mm chainline with zero offset and the wide crank would have a 55mm with zero offset (or 52mm CL if you had the ring w/ 3mm offset). The dub wide pushes the q factor out by 6mm I believe, so it seems like that would jive with the extra 3mm of chainline going from non-wide.
Correct. The DUB wide cranks (173mm q factor) will take a 3mm offset to run a 55mm chain line.
This article is pretty helpful and should walk you through what you need.
I have the XX SL pm crankset and other than having to buy new chainrings, I like this way more than the 4 bolt setup of the old versions. The thread on are easy, quick, and self tightening so it shouldn’t ever creak.
A buddy beat his off of his xx sl power meter cranks with a couple of pieces of 2x4 and a hammer. Managed to not damage anything but obviously not recommended!
I talked to a really helpful guy at powermeter city and it cleared up a few things that I was still confused on.
For the 168mm Q factor XX SL crank, a zero offset is needed for 55mm chainline and 3mm offset for 52mm chainline. There is also a 174 q factor crank option. For the non-sl XX powermeter, there is only a 174 q factor option.
One of my points of confusion was me assuming “dub wide” and 55mm CL required a 174mm Q factor crank. I thought dub wide was a factor of the bb width, but the bb width can be the same and the spindle is just longer. When you buy a dub wide BB cartridge, the only difference between that and a regular dub cartridge is the spacers included (at least that’s what he was telling me and he used to work at sram).
that’s absolutely correct, the different part numbers are just different spindle spacers included, that’s not that uncommon when talking BBs, ceramic speed have the same BBs for gravel and road only difference is the grease, same for gravel and mtb where spacers included are the only difference
I’m assuming then a 168 q factor xx sl isn’t a dub wide then considering it uses different offset chainrings for the same chainline as a wide dub spingle crankset
Yeah, that’s what had me confused. The bike I’m buying (epic 8) showed a dub wide crank/BB, so I assumed I had to use a “wide” 174 Q crank. He told me I just use smaller spacers with the 168 Q crank (no spacers on non-drive, 4.5mm on drive side). I don’t understand why so many bikes/cranks are going 174 Q factor if you can still use 168 and get a 55mm chainline. What’s the point of pushing the cranks out and then using an offset ring to bring the chainline back in?
I think a 174 is a more common used q factor for MTB then 168 which is more of a XC q-factor, but that still doesn’t explain why the xx sl isn’t only 168 why have two versions, also the one that comes with the full xx sl groupset is the dub wide 174
Another data point - he told me most of the OEM builds use the 174 Q factor version, but they hardly ever sell the 174 version aftermarket in the sl. I assume some BB’s are physically wider and require the longer spindle? Or do some people just prefer 174 Q factor on MTB’s so that’s what the OEM’s use?
