White Industries offers a really wide range of cranks, from their square taper ENO and VBC cranks, to their 30mm-spindle R30, G30, and M30 models. In this post we wanted to take a look at what the actual differences between the three 30mm-spindle cranksets.
Most of us have gotten used to not having any control over the q-factor, and at best minimal control over the chainline of our cranks because modern 2-piece cranks tend to not have any means of adjusting these factors. Because White Industries uses separate crank arms and spindle, and because those both pieces come in two different versions, you actually do have some measure of control over those factors.
For starters, let's look at what defines each model:
R30: R30 (narrow) arms, Road/Gravel spindle (for 68mm and equivalent bottom bracket shells).
G30: M30 (wide) arms, Road/Gravel spindle (for 68mm and equivalent bottom bracket shells).
M30: M30 (wide) arms, Mountain spindle (for 68/73mm and equivalent bottom bracket shells).
From this small list, you can see that the G30 crankset provides more chainstay clearance than the R30 crankset by using the same arms as the M30. As an example of how you might use this information, we've found that many times gravel bikes don't actually need the extra width of the G30 cranks, which means that if you would like to get the narrowest q-factor possible you have the option of using the R30 version. But what does any of this actually mean, and how can you decide for yourself which crankset will give you the fit and feel that you're looking for? Read on to find out.
In the photo above, you can see how much more the upper crankarm bows out. That's the M30 crankarm, which as noted in the list, is used to make the G30 crankset as well as the M30 crankset. And as you can see, the difference between the G30 and M30 cranksets is the spindle they use. It's really that simple. One very important thing to note is that the Road/Gravel spindle is only compatible with 68mm bottom brackets (and their equivalents in T47 and PressFit standards), whereas the Mountain is compatible with 73mm (and its equivalents in the other standards). For more on bottom bracket compatibility, check out this compatibility chart.
White Industries has handy technical drawings with measurements for the three cranksets, which is a very useful tool to help you decide which one will best suit your needs. They also list the q-factors for all three, which, for those who care, is very nice indeed!
If you look at the drawings, you'll see that the road crankarms have a 12.5mm narrower q-factor than the mountain/gravel ones. This is the actual difference in q-factor that results from the different shape of the arms, so it's the difference in q-factor between the R30 and G30 cranksets, because they use the same spindle but different arms. With so many bikes these days being designed with s-bend chainstays, it's often not necessary to have as much clearance between the crankarms, making it possible to run the narrower road arms on your gravel bike. For some riders, getting a narrower q-factor is an important part of leg and knee comfort on the bike, so we think this is important to know.
For us, the natural next question to ask is whether you could, or would ever want to run the road arms on your mountain bike. Of course, with many older mountain bikes, you'd be able to install a standard road or gravel cranksets (assuming the bike has a 68mm bottom bracket), but you would need to check beforehand to make sure you'd have clearance at the chainstays. This is where the detailed drawings are so helpful. One important consideration with this is that using R30 or G30 cranks on a mountain bike would give you a chainline that is 2.5mm farther inboard than you would get using the mountain bike spindle. Just to stir up this already-cloudy topic, if you wanted to do this while maintaining your standard 49mm mountain bike chainline, and you were using a 1X setup, you could install a boost chainring in place of the standard non-boost one. Of course if your bike uses a boost drivetrain, this wouldn't be possible, so it would be better to just go with the standard mountain spindle. All of this is possible because on White Industries R30, G30, and M30 cranks, chainline is determined by spindle length and chainring offset, and not the crankarms.
But say, just for kicks, that you really like the narrowest q-factor you can get, but you have a 73mm bottom bracket shell, so you have to use the Mountain spindle according to the bottom bracket compatibility chart. You've measured your frame and you've looked at the White Industries' technical drawings where you've seen that the M30 cranks have a measurement from the centerline of the bike to the inside of the crankarm tip (the X2 measurement) of 74.8mm, but the road cranks have an X2 measurement of only 66mm. If you add 2.5mm to the road X2 measurement you can see what it would be if you substituted the mountain spindle spindle for the Road/Gravel one in that R30 crankarm. The result is 68.5mm for the X2 measurement. That's pretty narrow, but definitely not unheard-of for a mountain bike, so you might just be able to get your mountain bike set up with a q-factor of only 163.5mm by using R30 arms and a Mountain spindle. Just be sure to measure well!
In the end, we've found that most riders are quite happy with one of the standard options, but we find it helpful to know what's actually changing when you go from one model to the next, and we hope you do too. If you ever have any questions, or if you would like to get a special build, just get in touch, and we'll help you get the build you need.