Not content to stop at the BB30 setup of the Wolftooth GXP chainring, I was intrigued about its use on other cranks. Obviously the folks at Wolftooth offer rings for bolt patterns, the 104BCD was an early option for Shimano users, but Cannondale Hollowgram owners needed a custom spider which NSB provide. my search yeilded nothing for Lighting and S-Works owners other than production of the 120BCD rings to fit Sram XX spiders – the problem is that the smaller tooth size on the 120 BCD is 36T -Ouch!
For someone that has the 11 Speed XX1 10-42 cassette that may be a viable option but converters on 10 speed with a maximum cassette sprocket of 36 teeth (General Lee cassette conversion aside) that may be a big ask in mountains – kinda where these things are going to be ridden – That’s OK for the chair-lifted gravity and enduro bunch, but pedaling up hill on loose 15% grades or more is almost out of the question unless you’re a superhero.
Having just received my S-Works crank arms from Specialized’s warranty dept I decided it was time to get creative. First I needed to make the spider lockring tool to remove the XX Spider and get to the wavey mounting area of the crank arm. I scrounged the right diameter metal tubing that used to be a motorcycle inner fork leg. We cut it to the desired length and slotted it to leave the teeth raised to engage the ring. It has 8 points but I just made my tool with 4. Its a bit crude at the moment but I’ll clean it up soon.
Once it was opened up I fitted the Sram supplied spider and found it to be a bit loose as the patterns don’t match, I wasn’t surprised that it was loose as they are not designed to ever mate, but I was happy that it actually went over the spline without any mods. We made a quick plan to fill a void in the mismatched patterns and locked down the spider ring – solid! But this wasn’t the spider I wanted to fit… I wanted to get the Wolftooth ring on there!
I stripped off the XO cranks and removed the GXP direct mount ring I already owned and tentatively slid it over the S-Works arm spider mount… it didn’t float on, the machining tolerance was tighter and my initial thought was that I’d need to file it down, but after a firm press with just my bare hands the GXP ring slid down onto the spider boss and gripped solid! There was no fore/aft movement or rotation like the genuine spider at all! To make the patterns mate I did have to rotate the Wolftooth ring about 10-15 degrees clockwise to find a location it would drop into, but since there is no shifting going on, no ramps or pins or second blade to consider so it doesn’t need to line up with the crank arm!
I locked the lockring down with a bit of loctite blue and took a look at the chainline angle of the ring and hoped it would clear the chain stays without too much spacing or reconfiguring. I now have a box full of Specialized spacers from various cranks so it wouldn’t be too difficult. My only fear was that it required a lot of spacers and the bearing pre-load would lock up the BB.
I slid out the XO crank arms and cleaned up my bearings while it was all open, then pushed in the S-Works drive side with only the bearing dust seal – it would need some spacers and I gathered up some that were fitted when I ran this crank as a double. The conical cups have different widths, I put the wider of the two on the drive side with wave washer and the dust seal and pressed it in – perfect! Then put the smaller conical spacer on the non drive side also with a wave washer and the dust seal and tightened it all up. The clearance was good – about 10mm and the crank spun like a dream. I checked for play from side to side and was happy with it as is – Unbelievable, this took less than ten minutes!
Here are a few pics just to show it mounted up and the chainline etc… Firstly top down to see spacer offset.
Clearance of the chainstay for 34T blade, would be even more on a 32T blade…
The chainline view from back to front… practically dead straight when its in the middle of the cassette.
My initial ride was a baptism of fire with some monster climbing, fast rocky descents, a mix of tar, concrete, roots, rocks and gravel fire roads and singletracks. Pretty much everything on offer. As can be expected it performed flawlessly and I’m yet to drop a chain 🙂