Gear

Technical FAQ: Brand compatibility and cracked carbon posts

This week, Lennard Zinn addresses several follow-up questions about a variety of issues

Ultegra crank, Force group

Dear Lennard,
I currently run a Force 22 groupset with an S-Works crankset. I’d like to get a Stages [power] meter, but the only SRAM crankset they offer is Rival, which I don’t want to run. Looking at their Ultegra offering, I was wondering if it would be possible to run an Ultegra crankset with the rest of the Force groupset. It seems like I should be able to, as the indexing is dependent on matching mechs and shifters, and I’ve run Shimano cassettes many times. Am I missing something, or should I give it the green light?
— Patrick

Dear Patrick,
An 11-speed (or 10-speed) Ultegra crank will work fine with your SRAM Force 22 group.
― Lennard

More on broken seatposts

Dear Lennard,
On your recent Q&A with the chap that keeps breaking carbon posts in his Serotta, I didn’t understand your note about the limited 27.2 options.

I ride a couple of Moots, a Serotta, and a Koga, all of which have 27.2 seatposts and do not have independent binder clamps. I use either ENVE or Ritchey 27.2 carbon posts without issue. I weigh 190+.
— Rob

Dear Rob,
Upon re-reading that column, I see that I did not sufficiently clarify the point. When I wrote, “If your frame has the binder tabs welded on (rather than a separate band clamp), and your bike takes a 27.2mm seatpost, you are out of luck and should look for a different material other than carbon fiber for your seatpost,” I was referring just to Harry and his bike. I did not mean that everyone with welded-on binder tabs and no room for a shim sleeve between the seat tube and a 27.2mm seatpost (like you) is out of luck. Rather, I was making the assumption that Harry’s clamp had gotten distorted, or he was over-tightening the bolt, or both, and he was driving the corners of the seat tube slot into his carbon post. So he needed to abandon that setup if he couldn’t get a shim sleeve in there to protect the post from the slot.

I realize that there are plenty of people riding carbon posts with welded-on binder tabs who have had no problem. I do think that the stress on the post and consequent likelihood of seatpost breakage is higher with a configuration like this (where there is a slot pushing into the back of the seatpost at its most highly stressed point, namely where it enters the frame) than one where there is no slot contacting the back of the seatpost. Nonetheless, many people do not break their seatposts in bikes like this, including relatively heavy people like yourself, and a big part of that is tightening torque on the bolt, something I neglected to discuss.

It’s possible that Harry was over-tightening the bolt, which would drive the corners of the slot into the seatpost. If that was the case, it may have not just been that he leaned on the wrench too hard, but it might also have been that his seatpost was sliding down, and he kept tightening the bolt over time to keep that from happening.

I ought to have also discussed using a torque wrench and not tightening beyond the recommended torque for that bolt. And, if the post slips down with the bolt at the proper torque, rather than tightening it further, the post should be removed, coated with carbon assembly paste, and re-installed, once again to proper torque.

I hope that’s now clear.
― Lennard

More on mixing road and MTB Di2 components

Dear Lennard,
I thought I would do a follow-up report for you about the XTR Di2 compatibility with road equipment. As you know, I found and you confirmed that an XTR Di2 rear mech will work fine with 11-speed Di2 road shifters, but it won’t work with a non-XTR Di2 front derailleur. I now have an XTR Di2 front derailleur, and it does in fact work OK with the road Di2 shifters. However, the cage on the front mech [derailleur] won’t work well with a road 50/34 crankset. It is possible to fiddle around with it and get it to work on one end or the other (i.e., the small chainring will work without noise on the largest 5-7 cassettes on the rear, or the large will work with the smallest 5 or so cogs on the rear, but there isn’t a way to trim the front derailleur to work on all with both chainrings). So, I think that the only solution, unless Shimano changes the programming so the XTR rear will work with a road front, is to get an XTR 2×11 crankset. This will limit a bit the high gear (38 teeth is the largest 2×11 available), but it is workable for a steep long mountain road climb. I am going to set up my travel bike that way for epic climbing trips.
— Mark

More on changing road tubeless tires in the cold

Dear Lennard,
In response to Alex’s Technical Q&A topic of having difficulty removing a Hutchinson tubeless tire in the cold. Specifically, Alex asked if there was a magic tool to remove the tire from the rim, as he couldn’t get it off after 30 minutes of effort. What wasn’t clear in the question and response was whether Alex tried a plastic tire lever? He mentioned the tire came off by hand back at his house, so it sounds like maybe he tried using his hands only in the cold. I have been running tubeless for three years now on two road bikes, and had a few roadside tube installations when something tore a hole bigger than the Stan’s [sealant] could solve. I have used a Pedro’s yellow plastic tire lever every time to get the tire off, as I would rather get back to riding quickly than struggle to remove the tire. In fact, I use the same lever at home to pop on the last several inches of bead when I install the tires in the first place. So the answer to Alex’s question could be that yes, indeed, there is a magical tool to remove tubeless tires, and it is a Pedro’s tire lever.

I think probably the coldest temperature I experienced was in the 40s though — but that said, I suspect it would work just fine at freezing temperatures. It may also be worth noting that I gave up on Hutchinson tires a couple years ago and find the Schwalbe Ones and IRC RoadLites much easier to work with and more supple, at least compared to the Hutchinsons I remember from three years ago.
— Jim

Dear Jim,
You could have a very good point there! I had just assumed that Alex was using a tire lever, but it’s possible he was not!
― Lennard

More on mixing 9-, 10-speed Shimano parts

Dear Lennard,
One caveat for Stuart is that the newer 9-speed MTB derailleurs do not have a cable adjuster. That seems to have disappeared around the time of the [Shimano] Shadow derailleur. I’m sure Shimano realized it was largely redundant on MTBs, because of the adjuster on the MTB shifters, but of course those don’t exist on a road bike. Down-tube trim adjusters seem also to have largely disappeared.

Most of my buddies put their inline adjusters up near the shifter, but I put mine on the rear cable loop. I still prefer to see the derailleur move when I make any adjustments, and because it takes two hands, you can’t really do any adjustments on the fly with these in-line devices.

Also, our LBS found this for one of my riding buddies. The clever folks at Jagwire make a clever friction fit into a ferrule receptacle. They are sold in pairs, so I’m guessing they are nominally meant to be stuck in the head tube, but they also stick nicely into the back of a derailleur, where the old adjusters used to reside.

They apparently are also doing an 11/36 11-speed electronic conversion for another customer, using pieces from a K-edge conversion kit. It seems SRAM is now making an 11/36 cassette for their 1X cyclocross drivetrains, so maybe we will see a real 11-speed Di2 K-Edge conversion kit in the near future. I could live with a 34/36 low gear.
— Steve