Michael Hanslip Coaching

If you want to go faster, you have to pedal harder

AXS Transmission

When SRAM introduced the universal derailleur hanger, I don't know if they knew where it was going, but it seemed a great idea. If you've ever broken a derailleur hanger you will know that there were about 1000 different models and it has to be the exact one. The whole idea of the UDH was that one derailleur hanger fitting on a standardised attachment on the frame meant any new bikes built to this standard could use any new UDH. A good start.
The bonus now is that those frames can remove their UDH and replace it with a Transmission rear derailleur. I've seen three or four videos of reviewers standing on the derailleur to demonstrate who solidly it is attached to the frame. The derailleur is anchored into the through-axle system so it is robust and secure.
Because there is no hanger, there is no B-tension screw. The derailleur has been redesigned to be set in a particular position during setup and then it remains there statically. There is a red sprocket on the cassette that reminds the mechanic which gear to set up the derailleur in. The derailleur is so tough that a collision with typical rocks or trees might not damage it at all, but if it does it won't be ripping the derailleur from the frame. And some sub-components of the derailleur are sold individually for rebuilding after a collision.
Also because of the way the derailleur is setup and because there is only one cassette it works with, there are no inner or outer limit screws either. Suntour invented the slant-parallelogram rear derailleur about 50 years ago. This is perhaps not as revolutionary as that, or perhaps it is. A big step forwards.
The new Transmission cassette and flat-top chain will only shift in the shifting windows. Hyperglide introduced us to the idea of shifting windows back in about 1990. The Transmission uses taller than normal teeth for all but the shifting teeth, so there can be no shifting except where designed. That can be perceived as a delay in the shift - waiting for it to come around. Several users I know don't complain about it and it seems fine to me.
Eagle was the name applied to everything new when SRAM went 12-speed. "Eagle Technology" SRAM called it. Given there is no real cross-over compatibility with Eagle and Transmission, they really ought to have called it another bird name (Condor for better soaring? Falcon for higher speed?). Naming oddities aside, Transmission seems a good step forward for AXS MTB drivetrains.

Transmission shifting pod

The biggest visible change with the move to "Transmission" drivetrains from SRAM is the shifting mechanism. It used to be a butterfly shaped rocker switch. One way for one direction of shift and the other way for the other direction (probably - the AXS app allows one to reassign all button functions). The shifter for transmission can only be called a pod - it is a small rounded-off unit with two buttons. It no longer connects to the bars via the excellent MatchMaker system (via the brake lever clamp) but now has its own figure-8 shaped clamp (one around the bars, the other around the round projection on the rear of the pod). It tightens via a single bolt in the middle of the "8".
I would say it is fair to call the pod controversial. People who were perfectly happy with the old AXS shifter have had to adjust to the new pod. The buttons have been known to fall off on rough terrain. It is highly adjustable, but not really in the direction I wanted to adjust it. The bolt in the middle is labelled "max 3Nm" but I tried that with a torque wrench and it was far from tight. In an era where everything bike is going lower profile (think the new SRAM brakes and their master cylinders sitting almost on the bars), these pods are very high profile.
Function-wise they seem fine. The buttons are easy to press. If you get it in the correct position, it takes only a light tap to effect a change.
Aesthetically, they don't pair well with the Reverb button on the other side - why isn't it a new pod too, off the same figure-8 clamp?

All things considered, I wouldn't rate the pod higher than a 7/10. And honestly, I don't think it really deserves that much.

Clipless pedals revisited

When I bought my first DH bike almost 15 years ago, I put clipless pedals on it. I couldn't imagine riding a DH bike as it is meant to be ridden (as much as that is possible without the talent and skills of a World Cup rider) on flats. Back then, I couldn't really imagine riding any bike on flats!
Fast forward through years of riding flats for everything from XC (but not racing) to trail and Enduro racing and never having had clips on my current DH bike - my recent day visit to Thredbo involved throwing the Crank Brothers Mallet DH Race pedals on the Sender and pulling the old Shimano DH cleated shoes out of the closet. It was an interesting day out. I had zero issues with clipping in (I'd hope not after all those years of being clipped) and having my feet locked to the pedal was fine (I didn't find it more reassuring in rough terrain as I assumed I would - perhaps never blowing a foot off my aggressive flats has something to do with that?). The Shimano shoes permit the cleat to go back quite far. But probably not quite far enough to mimic the location my foot sits on my flats. Obviously I didn't have to change my approach to jumps and drops, but I found that I was doing it differently until really late in the day when I'd made some adjustments.
The Mallet pedals are great. I can understand why so many DH racers use them. Easy in. Easy out. Good retention.
The Shimano shoes are very comfortable and provide decent foot protection too. So no problems there.
But I won't be keeping the clippy pedals on my Sender for the next visit. I want my flats back. Feet loose on pedals is the only way I can judge the amount of downward pressure I've applied through my feet: enough pressure means my feet stay locked on the pedals (and not-quite-enough pressure means my feet get skatey on the pedals).
Across numerous Enduro races and 1 DH race, I've never felt like flats were making me slower. Perhaps If I put in many days on the clippy pedals I could get a feeling of confidence and control superior to flats, but I do doubt it.

I'm sticking with my flats for the big bikes (Enduro and DH). I'll keep the clips on the hardtail, and swap them in and out on the trail bike as the ride demands.

Box Two Prime 9 drivetrain

Close to 20 years ago now I bought my first 29r. A titanium hardtail with XT bits providing the gears and stopping. That was my race bike until I got a full-suspension bike for that role and the hardtail was modified to be a singlespeed. Then about 3 years ago I bought a new singlespeed and the titanium bike went in storage. It came back out just before Christmas to become my son's new bike. But he needed some gears.
Box is a company that was known for making high-end BMX gear. They decided to get into MTB and eventually released four levels of related drivetrain components that are all 1x9 (Prime 9 = 1 x 9). The top one is quite expensive and called Box One. The cheapest one is not very nice looking and is called Box Four. The Box Two pieces aren't quite as flashy as the Box One, but much lighter and nicer than the Box Three level stuff. Seems like Box Two hits the sweet spot. Especially when it is on sale when you need it!

One small box contained the derailleur, the shift lever, the chain, the cassette (11-46 range), some cable housing and a shift cable. Instructions were provided online either written or YouTube. It all went together really easily. It did require a lot more B-tension than I expected to keep the upper jockey wheel from hitting the low gear teeth on the cassette. And when I was finished it was not shifting nicely into the second-lowest gear when coming from a higher gear (but it was fine from the lowest gear). No adjusting could quite get rid of that.

I checked the derailleur hanger and it was not perfectly lined up with where it should have been. Once that was fixed, then the shifting was perfect.

In use, the Box Two items work really well. I did find that the amount of pressure required on the shift lever reflected the gear the bike was in - some strange relationship between cable tension and lever effort that suggests Box hasn't nailed every last aspect of their design philosophy quite yet.

It was also my first exposure to anything in the CUES line from Shimano. I put new cranks on the bike because the new owner didn't need my old 180 mm cranks but by remaining in the Shimano brand I didn't have to change bottom brackets. The CUES crank preloads like a SRAM DUB crank, except there is no locking mechanism for the preload collar.

Only having 9 steps for most of the SRAM Eagle gear range means the steps are wider. In use, that seems OK. Especially for a fun bike. XC racing might benefit from more options, and any decent downhill slope (whether XC or Enduro or anything) would benefit from the 10T high sprocket the Box cassette lacks. But for a fun bike, it's great and you pretty much know what gear you need to be in at any time. Given that the entire box-set (pun intended) cost about the same as an XT cassette, it can't be just as refined and light as Shimano's second tier offering.

I like this brand. I'll be curious to see how it fares with use. I'm betting OK.

Braking bumps

What a difference a couple of weeks can make!
I spent a week at Thredbo ending just a few days prior to Christmas Day. There were zero braking bumps and very little trail damage of any sort. It was very pleasant really.
And then I returned on January 7. Braking bumps were everywhere, even in places where no one needs to be braking. Big holes on the trails in weird spots. There is this really fast descent off the Gunbarrel chair that was very rough before the holiday season and was completely, hand-hammeringly rough by the first week of January. Luckily it ends on a fire trail which is a great place to shake the hands out before heading into the next bit of singletrack. And this was on my DH bike, which is markedly more gentle on the hands than my Enduro bike (I really noticed it by riding them on consecutive days).

Braking bumps form on dirt due to the way a tyre under braking has a resonant frequency; the tyre is excited by a bump and hammers back into the ground immediately (creating a low spot) which leads to the next high spot, and so on. I noticed when everyone was on 26" DH bikes that riding a 29" Enduro bike on those trails that the big wheels would not "fit" in the braking bumps, so it was quite smooth. Now that almost everyone's front wheel is 29", all the tyres fit all the bumps. The solution is to either pick a line to the side of the braking bump line, or to hit the bumps fast enough to skip over the tops of the sequence. Neither is an option on some lines, but most of them permit one or the other.

Unfortunately, braking bumps are self-reinforcing. You see them, you ride into them, they are so rough you grab a handful of brake, and you then contribute to making them bigger and longer. Or you try to ride beside them with a handful of brake and you contribute to them getting wider. The only solution is no brakes. Which is admittedly very difficult in certain places.

The other thing I noticed in January was the many large holes high up in the berms. I think these are caused by the sheer volume of tyres running under high force up there, breaking the hard dirt surface layer and leaving behind a softer hole that can erode more quickly. Some of them are pretty bad but I was able to either go just above them or, thanks to the DH bike, right through them.