Bicycle Suspension Components and Electronic Monitoring Devices by SRAM

In this article, we’ll be discussing Bicycle Suspension Components and Electronic Monitoring Devices by SRAM, US publication 20210179222. The publication date is June 17th, 2021 and the filing date is Dec. 17th, 2019. This has not been granted yet.  

lol, this bike… Looks like it’s got AXS seatpost, though.

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10/1/21 Update: The FCC filing was just released this morning and we’ve got a look at what the actual product is going to look like and what it’ll be called. The AirWiz. I’m fairly certain this isn’t related to the active system patent. If it ends up being the active system, I’ll move this over to that article. I wouldn’t look too much into the 35mm thing. I assume that’s the width of the part itself, not the associated stanchion size. But, I’ve been wrong before.

And here’s the label for the rear shock, which I have no information on. This is what’s making me think it may be the active system, but the top cap looks too similar to this patent. OR, the top cap is associated with the live system. OR this rear label is completely different than the AirWiz. Only time will tell, because I can’t tell from the documents.

Also, note the CAD title for the rear. Super Deluxe Ultimate AXS.

Brief Summary (tl;dr)

SRAM appear to be working on a next iteration of their Shockwiz. This little device does, effectively, the same thing as the Shockwiz (measures changes in pressure), but the whole system is now located in your top cap, so it’s a way better-looking piece. SRAM have figured out a way to reduce the size of the sensor and circuit boards enough to package everything in a very small space. Additionally, they’re putting the antenna outside the body for improved wireless communication.

Background

Currently, SRAM offers a very lightweight data acquisition unit under the Quarq brand called the Shockwiz. I say lightweight because the current analysis software is phone-based, which doesn’t lend itself to true deep-dives into your fork data. It’ll give you suggestions based on collected data over a certain amount of time, based on how the engineers behind the device believe your bike should be performing.

It’s pretty simple: plug the Shockwiz into the air-side of your suspension. As you ride, it’ll collect information and automatically parse the data based on riding settings that you’ve chosen. Then, it’ll make suggestions based on the riding data, where you will manually adjust your suspension. Eventually, you should have a setup that’s 95% (conjecture) of the way there.

There are massive benefits to this kind of system, especially for the general public. As a casual rider, you don’t need a full Motion Instruments system on your bike – that’s just way too much and you’ll end up lost. There’s a term for that in the engineering world; it’s called ‘analysis paralysis’. That’s where you get some much information you can’t justifiably make any appreciable and timely adjustments. “If I do this, then that will happen. But, then this will happen and I don’t like that, so I’ll do this. But then this happens… Wtf”.

So, a little device that will parse your data for you and just tell you what to do sounds exactly like what we need for our basic-ass riding.

Why

SRAM don’t really have any specific problem statement, but I think this one is pretty obvious. With the continued push towards e-everything, this is just another piece of the puzzle. Moreover, SRAM already offers something similar, so they need to continue updating and improving to stay relevant.  

The complexity of bike suspension is, in my opinion, beyond the vast majority of consumers. If I’m honest, I typically just set my suspension to the middle and tune-by-feel from there. I’ve got no data to base my settings on, other than “this feels good”. Then, I’ll eat shit and say “No no, these settings aren’t right” and I’ll adjust it to another statistically unsupported setup. Most of you probably do the same thing. This little device should help that process and get your bike close to a perfect setup.

All-in-all, from a technical perspective, it appears as though they’re trying to make their analysis device much smaller:

… having the circuit board and the battery in the same chamber enables the use of a smaller housing compared to a housing having separate chambers for the circuit board and the battery. This results in a smaller, lighter, and more aesthetically pleasing package. In some examples, the battery is disposed within a battery holder that is coupled to the circuit board. This reduces the overall volume consumed by the circuit board and the battery and, thus, also helps reduce the size of the electronic monitoring device.

What

First, here’s a high-level line about what’s going on:

The electronic monitoring device may be implemented to measure the pressure (gage pressure or absolute pressure) of a mass of gas within a bicycle suspension component. The gas may be contained in a particular volume or chamber of the suspension component. In some examples, the electronic monitoring device includes a pressure sensor, such as an electro-mechanical pressure sensor, to convert a measured gas pressure into an electrical signal through a piezo-resistive or other effect. This signal can then be analyzed (e.g., via the mobile device 140) to determine the change of pressure within the suspension component and/or the measured volume or chamber.

FIGs. 2 and 3 show the entire fork system. Monitoring device 138 is the important part here. That’s the entire system.

FIG. 4 shows an exploded view of this new little thing. First, 420 is the valve, 422 is the valve cap, and 428 is the battery.

The important parts here are the sensor 444. This is what will detect pressure changes, and the system will (I think) save the raw data. The raw data will probably be exported to a phone for external calculations. I say “I think” because they don’t mention a processor or memory, but this thing has to have a memory somewhere, probably on the circuit board 426 or the flexible printed circuit board 445. I feel like there should be some mention of a memory in this document, but maybe nothing is stored in the top cap, and everything is stored on your phone.

FIG. 7 shows a detailed view of the device. Ultimately, here’s how this thing works. As the fork goes through it’s travel, the air will flow to the pressure sensor and the changes in pressure will be read at a certain frequency and stored. That’s it. I understand that may be perceived as too simple for a patent, but the uniqueness here is the packaging. The fact that they were able to make this small enough to fit into a top cap is pretty damn cool.

I started writing this assuming this device had a volume adjustment system similar to MRP’s Ramp Control, but it doesn’t, and my day is ruined. This analysis device appears to attach to typical volume reducers that are already on the shelf. The adjustment device 736 is the volume reducer. The volume reducer has channels 738 to allow air to be present at the sensor, so the sensor will still work with any amount of volume reducers.

And yes, this is wireless.

‘…the monitoring device includes a wireless antenna or communicator to transmit signals (e.g., data representative of pressure measurements) to one or more devices, such as [a] mobile device…’

They’re also very purposeful with the location of the antenna, which is located outside the housing, because they want to:

 “…reduce the amount of obstruction and interference caused by the first tube. Thus, the example electronic monitoring device has improved signal range compared to known devices…”.

FIG. 8 shows what you may see. I really like how low-profile and unobtrusive this thing is.

Conclusion

This is the kind of shit that gets me absolutely boned up. I fucking love DAQ systems and trying to figure out how to improve something, even though the SRAM engineers will (technically) be doing the improving. I also really like how SRAM are trying to help the general consumer with simple, easy-to-use systems like this. You don’t need an advanced degree in vehicle dynamics to improve your ride.

The first issue that comes to mind is getting fork grease in the sensor. I’m wondering if this would even be a problem, and if it is, have SRAM thought of a solution (other than cleaning it). Or does it even matter if you get shit on the sensors?

That then leads to proper sensor cleaning procedures. I know, for a fact, that cleaning a mass airflow sensor (MAF) in a car requires a fairly stringent process with specific chemicals (+90% isopropyl). I also know getting shit in a pressure tap in a race car can fuck up your data, especially if you’re doing any extrapolation. So, I assume fork grease won’t be good for the sensor, but I could be wrong.

Do they already offer raw data on their current Shockwiz? If SRAM can offer a way to retrieve the stored raw data, then I’m all over this thing. For anyone wondering; if they can offer raw data, you can just use Excel to parse the data and even make your own math channels to find statistical anomalies, trend lines, or general balance numbers. Granted, everything would be manual to start with Excel, but it’s better than nothing and it’s fun.

Good shit, Kev.

2 thoughts

  1. Excel? Man you engineers kill me. Just use some real programming language to process data, some stupid python will do fine.

    Like

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