Maddock Machine – Mad Dog Drum Brake Update

About a week ago I posted a solicitation for consumer feedback on the Maddock Machine “Mad Dog Drum Brake” (MDDB) to both the Tandem@Hobbes mailing list (yes, it’s still out there after 26 years in its original Listserver format) and the BikeForum.net Tandem forum along the lines of:

Just curious if any Hobbsians have any first hand experience with the Maddock Machine “Mad Dog Drag Brake” (sometimes called Maddox Drum Brake).

I wrote a piece on the brake during its development and then again shortly after its release in July 2013 and am curious to hear from users on how it has performed in the field. Just trying to come up with a balanced 3-year update as that particular blog seems to get a lot of traffic.

Feel free to shoot me a private Email or to reply here.

To date, just one lone reply from a loyal follower of our blog — Eric — who has one installed A MDDB on their quad but without sufficient use to offer much in the way of feedback on long-term use.  However, it was nice to hear from someone who actually bought one.

4513_editedFor those who may not be familiar with the MDDB (sometimes called the Maddox Drum Brake), it was developed by Tom Maddock of Maddock Machine when the only other drum brake that had been available for tandems — the Arai — was no longer going to be produced by the current owner of the intellectual property.  The Arai was a time-tested and proven drum brake that served a niche market with the tandem community that had a need for a constant-on / high-heat capacity brake to deal with long, steep descents or heavily loaded tandems.

I first wrote about the MDDB development activity in a blog entry back in November 2010 that you can read here. At that time they were looking for tandem teams who could support the beta test program.

My next mention was in July 2013 when it finally came on the market: that blog entry can be found here.  Distribution channels were pretty narrow given that during the protracted development cycle dual disc brake equipped road tandems came into their own and were providing tandem enthusiasts with inherent, higher-heat capacity braking than the rim-brake equipped models they were now replacing.  Off-road tandems probably did a lot to build confidence in disc brake systems as we’d even had those on our first Ventana tandem back in 2000.  To their credit, Cannondale defied the nay-sayers and were the first to introduce the dual-disc equipped road tandems well-before anyone else.  Co-Motion was next to offer the dual-disc a standard brake offering.  Other custom and small-volume, high-end builders like Calfee and Seven were also offering road tandems with dual discs.

Therefore, given the changes in the market and product offerings, perhaps the number of drum brakes needed to satisfy consumers is actually now quite small… and may be why I’ve had so few inputs based on my recent solicitation… well, OK: one from a private owner.

However, I do have another data point from April that I’ve been sitting on while waiting to see consumer mentions or product reviews of the MDDB that independently corroborated or offered a counterpoint to my other source.  Alas, there have been none of those either.  I even reached out to a friend in the tandem business to see if they had any perspectives — positive or negative — to offer and to date have never heard back.

So, in the interest of transparency and with the usual caveats, i.e., your results may vary, here’s a summary of what has been shared with me by someone who has been in the tandem business for many years, both as a manufacturer and retailer.

  • They’ve installed a few MDDBs but based on customer feedback no longer offer the brake as an option or aftermarket accessory.
  • The consumers who bought the brake were seasoned Arai drum brake users who were looking to the MDDB as a lighter-weight alternative for their European tours where long descents are quite common.
  • The early adopters were only to get about two (2) seasons out of the MDDB and experienced overheating issues, e.g., anodizing discoloration and melt-down of brake pad material.

As for why the MDDB did not work as well for the early adopters in this sample, the default assumption is that the lack of the large heat-sink / fins that were part of the original Aria drum brake reduces the MDDB’s ability to withstand the same amount of heat from demanding descents: Arai at left, MDDB at right.

arai 4513_edited

 

Similar issues with regard to loss of heat capacity were also reported with Arai drums where the cooling fins / heat sink material had been removed for weight savings in a variety of different postings to the Tandem@Hobbes forums over the years.  At right is a photo of an Arai drum brake with the materials removed installed on a Trek T2000 with what appears to be a trailer hitch on the left end of the rear axle.

 

However, what Maddock Machine zeroed-in on was a deviation from their very explicit MADDB installation guidelines relative to reaction arm alignment with the frame mounting point, aka, Pacman.

screen-shot-2016-09-25-at-8-29-28-pm

 

My source volunteered that they did, in fact, use bolts that were ~5mm longer than the ones supplied with the MDDB.  However, it was his assessment that it was the only way to make the MDDB work.  Moreover, it was common practice to use a shorter bolt than was spec’d for the Arai drum brakes and the length of that bolt was not crucial.

Having worked in the aerospace and defense industry supporting the design, development and manufacturing of aircraft and related systems, I can appreciate why design standards and subsequent technical, maintenance & flight manual details are so darn specific as any deviation beyond the cited limits invites all kinds of problems.  So, as a third-party observer of the purported issues and deviations from installation specs provided by Maddock for the MDDB, I’m inclined to side with Maddock since they actually provided a spec.  Looking back at the Arai, I believe most of the “specs” and user manuals were materials that tandem builders like Santana developed for customers or dealers like Mark Johnson at Precision Tandems who maintains a rather comprehensive web-based guide for customers.

However, that said, I’m also a big fan of empirical data and experience, especially when it comes to tandems since so many things that either should or shouldn’t work on a tandem defy logic and engineering intent.  As noted by our source, installation of the Arai on the very non-standardized variety of frames with rear wheel spacing ranging from 130mm to 160mm required some fudging when it came to getting everything aligned, so it would seem logical to assume that a very similar brake would not be adversely affected by similar adaptations of the reaction arm interface with the frame.  Moreover, and being very sensitive to how either disrupting air flow or removing heat reducing features adversely affect the running temperature of our air-cooled motorcycle engines, I can also see how a shaved Arai or a clean-sheet drum brake design that mimics the shaved Arai could reduce the heat capacity of the drum brake and induce brake fade and the associated issues that come with overheating any type of brake.

In conclusion, I’d really like to hear from users who can provide those all-important first-hand reviews and insights into how the brakes were used and any issues that may have occurred.  My source makes a very compelling argument for why they opted to drop the MDDB from their options and accessories based on their early adopter experiences: again, this is not his first rodeo and I sincerely respect his experience, expertise and desire to provide customers with products he can stand behind and support.

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About TG

I've been around a bit and done a few things, have a couple kids and a few grandkids. I tend to be curmudgeonly, matter-of-fact and not predisposed to self-serving chit-chat. Thankfully, my wife's as nice as can be otherwise we'd have no friends. My interests are somewhat eclectic, but whose aren't?
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