Posted Nov. 3, 2004
Cool 3-ring guide: Heim 3Guide

Here's a cool item for you all-mountain rangers who like to run three rings yet keep your chains gripping your teeth instead of snaring your feet.

Who makes it:
The Heim 3Guide is the baby of John Heim, who owns Montara Design High Performance MTB Components -- "Shaped by the mountain ... hardened by competition." The mountain in question is Montara Mountain, a sweet riding spot (here's an 8mb Quicktime video). Jon is literally a super genius mad scientist. He worked as a lead researcher at Stanford Research Institute, and now he's running a spin-off company that makes artificial muscle. Yes. Cool.

Jon makes chain guides and bash guards, but a couple years ago, after he fed a derailleur to the hungry rocks of Northstar, he came out with a shaft-driven downhill bike. It was cobby, but it showed promise. Here's the story.

How it works:
An aluminum plate sandwiches between your BB shell and flange and holds a roller behind your big ring. The roller is tapered, with a flange on the outside. The flange retains your big ring, and the taper nudges your chain toward the big ring when you backpedal.

More than you wanted to know: Dropped chains don't happen at the top of your ring. A correctly adjusted derailleur holds your chain on top, and if the chain does drop to the inside you can always pedal it back onto the ring. Catastrophic chain loss happens at the bottom of your ring. When you hit bumps, your chain pulls downward then springs back up and goes slack. If it wanders outward during this slack moment, say goodbye. The chain peels off the ring and hangs off the outside of your derailleur cage. Your only chance is to shift to the middle position and try to pedal your chain back on. This can be tricky on a fun descent. The 3Guide is designed to eliminate this slacking off.

In action:
I've been running 3Guides on and off since summer '02, and I've never dropped a chain with one. We're talking about tons of cross country, a few downhills and lots of super Ds.

Bummer: The hard roller makes a bit of noise, but it's no big deal. The new rollers will be softer and quieter.

Watch out: If you mount the guide too low and forward, it will catch on rocks and get bent. Make sure you tuck the roller up behind your big ring.

The verdict:
The Heim 3Guide keeps your chain on, and it lets you run three rings. You can also run two rings and a bash guard, or you can run three rings AND one of Jon's universally drilled bash guards, which has to be the world's most versatile setup. If you want to run multi rings and feel confident hammering out of corners, this could be your ticket.

Coming soon:
Jon has made some improvements for '05:
  1. Slightly thicker (.25mm) plate, through the magic of modulus => twice as stiff as the '04, yet only 8 grams heavier
  2. Shorter plate - 48t max, more clearance for most installs, 52t never used anyway
  3. Modified ISCG mount - allows use of 1 ISCG hole in addition to the BB mount
  4. 2-ring specific roller available- 2-chainrings wide instead of 3, allows optimum tuckage on 2-ring + bashguard setups
  5. Red roller available
  6. Softer durometer roller available
  7. New bashguard sizes - 36, 40, 44, in addition to the existing 38, 42, and 46
  8. "Web" removed from top and slot widened on bashguard, allows more clearance on some installs
  9. Offering the guide and guard as a packaged system, both 2 and 3 ring versions

Disclaimer:
Since I'm encouraging you to spend your money on this item, I think it's important to tell you where I'm coming from. I know, like and respect Jon Heim. He's a good man, a good rider and smart as hell. As a matter of fact, I think he's the world's smartest projectile. I built his website for him. As part of my payment, he flowed me a guide and a bash guard. There. All honest.

For more info on 3Guides and Super D bash guards, check out www.montaramtb.com

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