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Review: Gamut’s Totally Revamped P20S Chain Guide

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Gamut USA has quietly been producing one of the most highly coveted chain guides on the market for a number of years. Their guides adorn everything from the trail bikes on your local bike shops showroom floors to the world cup downhill rigs raced by Aaron Gwin and Greg Minaar.

This past year, the company released a completely revamped version of their beloved guide which introduces several new features they claim reduce overall weight, increase durability, lowers rolling resistance, and reduces noise.

We’ve been putting hard miles on our test unit since August. So does it live up to the manufacturers claims or did it leave us screaming damn it Gamut?


Claimed weight for an ISCG 05 P20s is 177 grams. It’s always a nice surprise when components in at roughly the manufacturers claimed weight. The new Gamut weighs 3 grams less than E*Thirteen’s taco style LG1+.

Plastic bash and ISCG 05 back plate.

Assorted mounting hardware.


The company extensively redesigned the bash guard on their new P20 model. The new bash is lighter, stiffer, and stronger due to the triangular shaped cut outs and the new graphics add at least an extra 2 horsepower to any bike.

The biggest improvement is the addition of aluminum inserts in the light weight polycarbonate. With the old design, it was easy for the overzealous mechanic to unevenly or over tighten the chain ring bolts which could potentially cause a crack of bubbling to occur.

Another new feature is counter sunk bolts/backplate. This allows the granny tabs on cranks to clear the bolts on the backplate without having to plug in the grinder.

The last big change comes in the form of a redesigned lower guide. The new lower uses an o-ring to keep things moving freely. The company claims the redesign offers lower rolling resistance , diminishes noise, and decreases maintenance. The sleek  new roller design also offers less to catch on when bashing over obstacles than the old roller design.

The old circular roller required the bearings to be repacked once every insert metaphor for absurdly long period of time here (unless you lived under a black stormy rainy cloud).


Installing a chain guide properly can frustrate everyone from the home mechanic to the experienced shop wrench. It’s not a difficult task but every setup is unique and often requires an arsenal of washers, grinding, and some foul language before everything lines up.

The upper and lower guides  are keyed and then affixed to the backplate by an Allen bolt. The package contains a set of washers to help  space the back plate and a set of keyed spacers that fit behind the upper and lower plastics for fine tuning.

Setup was completely painless. On our test bike, utilizing two different set of Shimano cranks, we didn’t have to resort to fiddling with spacers or washers. The components literally worked right out of the box. Perfectly. The taco guide previously on this bike took several washers, a six pack, and a date with a grinder to eliminate chain rub on the upper guide.


We found the perfect place to test out the new guide at this little trials spot in the woods. No funny crashes but it certainly took a few failed attempts to clear over the stumps. 

There’s only one thing a chain guide has to do and just one failure is all it takes to ruin a day or race run. We took our little 4″ test sled and rallied everything from downhill trails, epic “all mountain” days, even the local dirt jump pack, and never dropped a chain.

The terrain isn’t very rocky in our neck of the Northern California redwoods but there’s an abundance of downed trees over the winter. The bash ring has withstood multiple head on collisions with large logs and survived virtually unscathed – with the exception of a few minor cosmetic scratches. Since the bashring in this design takes the brunt of any impact rather than the backplate on taco guides, we didn’t have any experiences issues with back plate bending or flexing.

The newly redesigned lower guide tucks up into the bash ring sleekly and also slides over obstacles better than the previous design. We also appreciated how the new design isn’t as vulnerable to impacts as the old roller design. The new “silent roller” isn’t substantially quieter than previous designs, but since we all work on our own bikes, we universally applauded the idea of less moving parts. Compared to the other bikes in the garage equipped with the older style circular roller, drag appears to be roughly the same.

Initially, there were some issues with heavy drag on the test guide that was sent out. This was an early unit and even with generous lubrication the cranks would barely spin a full revolution (even after a longish break in period.)  Gamut sent us new production plastic upper and lower guides and a few o-rings which where harder and noticeably reduced drag. The original O-ring and plastics had roughly two hundred miles before being swapped out and only the O-ring was beginning to show the slightest sign of wear. The company ships it guides with a handful of O-rings and they can probably be sourced from your local hardware store in a pinch.

The newly revamped Gamut guide offers several key new updates which help put the company back on top of the pack. The new aluminum inserts in their bash rings, counter sunk bolts,  and low maintenance design is indicative of a company that listens to customer feedback. Overall, the design works really well and is one of the lightest non-carbon chain guides on the market. The only real nitpick is that the Gamut system has a little more drag when flipping the pedals than some comparable products, but we couldn’t tell the difference once we got on the bike and hit the trails. If you want a hassle free low maintenance guide then the new Gamut line up is well worth checking out and we look forward to seeing the new design make it’s way into production across the entire line up of single and double guides by later this year.

TL;DR? Here’s the break down:

What’s Hot
-Incredibly simple installation process
-New design incorporates aluminum inserts into the bash ring
-New lower roller has less moving parts
-Never dropped a chain

What’s Not
– Very sensitive to properly oil chained
– More drag than comparable systems in Bike Stand



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11 years ago

nice review.

Betty Beige
Betty Beige
11 years ago

Gamut is Great, well made by people that actually ride! Too bad everyone is ripping off their designs..

11 years ago

Switched over to Gamut from e13 during slalom season and the review is spot on. It’s much quieter due to the bottom guide and moves more freely. Good grassroots program too.

11 years ago

A little behind the times, eh Gamut? Just now doing counter-sunk mounting bolts? I’ll stick with my TRS+ guide thank you very much.

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