REVIEW

Gamut P-20 Chainguide

Chainguides -- are they necessary? Are they just an accessory for the showroom floor? Well, the answers are no and absolutely not. Of course they aren’t a necessity, but if you wanna go fast, there’s only one way to keep your engine connected to the rear wheel. The chain must stay in place on the chainrings and cogs to win races. Enter the Gamut P20 Chainguide kit. We bolted one to our trusty Turner RFX to put it to the test. After a couple of months of hard riding, we’ve learned a few things.

Gamut has been in the game for a limited number of years, but this product rides on the success of their G45 and P40 chainguides. Both have earned themselves a reputation for functionality and toughness. The Gamut P20 Chainguide is the little brother of the P40. It is scaled down for use with a 32-34 tooth chainring. We used a 34 on our test mule. In essence, the P20 appears to be standard fare – a boomerang allows a mount for a pulley at the bottom, a nylon guide prevents the chain from derailing at the top, and all is coupled with a polycarbonate bashguard. However, on closer inspection, we found some interesting design ideas that other brands' products lack.

Everybody knows that a stiff bashguard, bolted to the crankarm spider, could possibly bend the crank or bottom bracket spindle if we slam it into the wrong rock, at the wrong time, and with a little too much inertia. While there is always more than one way to skin a cat, Gamut has approached this problem with their thinking caps on…or maybe their helmets. The engineers at Gamut theorized the best way to preserve the bike and all of its bits is to absorb and disperse the stress of an impact, like a bike helmet would protect our heads when we miss our line through a nasty rock garden. So instead of a solid slab of plastic for a guard, Gamut’s P-series chainguides have polycarbonate bashguards that are hollowed out on their backsides with enough material left to preserve their strength, yet allow nasty impacts to be absorbed by flex within the bashguard structure.

We were a little worried at first that the guard was a tad too light. We thought maybe the Gamut guys and gals took away too much of the “beef” that we always thought we needed. We questioned whether or not the bash guard would last very long if we abused it.

When we installed the P20, some other issues came to light. The Gamut guide comes with all of the necessary hardware to attach it to the bike, including extra shims to adjust the rollers and guides. One of the first things we noticed was the buttonhead bolts and the lack of chamfering on ISCG mounting slots on the boomerang. Our test bike had an XT crank that was originally a triple and at this point we suspected that the inner chainring mounts weren’t going to clear the bolt heads. We were right.

We did a wee bit of product research (ed. we read the directions) and realized that the boomerang can be flipped over to re-orient the whole unit relative to the ISCG mounts on the frame to accommodate different chainstay configurations or frame geometry. We thought this was a great idea, and fearlessly proceeded to grind and then file away the inner ring mounting stubs. Who needs a granny anyway? Readers be aware, our other experiences with Gamut P-series chainguides have necessitated the use of a single speed specific or similarly modified crank.

Once we finished with the custom work on the crank we checked everything for fit. Perfect. We had zero issues with the rest of the installation. On our test bike, we didn’t have to shim or otherwise fiddle with the roller and top guide to get everything in line with the chain and front ring. The total installation, minus the work on the crank, took about 30 minutes. We installed the unit “as-is” right out of the box. It didn’t appear that we needed to remove the guides and flip the boomerang for our Turner RFX application. We took it for a test ride and made one final adjustment to “re-clock” the boomerang so that the top guide wasn’t riding on the chain when we had the bike sagged with rider weight.

The Gamut P20 chainguide worked flawlessly for us for the duration of our test period. First and foremost, we haven’t lost the chain. No matter what abuses we’ve tried to dish out, the P20 has held it in check. This kind of security is confidence inspiring. With the Gamut chainguide, we know we can stand on the cranks and pedal as hard as we want, through the roughest of terrain, and we’ll not end up with a knee into the fork crown as an appetizer before we have the handlebar and stem as a meal. We’ll wait for the post-ride burger, thank you. As expected, we’ve tagged the bashguard a number of times on rocks and logs. The P20 held up just fine. While we can’t say that these impacts have been analyzed with any sort of critical data or with any objective scientific methodology, we’ve tasted the Kool-Aid and it was a great flavor. The lightweight Gamut bashguard did its job well. No matter the severity of the hit, we never felt like we would end up with damaged drivetrain parts. Post ride inspections supported our notions. Could we possibly destroy everything with a massive impact on a rock? Surely. The crank might be our last concern at that point.

As with any other chainguide, the Gamut P20 makes a bit of noise as the chain rides up and over the lower roller. Where some other makers use a toothed jockey wheel, similar to those found on rear derailleurs, the Gamut uses a smooth nylon pulley, riding on two sealed cartridge bearings. It is lipped on the inside to prevent the chain from contacting the aluminum boomerang. It is also wider than what we’re used to seeing, but we noticed that when we shifted the bike in the stand that the chain can glide into a new position on the roller. There is no opportunity for the chain to rub on any part of the guide or bashguard as we shifted from one gear to the next. That is a nice feature.

There is no adjustability relative to the crank centerline for either the lower roller or the nylon guide at the top. We wondered about this simplicity, but our concerns were allayed by the function of the unit. In reality, there is no need for this kind of adjustment. Gamut’s use of three different size chainguide kits for differently sized chainrings makes perfect sense. There are no superfluous slots or holes to weaken the boomerang. It is as tidy, as tidy gets.

The Gamut P20 Chainguide Kit looks to be a throwback to earlier days and designs. The guys at Gamut didn’t just get a Fisher-Price “My First CAD Program” for Christmas and go berserk. It seems to us that they recognized that sometimes simple is quite frankly, better. Aside from a handful of bold color options and the energy absorbing bashguard design, there are no swoopy shapes or trickery just to add flash. The P20 is a refined version of what we’ve been using for years now. It is lightweight, at 213 grams and has a lower retail cost than the competitors chainguide systems. As far as we’re concerned, there is a lot to like about the Gamut P20 Chainguide Kit. Like Neil Young stripped down for an acoustic solo set, simple is good.