Independent Drive for an Independent Rider - 2008 GT DHi Review

Bike's in general have developed an immense amount in the past 10 years. Like a fruit bowl on the porch the biking industry has blossomed to its ripest, but it will not go rotten. In the past 10 years we have seen inventions that have blown our minds. Everything from suspension, to braking, to single sided swing arms, and we event went as far as to invent the gear box.

In our day to day ride we don't really stop to pay attention at what is really going on. Whats moving, whats shrinking, whats growing, and whats slowing us down are some of the things we may over look, but with minor adjustments or alterations we can improve our ride so much more.

Read on for more to see what I'm rambling about....No matter what hill, what chair lift, or whoevers truck bed I'm in the topic of "how amazing my bike was riding" always comes into play. Just like a womens locker room, somehow you always end up hearing something about everyone. Maybe you dont care that Tom's run could have been so much faster if his shifting worked, or how James has to be home in time for dinner, but your still going to hear about it.

However, the one conversation you always hear, is about the negatives in bikes. Little things that could be different, and that you feel could improve the bikes feel or overall ride. Well, believe it or not, these little "tid-bits" of information that you elaborate to the back of your friends full face helmet are what built the bikes we ride today. Everything that you suggest could be different has been looked at, and been tweaked or adjusted to its best feeling.

There are a couple of things that "plague" bikes, and take away from our everyday ride. Brake jack, pedal kick, chain growth, and many other things take away from our rides, but without these things acting against our ride in theory we would have a perfect run. We have all heard that saying "in a perfect world.." so we all know that the world isn't perfect, but we deal with what we can.

Recently I have been testing one of the 2008 GT DHi bikes, and I have to say it is definitely 1 of its own. Not only is it one of the most eye catching bikes on the hill to its robust design, carbon seat mast, and incredible speed, but I have to say that it has been one of the most comfortable rides I have had in a while. In this review, I am going to address the positives and negatives of the 2008 GT DHi to give you guys a taste of what the big bikes are made of.

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ID means independent drivetrain, which is a suspension system utilized by GT. This system is used on there full suspension bikes, including the world cup ready DHi downhill bike. Bryn Atkinson has been rocking out on the DHi for a while now, which means it is race tested, and ready to take some abuse, however I don't know if I am.

From the factory the frame weight's 11.7 pounds, which is a reasonable weight for a 8" travel downhill rig. The frame is constructed out of 6061 Aircraft grade aluminum, which has been formed and heat treated for maximum strength to weight ratio. It features a 4 bolt carbon seat mast, which features a nice high gloss finish and rounded edges to ensure you don't do any damage to yourself. I have to say, the bling factor of the seat mast itself was enough to make me want this bike. Its such a change for a production downhill bike to feature so much carbon, especially in such an important part such as the seat mast.


The DHi features a 9.5 inch eye to eye shock length, with a 2.75 inch stroke. This keeps the rear end sensitive through the travel, to maximize the time the rear tire spends on the time. The more time the wheel spends on the ground, the more control you have, and the faster you will go. Once again, thats just a theory, don't quote me on that. With a 9.5 inch eye to eye the DHi pumps out 8 inches of rear wheel travel (210mm). This travel is delivered through one of the new 2008 Fox DHX 5.0 Air shocks. This year fox has changed up the Pro Pedal setting from a dial, to a switch. Basically, fully on, or fully off, no in between.


Utilizing a 64 degree headtube angle, which is equal to a Orange 224, the front end of this bike is ready to plow. However, compared to the Orange 224, the seat tube angle is much slacker at 66.5 degrees, a full 5.5 degree's off the Orange's seat tube. Judging by the angle's of the frame the DHi was designed to be a tank. When cornering the 64 degree headtube angle is quite noticeable once your past the apex of the corner. The front end starts to climb away, as the rear end squats, steepening out the angles a little bit more. The DHi has a fairly large wheelbase at 1141mm, or 45 inches, however when your riding it doesn't feel that long at all. It jumps across roots and rough sections like nothing was in its way. I found while riding the DHi it always stayed in an upright position, where I felt comfortable viewing the on coming terrain, but wasn't so close to the bars that it was sketchy. All in all the position that I was placed in was comfortable, which in turn makes for a better all around ride.

So, some people may look at the DHi's lower bottom bracket section and say "what the funk is that creation?". Well, in all honesty I said the same thing, but once you read up on it you get a good understanding of it. The problem with most bikes is that the rider experiences pedal feedback. This means that as the suspension travels through its movement, the chain gets tighter, which in turn requires more power from the rider to get them moving again. The solution, or how GT fixed the issue, create a bike that has a completely independent drive system. As the suspension is compressed on the DHi, the bottom bracket is swung backwards by the linkage, which in turn adjusts for chain tug by lowering the pedal position, creating a resistance free pedal stroke, meaning your hard earned energy will last till the end. Here are some images to help with this:


And if those didn't help at all, check out GT's way of describing it to us.

The attention to detail on this frame definitely got me. All the welds are perfect, and visually there is no spots that look like they could have "lost some weight". The swingarm section contains a sort of cable "guard" which runs over the cable guides to provide some safety on crashes. This way, you dont end up with a pinched deraliure cable or worse a pinched brake line. It also comes stock as a Maxle axle in the back, which is super cool, but something we have been seeing all year.


The DHi also has some cool features when you purchase the frame. Seeing as its such a odd sized chain line at 57.5mm, GT has supplied the purchaser with a set of Shimano Saint cranks, and a E13 Chainguide system. This will aid the new GT owner in getting his/her bike running ASAP, and less messing around with cranks and guide setups. As well, GT supplies you with a seat post clamp, and a headset, which are both really big helps when building a frame up from scratch.

So enough with about angles and weights, everyone wants to know how it rode. Well, the DHi is unique due to its drivetrain. Utilizing a system that is dubbed "ID" or Independent Drivetrain the DHi experiences very little pedal bob, or pedal feedback. The way it works, is GT has separated the drivetrain from the front triangle. All the pressure you are applying to the pedals is being fed directly to the deraliure, its not dodging in and out of linkages. What does this do to the ride? What this means is the 100% of your power is put into the bike, compared to a conventional bike, where 15-20% may be lost to suspension bob and feedback, leaving you with 80-85% pedaling power. Basically, you get back what you put in, and in turn your able to ride longer, and push it that much further. On an average mountain ride its not so noticeable, however after a couple hours of abuse at Whistler Mountain bike Park it came into play.

Just like when you get a fancy new car, everyone was interested in the DHi. Seeing as the DHi has lots of features that can easily be brought into conversation, every person that rode the DHi had a different impression on it. The general understanding was its a do everything bike. Point it in the direction you want to go, and it will do the work for you. I am not trying to say that the DHi can pick and choose its own lines, I am trying to emphasis just how well it works. Once the suspension was setup correctly the DHi tracked so well over rough terrain it was nice. Utilizing a basic single pivot suspension design there is nothing funny going on, just up and down, which makes for a predictable ride. The ride may be predictable, however its only as exciting as you make it. The DHi is a really active bike, and was really fun to play with through rooty or rocky sections.



One downside that the general consensus of riders experiences was crank drag. No, im not contradicting what I said earlier, I am talking about hitting cranks and pedals on the turf! 14.25 inches may seem like a high bottom bracket, however under suspension compression it swallows through that very fast. It could be something to do with the Independent Drive system, and the fact that the bottom bracket hangs lower than most bikes, or the fact there is a 36 tooth chain ring, but it is low, and it does hit. That being said when the DHi sat high in its travel I never experienced an issue such as that.



Being such an eye catching design and construction anyone who jumps on GT's DHi feels like they have to pin it. Its definitely a get on and go bike. The DHi sits in a comfortable sag while idling along, but once speed comes into play the geometry starts to change. As stated before the DHi is a squatter, its one of those bikes that just plain out works. The DHi does what you want it to do, weather its roosting corners or pinning steeps. One downside about Single Pivot bikes in general is the brake jack. Seeing as there is only 1 pivot, once the brake is locked the rear end does not move, at all! Some bikes are compatible with a floating brake addition, however I did not research the availability on it for the DHi. Brake jack isn't a big deal, however once you have rode a bike that has active suspension under braking it will feel like night and day.

All together the DHi worked really well when it was in its element. It dominated in rough conditions, where it could be held wide open, with all cylinders firing and no restrictions. Some places where it fell behind was obviously tight trails (30" wide bars didn't help). I noticed that on trails with a lot of roots, and impending items on your smooth lines the DHi did ok, but as soon as it got to slow to hold its own momentum it died. It was fairly good at jumping, but did not compare to a bike with a more advanced suspension platform such as a VPP, or a 4-bar suspension design. All in all, it is what I expected out of a massive, plow bike really. Point and shoot, and hold on, because it will be screaming in no time.

Heres a video showcasing the DHi's riding characteristics.

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Got a Comment?

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One last thing I would like to address is the fact that I did run into issues with the pivots. The DHi uses a pinching system on the bearings, however I did experience the pivots coming loose, and the need for a replacement frame was issued. The DHi is not a maintenance free bike, it will require you keeping up with tightening bolts, checking pivots, and all of the above.

My overall impression on the DHi was its really good at what it does. Its a very unique looking bike, so its good at catching peoples eyes, and starting conversation. Its a unique style of ride, due to the ID system, and its robust angles. All together I had a really good time on the DHi, and I would suggest anyone who is interested in the DHi or the ID system to check out GT Bikes.

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Editors Note: GT Recently released their replacement for the DHi for 2009, the Fury. GT has taken the carbon manufacturing process 1 step further with the creation of a completely carbon downhill bike. Look for the Fury in 2009 from GT.