8275 is a curious flagship in the Technic timeline. Designed by Markus Kossmann, the motorized bulldozer was the very first Technic set to feature the brand new Power Functions system unveiled in 2007. Beyond doubt, the model was primarily a showcase of the range of capabilities of the new electric system. The IR remote, first for LEGO, is used to control all functions. The battery box provides power for the two XL motors, two M motors, and two IR receivers. The two XL motors together supply the torque to drive the bulldozer on its chain tracks. When riding on a non-slippery carpeted surface, this massive beast is capable of pushing or towing impressive loads. This quality of the model was demonstrated in a promotional designer video where the bulldozer is shown towing a conga line of other Technic models and a skateboard loaded with heavy trophies. The model comes with two ball pins at the base of the rear-mounted plow which are used as attachment points for the tow line in the video.

The box is enormous for this set. One needs to take a few steps back to see the model on the top cover - from up-close it looks like a pile of giant studded yellow beams. Despite its size, the box feels rather on the empty side, which was typical for the flagships of that era. While the parts and the instruction booklets can easily fit in a box half the volume with room to spare, apparently LEGO felt that a supersized box would emphasize better the scale of the model, attract more attention on the shelves, and generally boost sales. Thankfully, the LEGO boxes of today are much better packed with bags reducing dead volume.

There are no numbered part bags which sets the stage for a lengthy sorting session before the actual build can commence. The first third of the build is not particularly exciting. There is a number of support structures assembled from a large amount of small connectors, axles, and pins. The functions and shape of the model are hard to see until the very end of booklet one. The second instructions booklet completes the bulldozer with the exception of the attachments. The bucket assembly is so massive that it warrants the entire third booklet in tandem with the plow.

The finished model looks imposing. I wouldn't call it pretty, but it sure resembles quite well a real caterpillar bulldozer. While not the best display model out there, this flagship is exceptionally playable. The remote control is fairly intuitive even with the need to switch channels to go from driving to attachments control. I am guessing that a second remote is intentionally not included because the driver is not supposed to engage all motors at the same time. Running 2 XL and 2 M motors loaded can exceed the maximum current capacity of the single battery box tripping the overload protection circuit. The chain tracks drive smoothly overall but the model will catch on small parts left on the floor. Others have complained about the ability of the model to track a direction due to the asymmetric use of the two XL motor's torque (the torque from one of them is routed through the model's "engine") and manufacturing variances in the XL motors. My bulldozer tracks fine, but it is probably worth comparing the two motors' power before the build and using the more powerful one for the "engine" route as suggested by previous reviews.

The weakest part of the design is the bucket attachment and its lifting mechanism. With only four attachment points, the bucket tends to wobble slightly side-to-side. Its weight proves problematic when the torque needed to lift it exceeds the slip threshold of the friction gear that it routes through. In my model, I found out that the friction wheel would skip a lot when lifting the bucket, which was disappointing. Since I purchased the set second hand and it appeared to have seen a fair share of use, I am guessing that the two friction wheels I have may be a tad worn down (although I did not detect any noticeable problems when testing them by hand ahead of assembly). A closer investigation revealed that a key source of the problem (beyond the sheer weight of the bucket) is the high friction on the axle supporting the worm gear that lifts the bucket. As it turns out, the center hole of the #2 axle and pin connector that the axle is routed through is tighter than the holes in the standard studded beams creating unnecessarily high friction. I swapped it a couple times and found out that the otherwise identical connectors actually have different friction characteristics (apparently, a manufacturing issue). This paired with the imperceptible bend in the axles in my set and the slight misalignment between the connector and the shaft the axle runs though on the opposite side of the worm gear results in significant friction. I was able to reduce this friction somewhat by selecting a connector-axle pair that exhibited less friction, but could not bring it down to what would be normal for technic. It is a notable design problem.

To resolve the bucket lift problem, I decided to implement the solution that others have suggested. In a nutshell, it involves gearing down the bucket mechanism by replacing two 16-tooth gears with an 8-tooth gear and a 24-tooth gear in step 18 as follows:

It was hard to implement this fix on the assembled model (at least an hour worth of work). The result was really nice however - with the fix, the bulldozer no longer has trouble lifting the massive bucket. It does it slower with the down-gearing, but reliably smoother and without skipping.

I strongly recommend this modification during your build. Without it, you may be set for disappointment. As it turns out, the bucket lift mechanism operates near the limit of the torque tolerance of the friction wheel. Chances are more than good that your friction wheel will be skipping or the bucket not able to lift without help. It's nearly impossible to tell on which side your specific friction wheel torque tolerance vs route friction balance will land no matter how carefully you ensure that axles spin freely. The rear plow mechanism works well enough for the most part, so no modification is needed there.

Thinking to whom to recommend the 8275 Motorized Bulldozer, I am not able to find an easy answer. In my mind, 8275 model is at least a solid 4.5, but not quite a perfect 5. The cliche "a must-have for serious collectors" still holds true since this is a historic model that offers solid playability and impressive might. On the flip side, there are some more recent (as well as older) models that offer more interesting functions packed with better display aesthetics. To be fair, 8275 does feature an interesting chain track rollers mechanism and unique large plate-based bucket. However, if you are already familiar with Power Functions, there is not much more in terms of clever mechanics worth studying in the model.

This is an incredible model, one of the best I've known along with 8880 supercar, 8110 unimog and 9397 logging truck...

Pros

• Blade and rippers work awesomely.
• Good design, it looks great.
• It's very good for the first model with modern tracks and motors.
• Very good for scale collectors.

Cons

• Low positioned motors so you can't take it outside in the wet.
• Fault in the instructions.
• On my model the lower track supports jam sometimes.

Overall the model is a must get for any serious lego collector.

I got this set for Christmas about 4 years ago for $149AUD, finished it within 24 hours, played with it for another 24 hours then put it on the top of my shelf which it later fell from a year later.

Pros

• Amazingly beautiful design.
• Easily completed.
• Very well built/constructed, very sturdy.

Cons

• Wheels/tracks tend to snap apart easily.
• Does not survive 2 metre drop.
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To this day I have not rebuilt it - trust me it is on my to do list because this is such a good set to build. This is one of the most expensive Lego sets now going for about $600AUD on sites like ebay.

This set introduced the Power Functions remote control in the Technic line. Great functions and playability. Good design.

Parts

Power Functions elements in big amount - 2x M motors, 2x XL motors, 2x IR receivers. One of the first models with Link Tread Wide element (www.bricklink.com/catalogItem.asp?P=57518).

The build

Very good and challenging building process.

The completed model

Functions and playability are the key strengths of this model. First ever PF remote controlled Technic set.

Design is good but not exceptional, it looks like something in between a Caterpillar and a Komatsu dozer. Personally I'd rather a Caterpillar design with the typical High Drive.

Summary

All in all a true flagship set. First ever PF remote controlled set and best Technic dozer set ever. Design is good but improvable.

This recently showed up again in the Lego online shop for about £75. If you add up the cost of the separate PF parts this comes with it’s almost the same price. Unfortunately it’s got quite a high demand and was sold out. I got mine at a lot more but it’s still very much worth it.

The instructions are great. You don’t really know its coming together until the end. I had piles of pieces left with only about 20 steps to go! There are 3 books in total.

This set harks back to studded parts. And in many cases not for any real function. In fact this set has the most non-specific technic sets I have seen for ages. Lots of plates and studs. Good to see and this model looks great for it. Even without stickers.

The tracks are a novelty. The way this model spreads its weight onto the tracks with 6 little wheels on either side is useful to know for MOCs.

There are a lot of cables in this model and I found myself carefully routing them. The cables themselves are delicate and require care when bending round corners etc and undoing twitsts. If you do not get the correct routing from the XL motors to the IR sensors you will find they don't reach, something I had difficulty with.

The model is far wider, taller than and almost as long as the 8258 crane truck with the ripper extended. The size of the box backs this up, its big.

The 2 XL motors give this model a good amount of shove. There is surprisingly little gear reduction yet the heavy model can climb steep slopes and push/pull a surprising amount of weight.

I am new to the IR remote functions and I was pleasantly surprised with the range and control it gives. This model is set out so channel 1 allows each switch to control either track and channel 4 so that each switch deals with either the ripper or the blade.

The model is packed with features the motors, battery and IR sensors are all packed into the compact body. The PF functions are superbly implemented. Great speed and strength of motorisation and no gear crunching at the limits like you get in so many other PF sets. The battery box slides in and out really easily making battery swaps easy. Yes the ripper can get in the way but with 4 pins it can be removed easily.

The front blade is not perfect. The sides are a bit fragile and the arms which come back to attach mid model have a lot of lateral give in them. Actually when you push something the blade pushes against the engine grill on the main body which provides rigidity. Those cylinders above the blade are not for real. The blade is raised by the rotation of a shaft which lifts the blade via arms, just in front of the engine, its not linear actuators.

The rear ripper is better than I expected. It is strong enough to lift the rear of the model. This is operated by a worm wheel.

Its worth noting the little cab doors open, it looks like there are towing points at the pack and the engine cover opens. Of course the engine is only driven by one track but I do not see how it could be done otherwise.

I bought this for parts but I love it so much I will keep it built for a good while. An essential purchase for any Technic fan and by far the most functional and interesting model of late, even if it has slightly less parts than other flagships.