Big Shocks has been around since 2009 and their long travel Bonzi edition shocks are extremely popular with the mud truck crowd due to their large available sizes, unique attributes, and affordable price.
Big Shocks is based out of Big Rapids, Michigan where they can be reached by phone at 231-679-0760. Their website is BigShocks.com
In this review we will refer to these shocks as "Big Shocks" because we found the actual brand name "BigShock.com" too awkward to read in a sentence. Second, this particular model of BigShocks.com shocks are called the "Bonzi Edition" which we have to assume is an alternative spelling of bonsai because the only thing that comes up when you Google "Bonzi" is an animated purple monkey that you can download on your desktop. Third, while their name implies that these shocks are big, they are the same size as every other coilover in this category.*
*For this review we are testing their 2.25" body Bonzi shocks because our requirements were 12" of travel and their 2.5" body Bonzi shocks start out at 14". We we're told that all of their shocks are built the same way (just with larger or smaller components) so this review should be accurate for their 2.5 and 3.0 body shocks as well.
The Ordering Process
We called Big Shocks anonymously and our call was answered on the second ring by someone that was driving at the time. The person we spoke with was extremely friendly and more than happy to answer our questions. He asked all of the right questions about our fictitious project and made recommendations that we found to be accurate and honest. We asked about custom valving and the call got dropped. We called again 1 minute, 5 minutes, and an hour later with no luck. We called the next day too but never got through or a call back. Based on information found on their website, it does not sound like custom valving is an option, however, replacement parts seem to be readily available. We ordered our coilover on their website and it shipped out a few days later.
Shipping and Delivery
We received our Big Shocks coilover 4 days after the order was placed via UPS. The shock was double boxed and padded with some craft paper and bubble wrap around the reservoir. It arrived in very good shape with no marks or scratches and there were a few extra freebies (koozies and decals) thrown in which is always a nice touch.
Big Shocks 2.25 x 12" Coilover, Remote Reservoir, No Springs
The first thing we noticed about the Big Shocks Bonzi edition coilover is that it has several non-traditional design elements. The cylinder is not threaded and there are heim joints at each end instead of spherical bearings. The reservoir is marked "Max 100 PSI" which we find to be quite low for a performance shock and there was no rubber bump stop on the shaft. None of the components are anodized, painted, or coated, giving the shock a bit of a bland look other than the glossy reservoir decal that sticks out nicely in contrast.
Heim joints are used instead of spherical bearings at each end.
A retaining ring is used to position the upper coil "nut".
There is no rubber bump stop on the shaft.
The reservoir is limited to 100 PSI pressure.
The shock cylinder is aluminum instead of steel.
Despite the differences seen on the exterior of the coilover, the Bonzi shock opened up following standard performance shock servicing steps. The wiper cap is locked into place with a set screw that was tight but loosened up easily with a small tug. The wiper cap unscrewed easily by hand to expose the seal cap which moved down to release the retaining ring that holds it in place. The shaft assembly came out with moderate ease and the oil was poured into a clean container and showed no signs of any contaminants.
The shaft assembly is a snug fit in the cylinder thanks to the massive and plentiful o-rings.
Two (very tight) wiper seals appear to be all that keeps the oil in the cylinder.
Two o-rings are used on the piston instead of a wear band.
There is no DU bushing or o-ring in the seal cap, only a wiper seal.
Very clean shock oil, no particles or contaminants.
Removing the top cap was surprisingly easy, it cracked loose with a slight pull on some large pliers and then unscrewed smoothly by hand. Looking inside revealed another unique design feature - an internal cap sits inside the top of the cylinder (sealed by an o-ring) and creates a large flat surface to seal against a rubber ring in the top cap. We did find it strange that no thread locker was used to keep the assembly tight.
The top cap came off almost entirely by hand with no signs of thread locking compounds.
The 1/4" reservoir port seems small, but it may be part of the damping process.
The top cap is threaded 1.32" deep for the upper heim joint.
The use of heim joints instead of spherical bearings is an interesting decision. They are easier to replace, offer some coilover length/height adjustability, and make the shock significantly easier and cheaper to manufacture. Using the lower heim joint to attach the lower spring plate to the shaft would make changing springs a bit more of a hassle compared to traditional coilovers.
Removing the lower heim joint revealed some rust and residual moisture.
The heim joints appear to be cheap, generic import models with no markings.
The end caps on the reservoir are held in place with retaining rings that are exposed by pushing the end caps in from each side. With the end caps and internal floating piston removed, we again noticed a bunch of o-ring and no wear band. We removed the o-rings to check the fit of each component in the reservoir cylinder and found them to be very loose, which of course explains the need for such large o-rings.
Large o-rings provide excellent sealing and compensate for the poor tolerances.
Two o-ring are used to seal the internal floating piston with no wear band.
The reservoir seems well suited to handle far more than the 100 PSI posted max pressure.
The reservoir has a very nice finish and the decal looks very sharp and professional.
A 3/8" hydraulic hose with crimped fittings connects the reservoir to the shock body.
The coilover hardware on the Big Shocks Bonzi coilover is all extremely beefy. The top and bottom spring plates are machined from aluminum and have tight tolerances to the shock body and shock shaft. The slider is machined from a hard plastic (that almost feels like plexi-glass) and is also a very snug fit. Instead of a threaded body, Big Shocks uses 21 grooves spaced 1/4" apart to accept a retaining ring that holds the upper spring plate (coil nut). We found the ring difficult and awkward to remove and re-installing it in a new position required pliers and a hammer to push it into place. The ring only seems to cover about 2/3 of the circumference, which is a bit concerning, and we still can't understand why aluminum was used for the main cylinder.
Oversized top and bottom spring plates fit all of our 3.0 springs very well.
The retaining ring used for the upper plate is undersized and awkward to move.
Preload adjustments are limited to 1/4" increments and require external spring preloading.
The slider is a snug fit on the cylinder and to all of our 3.0 springs.
There are no stop nuts to allow a spring rate transition.
The strength and wear resistance of the aluminum cylinder is a major concern.
Shock Shaft and Piston Assembly
The shaft and piston assembly of the Big Shocks Bonzi coilover has most of the same components found in a traditional performance shock, however, it is clear that a lot of shortcuts have been taken to simplify production and reduce costs. The wiper cap and lower seal cap are solid and well made, although, between the two there are only two wiper seals and no o-ring or bushing to guide the shaft. A loose fitting ring of PVC pipe is used as the shaft spacer and the piston is very simplistic in design. Just like in the reservoir, o-rings are used instead of a wear band on the piston. Two identical shim stacks made up of only two 0.015" shims each are used for compression and rebound damping. Finally, the lower end of the shaft is internally treaded to accept the lower heim joint.
The 1" diameter shaft is the largest of all the shocks in our test.
There is no bushing to guide the shaft through the lower seal cap.
Two o-rings are used instead of a wear band on the piston.
The PVC pipe shaft spacers makes contact with the compression shims.
Compression and rebound damping are the same and made up of only 2 shims.
The piston has 3 drilled bleed holes with 2 tapped and plugged.
All Big Shocks shocks are pre-built and sold with the shim stack configuration listed below. We were unable to find the specifications of the oil but it appears to be medium weight shock oil. The recommended pressure for the reservoir is 100 PSI.
The following is a list of component materials, dimensions, weights, finishes, and other important details as they pertain to each individual part. Each component was measured multiple times with a highly precise caliper and scale.
11.0 lbs. Overall Dry Weight with Hardware
2,090 grams of Moving Weight
805 grams Dry Weight Without Hose
Medium Weight | Gold / Yellow
16.375" Long | 2.260" OD | 2.00" ID | 0.130" Wall | 567 grams | Aluminum | Bare
2.700" Tall | 2.465" OD | 5/8" x 1.50" Inner Thread | Aluminum | Bare
Top Coil Nut
1.640" Tall | 0.394" Spring Perch | 3.480" OD Spring Seat | 306 grams | Aluminum | Bare
1.508" Tall | 3.618" OD | 2.277" ID | 0.371" Wide Spring Seat | 0.120" Wall | Plastic
Lower Spring Plate
1.176" Tall | 0.398" Thick Seat | 3.475" OD | Aluminum | Bare
Heim Joint | 0.625" ID | 0.748" Ball Width | 5/8" Shank | Chrome-Moly | Imported
1.749" Overall Width | 5/8" ID | Steel | Plated
16.00" Long | 0.999" OD | 1,531 grams | Steel | Chrome
0.836" Thick | 1.979" OD | 0.249" ID Ports | 81 grams | Aluminum | Bare
0.408" ID | Various OD and Thickness | Steel | Bare
0.882" Tall | 1.897" OD | 1.600" ID | 17 grams | PVC Pipe
Seal Cap / Guide
1.806" Tall | 1.980" OD | Wiper Seal Only | 154 grams | Aluminum | Bare
11.00" Long | 2.260" OD | 2.000" ID | 0.130" Wall | 417 grams | Aluminum | Bare
Reservoir Valve End
1.981" OD | 0.919" Thick | Brass Schrader Valve | Aluminum | Bare
Reservoir Hose End
1.985" OD | 0.947" Thick | 0.450" Bore | 3/8" NPT Thread | Aluminum | Bare
1.981" OD | 1.296" Thick | 0.210" Deep Hollow | 151 grams | Aluminum
17.0" Long | .668" OD | 0.375" ID | 3,000 PSI | Steel Braided | 3/8" Fittings| Rubber
Summary / Conclusion
While we credit Big Shocks for doing things differently and building their shocks in the US, there are simply too many flaws with their Bonzi shocks to justify anything near their $390 price tag. We understand that labor and materials are more expensive in the US and that requires cutting corners to make a profit in this price range, however, removing the stop nuts and using a system that requires a spring compressor to preload your springs and set your ride height is simply unforgivable. For about $150 less, you could keep you money in the US economy and run an F-O-A coilover that is similar in quality but functions like a traditional coilover.
The Good Stuff
The Bad Stuff
No custom valving option
Friendly customer service
Aluminum shock cylinder
Low overall weight
No stop nuts / secondary nuts
Replacement parts available
Awkward preload adjustment system
Snug slider and spring plates
Imported generic heim joint ends
Heavy duty wiper seals
No wear bands on pistons
Simple and unique design
No shaft guide bushing or o-ring seal
Very easy to service
100 PSI rated reservoir
Made in the USA
Poor tolerances on reservoir components
No bump stop
PVC pipe used for shaft spacer
Shaft spacer makes contact with piston shims
No coatings on the aluminum components
The Final Word: We find Big Shocks to be an example of what happens when someone decides to reinvent the wheel. There is a reason why most performance coilovers happen to be very similar in their design and that is because off-road racers have refined that system over many decades. We commend them for their attempt at being different but in order to make Big Shocks a contender in the performance off-road shock market they will have to first catch up to the rest of the field.