The S-Model M551 Sheridan was moulded with a simplified wheel and track assembly, which offered better detail than
most 'quick-build' kits. However the kit still had some detail compromises. In particular, the top run of track was depicted as sagging on to the tops
of all five roadwheels, whereas on a real Sheridan the track would normally just touch the top of the middle roadwheel. OKB Grigorov has released
this 'chassis correction set' to allow modellers to replace the kit tracks, roadwheels, sprockets and idlers.
The set consists of 32 grey resin parts, and 2 photo-etched parts. The resin parts include 10 pairs of roadwheels, a pair of idler wheels and a
pair of sprockets, and 4 lengths of track. The sprocket teeth are provided as photo-etched parts. The parts are very well detailed and cleanly cast.
The roadwheels are a definite improvement over the S-Model parts. They feature curved contours on the roadwheel face, and correctly depict the
undercut rim of the wheel. The roadwheels scale out exactly to the correct 28 inches in diameter.
The idlers and sprocket parts look almost identical, but OKB Grigorov correctly represented the subtle difference in the hubs. The photo-etched
sprocket teeth seem too thin to me, and could probably be improved by gluing the metal parts to some thin card. The idlers and sprockets scale out at a
hair under the correct diameter of 14.5 inches.
The tracks nicely represent the Sheridan's T138 single pin tracks, including the unusual double row of center guide teeth. The tracks are
about 0.5 mm too wide to depict the 17.5 inch full size tracks, and the pitch is almost spot on 4.7 inches. The track castings are not completely
straight, but the warp should be fixable with careful gluing.
To this point everything sounds great - but there is a major issue with the tracks, at least in my set. The real Sheridan had 102 links per track,
for a total of 204 links per vehicle. The OKB set provides 4 runs of 42 links for a total of 168 links, meaning you'll be short about 36 links for the full
vehicle! If you measure the S Model suspension, you need about 165-166 mm of track. My set provided 4 x 69 mm lengths of track, or 138 mm per track. I
checked the set on OKB's online store, and the picture there shows only 4 lengths of track per set. The same picture showing 4 lengths was posted by
Georgi on this site back in 2014. I brought this issue to OKB Grigorov's attention in July, and have yet to receive a response. I did find a picture
of the set contents at web store Hobbyterra which shows 6 lengths, so perhaps the issue has been corrected in more recent packages.
Note that OKB Grigorov set S72105 provides the same wheel parts, with the only difference being that the tracks are described as damaged -
i.e. each link has two cavities where the rubber track pads would normally fit. While rubber pads certainly did fall off in service, it is unlikely
that every track link would lose both rubber pads, unless the tank was completely burned out. Heavy use on the tracks might wear the track pads flush
with the surrounding metal. Interestingly, the 1/35 Academy M551 was also moulded with no track pads, and was heavily criticized for this (along with
many other issues, sadly almost all of which were passed on to the S-Model kit).
To be somewhat pedantic, this set is described as a chassis correction set. It certainly improves the wheels and tracks (at least 83% of the
track!), however it does not 'correct' all the flaws of the S-Model lower hull, such as not depicting the offset between the left and right side roadwheels,
an incorrectly located drive sprocket, incorrect lower hull angles, etc. However correcting all of these would have likely required a complete resin kit.
I would caution anyone who has purchased this set to examine the contents carefully, and contact OKB Grigorov if there are only 4 lengths of track
in the set. Based on the contents of my review sample, I cannot recommend this set.
Preview sample courtesy of OKB Grigorov via Paul Giles.
OKB Grigorov products are available at