TOPIC:

What we know (collectively) about "mk.1" and "mk.2" Special Racing Buggy (SRB) chassis differences (corrections / additions encouraged):


"Mk.1" and "mk.2" is just shorthand - Tamiya didn't simply switch from producing kits with all "mk.1" features to kits with all "mk.2" features, unlike the SWB/LWB Wild Willys with al lot of the versioned parts not being interchangeable (and even they didn't have a firm switchover of all parts), with the possbile exception of mk.1 super gear covers and the right hand gearcase, both generations of SRB parts are compatible with each other. All you can really say is that the more "mk.1" features a chassis has, the earlier the kit was in the production run, and the fewer it has, the later it was in the run. "Early" or "late" would be just as valid.

Just how many features you have to have before a chassis/car can be called a "mk.1" or "mk.2" is also open to debate - for the sake of discussion I'd say that you'd have to have all of them to be a described as such, but for a few less "mk.1 but with ..." , a few less than that & "transitional" might be better", a few less still & "mk.2 but with ...". "Very late" applies to some Sand Scorchers (see later).

This doesn't refer to the re-releases (though there are lots of changes on them too).




Rough Rider body: apparently the earliest have "BUGGY" misspelled as "BUGY" on the underside, on later ones it's corrected;

Front arms: "mk.1" arms are thinner around the middle & more prone to bending, "mk.2" arms are fatter;

front shock tower spring stops: "mk.1" has M2 screws (with cast in addtions on the back side for the threads),mk.2 towers have pegs moulded on the front and flat back;

mk.1 bumper is black (some with the "BUGY" misspelling), mk.2 are grey/beige;

Sand Scorcher front boy body extension: body clip location is a circumferential groove on mk.1, replaced by a hole on "mk.2"s;

mechanism box - very pale (aging to yellow) on mk.1, darker (slightly smoke tinted) aging to brown(er) on mk.2;

rear arms - mk.1 has a wide hole on the inside the same size as a 1150 bearing (whether it's meant to have an extra bearing in there is open to debate), mk.2 has a more solid back;

gearbox casings: at the rear, the rear cage lower mount point is two thick "brackets" on the mk.1, the mk.2 has this space closed off. At the front, the mk.1 has spurious round lugs at the sides of where the rear well nut fits, on the mk.2 there are extractor pin marks (a slightly rasied small round circle) & a slightyl ragged section on the edge above, suggesting the pour path/method was modified.

Apparently the right hand side clear plastic gearbox cover comes in "short" and "long" versions, which shows itself as the pinion appearing off centre (and one of the screw holes not lining up) if a "mk.1" cover is fitted to a mk.2 RHS gear case ... this also implies there are further differences to the RHS gear case (and different problems is a mk.2 cover is fitted to a mk.1 case). The Super Champ (and possibly last of the line Sand Scorcher) spur gear cover is as the "long/mk.2" cover, but has a small hole near the pinion;

Universal joints: these are brass on all Rough Riders and Rangers AFAIK, but the very lastest Sand Scorchers had the green/back hardened UJs from the Super Champ.

FRP chassis plate: earliest mk.1 is regarded as having a "short" front end (looks exactly like someone has taken a millimeter or two off the mk.2 FRP plate), and the servo saver M4 mounting screw holes is also slightly further forward compared to the mk.2;

Servo saver: apparently the front spring retaining loop is flush with base edge on mk.1s, but slightly reccess on mk.2s. (I guess I've never seen a mk.2 version?);

M2 screws: almost all SRBs have a slotted head M2 machine screws, but some of the very last Sand Scorchers have cross head screws;

Rod ends: plastic with separate brass ball joint on all SRBs except the Super Champ (and some of the very last Sand Scorchers) which had hardened steel outer with a captive ball;

Ranger F-150 XLT differences (in addtion to the above): earliest trucks are "short front wheel arch" with approx. 20mm (TBC) forward of the front edge of the door shut line (and decals to match) at the lower rear point on each arch, on mk.2/long wheel arch bodies the arch to door shut line dimesion is much shorter (say 10mm - TBC). Additionaly, there are anecdotes that the front wheels were also changed to have more offset on "mk.2" Rangers - however what I've seen tends to suggest that all Ranger front wheels have the extra offset - but it's only a very small amount (3mm) and only compared to the later Brat and Pajero wheely.

Excellent summary, Jonny! I expect this to turn into an article at some point

A couple of points from me:

• I have not heard of the body having the misspelled "BUGY", only the bumper.
• The gearboxes also have some "layout" changes on the outside, probably reinforcements of the bearing recesses.
• If I recall, there are also some changes where the rear roll bar attaches to the gearbox.
• The LHS plastic motor cover has two different layouts. Different placing of one screw hole, (again if I recall correctly...)
• The Super Champ has different dia hole for the rear A-arm suspension pins (thicker pins) (SC specific though)
• Never seen a Scorcher supplied with "Super Champ" universal joints
• Never see a Scorcher with Super Champ steering rods/rod ends.

Jonny, I saw several topics on srb here. And I have a big matter with your last post. What can I do to have coherent chassis? I bought a spares lot. And I built 1 superchamp and 1 sand scorcher/ranger. Could you say me if I need to rebuild them? I would like to have 1 or 2 really coherent srb. Not a job lot rebuilt.

Distribution of "mk.1" vs "mk.2" (early/late):


Rough Rider: c. 45% can be considered "mk.1", c. 55% "mk.2";

Sand Scorcher: c. 24% mk.1, c.74% "mk.2", and less than 2% "very late";

F-150 Ranger XLT: c. 30% "mk.1" and c70% "mk.2" (going by the body - though apparently the body was one of the first things changed as looking at just the chassis in isolation the ration is 36/64).



This is just from observation of eBay sales over the last 4 years so although there are some issues (not a huge sample size, and is it even representative of the numbers sold?) it's what we've got ...
If someone wants to go through every single SRB gallery entry on TC & tally the results I'd be quite happy to compare them






As a footnote, the proportions of cars sold on the SRB platform (from the same sample set) was:

Rough Rider 22%
Sand Scorcher 44%
F-150 Ranger XLT 21%
Super Champ 13%

Very informative JR
Has put me right off getting involved with SRB,s , so many connotations and so many mistakes to be made

I would caution against using both ebay and TC (except NIBs) info as info source on definitive judgement on Mk.1 Mk.2 discussions. Anything built must be looked at with caution in my mind. Back in the days, noone cared about "authenticity" and spare parts were usually Mk.2 productions, so Mk.1s were diluted with Mk.2 parts during their use.

The most trustworthy source would be the NIBs on TC (and elsewhere), but keep in mind that even internals of NIBs is known to be swiched/traded in the aftermarket to make up a complete NIB.

I fully support the theroy that Tamiya swapped out parts during the production run, that is the sensible way of doing it for a company, but you can never trust that the built models we see today actually was in that configuration when they were NIB.

larbut wrote:

Excellent summary, Jonny! I expect this to turn into an article at some point

A couple of points from me:

• I have not heard of the body having the misspelled "BUGY", only the bumper.
• The gearboxes also have some "layout" changes on the outside, probably reinforcements of the bearing recesses.
• If I recall, there are also some changes where the rear roll bar attaches to the gearbox.
• The LHS plastic motor cover has two different layouts. Different placing of one screw hole, (again if I recall correctly...)
• The Super Champ has different dia hole for the rear A-arm suspension pins (thicker pins) (SC specific though)
• Never seen a Scorcher supplied with "Super Champ" universal joints
• Never see a Scorcher with Super Champ steering rods/rod ends.

- I did see photgraphic proof of it somewhere;
- very possibly, I (or someone else) needs to make some proper comparison photos
- ditto
- ditto
- I should have remembered that, having moaned about the bodging someone did in that regard to my Super Champ;
- it's not just me, mine could possibly have been discounted as a upgrade/repair, but someone on TC (can't find source to cite) was credible with their information about long term ownership & "very late" Scorcher parts;
- again, could be just me - but IF you accept that Super Champ spur gear covers and UJs appeared in some Scorcher kits, this is not so much of a leap?

stingray-63 wrote:

Jonny, I saw several topics on srb here. And I have a big matter with your last post. What can I do to have coherent chassis? I bought a spares lot. And I built 1 superchamp and 1 sand scorcher/ranger. Could you say me if I need to rebuild them? I would like to have 1 or 2 really coherent srb. Not a job lot rebuilt.

Don't panic - this is not new information & if you were happy with your cars before reading that post, you should still be happy after reading it

Lar's view on the "mk.1/mk.2" debate are quite clear (it doesn't really matter that much), I believe in it a lot more than he does - but even so I would like to think I'm pragmatic about it, for example I would say that on somewhat more than the balance of probabilities, you are unliikely to see skinny front arms, front uprights with screw spring stops and "early" gearbox halves on a Super Champ, for example, but on any of the first 3 SRBs, either would be "correct".

Post some pics of those 2 cars & we can compare

goldfish999 wrote:

Very informative JR
Has put me right off getting involved with SRB,s , so many connotations and so many mistakes to be made

That really wasn't the point of this ... but there is quite a lot to unpack, especially as the re-release changes really ought to be considered too. I don't think I'm really the one to this TBH - I don't have a full perm of SRBs, or any re-re cars - even if I do have some re-re parts...

I think the main thing when buying is to read up on what you're interested in, so as not to get sucked into what's sold as "rare", and not to get suckered into re-release passed off as vintage - for instance, is that "rare, original black bumper version" Rough Rider as stated, or does it have re-release front tyres, re-release bumper & radio box? Is a Super Champ made up from a mix of parts, some earlier? Dies a Sand Scorcher have a re-release body? The more you pay, the more a car ought to be "correct" - or at lease plausible.

larbut wrote:

I would caution against using both ebay and TC (except NIBs) info as info source on definitive judgement on Mk.1 Mk.2 discussions. Anything built must be looked at with caution in my mind. Back in the days, noone cared about "authenticity" and spare parts were usually Mk.2 productions, so Mk.1s were diluted with Mk.2 parts during their use.

The most trustworthy source would be the NIBs on TC (and elsewhere), but keep in mind that even internals of NIBs is known to be swiched/traded in the aftermarket to make up a complete NIB.

I fully support the theroy that Tamiya swapped out parts during the production run, that is the sensible way of doing it for a company, but you can never trust that the built models we see today actually was in that configuration when they were NIB.

I think I put if enough caveats in there, but you do bring up an interesting point re their interpretation ... I saw the Sand Scorcher figures as different to the Rough Rider due to the Scorcher being released later, and being interesting to buyers for much longer - but you could equally hypothesise that the Scorcher was crashed more - and wonder if it was due to a different buyer profile, or was due to body charactaristics