2 Sperry Rand Tricubs - restoration project thread

Mini Bike & Go-Kart Parts

Frames and small parts back from powdercoat.

I don't have a lot of stuff ready to reinstall yet, so I can't dive right in on assembly. I have collected many of the small parts... bearings, hardware, etc, and new custom brake cables are on the way. I have some parts that will go to zinc plater next week, along with the chrome handlebars ($gulp$). I still need to rebuild diffs, clean axles and jack shafts, clean wheel hubs, dismount front tires and powdercoat wheels. Also I need to re-convince myself that I've made the correct decision on replacement rear wheels and tires. More on rear wheels/tires in a future post.
In the lull here while I'm waiting for some stuff to arrive to begin reassembly of the twins, I thought that I'd discuss the rear tires used on these trikes.

First, the history lesson...
The early Tricub production had only one-piece balloon rear tires installed. These are tires molded directly to small diameter rims with tiny 3x2 bolt pattern. As far as I can tell, the early Tricubs were 5hp (model 35) only. These one-piece tires can also be found on vintage 6x6 amphibious ATVs and Honda ATCs. Various versions show up on eBay once in a while for big bucks, if they're useable. However all of these are larger diameter than the ones used on Tricubs and, in fact, I have never seen any proper-sized, one-piece tires as used on Tricubs for sale in any condition, at any price. My 2 5hp cubs both came with this these original balloons installed. The 1st unit's tires showed multiple plugs, patches, oozing green slime and some rot... not holding air, so replacement, conventional tires/rims were ultimately required. The 2nd 5hp unit (the survivor) also still has the balloon tires, but these are still very nice shape, holding air and no evidence of plugs or rot. Due to the rarity, I use this set only when displaying the unit and install alternate tires/rims for recreational activity.
Original 5hp balloons

At some point later in production, the 8hp units were launched (models 38 and 38E). My 2 38Es are the topic of this thread. I do not have any evidence other than my observations over years, but it seems that concurrent with the 8hp launch, the balloon tires were dropped for conventional tires and rims on all subsequent production of 5hp and 8hp units. The only original, later version tires that I have ever seen have been Carlisle 21x12-8 ATV mounted on 8x9 rims. These tires had a shallow, chevron tread pattern that mimicked the balloons.
Original Carlisle 21x12-8

Now the dilemma...
Up until recently (maybe 3 years ago), Carlisle AT 21x11-8s were still available and nearly identical to the original tires. I had been planning on using these for these restoration projects until I discovered that they're no longer produced and I haven't found any source for affordable old stock. Carlisle now produces the AT101 in 21x11-8 size which are similar, but chevron tread is more aggressive... more like an ag-type tread. There are many similar sized ATV tires available with knobby or modern hybrid treads, but I really want to try and maintain the vintage original look as close as possible.
Discontinued Carlisle AT 21x11-8

The unit A of this thread came with original tires and wheels. The tires were obviously shot but I had planned to use the rims. Sadly, I later discovered that the rims were also unusable due to rust-thru in a few places along the bead... too much damage to consider trying welding or any other restorative process. Anyway, the closest rims that I could find are 8x7 trailer rims with correct centered dish and the correct 4x4 bolt pattern. Unit B had some kind of trailer tires and rims installed when I got it, so I knew that I was going to replace these from the start.

At this point, I have the 1st set of the AT101s installed on the 8x7 rims and it looks ok except that due to the narrower rims, the tires end up with a rounder profile than I would like. Unless I can find some other combination that is a lot closer to the original package, I'm going with this combination.
Current Carlisle AT101 21x11-8
Some parts are starting to filter in that were at outside services… front wheels have been powder-coated in proper argent silver, brake and clutch parts zinc plated and aluminum rear hubs media blasted. I’m not quite ready to do much reassembly on these rolling frames yet, but shouldn’t be much longer. The handlebars are still at chrome plater… probably another 3-4 weeks out on those. I still need to rebuild the diffs and some gears are not in great shape.

Subscribed! Awesome work! So glad I found this thread and this forum in general. I'm going to be slowly restoring my Tricub 35 (1972 or 73) starting with the original engine. I think I've seen your posts over on 6x6 World or Three Wheeler World too. It may have even been you who emailed me an owner's manual several years ago.
Subscribed! Awesome work! So glad I found this thread and this forum in general. I'm going to be slowly restoring my Tricub 35 (1972 or 73) starting with the original engine. I think I've seen your posts over on 6x6 World or Three Wheeler World too. It may have even been you who emailed me an owner's manual several years ago.
Welcome to the fun, nez. Keep us posted on your project.

I'm currently in one of those lulls that happen too often during these projects. I have still been active collecting some missing parts. I just found original type air cleaner and intake for the unit A replacement engine. It's amazing how many different intakes were used on these Briggs and of course, the one I needed is the most uncommon. I'm glad that I have the original unit B engine to use as a model. I am pretty much ready to make these frames into rollers. I plan to work on the engines over the winter months and hopefully on to the bodywork in spring. Hey, I never said that this was going to be a quick project.
I'll start a build thread of my own once I really get started.

If you don't mind, I need a little assistance if you have your trikes nearby.

What is the outside diameter of the Comet brake drum? I'm guessing it's 3.75" since that is the smallest brake band I can find. Just trying to avoid taking the jackshaft apart at this present time in order to get the brake off to measure it.

Also I couldn't tell in your pics, how is the return spring for the brakes set up? Mine is missing the spring (probably why the brake has never quite functioned right). In the manual, it looks like this:


The spring is apparently part of Brake Cable Assembly 540441 but surely I can rig something up once I see how it looks on an original machine.

I know what you mean about the lull in the project - I plan to work on my engine build over the winter and I "might" start on the body work in the spring. Or maybe not, depending on how many more mechanical issues crop up. It definitely needs a new front tire (huge crack in sidewall) and front wheel bearings. Of course that original tire is no longer produced, and all I can seem to find in a 15x6-6 are lawnmower type turf saver tires.
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Nez... The brake drum outside diameter measures 3-11/16", so it is probably referenced as 3¾" drum for replacement band. The return spring is a common compression spring that is installed over the cable between the band and the adjuster end of the cable housing. Looking at my Minicub, it is ~3/8" diameter x ~2½" long, installed... so probably about 3" long relaxed. I'm sure that something suitable can be found at a local hardware store. The Carlisle 15x6-6 turf savers are about as close as you can get to original front today and are really not a bad substitute. The wheel bearings and seals are pretty common items at most any industrial supply house. The bearing p/ns shown in the Tricub parts list are still active New Holland p/ns.
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Thank you!

Great to know the bearings are still available through New Holland.

I spent about 2 hours last night taking the front wheel off and removing the bearings/races. As expected, the bearings were completely trashed (came out in pieces). They were really nice American made Timken bearings, so hopefully the replacements are of comparable quality.
The bearings are fairly common and NH parts counter probably isn't the most economical source... just pointing out that a few items are still in the NH system. However, nothing is available that is specifically unique to these trikes. Your bearings probably haven't been lubed since new. They were protected with nice seals, but there's no way to properly add grease to the bearings without taking the wheel apart. The seals are only an attempt to keep dirt out. Be sure to completely pack those bearings during assembly. The NH p/n for the seals is not active, but I do have a good cross-ref.
I got 2 bearings at the New Holland dealer today (they had 12 of them in stock) and a compression spring that looks like it will work for the brake. They are still American made Timken bearings so I'm happy with that. Spring was made in USA too.

Didn't see your post about the seals until it was too late. Mine actually had a National brand part number stamped on them so I had my local NAPA look them up since the NH dealer didn't have them. It looks like they are just seals for trailer wheel bearings. As soon as I pick them up tomorrow I will share the part number with the forum.

The only thing I need now, are the parts called "Spacer" that go between the forks and the bearings. Mine are pretty well worn and I'd like to replace them. I went to 5 places today but nobody could match anything up. If I can't find a suitable replacement online somewhere, I may have a machinist make them for me. Unless you have a source for those too!
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I don't know if the spacers can be matched with any std, off-shelf part or not. Mine measure 1.125 OD x .754 ID x .53 long. McMaster-Carr has tube stock with proper OD/ID that these could be cut from... 1 foot length is about $13 + ship.
Believe it or not, there has been some slow progress on these engines. Just now staring reassembly of the Unit A transplant engine and the unit B original engine remains assembled as a model for all the unique matching trim parts.

Just some of the collection of NOS B&S items that I’ve collected for this project.

The Unit A engine with valves, crank and cam installed.