Original-looking tires

[Steve Swan]

Steve, your Norton Commando is superb and the TT100 tire him doing very well... Super Look!!

Thanks, very kind !

[markb]

So I went home last night still thinking about tires and decided to check what I have.  Two big surprises.  I first checked what was on the early diecast.  Bridgestone AC03 on the front and AC04 on the rear.  What the…I thought the 04 was too “thick”.  I checked the clearance to the chain guard and it is close but there is clearance.  I put these on over six years ago and before getting into the sandcasts so I’m not sure what I was thinking when I chose them.  However, looking at the AC04 it is too wide to look “correct”.

Second surprise.  I’ve got rolling frame 1990.  I checked the tires on it and unfortunately there is a 16” wheel and tire on the rear.  But I was shocked at what I found on the front.  I couldn’t find the name Bridgestone on it but it does have the letters BS.  Here’s a look at the tread.


Here’s the size.  That’s correct.


And the model is a SUPER SPEED 21.  Anyone ever hear of it?


So is this a correct, vintage tire?  I think it would clean up pretty good.  I think the pictures actually make it look worse than it is.  Realistically what are the chances of finding a vintage rear tire?  It makes sense that there would be more fronts around because they didn’t’ wear out as fast.  Does anyone on the board have one they would sell me?

Another thought, Steve would you be interested in selling your 02?

[Steve Swan]

Mark, that BS tire looks like the right correct original one.  Let me take a look at the K1 in my shop, it's a super clean, 6k mileage. with original front.  I'll see what it say on it.

Sorry, I'm using these Accolades on 2157, as the Dunlops are about gone.

These rear Accolades have to still be out there, new and in good used condition, at salvage yards, i have seen used ones on ebay.

[markb]

I've done some research and it appears that the BS Super Speed 21's are correct tires.  (I think there is an early Dunlop too that could be correct).  Checking around I actually have a couple of leads on some sets of used ones.  One of the guys says he has three or four sets but I haven't seen them or even pictures yet.  But here's the crazy part.  He says why don't I just buy new ones.  He claims that new ones can still be bought in Japan for about $400 each.  The problem is that can't be ordered and shipped.  They would have to be purchased by someone (living?) in Japan and they would have to ship them (legal?).  Can anyone here confirm this?  If so is there anyone on the board in Japan that could buy me a set and ship them?  Unless one of these used sets is super nice I would be tempted to buy them.

[markb]

Some additional info:

The 69.4 parts manual specifically calls out a K87 Dunlop for the rear.  I don't know if it had the same tread as the K-87's currently available.

I found a reference that said the Dunlops used on the early CB-750's were an F-6 on the front and a K-87 Mark II on the rear.
The same source says the Bridgestones were a Super Speed 21F2 on the front and a Super Speed 21R2 on the rear.

[Steve Swan]

Ah !    i see that..... now!    BS or Dunlop.  helps to thoroughly read literature.  now if i could just remember what i read.... 

[CBman]

markb: I have info the first bikes had Dunlop F3, later sandcasts had F6.

[markb]

So are you saying only Dunlops on the early bikes?  I'm assuming the F-3 and F-6 were front tires?

[Erling]

My front wheel stands with original tyre on.
Dunlop Gold Seal G-233.
Made in Japan.
Frame Vin 1676.
     Erling.

[markb]

The plot thickens.  I kinda remember Gold Seals back in the day.  So it sounds like there were probably several options for stock tires.  Can anyone say for certain that both Bridgestones and Dunlops were fitted to sandcasts?  Does anyone have photos of some of these tires?  I'd like to know if the treads of both brands were similar.  After seeing pics of the BS Super Speeds they sure match what I remember they looked like.  Here's a pic of the rear.

[Steve Swan]

As soon as i get a chance, i will look through my library of magazines and brochures and see if there are any good pictures of tires.  will get back in next week, no more than 2.

[Sam]

Mark,

Not sure if this will help, but my 10/70 K1 has the original tires on it. Dunlop Gold Seal K87 on the back and Gold Seal F6 on the front.

I compared them with the K87/F11 combo that Yamiya sells (which I put on both of my Sandcasts). Very very close. The F11 is a bit less "stripy" if you will than the F6. Otherwise, they are great. In my opinion, the K87/F11 combo is worthy of your superb bike.

[markb]

It all helps.  I've learned a lot in the last couple weeks about these old tires.  I'm still trying to track down a (better than) decent set of BS Super Speeds.  If all else fails I'll do the Dunlop K87/F11 option with no reservations.

[Steve Swan]

if we don't already, it would be nice to have pictures of all 4 these tires.  tread design and nomenclature on sidewall.

[DW69K0]

On our site is a late pre-production picture of a Bridgestone Superspeed tire, so Honda have to equip Sandcasts with both Bridgestone and Dunlop tires.
Best,
DW

http://cb750sandcastonly.com//images/latepreproduction02.jpg