SFC replica hubs in aluminum

That's something I can agree on Ron, but they need a wider swingarm as well.And then you get into chain run.
 
Big mistake by Breganzie we needed that 4" wide rear rim.

I would say the swing arm and chain location could handle a 4" rear rim mounting a 130 that plants good.

Sad that the 120 Phantom died - It was perfect for our bikes.
 
Laverda SF said:
The SF, SFC and 73 Jota's had 3.5" wide 18" Borrani WWM rims with Breganzie BREV Drum Hub's - Period.

Granted I always wanted a wider rear rim to trustfully mount a 130x80 18 - 120's were best but you get them any more.
110's work on the front.

Look at my 750 SF0 Avatar - That's an old 120x80 18" rayon radial Phantom - As if they still made them ;o)

Closet you can get is a Bias 130 Bridstone BT 45 and then you need balls to roll the bike over.

Suggest you keep tier size down to 110 on the rear and 100 on the front to feel comfortable.

We working with a 3.5"x18" rear wheel.

Borrani didn't make a 4" rear rim to mount tires of our choice wide enough that didn't interfere with the chain or swing arm.
Click to expand...

The widest rim that the factory originally offered was a 2.50-18" in cast alloy, for both the twins and triples, from the 750 SF3/1000 3CL to the RGS... period! :D

This was for rear fitment only, the fronts remained at 2.15-18".  Stock wire spoked rims were WM3/2.15-18", front and rear, the only difference being the angle of the spoke drillings.  These were normal, almost universal, sizes, used by the majority of the motorcycle industry at the time.  It took until the mid-80s for wheel rim sizes to dramatically increase, keeping up with tyre technology that was advancing in leaps and bounds!  Many jap road bikes were still on 1.85-19" front rims at the beginning of that decade, 18" gradually taking over, followed by a short disastrous intermezzo dabbling in 16", 3.50-17" front and 5.00-17" (and more!) rear becoming the norm by the mid 90s.

The 1985 (750s long-forgotten by then...) SFC1000 originally got 2.50-18" front and a 3.00-18" Oscam cast wheels, this was changed to 2.50"/3.50" wire spoked wheels for the final "Classic" batch. 

Fitting a 120/90 tyre to the stock 2.15" wire wheels is, imho, a total waste of time and money, only about 1/3 of the available tread can be effectively used, not to mention what a bitch these are to fit and remove!  The cast 2.50" rears only just cater for the 120/90 or 120/80, still a royal pita to fit and remove.  Anything larger, again, a waste of time and money.  Yes, I am aware that the factory specified a 130/80 for the rear of the RGS, but a quick glance at a worn example will show that only a fraction of the tread is actually used.  I suspect the size was specified more for street cred than anything else.  The 130/80 fits and works fine on a 3.50" rim, as does a 140/70, both do not interfere with the run of either a stock #530 or #630 chain.  A 4.00" rim makes even better use of modern multi-compound tyres such as the Bridgestone BTs, the softer side portions can be used to full advantage at full lean, giving a large, re-assuring contact patch.  Chain run can be a bit close with a 140/70 / #630, using a #530 or #520 gives enough space for up to a 160/70 tyre.  The RGS swingarm will take up to 160 width, the 180 triple swingers get a bit cramped by then.  Easy to swap it for a 750 swingarm, RH axle mount requires a little altering to omit the hollow axle used with drum brakes (Rear-disc 750s used the triple swinger). 

I'm quite certain that load indices are not an issue, I don't see a Lav getting anywhere close to the 300-350kg load per tyre stated for the smaller sizes.

Don't need no balls to lean over a RGS till it scrapes on a 130/3.50" combo Ron, a lot more re-assuring and safer than a 750 running on 110/100 road tyres at full lean! :D

Thank heavens the Phantom disappeared, marginal in the dry, lethal when wet.  Todays worst tyres are probably head and shoulders above what the old Pirellis had to offer.

piet
 
I have just replaced my rear tyre on TOG with a like for like (still got plenty life left in the front) Avon Roadrider in 120x90x18.

I have been very happy on this pairing (front is same type in 100x90x18) and have gone again in same format, no difficulty in obtaining the 120 rear (Ron?)

Next time it will be for a pair and I might change if supplies of Roadriders dry up, never have used Bridgstone
Battle axe and might do so, but I have a feeling they are already starting to be superseded, by another make?

CLEM
 
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