Big Wheels Q

[Gianni]

I think I will have to use a Boranni WM3-18 x 36 with Record 4647 for my 450 Shottie rear wheel, can't find it in WM2. What tire size
should I use? Will it dull the handling? Will an old plod like me even notice. What maker used that drilling as standard? Thanks
John

[Eldert]

Hi John

a WM3 should be OK . Ducati used them to on the 450 RT's and type 2 Scramblers .

the drilling code for the Borrani WM3 Ducati used was 4626 .

you might have to flip the bolts around that holds the fender and the seat . the head on the inside and the nut on the outside .

Eldert

[Gianni]

Thanks Eldert. I am going to have to go through my rims. I think that this past year of lockdown has turned my brain to mush. Soon to be free.

I used to have a Borrani application chart, but it is now lost to the ether.

I went through my rims for the 3 road singles I have.
My '74 MK3, purchased relatively intact, are complete wheels. Front is 4741 WM2-19-36, rear is 4647 WM2-18-36. I would think that the MK3D from 1971-2 would be the same, except for the front being an 18" rim. I do not have the front.

I would expect the 1974 MK3D would have the same rear as the other 2 bikes. I have the 4647/1 WM2-18-40 front.

4626 WM3 18-36? You mean on the RT? Did the Shottie use a different rear Record than the rear Blue & Gold? Weren't the rear brakes all the same- 160mm?

Looking more closely, my WM3 is a 4743 with 18-36. Might anyone know it's fitment. Does the drilling have anything more to do with distance from rim to hub flange on both sides? Is there some sort of angular component also specified in the Record No?

Here is an oddball. I have an WM2-18/36-4403/cross. I always assumed it was from an RT. I have counted about 6 times. It is 40 spoke. Too much grappa for Guido at lunch? Could use it for an off-road Yellow Disc Sport.

I guess I can get the two missing rims as Borrani WM2 re-pops, but I want to get the Record No. right for stamping and drilling.

Do I have the correct Record No. for the 3 bikes rims?

I always mess up the spelling on Borrani. My head hurts. John

[themoudie]

Aye Gianai,

Just for the record, I have a couple of MKIII 450, blue and gold, bikes; one registered in 1973 and the other in 1974. I haven't bothered to check engine/frame numbers against possible manufacturing years.

Both machines have a "Borrani WM3/2.15 - 18/36 RECORD RM-01-4626" rim fitted for the rear wheel and to my knowledge these are their original fitments.

I have run 3.50, 3.60 and 4.10 Avon Road Runner, Dunlop TT100 and Hiedenau K36 on this rim and only the 4.10 size requires the reversal of the seat retaining bolts and nuts to gain running clearance. Reducing the depth of the bolt head by half also helps. I prefer the two narrower fitment sizes and these days run the 3.50 size. Also, because of it greater diameter the 4.10 tyre can be made to rub the underside of the mudguard if you have the suspension set on the "soft" side or are carrying a passenger. With a two up total weight of 22 stones (140Kg), riding down the A68 between West Woodburn and Corbridge and aviating off the top of the crests resulted in some interesting wear patterns to the tyre tread! My wife to be and I back in the 1970's, when roads were less congested and there were no speed cameras or "traffic calming measures" on that glorious piece of tarmac from Edinburgh to Darlington.

Good health, Bill

[Gianni]

Thanks for that Bill. Now my head really hurts. A WM3 4626 as standard fitment. I don't believe that the rims on my Blue and gold have been replaced. This bike died of neglect, not in a wreck. Clock only shows about 3,000 miles. Maybe this disparity can be put down to the parts shortages
extant by 1974. Might also be due to Berliner's sense of esthetics. If Berliner didn't get what he wanted from Ducati, he wouldn't buy.

I have a couple of WM3 4626 rims. Both are half of two sets probably more suited for 750 twins, and shan't be broken. I don't need them, but some twin owner might.

Somehow I had always believed that the Borrani shod MK3 all came with WM2 front and rear, std. I think the earlier MK3 came with steel WM3. I think that I will use what I have and buy the Silver Shotgun front rim and Yellow Single Disc Sport rear rim as Borrani re-pops. Would anyone here know what width and Record No. these 2 bikes came with. (well, we all know that the Silver Shotgun front was WM2).

Thanks to any who might know. John

[double diamond]

I have a few Borrani applications that I’ve managed to collect from various sources. My record lists a 4403 as a 40 hole 19” front for a 750GT/Sport. 4626 appears as the 18” rear for this same model.

A 4743 is recorded as Laverda SFC rear disc brake hub.

Some of these Ducati applications came from the Back to Classics website so you might have a look there.

[double diamond]

Can anyone identify the application for a Borrani 4607 WM3/18/40? Very unusual dimpling pattern an drilling. Never seen anything like it.

[Eldert]

the rear drum brake beveltwin 750 GT and Sport has a WM3 4626/1 and that rims is 40 spoke holes .

Eldert

I have a few Borrani applications that I’ve managed to collect from various sources. My record lists a 4403 as a 40 hole 19” front for a 750GT/Sport. 4626 appears as the 18” rear for this same model.

A 4743 is recorded as Laverda SFC rear disc brake hub.

Some of these Ducati applications came from the Back to Classics website so you might have a look there.

[Gianni]

Whoowee! I gots an SFC wheel! Maybe I can do a swap? Any good Lav forums?

Well Eldert. I've had my '73 750 GT sitting in a corner since 1985, never noticed that /1 on the rim.
It is actually worse, I have 4 sets of 750 Borranis.

Back to classics Shows all years 1971-1974 WM2, front and rear. All rears, WM2 4647. 1971-73 front wheels, WM 4647
1974 front. WM2 4047 (should be 4647/1). Don't list Blue and Gold. Mine is 19" 4741 front, 4647 rear. A special for Berliner.

What I think I can take from this: WM2, front and rear, at least isn't wrong.

More than 1 Record No. might well pass the train spotters.

If it fits, that is all I need.

I don't know what the WM2 18" Cross wheel is from. Wouldn't the RT have a 21" rim? Rear wheel? It was marked 36 spoke, but is 40.
It would serve on a Yellow Single Disc Sport. The Super Sport used an 18" front, so this could go on all of the twins.,
if one were needy. Also, the same record number can apply to both 18" and 19" rims.

Thanks for helping me hash this out.

Any recommendations on what could be a good substitute for the rear drum? Something Japanese? I am short one. I have scramblers spares, I expect road bike spares might be hard to find. I have an extra 750 rear brake, which is large and heavy. This will be for the disc brake bike.

[double diamond]

Is your 4743 a complete wheel or just the rim?

Marnix Van der Schalk (vanderschalk.com) is the Laverda SFC expert. I expect he can verify if your rim fits an SFC.