Disc brake front hub question please

[graeme]

I am trying to build a front wheel for a ‘74 type front disc yellow bike.
I have two 4647 WM 2 18 inch x 40 spoke Borrani rims as was on yellow disc bikes front.
I bought a new hub from Italy as per SS twins as I thought the hubs were the same as SS ?
It seems that is not correct as the spokes don’t line up with the rim.
It’s like the spoke holes in the hub are drilled arse about?
The new hub is the type that can accept 4 or 6 bolt disc mount.

Any thoughts ?

I checked my yellow bikes front wheel lacing and laced this new hub and original rim the same but the last side of spokes don’t match the rim.
The last side of inner spokes do not line up with the rim drilling’s.
Doesn’t matter how I start I still get the same result.
More red wine didn’t help....

Graeme

[Duccout]

Hi Graeme,

Old Racing Spare Parts in Italy list the same hub as correct for the Singles and the Twins, so in theory the hub must be correct. Is it possible that the hub drillings are at a different angle to the original rims ? Maybe you will have to have a rim drilled to match the hub? In short, I dunno!

[Duccout]

You may have a problem: the 750 part no is 0795. 77. 150, but the Singles hub is 0797. 77. 153.

[Eldert]

Hi Graeme

are you sure you have the correct rim ?

4647 is a rim for a drumbrake . the rim for a discbrake single is a 4647/1

Eldert

[Ducadini]

Always assumed the singles and twins hub was the same
Pretty sure in one of my wheels there's a single part.
Never noticed it.

ciao
ducadini

[blethermaskite]

Hi Graham, here are a couple of photo's of my 250 desmo front wheel rim and spoke pattern, I suspect you have the wrong rim?
Cheers,
George

[Eldert]

Always assumed the singles and twins hub was the same
Pretty sure in one of my wheels there's a single part.
Never noticed it.

ciao
ducadini

Hello Jozef

a twin 18 inch Borrani is the 4777 . a 19 inch twin Borrani has a 4403 drillingcode

Eldert

[graeme]

Last first,,,
George, thank you for taking time to post pictures of your 250 wheel. You were correct, wrong rim.

Ducadini, the hub does fit the single front rim, but not the rim I tried yesterday.

Eldert, you are correct, 4647/1 does fit the hub I bought. 4647 is also the number on the rear 36 spoke drum on yellow bike.

Duccout, thank you for supplying the part numbers.

I have 2 Borrani WM2 x 18 inch x 40 spoke rims. (3 if I count the one on my '74 450)
The one I polished is stamped Borrani WM 2 18 Record RM01 46. This I wrongly assumed was the correct rim but was not completely stamped for some reason. It also has a "Made in Italy" sticker inside the rim. It seems to never have had a tyre fitted.
This rim laced correctly inner and outer spokes on one side and outer spokes on the other side. But the inner on this side don't line up with the rim drillings.

The other rim I thought to save as a spare for my '74 yellow bike as it is fully numbered correctly.
Now I will polish it and use it with the new hub. I did temporarily lace it and all is good.

The Moral,,,,, don't trust unknown parts.

Thank you all,
Regards
Graeme

[Duccout]

Think how boring life would be if everything went perfectly!

[graeme]

Ha, too true