B31 (1951) front brake woes.

[Beeza jon]

I've got one of those head scratching problems. I recently removed the front wheel of my tele rigid B31 for fitment of a new tyre. All ok. However, upon refit, the tyre now fouls on the off side main stay (fork brace) regardless of what I try. The tyre is the same size and make as previously fitted. I have not lost any spacers and have consulted in detail the parts book, but cannot find anything amiss. The only clearance I can create is by not fully tightening the front wheel spindle, however this surely can't be any good.
So gentlemen, suggestions and thoughts much appreciated.

[limeyrob]

Is this the 7" brake with the locating peg?  If so how is the peg sitting in the fork leg?

[V500]

if it's the 7" front brake have you located the circular properly in the fork leg locating lug? If it's the 8" have you pushed the wheel locating sleeve fully into the nearside fork leg?

[Beeza jon]

It's the 7" unit. As far as I can see it's locating ok in the fork leg.
Does the nut which secures the brake unit onto the tubular "sub axle" shaft need to be in any way tight? If I leave it comparatively loose, the problem of fouling appears to be less of an issue.

[limeyrob]

Yes it needs to be tight. It pulls the brake plate up and also holds the inner race  of thee bearing.  Tighten it then look for what else is wrong.

[Beeza jon]

Thanks for that. I rather thought that it did.
Currently in the shed, and will report further soon.

[Beeza jon]

Ah ha. Well gentlemen. It appears that I am entirely to blame for my own woes.
I have just double checked my tyre sizes.....
Previous fitment,  3.00 x19.....
New tyre.......3.25 x19. I'm sure that we all know and recognise what has occurred. I feel like a proper fool.
However.....would anyone care to buy an unused 3.25x19  Metzler block C ?
(Available soon...ish) ...

[V500]

I probably would. DM me when it's ready...but no hurry.

[Pete C]

3.25 x 19 should not be a problem, this is what I have on my B31.

[limeyrob]

Yes I would expect a 3.25 to be OK but perhaps because its an early bike the yoke spacing is less?  Or maybe the Metzler  is just that bit wider.  In period it would have been a Avon ribbed (since the front only steered, no braking forces) : ) and those ribbed tyres were close to a circle in cross section so they were narrow.

[neil1964]

Is your rim off centre in the forks?

I would expect 3.25 to fit easily.

[Derek996]

The owner's handbook for the 1946-55 B31 specifies 3.25 x 19 tyres front and rear, so something's not right. As Neil suggests, is the wheel central in the forks? Has the wheel been rebuilt at sometime with the wrong offset?

[scifi]

Are the Spokes and Nipples many years beyond being adjustable. .?   The tyre should be central for any size of tyre.

[Janacek]

325 19 should be right.Has the wheel been rebuilt? It could have been rebuilt with an (inadvertant) offset.

[Beeza jon]

Thankyou all for your replies.
As recieved, both wheels (and tyres) had been on the bike since at least the 1990s. The overall condition of both wheels strongly suggests that they are almost certainly as they came from the factory, in as much that the rims, hubs and spokes all carry a concurrent patina. The tyres had a 1996 production date. The rear was 3.25 and the front was 3.00. This appeared to have worked, and had presented no obvious problem.
The replacement rear tyre has gone on and in very well, but it appears that the new front (3.25) clearly catches on the O/S of the fork main brace when the axle is correctly tightened. I am fairly certain that it can only be the larger width which has presented the problem, but will endeavour to examine the issue of possible wheel off set.
I hope to have further news soon, but a full time job rather gets in the way. Thanks again chaps.