More spokes questions: 1930s 32h tandem front wheel

[RobC]

Along with all my other projects I'm currently restoring my grandparents' 1930s Grubb tandem.

The rear wheel is fine: chrome and hub in good condition and 40 extremely thick galvanised spokes.

But I've dismantled the front wheel because the rim and spokes were in a very poor & corroded state. Spent last night stripping and regreasing the hub with new bearings and it's nice and smooth. There was a bit of wear in the cups but not bad for 80+ years.

Interestingly the rear rim is 590 (1 3/8" tyre) and the front is 597 (1 1/4" tyre) - was this 'the thing' to have a thicker tyre back in the day due to the heavy load at the rear of a tandem..?

Anyway what spokes would be recommended for the rebuild of the front? I'm thinking of replacing the rusty 597 front rim with a 590 rim for F/R consistency's sake, and due to the now very limited choice of tyres in 597 size.

Many thanks as ever

[Brucey]

it really depends on how the hub is drilled, if it is a hub brake or a rim brake, and if you are concerned about matching the rear rim or not.

BTW in terms of tyre availability there is something to be said for using a 584 (650B) rim instead, but this might not be suitable for other reasons.

For spokes I would suggest 13G PG would be about right, but 13G/14G might be OK with a stiff rim. In any event you have to be able to fit the spokes into both the rim and the hub.

cheers

[Gattonero]

Along with all my other projects I'm currently restoring my grandparents' 1930s Grubb tandem.

The rear wheel is fine: chrome and hub in good condition and 40 extremely thick galvanised spokes.

But I've dismantled the front wheel because the rim and spokes were in a very poor & corroded state. Spent last night stripping and regreasing the hub with new bearings and it's nice and smooth. There was a bit of wear in the cups but not bad for 80+ years.

Interestingly the rear rim is 590 (1 3/8" tyre) and the front is 597 (1 1/4" tyre) - was this 'the thing' to have a thicker tyre back in the day due to the heavy load at the rear of a tandem..?

Anyway what spokes would be recommended for the rebuild of the front? I'm thinking of replacing the rusty 597 front rim with a 590 rim for F/R consistency's sake, and due to the now very limited choice of tyres in 597 size.

Many thanks as ever

You may want to have a look at importers/distributors of Dutch bikes to source out a steel rim and 13g spokes as they are often used in their kids/utility bikes. Most of them have good prices too. Make sure the hub can take 13g spokes, or has enough material in the flanges

[RobC]

So I managed to find a nice Dunlop 590 rim in good condition from roughly the right era, and have now laced up the wheel with DT Alpine III spokes. Initially I put washers on the spokes, but they would not get snug with the head due to the flange upto the head (is flange the right term here?!) meaning that the spokes were somewhat inflexible.

Therefore I relaced without washers. I haven't tensioned or trued the wheel yet.

Pics below - do you think this is acceptable or do I really need to use washers - and if so does it matter that the spokes will need to be forced that bit more into position during lacing? Thanks

[Brucey]

IMHO it would be better with washers. Cold-setting spokes at the elbow to fit properly is common practice.

With a steel hub it is a very good idea to re-use the spoke holes in the same pattern where possible; the corners of the holes in the hubshell will be rounded and will be kinder to the spokes.

cheers

[Gattonero]

..
With a steel hub it is a very good idea to re-use the spoke holes in the same pattern where possible; the corners of the holes in the hubshell will be rounded and will be kinder to the spokes.

cheers

Not just iwth steel hub shells, I always sort the spokes in 4 batches: Lh & RH, inbound and outbound of each. Takes only a minute or two but it's peace of mind. At least, divide them between inbound and outbound spokes.

At the bottom they're easy to spot the difference in shape at the J bend


(edit, pic added)

[Cyril Haearn]

Might they not wear through eventually?

[Brucey]

generally speaking you only get wear if the spokes go slack in service and they only go slack in service if the wheel isn't built right to start with.

Primary causes of the wheel not being right from the start include

- that the parts are not correctly specified for fit and/or envisaged service loads
- that the wheel is built with the wrong tension setting
- that the wheel isn't stress-relieved
- that the spokes can settle in the hub in some way

Settling includes that the spoke deforms the flange (aluminium hubs), that the spoke elbow bend opens up (e.g. if the spokes don't fit well in the hub), the spoke head settles more into the far side of the flange, and that the flange gouges away at the inside of the spoke elbow.

If you re-use the original spoke positions in a steel hub, several of these mechanisms are stymied.

I suppose that with a new steel hub flange, without countersunk holes, it might be possible to use enough spoke washers to pull the elbow against the flange in a potentially detrimental fashion. But with a re-used hub, this is less likely to happen.

cheers

[RobC]

Thanks for the advice. Will relace. Enjoying learning all about wheelbuilding with your help!

I did want to use the holes as they were originally but: when I was doing the trailing spokes I put the spokes in the same way on the first flange, yet when it came to doing the other side's trailing spokes, if following Sheldon's instructions, I had to use a hole one along from how it seemed to have been laced before - otherwise the spoke would be in the incorrect position (according to sheldon). Therefore on one side the spokes are in the opposite way round to the wear in the holes. Does that mean it used to be laced with a different cross pattern?

[Brucey]

it probably means that the rim that you are using now has the 'other handed stagger' of the spoke holes vs the valve position.

If you have a small round Swiss file, it isn't a bad idea to make a small radius on the 'outside' spoke holes at least, on the 'wrong' flange.

cheers