406 / Nexus 8 wheel build : to dish or not to dish

[syklist]

I am going to be ordering rims and spokes for the wheel build soon so need answers to a couple of questions. Looking at the data on this page the Nexus 8 hubs I have ordered (3rd column) have a dishing distance of 2.7mm to the non-drive side. The OLD is 132mm and the rear forks on the bike in question are 135mm wide.

If I build the wheel without any dishing, centred on the centre of the flanges and put a 3mm spacer on the non-drive side, by my calculations the centre of the wheel will be 1.2mm off centre in the direction of the non-drive side.
1) Are my assumptions and calculations correct?
2) If yes, then in practice, would I notice any effect of the wheel being 1.2mm off centre? The Bikes are going to be used for touring (18kg luggage + child trailer) with the rear wheels will be running tyres in the range of 47-55mm wide. Mostly to be used on asphalt roads but a fair bit of gravel roads too.

Edit: supplementary question, 2 cross or 3 cross spoke pattern for the rear wheels (36 spokes)?

[Brucey]

Those dimensions are close but not identical to those here

http://www.kstoerz.com/freespoke/hub/168

but it is moot, in that perhaps you can't use the hub like that; the LH locknut is the sort with the ridge on for a roller brake; this will need to be changed or be added to anyway, you can't leave this bearing against the dropout.

I think if you respace in the way you suggest you should check that you can still fit the cover over the roller brake fitting (without which water tends to get into the hub). If you can overcome that (oughtn't be difficult, I think it works out the way you want when you fit the standard parts) and still have a good chainline, go for it, why not?

BTW most folk would build x2 but on 406 rims the real trouble is arguably caused by the way the rim is designed; some (large) spoke angle is inevitable and a bad rim (in which the nipple cannot articulate enough) just makes it a lot worse.

cheers

[Mick F]

I built the wheels for our bike Barbarella. 8sp Nexus and roller brakes.
She has 27" wheels and looking at the data I kept from the spoke calculator, the rear wheel came out as 291.8mm left and 291.2mm right.
Dunno now because it's a long time back, but no doubt I bought 292mm spokes for both sides.

I know her wheels are much bigger than 406, but the length differences are minimal.

For interest, this was the front wheel.

[Brucey]

the smaller rim does exacerbate any spoke length differences there might be, but it is unlikely to be more than 1mm between sides even with 'full dish' -such as it is....

cheers

[Mick F]

That's what I thought.

Build the wheel so the rim is central between the locknuts. Same spokes both sides.
2x seems right for a 406.

[RickH]

My 406 / Alfine 8 / 36 spoke wheels on the Circe tandem came built 1x. They are fine as long as the spokes are properly tight (which means they ping a much higher note than if you are used to properly tensioned "big" wheels).

I considered respoking them to 2x but it was balancing consideration of spoke angles at the rim against more tangential spoke angles at the hub. When I considered 3x it seemed pointless as, by my reckoning, the 3x spokes would have to pass the hub hole that would be used for the 2x build & would have to bend around the elbow of the spoke coming out of that hole. I assume a Nexus hub has similar sized flanges.

Rick.

[SA_SA_SA]

Whats wrong with your Bromptons?

[syklist]

Whats wrong with your Bromptons?

Nowt, well apart from that CR18 rear rim, but we knew about the tyre removal problem before doing the Nexus 8 conversion. I am not too keen on the idea of fitting a Weber coupling to the rear fork of a Brompton and towing 35+kg of child and trailer behind it on a longer tour. Apart from braking being marginal there will be a considerable increase in the forces on the rear hinge pin, which IMHO is rather under engineered as it is. The Dahons seem a better bet to me for such tours.

We bought the Dahons in 2009 to supplement the Bromptons which, with their SRAM 6 speeds were not really suited to touring apart from in flat places like Holland. The Dahons promised much, a good range of gears, V-brakes but we had problems with the rear wheel spoke nipples loosening repeatedly which eventually was fixed under warranty. The LBS in Holland that did the repairs was advised by the Dahon importer to rebuild the wheels properly and loctite the nipples in place. In the intervening period we realised that our bikes needed IHGs (we bought some VSFs with Rohloffs in them in 2008 and stopped using our derailleur bikes) and that the SRAM DualDrives were basically 3x8 derailleur systems and had most of the inconveniences of a normal 3x8 derailleur. Our gear system of choice is the Rohloff but the hybrid Nexus 8 + double chain ring system now installed in our Bromptons is a usable compromise, certainly much preferrable to a DualDrive. So now it is time to change the Dahons over to the same gear system as the Bromptons and take them touring.

[syklist]

Thanks for the replies, I think I will check spoke lengths a few times with slightly different parameters and see what comes out. 2x spoke pattern seems to make sense to me, it worked fine on the 349 rims in the Bromptons.

[SA_SA_SA]

...that CR18 rear rim, but we knew about the tyre removal problem before doing the Nexus 8 conversion.

Greenspeed make(made?) a 36 spoke 349mm Velocity Sims rim (was used for their Brompton front hub brake wheel) which avoids that. Perhaps they would still make 36 spoke 349 rims if asked...
http://www.greenspeed.com.au/gsparts.html

[syklist]

...that CR18 rear rim, but we knew about the tyre removal problem before doing the Nexus 8 conversion.

Greenspeed make(made?) a 36 spoke 349mm Velocity Sims rim (was used for their Brompton front hub brake wheel) which avoids that. Perhaps they would still make 36 spoke 349 rims if asked...
http://www.greenspeed.com.au/gsparts.html

I looked at Velocity rims a while back, I found a place in the UK that could get them. IIRC around ukp 40 a pop plus a special order charge of 40 ukp. So ukp 60 a rim. I will consider it if I ever decide to go the whole hog and do a Rohloff conversion on the Bromptons. Velocity Aeroheat rims are usd 80 in the USA.

[[XAP]Bob]

You can run a bike with offset wheels quite happily, you certainly won't notice 3 mm.
Mr Burrows runs various bikes with much larger offsets, and it simply doesn't matter...

I mean you notice it for short while, but it's not inefficient or difficult.

[syklist]

Well I have ordered the spokes and rims to be used with a 2 cross pattern. I checked on Edd with various combinations and the results that came up suggest that the spokes lengths I have chosen would allow me two choices when building the wheel. I can center the rim between the flanges or center the wheel on the OLD with the same spokes. Thanks for all the replies.