I have created a humdinger of a conundrum for myself….

I have a lefty max waiting for a wheel.

I have a Project 321 hub waiting for rim and spokes.

the rim is a Rabbit Hole, the issue is that I need to offset/dish the wheel to accommodate the girth of the 29×3 knard from the stanchion of the lefty.

1. Anyone done this yet?
2. What dishing will work(as in how much do I need)
3. What spokes should I use, and what length should they be?????

Help?

Let me get this right, I had to google knard, so its a £75 fat 29 tyre..

Then to make it fit your going to offset your front wheel to one side so its not in line with the rear?

Possible but how much out of line do you need to go for clearance?

Your going to need to fit the knard tyre to the rim measure it all up, use a normal lefty wheeel in the fork measure that & work out your offset, then you will need to add 5mm min I rekon for tyre deviation & wheel flex etc. Not until this point can you begin to worry about spoke lengths & I dont think a calculator is going to help.

I’d post the whole lot to someone who knows what they’re doing and give them the headache 😉

Yep, you got it.

Have a secret weapon of some special clamps to allow me to re-set the fork to centre.

What ever you say, this will be a FUN bike, not an easy bike to build or ride

😀

So you get the wheels in line, OK that sounds better…. do what wwaswas says, take it to a LBS thats sells Cannodale as they will have the approriate kit for building lefty wheels, then let them sort it out as they will have all the different spoke lengths there to try out until its right.

Have a secret weapon of some special clamps to allow me to re-set the fork to centre.

If this is the case won’t they be able to correct the dishing as well?

Only if I get the correct spokes…

Interesting project – I like it. The hard part will be working out how much offset/dishing you need. tinsy has about the best method on that I reckon. Though you’ll probably be able to get info on how wide the Knard is on a Rabbit Hole (some people I’m in contact are using that combo, so I could ask for you). The question then is how much clearance do you have on the fork as standard – again you may be able to find that out, I can’t think of an obvious way to measure it without putting a built wheel in.

The spoke lengths are easy though. I use spocalc.xls from http://sheldonbrown.com/rinard/spocalc.htm to calculate spoke lengths, and you can enter a rim offset directly into that. Given the Rabbit Hole spoke holes aren’t in the centre you’ll have to also subtract their offset from the flange width dimension on both sides. If you want to use another calculator then simply subtract your rim offset from the right side flange width and add it on to the left side flange width (also subtracting the spoke hole offset from both sides). At which point you realise another advantage of your plan – you’ll decrease the dish of the wheel – given the narrow left flange and the offset of the spoke holes in the rim, that’s almost essential as otherwise you’d have very little spoke angle on the left side.

I just had a play on freespoke which is a US tool used by Fat Bike wheel builders. It seems that the wheel would fit in standard guise….just with a 1mm(ish gap to the stanchion, so a -5 offset it does indeed remove the dishing of the wheel created by the lefty hub. This feels like voodoo going my way right now….

You realise you are going to have to post pictures of the end result whatever happens 😉

So the clamps pull the fork over further to the left. Unless there is a special hub then you still need a lot of dish equivalent to standard plus the off set of the special clamp.

shortcut – the offset fork will decrease the dish, as the midpoint of the flanges is normally to the right of centre to give space for the disc. For the lefty hub in the database of the spoke calculator I linked to above, a 6.5mm offset to the left of normal would provide a dishless wheel (5mm is close enough, but if it was me I’d be tempted to go for the extra 1.5mm if you’re making custom parts, as the extra clearance won’t do you any harm). The only downside is that you’re increasing the leverage on the hub.