Radial lacing a no-no on hubbies

[John in CR]

Radial spokes always seemed wrong to me, though I lacked an explanation and I've seen a number of people say radial lacing is just as strong. Sheldon Brown's site explains it here http://sheldonbrown.com/wheelbuild.html go most of the way down to Radial Spoking. The small hub part doesn't fit our applications, but the big changes in spoke tension during braking or acceleration certainly does. I also found some motorcycle wheel info recommending against radial too.

Before those who have used it without issue step in with their anecdotal evidence that radial is ok, the physics is against it, so do you really want to recommend something more likely to suffer a catastrophic failure?

I was about to give radial a go, and now I'm glad I did some research first, and I thought I should share what I found since contrary info is floating around on the forum.

John

 

[Ricky_nz]

I rode my GM 1000W hub for about 150Km laced radially into a 26inch wheel.
It seamed to hold tension and I was riding over a bumpy path at times.
One spoke came a little loose but that could have been because of my poor lacing job (it was my first).
The spokes were quite thick as came originally with the hub and had been laced into another rim as 1 cross previously so were stretched before use.

I wouldn't trust it for a permanent setup or one with disc brakes but short term it did ok.
There was no disc brake on the wheel and the HUB was relatively low torque.

Laterally the wheel didn't seem too bad but I certainly didn't want to push lots of torque into it.

 

[dogman dan]

Part of why I chose the other disadvantages of 26" wheel on my cargo bike. It would handle better with a small wheel. But it was just easier to go 26" for a good strong single cross spoked wheel. I think it's clear that a cheap build on a 20" rim can suck. But maybe with the right rim and spokes, it can be ok. I just didn't think it could be ok for huge cargo loads.

I have thought about building another one, but starting with a scooter motor with a cast wheel and rim. Chances are I'm too lazy to ever do it though. I'd have to build a swing arm, rather than just use one from a stock bike.

 

[Cargo_Tom]

I've given a stock 9C 2812 20' 14ga radial lace a thorough beating and I can attest that radial lacing did NOT work out for me

common 700 lbs cargo loads in a 72v45A infinion setup. Tons of torque, lots of weight.

At the one year mark the spokes started making squeaking noises when activating the throttle or the regen. I reckon they had started lengthening (non-elastic deformation) and losing tension at that point.
I tried tightening them them up, but they had become brittle as I had 9 spokes break on me in 15 miles of travel after that.

I ordered butted 12 ga spokes from JRH for a single cross relace into a wide, welded steel rim. That should git R done. The 9C hub needs a final paintjob and the longjohn becomes road worthy again.

 

[liveforphysics]

If you have no angle in your spokes, you can't transfer any torque. This is because when the spoke is perfectly tangent, it's an infinity:1 mechanical leverage, so any amount of torque transfer, no matter how small, makes infinite pulling force on the spokes.

Because of this, when you load a radial spoked wheel, step one requires the hub rotating in relation to the rim to put some amount of angle in the spokes which enables them to transfer torque.

When your wheel is laced with spokes that are already at an angle, it can transfer torque without needing to deform first, as well as radically reducing spoke loading for a given amount of torque you're trying to transfer.

 

[grindz145]

More crossing is more better (where applicable). The only time radial lacing should be evaluated is when there is not enough room for even a 2 cross.

 

[izeman]

depends on rim size. works great for big dd motors and eg 20" rims. spokes are shorter then 10cm/4in. so crossing them is really difficult. rode this with 13 ga high quality spokes and good rims for 1000km+ and 5kW peaks. didn't have to tighten a single spoke since. wheel is still 100% true.