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G’day Doc, I really enjoy your technical column and have learnt a great deal. I was riding back home from Sydney and called into an aftermarket shop the other day and they were doing a big front wheel conversion on an Ultra. It’s something that I have been thinking of doing to my bike.

They were friendly enough but didn’t want to answer too many of my questions. I notice from the mags and websites that when they put a big wheel on baggers they usually only run one disc rotor and one caliper. Do you know why this is the case? Also, in doing that, how does it affect the operation of the ABS system?

I understand I will have to change the front guard and make some changes to the forks – using different trees, I should imagine. I’d appreciate as much information on this matter as you can provide me with. Thanks very much for your help on this one, Doc.

– Don

Hi Don, the reason for running just the one caliper is to show off the trick front wheel that is usually fitted. And no, the ABS still works but, obviously, one caliper is going to give you less braking than two – though I don’t see this as a problem.

Some aftermarket wheels come with an ABS-compatible bearing already fitted. Certainly this is the case with the 23in WanaRyd unit I am about to fit to Ugly Betty, my 2012 Road Glide. I will be using Ness triple trees, which are pretty neat units and certainly, as with other Ness products, they’re of top-shelf quality. You can check them out at:

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