EASY Wheel Swap?? HAH!

[crazy steve]

After reading here on the list multiple times that the 16" Special wheel is a 'bolt-on' to the Standard ('all you need is the specials' wheel spacer'), well... it ain't true.

I found this out today when I trial-fitted my modified HD 4-piston caliper and I couldn't even get it in between the 16" wheel and the swingarm. Mind you, it fit fine with the stock 17" wheel. At first I thought the drive splines weren't going in all the way, but after eliminating that, I started measuring things. After an hour, I figured out that the difference is where the mounting face for the rotor is; on the Special wheel, it's .300" further out. WTF? I'm still trying to figure out just why they did that, but the interesting thing is if you reuse the stock rear brake, the steel caliper bracket ends up seriously misaligned. You have to discard the spacer that goes between the two stock 'standard' caliper brackets to make it fit in the swingarm, and that twists the steel bracket into a real bind. So it you do this swap, you'll have to bend/tweak that bracket until everything lines back up. For a bike that wasn't made that long or in that many models, there sure are a lot of inexplicable differences. I mean, good design in one place, then move to a 'WTH were they thinking?' spot...

I'm mostly just venting (I spent about three hours on this today) but I'm over it now. The Harley caliper will make another trip through the mill to get whittled on some more until it fits... and it will, I swear.

'78E original owner

[clcorbin]

well... it ain't true."

I found this out today when I trial-fitted my modified HD 4-piston caliper and I couldn't even get it in between the 16" wheel and the swingarm.

I hate to tell you, ANY time you start combining modifications you are in NEW territory and it may or may not work. Put the stock brake caliper on there and THEN see if it is as easy as everyone says. But either way, your opening statement simply isn't relevant to the swap at hand simply because of the OTHER modifications you have done.

But, good luck getting everything straightened out and working with the wheel and and brake!

[crazy steve]

..Put the stock brake caliper on there and THEN see if it is as easy as everyone says...

I did trial-fit the stock brake in there; it ain't no bolt-on.... unless you're counting on tightening the axle will warp the steel caliper bracket into place.

'78E original owner

[WMarshy]

If my mind serves me correct, you have to use the spacers and caliper mounting bracket from the 16" wheeled bike, (calipers should be the same I think ). It sounds like you are trying to use the caliper bracket from the 17" std wheel, correct? Big no no...

[Ivan]

I think the popular mod is to put the 17" wheel on the special. I know for a fact that its a matter of spacers that way, because Russ did it and I didn't have to make him any parts. hehe.

The other way around though, I would have to look at. If you find you need spacers or whatnot, I think I have a couple laying around.

[WMarshy]

Ivan,

From my understanding the 16" wheel has more available tires to choose from... making it more desireable. IDK, I have a 17" wheel and thought I read that you have more options with the 16" and therefore its the more desirable size...

[Ivan]

Yeah, there are more choices for the 16. But, the 17 on the special gives a little boost to the gearing like a 750 final drive, and raises the rear a tad for a bit better cornering clearance. I think there is more. I know that rear wheel was a big topic on the comparisons that Bob Jones wrote about in his book. When I get to spend more time in AR and the amazing twisties there, I will probably switch to the 17, so I can bend it over harder in the corners.

[WMarshy]

Huh, I think thats the first time I read about someone wanting the 17 over the 16...I would think the RPM change would not be noticable... I thought it mainly came down to tire choices. Of course, all of your additional lean angle dissapears when you put on a 4-1 Jardine. Be ready for fireworks!

[crazy steve]

What brought all this on was a desire to have more tire choices, and strangely enough, the hope that I could use a larger diameter tire. You're limited to the 130/90-17 if you run the 17" wheel, and that size isn't even as big as the original 4.50-17 the bike came with. If my calculations are correct (and except for the 'WTH?' relocated Special rotor, they have been so far), I'm fitting a 160/80-16 rear, which has a slightly larger diameter than even the 130-17 and is very close to the original 4.50-17. And yes, I've modded the swingarm; this size is very close even with the mod, but will fit.

And Marshy is correct; after venting/posting I checked the parts fiche and if you swap to the Special wheel, you need both the spacer and the caliper bracket from the Special to make it fit... unless you work over the standard bracket.

'78E original owner

[Ivan]

Do you have a bracket? I am sure I have one if you need it. Its yours if you donate to the "Trainzz Memorial Thunderpig Resurection Fund" which I am planning on starting about the first of June or so. I don't know what its worth, but it'll be reasonable.

[crazy steve]

Thanks for the offer Ivan, but I've got a 'plan' now. I'm using a modified late Harley touring 4-piston rear caliper (to match the ones I'm putting on the FJ forks I'm also installing), and after discovering the rotor difference, have figured out a 'redesign' to get it on there. With some more machining on the caliper and slight mods to the 'standard' bracket, I'll get it to fit. The Special bracket would actually be more work for this...

As a side note, this caliper is the part I offset-drilled the axle hole in after pressing in a 'reducer'. Heating the caliper enlarged the hole by .004", so I made my bushing the same amount larger and sandblasted the mating surfaces. I used JB Weld as my 'lube' when pressing them together, and that puppy is in there. No pins or welding; but it didn't budge when I drilled the new axle hole, so no worries about it moving...

'78E original owner