Topic: Flipping lower legs relocates calipers behind forks, benefits?

[kwaggs27]

So Im doing a dual disc setup on a cb500 and was thinking about switching the lower legs and putting the calipers to the rear of the lower. Is there a benefit to having the weight to the rear of the front axle or a benefit to clamping the rotor as it spins up or as it spins downward in the stock location? Im no scientist but there has to be some sort of difference to caliper location and clamping reaction to a spinning wheel.

[gane]

K, I swapped forks side to side,  & run my calipers  (trailing or behind legs) thinking  that with the  weight of calipers lower & behind the wheel center that the "flop" at low speed/extreem steering angle would be less. Having never tried the alternative, I don't know if there is a difference.... I do feel that "trailing" calipers  are cleaner looking... Lead or trail, makes no difference in braking..... swapping  forks does mean the fork drains will be a little different . &  depending on model  you may have to turn "fork brace/fender mount" around... & in any case if using stock calipers  (if memory serves) one side will have bleeder in the wrong position. I just dismount when bleeding, but have read where if Industrious enough, you can remove the "sealing face" inside caliper, thereby converting to correct bleeds, & getting rid of the steel lines using banjo bolts for brake lines... luck G

[faux fiddy]

500 likely has the same calipe which is the same as the 550, which is the same as the 350f and probably the 360.

The mount for it uses a spring loaded 'guide' for no other word for it, that rides on the disc. it depends on the direction of the rotation of the disc to center itself.

Short answer - no this can't be done successfully  with the unmodified stock parts.

[MCRider]

Gane is pretty much right. Besides the aesthetics (some think it looks better, others don't) the theory of putting the weight in the back is that its closer to the pivot line of the steering stem and the "flop" as mentioned is less or nearly zeroed out. BMWs of the era put them on the back and very low, I think they believed in it. This is a very obscure (?) or minuscule benefit, hardly noticeable to anyone not on a race track, although i thiink i can feel it on the street. But it may simply be a wishful thinking thing.

Putting the caliper on the back will act as the little fender over the disc that is otherwise used to keep water from flying off the disc and hitting higher up, including the rider.

All the points Gane mentioned pertain.

No proof, but i can't imagine that there is any difference in grabbing the disc that is of value.

[MCRider]

No personal experience with the 500, but looking at a 500K2 microfiche, the caliper hanger is very similar to the cb750. I don't see any reason it wouldn't work on the backside, swapping the lower legs of course.

[faux fiddy]

No personal experience with the 500, but looking at a 500K2 microfiche, the caliper hanger is very similar to the cb750. I don't see any reason it wouldn't work on the backside, swapping the lower legs of course.

It's made to be dragged along the disc, not pushed.

[MCRider]

No personal experience with the 500, but looking at a 500K2 microfiche, the caliper hanger is very similar to the cb750. I don't see any reason it wouldn't work on the backside, swapping the lower legs of course.

It's made to be dragged along the disc, not pushed.

Many of us have done it. It works fine. Need a picture?

[kwaggs27]

I would personally like to see a picture if you have one handy. Im seriously considering switching sides for looks if nothing else.

[faux fiddy]

I would personally like to see a picture if you have one handy. Im seriously considering switching sides for looks if nothing else.

Look at your mounts. Is there a pivot and a spring that lets the caliper ride the center of the disc? This just doesn't work quite as well, if at all, the other way.

[MCRider]

I would personally like to see a picture if you have one handy. Im seriously considering switching sides for looks if nothing else.

Look at your mounts. Is there a pivot and a spring that lets the caliper ride the center of the disc? This just doesn't work quite as well, if at all, the other way.

It may not be as elegant as a bike that is designed for rear mounted calipers, it simply and absolutely works fine on thousands of motorcycles that have done this. Including high performance racebike applications. It is not even an issue.

[MCRider]

I would personally like to see a picture if you have one handy. Im seriously considering switching sides for looks if nothing else.

This is the setup I ran for decades and 10s of thousands of miles. The CB750 has the pivoting arm that the caliper mounts on, with the spring and screw adjuster. Granted the design was for a pull effect, but pushing on the pivot pin makes no difference. I looked at a 500K2 and the design is virtually identical, just some small differences in the shape of the parts.
Pardon the chrome makes it hard to see details.   

[Ringo]

Very nice MCRider.  For street use (ie with a speedo), would having the speedo drive run backwards present a problem?

[MCRider]

Very nice MCRider.  For street use (ie with a speedo), would having the speedo drive run backwards present a problem?

Only the fork legs are backwards. The wheel is still the same. Note my speedo drive on the original right hand side pointing back to the bike. Not an issue.

[Ringo]

Oh, I didn't even see that!  Silly me. 

[MCRider]

You know, I set all this up years ago. The design of the caliper mount is not the problem, and I obviously have the speedo drive in the right place, but there may be some issues I'm not remembering that I had to work around. But, nevertheless thousands of bikes have been so converted.

[BLUE71TURBO]

I would personally like to see a picture if you have one handy. Im seriously considering switching sides for looks if nothing else.

This is the setup I ran for decades and 10s of thousands of miles. The CB750 has the pivoting arm that the caliper mounts on, with the spring and screw adjuster. Granted the design was for a pull effect, but pushing on the pivot pin makes no difference. I looked at a 500K2 and the design is virtually identical, just some small differences in the shape of the parts.
Pardon the chrome makes it hard to see details.   

             
              Hey MCRider, I dig your fork brace. What brand is it and is it still available ?

[MCRider]

Blue: I had it made by Saldana Racing Products in Brownsburg IN.

But TKat.com could do the sme thing, maybe better. A forum member just recently posted his information.

[SKTP]

Wow are those calipers chromed or just polished amazingly perfectly?

[crazypj]

You know, I set all this up years ago. The design of the caliper mount is not the problem, and I obviously have the speedo drive in the right place, but there may be some issues I'm not remembering that I had to work around. But, nevertheless thousands of bikes have been so converted.

Biggest issue I remember on my 550f was modifying mudguard bracket/fork brace.
 drilled out the rivets and flipped iy with spacers I think (it was over 30yrs ago  )
 Speed drive was a bit of a PITA but not impossible
 Well worth the effort, you can't have too much brake 

[faux fiddy]

I would personally like to see a picture if you have one handy. Im seriously considering switching sides for looks if nothing else.

This is the setup I ran for decades and 10s of thousands of miles. The CB750 has the pivoting arm that the caliper mounts on, with the spring and screw adjuster. Granted the design was for a pull effect, but pushing on the pivot pin makes no difference. I looked at a 500K2 and the design is virtually identical, just some small differences in the shape of the parts.
Pardon the chrome makes it hard to see details.  

750 has differences from the others, but I am not sure what the differences are other than sizes. Look at what you have to see the differences involved.

Two discs/calipers as you show is debateable whether  mounted behind  helps performance (other than 2x brakes). But the fact is the floating spring  system is marginal to start with as far as modern tech. As far as best possible configurations,myself, I can live with that single since it is stock, and that it will make my brakes not as good flipping it. I will not have twin rotors yet, as you have set up unless I do the real upgrade. If I do It will be with something made for it without the floating spring system. I will shop for that feature if I modify, because it is the way to go. It is easier to have the best stuff if you approach the situation at the steering stem, including forks, trees, discs and wheel.

The best is the  whole caliper is made of one piece of billet, instead of two pieces bolted together, which has been done. There is no advantage to your stoping power by flipping the stock setup, unless you  just like the look and will gladly compromise stopping power for "looks.".

How much $$ is where these questions are actually answered. Flipping your forks around in itself is about looks and decreased performance is guarateed  from stock setup.

[fishhead]

With the rear mounted calipers, the calipers are mounted closer to the ground and give a lower center of gravity (for the front wheel).

   When the bike is leaning in a turn, with the front mounted calipers, since they are mounted higher, they will "tend" to fall to the inside of the corner, since the weight of the calipers are higher.
   With the rear mounted calipers, since the weight is lower, the tendency to "fall" is lessened.
 This is the "flop" that Gane is referring to.

[bwaller]

Bottom line is the calipers are mounted closer to the steering axis. As mentioned you won't feel an improvement in braking but for the initiated there should be one in steering effort/handling.

Tree, not sure why you think there will be any less braking. Look at any new performance oriented motorcycle since these old timers....not many calipers mounted in front. It's all been mentioned, don't do it if you aren't a believer, that's great, but don't claim it will lessen braking force either.

[underachiever]

This has all been covered before. Search for caliper reversal and you will find all the stuff I eventually found when I was looking into it.

It seems fairly straitforward to do but there are a couple of things to deal with. The right side fork leg was never meant to have a brake on it from the factory so the mount was never cleaned up and aligned properly. This usually means having to space out the top two mounting bolts a little. Also when you flip the original fender brace you'll now find that the bend to allow the brake arm fitting is on the wrong side. You could either bend it to fit or I just made a new similar style of brace to fit the new setup.

As to whether there is a performance difference, I cannot yet say given the one 45 minute ride I've done on the one nice day we've had thus far.

I found arguments for and against, weight distribution, designed for pull not push, leverage angles of the brake against the disc etc.. In the end it's been done lots and it's your bike. Research it and if it's something you're comfortable doing and you see a benefit to yourself, then have at it.

Oh, and you'll need a new brake line.

here's a good place to start - http://forums.sohc4.net/index.php?topic=2579.0

tony

[MCRider]

Wow are those calipers chromed or just polished amazingly perfectly?

They're chrome. I have an account at Brown's Plating.    http://www.brownsplating.com/

[MCRider]

"decreased performance is guarateed"  huh?

Cite required. Can't understand why or how you can say that without an IMO qualification.