| Author | Message | ||
     Old_man |
I read in the magazines that some bikes have radial mounted disc brakes. Looking at the pictures, I can see no difference in the mounting. Can somesone explain what this means? | ||
| Mikexlr650 |
look at how the caliper is mounted | ||
| Not_purple_s2 |
Radial Mount  Traditional mount  On the traditional mount the caliper is attached from basically one end but the radial mount is attached at both ends. | ||
| Old_man |
I see the difference now. I don't see how it should make much difference in braking ability. | ||
| Akbuell |
The magazine guys say they give better "feel" at the lever, for more precise brake control. The turning rotor tends to lift the traditional caliper off the rotor; not so much w/the radial mount. Same with the radial master cylinder. The brake lever acts directly on the brake piston, instead of through a lever, leading to better feel. | ||
| Dentfixer |
The difference is that the mounting bolts are aligned with the radius of the brake disc, not perpendicular to it as is the traditional method. It does minimalize the caliper twisting or torque effect from the braking. | ||
| Blake |
I don't see all of the benefits touted as being inherent in the configuration for radially mounted calipers. They are not there. Structurally speaking, it is a much less efficient load-path that requires a lot more material in the bracket to achieve the same stiffness as the conventional mount. Note the much heavier bracketry required. The one major advantage to radially mounted brake calipers is that they are forgiving of slight lateral misalignment between caliper mounting and brake disk and thus eliminate the need for shims between the caliper and bracket. Another advantage is that the radial mount puts mostly pure torsion into the fork leg, no shear loading, which could account for some improved stability if the fork leg is too flexy. The Buell ZTL system eliminates so much of the tolerance stackup in the mounting of the caliper wrt the disk that it too eliminates the need for any shimming. The radial mount does so by allowing the caliper to move laterally prior to torquing the bolts. | ||
| Jaimec |
Other than "because they don't HAVE to," I can't see why Buell doesn't radially mount the ZTL caliper. That would be one way of shutting up the critics... | ||
| Djkaplan |
"Structurally speaking, it is a much less efficient load-path that requires a lot more material in the bracket to achieve the same stiffness as the conventional mount." I think the advantage is how the fastener supports the leading edge of the caliper body and caliper mount on the fork leg. The leading edge of conventional calipers are apparently flexing enough for racers to feel at the lever during the heat of competition; the radial mount supports the leading edge of a caliper (in relation to load direction) in a fashion that aleviates this. Fasteners are typically mounted in shear for caliper mounting, which is actually the more correct way to use a fastener for these types of loads. I think in the case of radial mounts, some of the ultimate load capacity of the fasteners is sacrificed for a more stable mounting arrangement for the caliper. (Message edited by djkaplan on May 20, 2008) | ||
| Xl1200r |
Other than "because they don't HAVE to," I can't see why Buell doesn't radially mount the ZTL caliper. That would be one way of shutting up the critics... Not sure about that... think about how long the mount would have to be in order to reach all the way out to the disc. | ||
| Firstbuell |
I heard somewhere that radial calipers are less time-consuming when assembling new motos on the production line | ||
| Jramsey |
I do believe Firstbuell hit the nail on the head. Some engineer came up with the idea of the caliper bolts being inline with the lower legs would speed up assembly time plus give the ad strokes some crap to pump the non knowing public. Look at NP2's picture, if it were truly mounted radialy the mounting bolt center lines would be intersecting with the axle center line the same as a spoke wheels do, not just in line with the vertical leg. (Message edited by J.ramsey on May 19, 2008) | ||
| Just_ziptab |
Why not just build the caliper as an integral casting in the fork leg, straight up from the axle? Just two bolts to hold the inner caliper half to the outer half in the leg.That would be cool if there was room for piston travel(?)Two (or four) pistons on each side of the leg. | ||
| M1combat |
Doesn't it have to do with allowing the caliper to flex with the rotor? Looks to me like it would take less time to install the old traditionally mounted calipers. | ||
| Toona |
To me, Two bolts to install are two bolts to install, doesn't matter what direction they are going in at...how could one be any faster than the other? | ||
| Jramsey |
Its the time that it takes to machine and assemble the part,in the production environment time is money..........just ask any bean counter, they have to justify their salary. | ||
| Djkaplan |
Rest assured that if radial calipers were actually cheaper to assemble, you'd see them on more than just low production, high performance bikes. Except for their odd ungainly appearance, I can't understand why anyone would have anything against radial calipers in theory. | ||
| Azxb9r |
The one major advantage to radially mounted brake calipers is that they are forgiving of slight lateral misalignment between caliper mounting and brake disk and thus eliminate the need for shims between the caliper and bracket. That in itself is very worthwhile, especially if you change wheels or have more than one set that you use. | ||
| Blake |
DJ, Regardless of the configuration, the caliper fasteners are still in shear. It's just that for the "radial" type, they also see some axial load component as well, but still mostly shear. There is no advantage whatsoever that I can see in load path, and as stated before, as far as the caliper itself and its bracket, the radial configuration has an inferior load path compared to conventional mounts. The conventional mount has a very short direct load path with little to no bending. Bending is inefficient and the radial mount must endure a lot of it. As far as they compare as perceived by racers, the ZTL-II brake system with its conventionally mounted caliper on the XBRR was rated by Jeremy McWilliams as being closer in performance to MotoGP than World Superbike brakes. That makes it better than anything else on the street. Draw yourself a free-body diagram of the two and I think you'll be surprised. | ||
| Djkaplan |
I'm more surprised at the mixed performance and reviews the new 8 piston ZTL-II has been getting in the moto-press. |
