And there it is. "If you look at any high performance vehicle." Are these the same performance vehicles that have water-cooled inline four cylinder mills with fully adjustable suspensions, chain drive, sticky radials, 4-valve heads, 390 lb curb weights, remote reservoir shocks, 14,000 RPM redlines, and all that other crap?

Making the argument that a 600+ pound air-cooled iron v-twin with belt drive and a flexi-suspension is a "performance vehicle" that needs state-of-the-art brakes is absurd. Different bikes, different missions.

 

If that was true, they could just mount a second caliper on the single disk, and save the weight and expense of an additional disk.

Again, as long has the brakes dissipate heat well enough to stay out of fade during the the type of riding you do, stopping distance mostly comes down to available traction between the tire and the road surface. Brakes that are capable of exceeding that available traction won't stop you any faster. If your brakes can stop the wheel from turning, more powerful brakes aren't going to make the wheel "more stopped" . If your brakes can take you to the traction threshold (which is where the strongest braking is to be had), stronger brakes won't improve anything. Once again, the main limiting factor is tire traction.

Some other factors affecting braking distances:
Center of gravity and wheelbase length. Did you notice from prior posts how in testing, they got shorter stopping distances out of the single-front-disk Wideglide and Rocker, than from many of the hardcore sportbikes? Both of these bikes have more-than-normal rake on the front end, which results in a longer wheelbase. That, combined with a lower center of gravity than sportbikes, allows harder braking without doing a "stoppie", or flipping the bike over the front wheel. Once you're braking hard enough for the rear wheel to leave the ground, you're done. Stronger brake application won't stop you any faster. All it will do is raise the rear wheel higher, or bring the bike over on top of you.

The wheelbase and weight distribution of the Widglide and Rocker allow true traction- threshold braking, without any worries about flipping over the front wheel, and without the need for brake modulation to keep it from happening. These bikes flat-out won't do it, no matter how much front brake force you apply, or how many disks you have. (although maybe they would with a super-sticky race compound tire)

A lower center of gravity is also the reason why Harleys can beat many vastly more powerful sportbikes in initial acceleration. The higher center of gravity and shorter wheelbase of sportbikes make them more prone to wheelstanding, so the more powerful ones can't use full power off the line.

So there's a lot more going on with braking than simplistic notions like, "More disks will stop you faster", or "more pistons in the caliper is better". Not that you might not benefit from better braking, if you actually track-race your Harley, or have lower-than-average grip strength.

Or if you want to go to dual disks just because you think it looks cool, or just because you like to modify and work on your bike, that's cool too. But it won't necessarily produce any improvement in actual real-world braking performance, and it might hurt handling a tiny bit because of the increase in un-sprung weight.

 

this type of sound reasoning is not allowed in hd forums... what you have just.... you have just created is a glitch in the matrix.




peoples heads are exploding all over the place.... some guy somewhere with a stage 4 sportster with turbo, ape hangers, forwards, short shots, and stock brakes is having a mental breakdown... "But, it's american MUSCLE!" i hope you are happy with what you've done here. you destroyer of dreams

 

It's possible that a narrow tire wouldn't see any benefits from dual disk brakes. It probably wouldn't bump the price up all that much and the negative aspect of having more unsprung weight might not be a factor either. The future might see dual disc on all models.

 

hd discontinued the dual disk conversion kits that were out there:
http://www.harley-davidson.com/en_US...ts/-J03183.pdf

evil

 

I wonder why they would do that.

 

Yeah, them reality-based, engineering-thought-type people sukk!
They should be banned from posting on this forum.

 

sales probably. lots of folks take/accept what they are given without question. most probably never even consider it because of the silly "it's a harley, they just [insert cognitive dissonance]" statements that people throw around to gloss over shortcomings. they don't bother with upgra [not nice, removed]

 

They can probably make a lot more money by selling someone who wants dual discs a whole new bike.
There seems to be a strategy of planned incremental "upgrades" to convince people that they need a new bike. Take the displacement increases for instance, from 88 to 96 to 103 to 110. They could have just jumped from an 88 to 110 in the first place, but then they would have missed sales to all the people who bought a new bike every time a slightly larger stock engine became available.

Don't underestimate Harley's marketing savvy!

 

i'm salty because i can't just go HD117 from HD103. what's different in the dyna 110. crank? tranny? why am i being denied