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300mm to 320mm

12K views 21 replies 9 participants last post by  hussain6474  
#1 ·
OK - braking gurus!

My question is : Do you think the difference will be palpable?. I really do NOT ride on my brakes - but I like having more safety margin.

My interest was indeed piqued by the Rottweiler kit. And with the 890R sporting 320mm, which are basically two 690R discs - my interest has been re-piqued.

The maths suggest about a 7% increase in surface area/revolution.

I know that Brembo and others do replacement discs that will drop on - but to avoid any potential hassles - I'd prefer them to have KTM emblazoned all over them. I have to be really cautious that "changes" are not visibly so. PP discs might work out a tadge more expensive than pure Galfer - But the KTM logo will convince testers.

I know that @EvansB2 likes the wave discs - But I'm not a big fan of profiled discs based on the looks. I am willing to be convinced - but I'd want some empirical convincing. The 890R discs are about 20% less than profiled ones.

I cannot see me changing calipers and M/C - just because of the cost. M/C - maybe (later) - And if so the 890R model.
 
#6 ·
I know..still... that was not the question but yes: changed the discs to PP waves ones, and yes, big difference.
Much lighter when you install them (nothing can be wrong about that) and feel more braking power.

So throwing in EBC pads on top...although i did not do it just yet, i’m sure you’ll get supersport like planted feel.
So before any master cylinder, new calipers Stylema blablabla...:
1. pads
2. discs
 
#8 ·
4*10mm thick spacers M10 clearance and 20mmOD. And 4*10mm longer caliper bolts from KTM. Exactly what Rottweiler provide. Hardly a Rocket Science thing. Already have some CNC 7075 Spacers - odd that :wink:

But seems to me a no brainer that if you want to lighten the front unsprung weight and go to alloy centered discs then one might as well go to 320 as well. So either 320mm profiled disks as Rottweiler or 320 890R discs.

Also worth noting that the JJUAN calipers were originally designed for 320mm discs. They would however not work well with 340mm. This from mates here that race at club level and have JJUAN fitted. Not on KTM though.

Obviously one would fit new pads with new discs and they'd be EBC HH.
 
#9 ·
If you were racing on the edge with constant high speed braking on the track, yeah, maybe you'll see the benefit of the extra 20mm but in all reality with street riding, there's no extra safety margin to be gained. The stock brakes will lock the front wheel and engage ABS no problem. If you want the "cool" factor of having 320mm discs, then they certainly won't be a downgrade (still lighter than stock discs and I believe about a pound heavier than the 300 discs). Like others have said, you'll see the best benefit from pads and a MC swap. Getting the brake feel how you want it is a great benefit. The mechanical and thermodynamic capability in the system is already there.

Who told you the stock JJUAN calipers are designed for 320mm rotors?
 
#10 ·
Who told you the stock JJUAN calipers are designed for 320mm rotors?
I think I have seen on JJUAN somewhere MAX 320mm. But like I say I have a mate here in Spain who races and builds bikes for other racers - The basic JJUAN calliper as on the 790 was made for 320mm - leastways that's what they say. Generally he fits Brembos anyway - but every so often a bit of local sponsoring happens.
 
#11 ·
With larger discs its going to make removing the callipers a tad more difficult, even now with the stock callipers i have to prise the pads apart to get enough free play to get the caliber off, my 1290 takes some pressure on the pads to get enough play to remover callipers. That stunt guy on here has no problem doing stoppies on the stock set up. The stock setup is great with better pads, but we all like a little bling, for me its always suspension where my $ go.
 
#12 ·
we all like a little bling, .
Yeah - and tbh that's what it would be if I did it. Part of MY problem is that I am highly inquisitive and when an idea hits me I have trouble letting it go.

My local suspension guy has made me calm down. Thanks to all here - the brake thing is fading too. Moving the lever perches solved the lever reach issue I had.

So I'll soon get bored and be asking more absurd things :wink: