Rear hand brake - major fading, solution??

[AgileMike]

I really love my Stark and the hand rear brake setup. However, I'm getting major brake fade after 10ish minutes of medium intensity riding. I'm going to order the BRAKING OVERSIZE REAR BRAKE ROTOR KIT for 19-22 generation KTM. I'm also going to contact Stark, as the CEO was saying they will be releasing a Brembo master cylinder instead of the Formula that was shipped with the bike.

Has anyone got a solid solution for this yet?

"Braking Oversize Rear Brake Rotor Kit | Parts & Accessories | Rocky Mountain ATV/MC

 

[Beagle]

Stupid question: does it come with stainless steel or rubber brakes hoses ?

 

[AgileMike]

They are stainless. It really seems like the Formula master cyclinder isn't very good. The Stark CEO mentioned it in an interview. I don't think it really needs an oversize rotor, I'm just trying to do anything to make it better.

 

[erSitzt]

Same here, hand rear brake was mushy from the beginning, not sure if it is fading while riding.. have to check next time.

 

[Theo]

Since we have a 2 years warranty, I would first of all contact Stark.
Anyhow, brake fading is supposedly caused by the fact that there is a significant amount of gas, instead of liquid only, in the brake system; this gas can either be air which has entered the system, for example during a fluid refill, or vapour from the fluid after it has overheated. If the problem happens after some minutes, I guess it's most likely related to overheating. Considernig that the Vargs have been produced recently, I would rule out the possibility of old brake fluid having absorbed moisture.
Personally, I use a street legal supermoto (non electric) in tracks even if it doesn't have a very high performance front brake; the first times I used it I got brake fading but I solved the problem using a fluid having a higher boiling point.
So, if I had that problem:
1) I would contact Stark,
2) if that wasn't successful, I would check the system without disassembling it, in order to find out whether there is something malfunctioning, like brake pads still biting after having released the brake lever,
3) if there wasn't anything obviously wrong, I would bleed the brakes using a high boiling point fluid; according to the manual it should be a DOT 4 type.

 

[Philip]

Here is one possible solution:

 

[AgileMike]

Since we have a 2 years warranty, I would first of all contact Stark.
Anyhow, brake fading is supposedly caused by the fact that there is a significant amount of gas, instead of liquid only, in the brake system; this gas can either be air which has entered the system, for example during a fluid refill, or vapour from the fluid after it has overheated. If the problem happens after some minutes, I guess it's most likely related to overheating. Considernig that the Vargs have been produced recently, I would rule out the possibility of old brake fluid having absorbed moisture.
Personally, I use a street legal supermoto (non electric) in tracks even if it doesn't have a very high performance front brake; the first times I used it I got brake fading but I solved the problem using a fluid having a higher boiling point.
So, if I had that problem:
1) I would contact Stark,
2) if that wasn't successful, I would check the system without disassembling it, in order to find out whether there is something malfunctioning, like brake pads still biting after having released the brake lever,
3) if there wasn't anything obviously wrong, I would bleed the brakes using a high boiling point fluid; according to the manual it should be a DOT 4 type.

All great advice. I have already replaced the brake fluid with VP Racing brake fluid and they are bled perfectly as I have a syringe type system to push the fluid up from the bottom. I will contact Stark, but I don't feel there is anything broken on the bike.

The rear brake works just fine when the brakes are cold. I'm getting a heating problem I feel. I will check to make sure they aren't dragging due to a setting issue. Since it's a hand brake, I'm fairly confident I'm not "riding the brakes" all over the track.

I definately use the hand brake more than a foot brake as it's much easier to drag it deeper into the corner and also use it on right hand corners. This could be part of the problem.

 

[rayivers]

If you're not already, I'd definitely try HH sintered pads - mine worked better when hot, even with the rotor almost glowing. I've had other pads that gripped really well cold-to-warm and faded when super hot; maybe something similar was used on your bike.

 

[C5tor]

You can eliminate this problem by not braking. Braking is for losers. If the throttle is not wide open, you’re not trying hard enough.

The great creator of thermodynamics did not grant you the ability to fling your bike forward with the impetus of 80 mighty, electric horses for you to simply waste such magic momentum at the cowardly hands of friction, drag, and fear!

In the words of Yoda (or maybe Ricky Carmichael), “No! Brake not. WOT or WOT not! There is no brake!”

 

[HadesOmega]

Here is one possible solution:

View attachment 11053

Wow that's some crazy flat track rear brake. I know I faded the brakes on the Redshift in the short track race.

It's too bad the Varg doesn't have a regen throttle. It is great on my Sur Ron Light Bee with EBMX X-9000 controller. All the engine braking you could want without the fade and it puts power back in the battery.

 

[HadesOmega]

You can eliminate this problem by not braking. Braking is for losers. If the throttle is not wide open, you’re not trying hard enough.

The great creator of thermodynamics did not grant you the ability to fling your bike forward with the impetus of 80 mighty, electric horses for you to simply waste such magic momentum at the cowardly hands of friction, drag, and fear!

In the words of Yoda (or maybe Ricky Carmichael), “No! Brake not. WOT or WOT not! There is no brake!”

I disagree you can NEVER have good enough brakes. If you can slow faster you can go faster. Especially the rear brake. The rear brake is a tool to scrub speed and get the bike pointed in the right direction when not used in conjunction with the front brake.

I'm not surprised such a fast bike doesn't have good enough brakes.

 

[rayivers]

You can eliminate this problem by not braking. Braking is for losers. If the throttle is not wide open, you’re not trying hard enough.

Enzo!! Be sure to add scratchy nasality : "La frenata è per i PERDENTI !! Se l'acceleratore non è completamente aperto, non ti stai impegnando abbastanza!!"

I'm not surprised such a fast bike doesn't have good enough brakes.

Neither am I, at least not anymore. Here is an old thread of mine, might be helpful for those who haven't seen it.

 

[spidartanks]

I dont mind my LHFB But would like it to be stronger as well - I will be looking forward to stark coming out with the Matching Brembo Master for the LHRB. i wonder if they will do an exchange program/good price to help out the early adopters?

 

[B. FRANK]

I disagree you can NEVER have good enough brakes. If you can slow faster you can go faster. Especially the rear brake. The rear brake is a tool to scrub speed and get the bike pointed in the right direction when not used in conjunction with the front brake.

I'm not surprised such a fast bike doesn't have good enough brakes.

you missed where it says chief comedic instigator under his name. he is a knowledgeable person who also injects humor into these threads....ie, he didn't really mean it.

 

[B. FRANK]

if both bikes are based on Ktm's wouldn't an alta lhrb set up work on a Varg? if you change the master cylinder you can have pedal and lever like I run on my alta (rekluse), or just the lever like alta released. never seen a Varg in real life so I'm just ASSuming.

 

[Philip]

@AgileMike - Brakes start dragging during riding and then overheat due to several possible issues. See if any of them could be the case:

1) Mechanical drag. Something is mechanical is keeping the wheel from spinning freely. This issue would normally be present constantly. Either the pads do not retract, or the floating caliper doesn't float, or something is bent, or someone messed up the installation of the brake caliper/disk somehow. If this is the case, you should be able to detect the drag by putting the bike onto a stand and spinning the rear wheel.

2) Hydraulic drag. Either the brake expansion reservoir is overfilled and is not venting to the atmosphere, or the brake lever is preloading the master cylinder piston not allowing the brake fluid to expand, of the master cylinder machining is messed up. In this case, the brakes would be okay when cold, but then after warming up they would start dragging worse and worse. You need to stop in the middle of riding and check if the rear wheel is spinning freely.

I cannot think of anything else. Hope you can figure it out. Good luck!

 

[smdub]

IME, the master is never the problem w/ brake fade. Hot fluid never gets to it. So swapping it might give you a different feel based on piston ratios but if you have fade now w/ a Formula master then a Brembo master will have the same problem.

As has been mentioned since you already have high temp fluid in there, try different pads (like HH). Organic pads fade badly when hot. Metallic pads typ don't.