Kart brake difference in feel and modulation

I am fairly new to karting about year and half into my foray…

So I am having hard time adjusting to feel of brakes on my kart (Swiss Hutless). They basically feel like a switch. They are super powerful but have almost no travel. I struggle at getting proper feel and modulation with such short travel after spending 25 years driving road car. I tried a few adjustment to cable slack, pedal position, fulcrum of pivot makes almost no difference.
The brake are described as a zero tolerance brake buy the vendor and by design have extreme short travel with floating rotor. The gap to pads and rotor is very small and floating rotor knocks back pad to limit drag.

I spoke to several different racers and gotten mixed and 100% different opinion on the brake system. Some guys say just deal with it other state they could not adapt and see this as compound issue for new karter.

They obviously work because some guy are absolutely killing it with this setup. I also let a local super fast junior driver use my kart and he was killing it on lap two so it works and more likely I am issue.

I fully rebuilt system and was thinking of changing to smaller master cylinder but not really much options. I would need something like a 17mm master cylinder as currently have 18mm +/- bore. I done this on road car setup when doing brake swaps to change brake pedal feel. I have access to fab mounting hardware so that not issue. Semi custom setup not a problem.

This all being said what kart brake setup or manufacturer offer brakes with maximum feel and modulation for an 40 something old fart.

I had a few bad race weekends and was ready to throw the kart off nearest bridge. But overall balance of kart is pretty good and easy to drive I just struggle to adapt to brakes.

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Braking feel is something that you can adjust pretty significantly.

On certain karts, the behavior you are describing is pretty typical, while on others it is not. For example, most Tonykart braking systems are well known to be ‘light switch’ in behavior. Having grown up driving OTK karts, I personally like this feel, and was able to deal with progressive brake pedals once I moved into cars without serious issue.

Setting that aside, there are a few common things you can do to help with your braking problem. First and foremost, look at your pedal and the ‘slave arm’ on your master cylinder. On many karts, both the pedals and this arm have multiple mounting holes. Depending on where you mount the brake rod in these holes, this can substantially change the behavior of the brakes. The more leverage you give yourself (i.e. the further the brake connecting rod is mounted from pivot points), the more responsive the pedals will feel. Closer to the pivot points, and the brakes will take more time to really grab, as well as more pressure by your foot (or at least it will feel that way to you).’

Another thing you can try is investigating different brake pad compounds. Some compounds are very very hard and sensitive, while others are softer, which of course affects braking performance. Not being super familiar with the Swiss Hutless braking system, I can’t give you specific pads, but a local dealer or Swiss Hutless tuner may be able to advise you better on this.

Last but certainly not least, you can play with rear track width. A narrower rear track will make the kart skittish under braking.

If you end up trying these options and are still unhappy, I’d recommend giving yourself more time to simply adapt to the braking feel. Different karts have different feels to their braking systems. Going with a smaller caliper or rotor is an option, but likely too extreme for this issue.

Kart brakes can be tricky if you are used to servo/power assisted ones. I have the same problem left foot braking in a car, because I’m used to applying a lot of force, comparatively speaking.

Eric has some good suggestions, but I think you might have tried some already.
Some other things to consider trying before re-engineering your brake system, or throwing the kart off a cliff :smiley:

  • Different footwear: Softer soles (maybe tennis shoes vs racing ones), thicker socks.

  • Strong pedal return spring: Try an exhaust spring on there so that you have more force to work against.

  • Heel stops: can help the accuracy of control. Your input on pedal is more “purely” managed by your foot/ankle, rather than your foot + the force of your body moving forward.

Give these a try and let us know what works.

On the brake pedal.
The higher position : less pedal stroke, less braking power
The lower position : more pedal stroke, more braking power

This comment triggers my BS vendor spidey sense.

Assuming you have a brake with the homologation number 65/FR/14 or 65/66/FR/14 you should be running a brake pad with part number 141.620 and it should be a pad with a black support. But there is also one with red support. Might be worth asking your vendor if this is a softer pad (normally red pads are softer with other manufacturers).

One thing I noticed when I switched to OTK several years ago was the brake feel. I actually have the opposite opinion as @Eric_Gunderson, OTK brakes are much harder to lock up and offer much better modulation in my experience. The pedal is firmer and isn’t a switch like the ART or Merlin brakes I’ve tried since. It takes some getting used to, but that firmer pedal allows you to control the lock-up or just before-lock-up braking smoother in my opinion.

I would say most kart brakes system are as you describe @Jamie_Gonzalez, very sensitive and easy to lock. Much more switch-like. Almost every other kart I’ve driven has felt that way. Obviously it works pretty well, just takes a bit of finesse to find that knife edge with your left foot.

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Just so weird coming from road cars for so long. Just no stroke to pedal. Like line pressure is super high.

I can see why brakes are setup like this as guys especially young kid get to limit SO fast on brakes and are off the brakes just as quick.

Trail braking or braking down to apex seems to be less popular…which is weird to me but again the other way obviously works as kids are blinding quick without. I have alot more confidence with trail braking at my current skill level.

But “I” just cant control the brake with consistency always bit of lottery if I am under or over limit lap to lap. I feel like if brakes had more physical stroke I would have more control and feel.

I checked of bunch of brake system just on kart stand and every one has way more travel/stroke.

Other than otk what brake system give max feel and modulation?

I agree. I have replaced 100% all parts on braking system and fully overhaul master and caliper with all new parts and no difference in feel or performance. They stop like crazy just no modulation/travel.

I have to check clk numbers but the pads for sure have red backing and per vendor they dont make a different compound.

The thing about brake feel though is that, the definition of feel is a little subjective down to each driver.

For example, I’ve always felt that OTK brakes give a terrible feel, unless you’re progressive with them, while my Ital-kart and Intrepid brakes gave better modulation.

It also depends on how well your brake system is maintained and pedal/brake rod settings that will help with feel.

Most of the difference in brake feel comes down to Pad material. Gas grooves and cross-drilling to a lesser degree and more for initial bite.
Likes others, I didn’t not like the OTK brake feel, so changed to FRIXA pads and it is a different beast. Also FIRXA use the latest Pad chemistry and principals, which means more consistent pedal in all weather and the brake rotor wear is next to nothing.

In short, start swapping out pads to you find something that suits your needs

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Not in karts, but in road cars the pad material had a huge effect on brake modulation. Stock had a big flat spot where the pedal pressure yielded no increase in stopping. the all of a sudden it would stop more. Braking didn’t feel linear. A change to performance friction pads gave so much better feel of pedal modulation.

Besides what is listed above
On your kart I would make sure all pistons were free and do a major maintenance over the winter. Also check the rotor warp, misalignment and major chips on the edge. Check that the caliper is aligned and not moving.

Of course make sure brake pad and rotors are cleaned and not contaminated.

Coming from cars has its challenges. I think the timing is one aspect. The lack of suspension make any road surface bumps easier for brake lockup to occur.

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I 100% rebuilt brake system.

New pad
New Rotor
New piston in caliper and master
All no seals
New Brake line
Check and reshim rotor.

Brakes still like a switch just slightly more powerful than with old pad and rotor.

@Jamie_Gonzalez I believe most people understand you have rebuilt the brake system. In that case, the fact that they behave like a light switch is arguably a good sign, as this means they are functioning well. What some are attempting to explain is that you may want to consider different types of brake pads, as different ones utilize varying materials, and therefore will affect braking feel. Just by changing your pads to a less ‘robust’ or aggressive material (inquire with Swiss Hutless reps), you can substantially change how your brakes feel.

I am striking out with alternate pads. Only 1 compound from Swiss Hutless and looks like ebc and frixa do not make a compatible pad.

Dumb question maybe but have you tried any other karts to see if they are any different?

Dom

I drove a top kart on one occasion them purchased a used kart. So I dont really have much feedback from other chassis/brake combo.

I have only driven 5 or so racking karts but brake feel hasn’t been wildly different across them. Maybe you can ask a few people if they are willing to let you try theirs for a lap or two. If their brakes feel totally different then there’s your answer. I’m sure guys like TJ have driven all the different brands and can attest as to wether there is a lot of variance.

Yeah like I mentioned, I feel like most karts feel very on-off switch-like. The OTK is noticeably different. Way back when I drove Haase those were very progressive too but not sure how they are today.

As Eric noted, I think pad material is the biggest element. The good thing about the big manufacturers is that most of them have offer a couple options of pad materials.

Keep in mind that companies like Parolin build chassis for a bunch of different brands, so anything made by them is going to have similar brakes and components. There are several big manufacturers like that, who build 90% of the different brands you see at the track, using the same components.

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I want to ressurect this thread as I have a similar issue. I have a 2017 Intrepid Cruiser MS3 with ROK GP setup. The brakes will lock the rear wheels if you really mash the brake pedle, but don’t have much modulation - they feel on or off. I have driven a friends 4 stroke Intrepid with Briggs, and his brakes have a lot more initial bite, and give me more modulation when threshold breaking.

I had my kart to a kart clinic where we bled my breaks which helped to give the pedal more feel, but still doesn’t feel as good as my friends setup. Is it even a fair comparison to compre brakes from 4-stroke and 2-stroke?

Looking at the calliper, the pads seem to have a lot of pad on them. Rotors are not rusty or scored. They don’t look glazed.

Do pads break down over time? These are the original set of brake pads from when the kart was new 3 years ago.

Suggestions?

Brake clean the rotor and pads?
Sand the rotor and pads?
Replace the pads?
Replace the rotor?
Bleed the brakes again?

Help?!

Thanks!

Check what type of pads your friend is on…could be the compound

@Jgbedford your initial comment on having to really mash the brakes to get them to lock perked my ears up. I have a suspicion that your solution might be rather simple - brake leverage.

In the case of your kart, perhaps where the brake rod connects to the pedal is different compared to other karts and how you prefer the brakes to feel. If you want more immediate bit, consider raising (upward) the brake rod position on the brake pedal - most karts have multiple brake rod mounting points, some even on the master cylinder slave arm as well.

Before you do anything else, check these settings.

Other potential issues that are highly likely include needing to re bleed the brake system, or replace gaskets in the system. Over time these components very easily wear or develop small leaks. Also, other users are 100% right that different brake pad compounds will feel different in terms of pad aggression.