King Quad 300 Disc Brake Conversion Kit - Suzuki ATV Forum
Suzuki KingQuad 300 Discussions for the King Quad 300

  • 1 Post By Dan_Goodwin
  • 1 Post By Dan_Goodwin
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post #1 of 6 Old 12-04-2017, 03:36 PM Thread Starter
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King Quad 300 Disc Brake Conversion Kit

One of my biggest complaints with a KQ 300 is the drum brakes and their sub-par performance in wet and muddy conditions, especially here in the south where mud is almost unavoidable. Aside from finding the rare (and expensive) OEM parts, there really isn't another alternative to a brake upgrade that is cost effective and 100% bolt on. After some research, I may have found a combination of parts that would be.

After comparing some part numbers, an Eiger 400 runs the same outer CV stub shaft and bearings as the KQ 300, meaning the hub fits the KQ knuckle. The Eiger does have a different bolt pattern, so you would need new front wheels for this conversion to work. A cheap option is to find an 11" Honda front wheel if the aftermarket doesn't have an option. I recently bought new tires, so I will be going the Honda wheel route to keep my tires.

The next step, and biggest challenge, is to locate the caliper with some custom brackets, much like the Honda brake conversions. Below I will be documenting my first pass at making these brackets, which is currently a work in progress. Material is 3/16" steel plate, which is slightly overkill but will certainly hold up to the abuse.

The goal:

Click the image to open in full size.

Eiger hubs and calipers on a stock KQ knuckle.

A template and some free hand plasma cutting yielded this:

Click the image to open in full size.

Click the image to open in full size.

The caliper and bracket butt up to each other, so additional tabs will be welded on to bolt the caliper on.

If there is enough interest in the brackets I can see about getting them professionally cut and offering them as a kit. A very rough guess would be $65 for a pair of brackets shipped based on prior experience.

Feedback is welcome here!

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Last edited by Dan_Goodwin; 12-04-2017 at 03:40 PM.
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post #2 of 6 Old 12-17-2017, 10:22 AM Thread Starter
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King Quad 300 Disc Brake Conversion Kit

The more I got to looking at the bracket, the more tricky I knew it would be to make and I remembered When looking at the Eiger hub swap, I noticed that visually the Eiger knuckle looked really similar to the KQ. Knowing what little I do about the ATV industry and manufacturing, I got on ebay and ordered a cheap Eiger knuckle to see how feasible this swap would be, which would do away with needing the bracket. Below is a knuckle from a 2wd unit (same as a 4wd).

Click the image to open in full size.

As I'm sure you've noticed, no those aren't from the same side of the unit ( thats the only side I had off my KQ) and no the steer arm isn't the same BUT the Eiger knuckle does fit! It mounts identical to the KQ knuckle and keeps all the geometry the same. SCORE!

The plan to fix the steer arm/ tie rod attachment is to tap and thread the steer arm where the tie rod used to go and use a long grade 8 bolt and spacer to raise the attachment point to the stock elevation. The stock tie rod end will need to be changed to a heim joint to attach to the bolt. I realize that this will be putting a lot of leverage on the Eiger steer arm, but since the KQ isn't exactly a high speed race machine, I'm confident there won't be any issues. I am hoping to have 1 side mocked up in the next few weeks to test this out.

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Last edited by Dan_Goodwin; 12-17-2017 at 04:28 PM.
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post #3 of 6 Old 01-07-2018, 07:12 PM Thread Starter
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Made a lot of progress this weekend toward getting the brake swap done, despite it being really cold here in the south. Since I don't have a shop yet, I had to improvise.

Click the image to open in full size.

I've had the intention of adapting my existing wheels to the new lug pattern or running some kind of adaptor. It never occurred to me to check and see if there was enough clearance, considering drum brakes are generally a smaller package than discs. Well...

Click the image to open in full size.

The decision was made for me- new wheels ( and subsequently, tires) it is. I'll be ordering a set of 12x7 4/110 ITP Delta wheels to match the front and 24x8x12 Mud Lite tires sometime soon.

Calipers mounted and bled:

Click the image to open in full size.

The last piece of this puzzle is steering, which was the biggest reason for pursuing the bracket in the first place. After talking with some folks that know much more about steering geometry than I do, attaching to the new location wont cause any bump steer issues due to the limited travel on the KQ.

Since the location of the steer arm has changed, the stock tie rods are too short and won't work. The fix for this is to source 12mm heims, misalignment spacers and inserts and tubing, which I found online from Steinjager. The reason for the 12mm heims is that the misalignment spacers step the bore down to 10mm and the hole in the Eiger knuckle is 10.3mm (close enough). I dug through my stash of parts and found some tie rods from another project with heim joints already installed. The tie rod was going to contact the upper control arm mount if it's not spaced up off the knuckle like this:

Click the image to open in full size.

I happened to have a set of wheels off another project I slipped on to check for clearances to make sure the bolt wouldn't contact the wheel:

Click the image to open in full size.

I lucked out and the tie rod I found slipped over the stock one, but building from scratch wouldn't be hard at all. I'll be adding a sleeve around the bolt to add strength and might even add gussets to the knuckle.

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post #4 of 6 Old 01-22-2018, 08:00 AM Thread Starter
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I've been slowly chipping away at this thing and made some good progress in the past weeks:

The straight tie rods pictured before ended up contacting the frame and wheels before full lock, so I made a mock up using scrap parts to get an idea of what I needed:

Click the image to open in full size.

Test fit with new wheels:

Click the image to open in full size.

Click the image to open in full size.

1/2-20 heims, jam nuts, high misalignment spacers and inserts were sourced from Barnes 4wd and .875"x.065 DOM tube was ordered from an online metal store to build new tie rods:

Click the image to open in full size.

After using some heat to bend the tie rods, I came up with this:

Click the image to open in full size.

Click the image to open in full size.

You may notice the long bolt holding the tie rods to the steering- while I would have preferred to mount a joint top and bottom, there simply wasn't room to do that. I am going to add some kind of brace to help support that bolt. Note that all hardware is metric grade 10.9 for strength.

I got it assembled and took it for a test drive on the new wheels and tires:

Click the image to open in full size.

A few notes and observations- I'll be the first to admit I don't know much at all about steering geometry, so getting this setup dialed in will be lots of trial and error (heavy on the error). I am able to get full lock in both directions, so I believe I can adjust out the problems I'm having. I think it takes greater effort to steer now since I don't have the mechanical advantage that I used to, but its not bad. The heims I bought are Barnes Economy joints and I'm very pleased with them, but I do wish they were stiffer. Since the tie rod has a bend in it, it likes to flop around, so I had to get creative with adjustments to keep the rods from moving too much. This is a problem with my design and not the heims though. All in all, I'm pleased- having working brakes is a nice change!

So, to sum this swap up, you'll need:

-Eiger 400 knuckles, hubs and calipers
-4/110 wheels to match the new bolt pattern
- Custom tie rods and hardware

I'll keep this updated once I get the steering dialed in.
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Last edited by Dan_Goodwin; 01-22-2018 at 08:11 AM.
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post #5 of 6 Old 01-26-2018, 05:41 AM
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post #6 of 6 Old 01-26-2018, 11:23 AM
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Looks good man.

2008 king quad 750AXI

5000lbs badlands winch with wireless controller
Pro Armor plates (all plates)
Full SYA Warrior riser and snorkel kit
Wild Boar radiator relocation kit ( I hope to be changing soon)
Twin air filter
Dual batteries
Bison hunter series front bumper
EPI mudder clutch kit with EPI severe duty belt
2 inch highlifter lift kit
MSA m20 wheels with 28 inch maga mayhem tires
M109R injector
VDI copperhead ECM (not a very good idea)
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Front and rear demon axles (been trying to destroy with no luck) came from
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