I was at a non-206 four stroke race recently and too my suprise EVERY kart I came upon was running 3, which differs from what I’m used to in 206 where even karts with a 3rd cassette option, usually only run two cassettes.
Just out of curiosity, how many axle bearing cassette’s are you running on your 4 stroke kart? And what motor are you running in 4 stroke?
I ditched mine for weight and because I don’t feel the difference in having it tight vs loose. Many other changes I tend towards first before messing with the third bearing so I tossed it.
I had 3 but with the Tony Kart I have the chassis is stiff enough so I ditched it also
I run the 3rd Bearing on the axle but only zip tied to the chassis.
I find it to be a handy way of deciding whether to go to a stiffer axle. Also in the wet i can just throw the bolts in to switch to a wet setup.
I switch engines on my chassis but make the decision based on the tires rather than engine type.
If it’s a hard compound and I need some flex I’ll run two, softer (Medium) I’ll run the three if the track calls for it.
Never would have thought of that, very interesting. 
Three, possibly due to power levels. I don’t know of any shifter karts that only run two.
I ran the last few days last season without 3rd bearing in my shifter. The rear felt softer for sure but I dont know how it affects durability - is the outside bearing bracket or out most frame tube over loaded. I have asked from fellow racers have they done it or heard anyone running a shifter without 3rd bearing. So far have only heard that I should run with 3rd or the frame brakes. I feel like it is just rumors as I havent yet found one that has actually run without 3rd and broke something
The third rail tubing in my kart has cracked twice right in front of the third bearing housing - its been welded twice. This has happened while using the 3rd bearing. I dont know is the load/crack caused by axle bending in curves or load being applied via the chain. My guess its the load from curves : axle tries to bend downwards in the middle - that pushes the third bearing bracket downwards - frame tube gets worked over and over again until it cracks
So - what about you guys here at the forum - Do you shifter guys have experience about not using the 3rd bearing - is your frame ok? And if so - what is the diameter of your frame? Mine is 32x2 mm
11 years of shifter racing experience here, and I would never run a shifter without the third bearing, regardless of tubing size. My logic is that with the higher torque of the shifters you would want all the support and stability you can get around the axle sprocket. We’ve even seen guys reinforcing the bearing carriers in order to increase rigidity. I just don’t see anything to be gained by running without the bearing…
I understand alot of people are referencing 2 vs. 3 axle cassettes in shifters, But I wasn’t talking about those, that is why I put this in the 4 stroke forum so sorry for the confusion.
I took some of the advice and I must say I’m little suprised. Decided to run the 3rd cassette in LO206, but I put the third cassette is in there loose, not bolted, but zipped tied so the rear isn’t overly tight. Even with the 50mm axle, the rear end felt great and not too tight.
Plan moving forward is to run both Lo206 and X-30 on the same chassis for a while, at least until I decide to pick up a second kart at a later date. 
I really didn’t want to have to remove and reinstall the 3rd axle cassette every time I switch things over. So in Lo206 I’ll zip tie it in loose, and throw in the bolts when I run X-30. So good advice, thanks
I run X30 with it zip tied. Keep it there in case you find you need the extra rigidity but it’s not necessary to run X30 with the third cassette.
I’m 6’1 200lbs and come across the scales at 385. I don’t run the 3rd cassette on the x30 (I know this is a 4 cycle thread) I have found for me it just stiffens up the rear a little more than I’d like. Plus it makes changing axles just a tad easier.
interesting that none of you run the 3rd bearing tight in x30. Im putting mine together right now. And fully intended to run it tight. Guess ill have to do more testing on that.
Yeah just do a session with it tightened down and one not. My guess is you’ll run with it loose after.
Just fyi cable tying it in place serves no purpose in regards to set up, it just keeps it in place. Keep the ties loose.
Yeah im familiar with it. I for a long time ran with them zip tied when i ran 206. But especially in the cold and rain up here in the PNW i am going to assume ill want that extra bite until summer. Ill find out this weekend.
On an OTK kart stiffening the axle frees the rear up. If you’re looking for rear “grip” you’ll want it loose.
Yes sir. That was the plan to leave it loose for the colder climate. Damn backwards OTK.
If you don’t mind. What seat do you use, and did you move the pedals?
I’m 6’3” and beer gut.
Bryan who are you asking, I didn’t see you quote someones response?
Myles Bland post. Also need 20 characters lol
