Bearings, roughly

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kamml53

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This weekend it was warm enough in the garage to tackle the axle replacement. Easy enough for the experts but an anxious task to undertake for the first time for me. That is what held me back last season, he was winning so I did not want to fix it if it was not broken. Well it needs "fixin" for sure. The left rear bearing was rough and gritty and the lube ring looked like it had some rotational wear. The right side was fine and still smoothly rotating with no wear on the lube ring. It appears that the axle is still straight but I am going to replace it anyway and keep the old one as a backup. Removing the wheel hubs was easy but the brake hub and sprocket had me using my bastard to smooth up the axle so I could gently tap them off. My right rear hub has a gnarly stud so I will keep it as a spare and I ordered a new one along with a couple of lubrication rings. I tried to mount a free float sprocket hub but I cannot get the keyway to line up with the clutch gear so I am going back to the old one with the rubber chain guard, it works as we never lost a chain and it lines up fine. I am going to fix both bearings to the axle. I have read where some folks prefer to leave one free to float but my kart bible says use both set screws. After 10 hours away from home each day I don't have any energy during the week to work the wrenches but one more warm weekend and the axle will be bolted back in if my parts get here this week. Still need to clean and maintain the Bully, ultrasound wash the chain, and change the motor oil, then the back end will be finished. On to the front, saying a quiet prayer to the camber & toe gods. Still need to mount the new body, and scale the bugger, whew this kart work never ends.
 
I'm responding in an effort to help you going forward and not to criticize. The "if it's not broke don't fix it" approach doesn't apply to regular maintenance. Your bearings should be serviced weekly.

Good idea to replace your axle and keep the other as a spare. That's odd that you can't get the new sprocket hub to line up. I'd go ahead with what you have and take the floating hub to the track with you and ask someone to take a look at it with you. Sounds like the keyway slot position is what is giving you fits.

It's a good idea to replace the studs in the hubs. Be sure to not back messed up threads through the hub. You might be better cutting off the exposed portion of the stud before backing it out.

There's a lot of info on this site about pinning both axle bearings. If you're "anxious" about the process, I would encourage you to reconsider. Pinning one side and using axle collars is a more common approach and less likely to bind.

Usually the more effort you put in to being prepared and having properly maintained equipment yields better results at the track and pleasant ride home.

Good luck to you this season.
 
You didn't mention if you were replacing the bearings. I would as all bearings should get replaced at least yearly. Same with the chain. I know people will argue but the kart gets a new chain each year. As for the oil change... If you left dirty oil in it all winter, then that's a shame. I change oil before leaving the track and as soon as possible after the race is over. Letting the sludge from dirty oil sink & settle in the bottom of the crank case is a mistake that is easy to avoid.
 
kamml53 said:
This weekend it was warm enough in the garage to tackle the axle replacement. Easy enough for the experts but an anxious task to undertake for the first time for me. That is what held me back last season, he was winning so I did not want to fix it if it was not broken. Well it needs "fixin" for sure. The left rear bearing was rough and gritty and the lube ring looked like it had some rotational wear. The right side was fine and still smoothly rotating with no wear on the lube ring. It appears that the axle is still straight but I am going to replace it anyway and keep the old one as a backup. Removing the wheel hubs was easy but the brake hub and sprocket had me using my bastard to smooth up the axle so I could gently tap them off. My right rear hub has a gnarly stud so I will keep it as a spare and I ordered a new one along with a couple of lubrication rings. I tried to mount a free float sprocket hub but I cannot get the keyway to line up with the clutch gear so I am going back to the old one with the rubber chain guard, it works as we never lost a chain and it lines up fine. I am going to fix both bearings to the axle. I have read where some folks prefer to leave one free to float but my kart bible says use both set screws. After 10 hours away from home each day I don't have any energy during the week to work the wrenches but one more warm weekend and the axle will be bolted back in if my parts get here this week. Still need to clean and maintain the Bully, ultrasound wash the chain, and change the motor oil, then the back end will be finished. On to the front, saying a quiet prayer to the camber & toe gods. Still need to mount the new body, and scale the bugger, whew this kart work never ends.
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There's some concerns here that others may have already addressed...DO NOT lock the bearings with set screws to the axle on both sides. Not sure what kart bible you're reading, but it's heretical.
Sure, everyone's got their preferred method, but I know of no one who prefers to lock both sides down solid.
Make sure that you got the axle back in the correct direction. Also check if it was offset at all or installed straight up. Keyways are often machined specifically for hub locations. Also, you can "flip" a hub to get it to fit sometimes since the pinch bolt or key are off to one side (depends on the hub.)
Engine oil should be drained hot at the end of the race day to help drain out any contaminants that are suspended in the thinner hot oil before they settle to the floor of the sump. You can soak some mineral spirits in the block and drain again, then blast out with brake clean to try to get some of the junk that typically gets stuck on the bottom of the sump, then refill with fresh oil.

-----
🏁Thanks and God bless,
Brian Carlson
Carlson Racing Engines
Vector Cutz
www.CarlsonMotorsports.com
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35 years of service to the karting industry ~ 1Cor 9:24
Linden, IN
765-339-4407
bcarlson@CarlsonMotorsports.com
 
Thanks for all the input. I bought Phantom's axle/bearing kit for my Kart model, so I wouldn't have problems. And yeah, I should have changed the oil sooner, but my engine investment is only about twice the price of a gallon of synthetic racing oil. If this were a HiPo and I had a considerable investment, I would certainly be more judicious. But I appreciate your sentiment; it is a good practice, and yes, I can be lazy. My so-called bible is "Oval Kart Technolgy, Beginner to Winner." It advises securing both bearings to the axle. Previously only the left side was locked down. What is the reason for locking only one down? I know it pays to listen to experience.
 
kamml53 said:
Thanks for all the input. I bought Phantom's axle/bearing kit for my Kart model, so I wouldn't have problems. And yeah, I should have changed the oil sooner, but my engine investment is only about twice the price of a gallon of synthetic racing oil. If this were a HiPo and I had a considerable investment, I would certainly be more judicious. But I appreciate your sentiment; it is a good practice, and yes, I can be lazy. My so-called bible is "Oval Kart Technolgy, Beginner to Winner." It advises securing both bearings to the axle. Previously only the left side was locked down. What is the reason for locking only one down? I know it pays to listen to experience.
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I think you are fighting terminology. Most of us "pin" one side (I prefer the side my brake is on). A pin is what I think you describe above, a set screw through the bearing into the axle (axle is drilled for pin to be in it). Some leave the other bearing loose. Some, like me, "lock it" using axle collars. 2 pins are very difficult to get perfect that you are not loading or binding the bearing. It is also not adjustable. The collars help keep the binding down and allow for "changes" during the season.
 
Went back and looked in my OKT book and he actually does suggest locking both sides down.
Photo on 2-28-24 at 12.11 PM #2.jpeg
 
XXX#40 said:
Lol he stole most of that information from this site.
That's what happens when you buy a book written by basically a new Karter.
Just like the dude on Facebook try to get people to let him show them with technology, said he was dispelling old racing myths, when I ask whats myths, he blocked me.
"One born every minute' comes to mind.
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Not saying that it's 100% accurate, but there is a lot of good information in the book. I don't know the guy from Adam, but I know that he started racing in 1979... hardly a beginner. I also know that he makes it a point in the beggining of the book to point out that he is not an expert in all things karting, that he relied on information from many of the people that are, and thanked them for their contributions.
Is there a lot of great information on here? Yes, no doubt. Is it always easy to find? Not really. His book lays everything out in a way that is easy for beginners to follow along and obtain a basic understanding of various karting topics. Does that make this site any less beneficial? Absolutely not. So why bash it? In fact, why sit around and constantly bash people, which you love to do? People like you discourage people from participating on this forum.
 
The lock-collar method also keeps your axle from having stress-risers ground or drilled into it....I've had axles fail at the pinning hole before. Spiral fracture. I prefer double bolt collar:
1709156021161.png
 
According to the book, which lists specific tracks, as well as individuals by name, that he raced with, his first race was in 1979.
Again, I don't know him. Apparently you do, and you say that is not the case. Its certainly possible that he made it up.
Regardless of when he started racing, I am fairly confident that he was being truthful when he made a list of people to thank for helping him with the book. Just to name a few:
Harrill Wiggins, James Stanley JR. (sales manager at PRC, reviewed every chapter for accuracy), Todd Miller (provided his wisdom of engines to ensure the information Was precise), Enik Sander (owner of Outcast karts, technical assistance and review), Jeff Hargaten (President @ Noram Clutches, technical review), Donnie Nall (Owner of Insanity Speed Elixir, technical support)

Many of those individuals are considered among the leading experts in their specific field. They all had a hand in the book and the information that went into it. I doubt he made that part up. My guess is, you have never read the book, but you will not let that stop you from having an opinion about it. You seem to have an opinion about everything and love to make sure everyone else knows what it is.

If you look closely in the mirror you are holding, you will see one of those "one born every minute", looking right at you.
 
Another question. Why does PRC use a small rear hub on the left rear and a much bigger rear hub on the right? Is this to provide more axle bearing surface for the pinch bolt? I don't understand the size difference.
 
kamml53 said:
Thanks for all the input. I bought Phantom's axle/bearing kit for my Kart model, so I wouldn't have problems. And yeah, I should have changed the oil sooner, but my engine investment is only about twice the price of a gallon of synthetic racing oil. If this were a HiPo and I had a considerable investment, I would certainly be more judicious. But I appreciate your sentiment; it is a good practice, and yes, I can be lazy. My so-called bible is "Oval Kart Technolgy, Beginner to Winner." It advises securing both bearings to the axle. Previously only the left side was locked down. What is the reason for locking only one down? I know it pays to listen to experience.
Click to expand...
I wrote an article for our our Tech Talk Tuesday series on our Facebook page almost a year ago to this date...
Here is the link: >> Pinning Versus Floating
I hope that works - if not, go to our Facebook page and click on the search bar in the upper right of the page, and search "lock" and it should come right up.

Yes, there are many ways to pin or float your rear axle. I took the time to describe why I do it the way I do. Some manufacturers are very adamant about pinning a certain side or the other, some don't care once you paid your money, but I don't know of any that recommend pinning (or set-screwing) both sides of your axle.
 
CarlsonMotorsports said:
Yes, there are many ways to pin or float your rear axle. I took the time to describe why I do it the way I do. Some manufacturers are very adamant about pinning a certain side or the other, some don't care once you paid your money, but I don't know of any that recommend pinning (or set-screwing) both sides of your axle.
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In the sprint world, pinning both side is normal. I wonder how they get away with it, whith much higher side loads? I'm inclined to believe JPMKarting and that this is a pseudoengineering phenomenon in karting. Now if the bearings weren't in self-aligning carriers, I'd think differently...
 
CarlsonMotorsports said:
I wrote an article for our our Tech Talk Tuesday series on our Facebook page almost a year ago to this date...
Here is the link: >> Pinning Versus Floating
I hope that works - if not, go to our Facebook page and click on the search bar in the upper right of the page, and search "lock" and it should come right up.

Yes, there are many ways to pin or float your rear axle. I took the time to describe why I do it the way I do. Some manufacturers are very adamant about pinning a certain side or the other, some don't care once you paid your money, but I don't know of any that recommend pinning (or set-screwing) both sides of your axle.
Click to expand...
I think most of that came about when the rear z bar was moved so far forward to provide extra lateral support.
I used lock collars just to keep the axle from sliding.
 
kamml53 said:
Another question. Why does PRC use a small rear hub on the left rear and a much bigger rear hub on the right? Is this to provide more axle bearing surface for the pinch bolt? I don't understand the size difference.
Click to expand...
Pinch bolt, the RR is so close to the frame it helps keep it there.
The RR takes abuse.
Phantom isn't the only one that does it, pretty sure every one does.
 
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