Topic: 1 1/4 Axle Bearings

[slow_mow]

Does anyone know if a bearing is made for a 1 1/4" axle bearing that will fit in a 1" axle cassette?  Looking at upgrading to a 1 1/4" axle this coming season, but would rather not have to cut my chassis up to do so.  Right now I'm using the 1" bearing kit from BMI:
http://www.bmikarts.com/item/1-Bearing-Kit-3-hole-400400-711

And maybe, to make this easier, does anyone know if the flangettes from this kit: http://www.bmikarts.com/item/1-1-4-Bearing-Kit-3-hole-400415-5973 have the same bolt pattern as the 1" kit?

Thanks in advance



 

[Rooster]

I can tell you that typical 1" Flanges do not fit typical 1 1/4" bearings.
As to whether you can buy a bearing that will fit, I do not know.

However...
Going from a 1" to a 1 1/4" axle is not necessarily an upgrade...

I have kept from posting this for a long time just because I did not want to hear the fight.....but I hate to see you go to alot of work for no reason! So here it is.

1 1/4" dia, 1/4" wall tubing is only slightly stronger than 1" solid bar of the same material.
HOWEVER, once you cut an 1/8" deep keyway into that tubing, it is significantly WEAKER than a 1" solid bar with the same 1/8" keyway.

Now there are advantages to the 1 1/4" tubing, the bigger bearing will spin more freely.
Personally, on my new build I am going with 1 1/4" simply because of parts availability.
When your at the track, something happens, everyone has 1 1/4" parts. My team mate runs 1 1/4", so by going with that we do not have to carry as much spare stuff!

But as far as strength goes, the 1 1/4" axle is not an upgrade. Add to that you can get some alloy 1" axles like I have on my current mower that are MUCH stronger and lighter than the 1 1/4" chrome. I think chopping up your chassis to make the switch would not be wasted effort and money!


OK...you can all tell me how wrong I am now.

[slow_mow]

Rooster,
  Thanks for the advice.  Early in the season, I bent a 1" aluminum axle, but since then have switched to a fairly expensive steel axle and have yet to have a problem.

  My big worry is that I'm building an engine this winter, and wasn't sure if the 1" would hold up.  Maybe I'll just give it a shot.  My worst case scenario is to buy a 1 1/4" aluminum cassette and drill and bolt it to the 1" hangers already welded into my chassis.

  If it does come down to going 1 1/4", if anyone knows of a bearing that would work, it would still be greatly appreciated.

Thanks   

[mopar218]

I used to race karts on dirt and I use to get the ultra free rolling bearings that is the way to go they cost more but worth it they lasted two seasons on a kart

[trbinrat]

1 1/4" dia, 1/4" wall tubing is only slightly stronger than 1" solid bar of the same material.
HOWEVER, once you cut an 1/8" deep keyway into that tubing, it is significantly WEAKER than a 1" solid bar with the same 1/8" keyway.

Ok Jon you've got me thinking is this based on calculations or eggperience

But as far as strength goes, the 1 1/4" axle is not an upgrade. Add to that you can get some alloy 1" axles like I have on my current mower that are MUCH stronger and lighter than the 1 1/4" chrome. I think chopping up your chassis to make the switch would not be wasted effort and money!

Unless your running Ti axle I think your wrong on the weight issue. A 1" chrome axle 36" long weighs 10lbs and a 1.25 x .250 wall 36" chrome axle weighs 8lbs. Now if you factor in the the smaller bearings for the 1" axle and the slightly heavier wheel hubs. I still think your 2lbs heavier


Mark

[Rooster]

Ok Jon you've got me thinking is this based on calculations or eggperience
Unless your running Ti axle I think your wrong on the weight issue. A 1" chrome axle 36" long weighs 10lbs and a 1.25 x .250 wall 36" chrome axle weighs 8lbs. Now if you factor in the the smaller bearings for the 1" axle and the slightly heavier wheel hubs. I still think your 2lbs heavier

Mark

The material strength is calculated/ simple physics.  When you cut the key way in the 1 1/4" tube you really kill its strength.

The alloy Axle I have is not chrome, honestly..I don't even know what it is? It was given to me, it originally looked very similar to an Azusa axle. I do not know what the stuff is, but it is light and strong. We have run machine ability and hardness tests on it and a simple bend test with a compareable piece of chrome tubing. This thing held up to twice the pressure of an un-keyed chrome tube! We just cannot figure out what it is! First look you think it is aluminum, but it rusts...and it is a bit heavier and alot stronger than any aluminum I have ever messed with.

[trbinrat]

Sounds like interesting stuff. Do you remember what the hardness was and how much it weighs per inch.

Thanks
   Mark

[Huffy044]

Rooster, I totally respect your opinion, however, I feel the added diameter of the axle greatly adds to the strength. I have been airborne many times with some really exciting landings, (look at my avitar), that is a Mod-X in flight. Knock on wood I have never bent a axle. However many of my fellow racers have. Again, not trying to start a contest here, just my opinion.

As to the question about the bearing, not sure what your asking, all the go kart companies sell the 1 1/4" cassitte type bearing, they are farily inexpensive?

[slow_mow]

As to the question about the bearing, not sure what your asking, all the go kart companies sell the 1 1/4" cassitte type bearing, they are farily inexpensive?

Tommy,
   I realize that, but what I was looking for was a 1 1/4 bearing with the correct o.d. to fit in my 3 bolt steel flangettes that I'm using on my 1" axle, if you click on the BMI links in my first post, you'll know what I mean.   

 Here's a picture that may give a better idea of my set-up:

[leadslead]

Are those the horses shoe ones o. Your mower to hold bearing

[slow_mow]

Yeah, they're the horseshoe shaped mounts

[BIG AL 202]

SO Rooster you are telling me I did good by making my axles out of t.g.p.!   I like TGP it's easy to work with and seems to be strong.

[Huffy044]

Slow Mow, I had 3 bolt flanges before I switched over to the adjustable cassitte, the new adj. cassitte hole bolted up to the 3 holes that the 3 flanges had. The adjustable cassetts are worth the money and trouble (If they dont bolt up for you) they are invaluable for weight jacking and squaring your axle in the chassis. If you send me the OD of you present bearing, I'll compare it to my 1 1/4" spare bearings.

[slow_mow]

  Huffy,
      If you have the bolt spacing on a 1 1/4" adjustable cassette, that would really help.  If they would bolt up, that would be the ticket, if not, like I said earlier, If I choose to go through with the axle change, I could always drill new holes in the hangers to accept the adjustable cassettes.  Still, a bearing that would swap right in would be the simplest route.

    I do know that standard 1" axle bearings have a smaller O.D than a 1 1/4" bearing. We just got another mower with a 1-1/4" axle that I got new bearings for, and they are obviously (to the eye) bigger.  I also know the bolt spacing on the aluminum cassettes in this mower (non adjustable) are farther apart than the bolt spacing on the cassettes in my mower.

   Now that our season is completely over, I'll begin tearing my mower down, and getting ready for 2012.  I'll report back when I get the O.D. of the 1" bearings.

Thanks for the input.

  

[slow_mow]

After more research, I think this answers the bolt circle question:
http://www.bmikarts.com/item/1-Aluminum-Bearing-Cassette-400151-5915

1 1/4" Cassettes have 3- 3/8" bolt holes on a 3 9/16" bolt circle

1" Cassettes have 3- 5/16" Bolt Holes on a 3" bolt circle

Does this sound right?