33" or 35" tires???

Discussion in 'Shop - Suspension & Steering' started by sickdayz, Dec 15, 2010.

  1. sickdayz

    sickdayz Member

    Joined:
    Jul 1, 2008
    Location:
    Jamestown, CA
    I wasn’t sure where to post this, so I thought “suspension” would be a good place.

    I have a small class 1 car that a race in the VORRA series. I have plenty of motor (about 500hp) and the 2D with 930 CVs and axles. I have been racing this setup for over 2 years and have only broken the axles a few times. That’s right; the 2D has been very good to me. I was using the Gear One 300m axles that do not have a shoulder, meaning the top of the splines are the same diameter as the axle center section. Those are the axles I have broken. I am now running 300m axles from KarTek; the ones with the center axle section that is the same diameter as the bottom of the spline. I have been told that these will be stronger.

    Anyway; I have been thinking about running 33’ tires instead of the 35’ that I run now, so that I would have less rotating mass. My question is, what is the advantage of running a 35’ over a 33’? Is it just the ground clearance? Is it that the larger diameter tire rolls easier over bumps? Traction?, any input would be great…

    I really think the 33” would be better for my car, but I don’t want to give up anything else that might be more important. Here is a pic of my car:
    [​IMG]
  2. bigtex

    bigtex Active Member

    Joined:
    Aug 19, 2009
    Location:
    Escondido. ca.
    I run 33's on my 1400 truck currently and on another 1400 truck I used to race we ran 35's and man I wish we had 35's on the current truck,yeah its nice in my axles and bearings but you do feel more holes,bumps,rocks...and when you come out of like a check pionts and the track has gotten like a washboard MAN you feel that too more,I would say stay with the 35's.hope this helps.
  3. sickdayz

    sickdayz Member

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    Jul 1, 2008
    Location:
    Jamestown, CA
    Thats the kind of info i'm looking for. Real world exp... Thanks...
  4. sickdayz

    sickdayz Member

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    Jul 1, 2008
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    Jamestown, CA
    50 people viewed this topic and only one has enogh experience in this to post...? wow...
  5. 43mod

    43mod Active Member

    Joined:
    Jun 15, 2008
    Location:
    colusa california
    order the 33s.when you find out they run rougher and give you less diff clearance you can make me a deal on them.33x10x15 will fit my TL just fine(baja ta).
  6. sickdayz

    sickdayz Member

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    Jul 1, 2008
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    Jamestown, CA
    No one asked you... Go back in your hole...
    I don't have a diff, i'm a buggy dork...
  7. KevinT4R

    KevinT4R Member

    Joined:
    Dec 6, 2010
    Location:
    Whittier, CA
    I just went from 33's to 35's on my 4Runner. Aside from gaining ground clearance, I found a few more advantages.

    --More sidewall (I've used 16's with both 33's and 35's) gives a smoother ride that you can really feel over small stutters.
    --Better floatation in soft sand
    --Improved wheel protection because there's more sidewall between the wheel and the dirt
    --Bigger tires mean smaller holes

    Drawbacks, of course, are greater fuel consumption, more strain on wheel bearings, more strain on steering parts, etc.

    It looks like your buggy has more than enough power and chassis strength to handle bigger tires. Go for it!
  8. 43mod

    43mod Active Member

    Joined:
    Jun 15, 2008
    Location:
    colusa california
    sure you have a diff,it gets closer to the ground every time the rear goes into bump.Mine stays at the same level all the time.if we were running rougher tracks i would bet you would be looking for 37s
  9. BRINGTHERUCKUS

    BRINGTHERUCKUS Nimrod de PMC

    Joined:
    Apr 28, 2005
    Location:
    Parker/Tucson, Arizona
    Keep the 35's i bet youd hit the skid plates more with 33's (less ground clearance at bump) and that crap hurts...
  10. sickdayz

    sickdayz Member

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    Jul 1, 2008
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    Jamestown, CA
    Thanks guys... Actually, when i build the rear shock mounts I set it for 4" of clearence with 33" tires at full bump, so that will still work...

    I'm leaning toward keeping the 35".
    BRP, 37" would for sure destroy my tranny...
  11. atomicjoe23

    atomicjoe23 Well-Known Member

    Joined:
    Feb 2, 2008
    Location:
    Silverdale, WA
    Things to think about. . .

    Section Width. . .if the section width of the 33" tire is skinnier then you will have less rolling friction, but less traction.

    As previously mentioned and in answer to your questions. . .35's will have greater ground clearance and you will roll over obstacles easier and you won't dip as far into holes as you would with 33's (depending on the size of the hole of course. . .).

    Questions about the axles you are currently running (Kartek) vs. the axles you were running (Gear One). . .where did they break at???

    . . .concerning the splines, do the Kartek axles you are currently running have a raidus between the spline O.D. and the axle O.D.? What about the Gear One axles, did the splines just end in a square shoulder or did the end of the spline grooves have a radius where they joined to the axle O.D?

    If one axle had a radius junction and one did not, that is the reason you are seeing a failure from the "stronger" Gear One axles (assuming everything else is equal. . .i.e. quality of the metal used, heat treat and temper, etc.) and not experiencing failure from the "weaker" Kartek axles.

    Assuming everything else is equal (I don't have these axles in front of me to look at, I don't know what they were heat-treated to, and what they were drawn back to post-heat treating) the Gear One axles should be stronger, but apparently they are not. . .so I'm assuming that it must be in the transition area from the splines to the actual axle body. . .

    I would be interested to hear about this. . .casualty of the trade I suppose!!!
  12. sickdayz

    sickdayz Member

    Joined:
    Jul 1, 2008
    Location:
    Jamestown, CA
    Hi Joe,

    I am thinking about running the same width tire, so that would remain the same. I was only looking at the advantage of a lower rotating mass. It seems that the down sides are as I suspected, a little rougher and ground clearance....

    Anyway; as for the heat treating of the axles, I don’t know the exact procedure, but would assume they are doing what they believe to be the best. Being that they are selling them all the time. They are both 300m.

    The Gear One axles have broken in the splines on the trany side all three times; once on the right side and twice on the left side. The splines do have a radius. See picture below.
    [​IMG]

    The KarTek axles are radiused down just behind the splines. See the picture below (Kind of hard I know).
    [​IMG]

    From talking to others they tell me that the KarTek design is stronger because it transfers the load more evenly. We’ll see…
  13. bigtex

    bigtex Active Member

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    Aug 19, 2009
    Location:
    Escondido. ca.
    I went and wieght one of my 33 wheel and tires and a 35 wheel and tire both are goodyear mtrs and their was only a 9.15lbs difference,so I think you will only reduce the weight so little that the advantage goes to the 35's because your tires will not fall into as many hole/chop which will help your axles last longer rather then falling into the holes and/or losing ground contact which axles do not like.
  14. sickdayz

    sickdayz Member

    Joined:
    Jul 1, 2008
    Location:
    Jamestown, CA
    I hear you, but keep in mind that 9lbs of unsprung weight is a lot and then reducing the diameter, which brings the weight radius closer is also an advantage. But I think your right; I’ll probably wish I’d kept the 35". Until I break that first axle again... :)
  15. socalmoto

    socalmoto Member

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    Oct 26, 2008
    Location:
    san luis obispo, ca
    1450 truck. I was amazed at the difference when we switched to 35s. It really does make bumps and large two tracks feel like not much is there. When we had 33s we could accelerate quite a bit faster. In the dunes we we able to get up to 98mph on 33s and with 35s i think weve topped out around 87 (all on gps). We had 33" bfg ats at 62lb per wheel+tire and the 35s we have now are bfg projects that weigh in at 112 per wheel+tire. Although the acceleration was slowed down a lot we are still a whole lot faster because with the 33s wed start hitting too hard and have to get off the throttle, the 35s we are able to get much higher speeds in the same sections. Stick with 35s, but it wouldnt really be that hard for you to find some used 33s at a tire shop and toss them on some wheels so you can try it yourself during a prerun. Time yourself and see what the difference is.
  16. DBMETALWORX

    DBMETALWORX Well-Known Member

    Joined:
    Jul 11, 2007
    Location:
    BUCKEYE AZ
    From looking @ the pix I say Kartek is the one, w/the smaller diameter on the axle. That will let it twist over the whole length, rather than @ the spline which is smaller diameter on the Gear 1..
  17. NIKAL

    NIKAL Well-Known Member

    Joined:
    Nov 20, 2004
    Location:
    San Diego
    One thing to think about is your car has 500 hp going threw 930 cv's and a Mendi 2D on 35's. Your axles might be acting like a fuse and this might be why your 2D has been so good to you. If you get stronger or bigger axles you might be trading axle failures for gear box failures. Because you could be moving your weak point from the axles to somewhere else. Just something to look at and consider. I'm sure if you called Mendeola they would tell you that you are beyond the limit of the 2D.

    Per Mendeola's website 2D specs.
    Max tire 33 inch BFG (Shaved)
    Max weight 2,200 lbs
    Max HP 375
    Applications: Sand Buggy, Lite Prerunner, class 10 or 12.
  18. DBMETALWORX

    DBMETALWORX Well-Known Member

    Joined:
    Jul 11, 2007
    Location:
    BUCKEYE AZ
    True, but the Kartek axles having a smaller diameter than the spline, lets it twist like a torsion bar, where the Gear 1 axles were smaller @ the spline. Making the spline weaker, since it's cut into the diameter of the axle rather than having a radius from the spline to the axle OD.. Does that make sense???
  19. NIKAL

    NIKAL Well-Known Member

    Joined:
    Nov 20, 2004
    Location:
    San Diego
    Sure that makes sense, but the fact that he is running a bigger tire and HP then the 2D and a 930 cv axle are really designed for is probably more the issue then the axle itself. The fact that the axle is continually twisting could be causing the failure too? A 930 axle is only 28 spline and a 934 is 33 spline or you can get the bigger 35 spline. I know in the past when I was racing in the in-house Jimco 10 car we used Pro-Am's mid board hubs, 934 cv's and axles with 33 BFG Baja's and a type 4 vw engine. We were under powered for our driveline, but never had a part failure. I still think he has too much tire and HP for his driveline setup. Sure he can move up to 934 cv's and axles, but I think when he does he will see failures in his gear box.

    Sickdayz,
    Just out of curiosity does your car run a mico stub setup or does it have a mid board hub? Also what is the axle length? Because the longer the axle the less leverage is needed to twist it.
  20. burninfuel

    burninfuel Active Member

    Joined:
    Jun 27, 2009
    Location:
    Fish Springs, Nevada
    943's gundrilled from TCS, tubes twist better than solid, less weight. try it you'll like it.
    I think the splined broken area is from tooo much heattreat and not bringing them back to a lower tensile rating, 500hp and 930's sound like an issue from the start.
    Last edited: Dec 17, 2010

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