84 replies to this topic

[Rick]

I have been wanting to ask this question publicly for some time, hoping someone else would bring it up.

What is your experience with the two configurations?
Which do you prefer, WHY?
IYO, is one faster than another? How much faster is one over the other?

It would also be nice if the fast guys and expert builders chime in and relate.

[slotcarone]

Rick every retro chassis I have ever built has been hypoid style. I have never had any problems with gears. The lower mounted motor gives a lower CG which can't be a bad thing so I see no reason not to build this way.

[Phil Irvin]

Rick,

I have used both and I can't really desern much difference. I have two triangle that are very slightly different in the center section plus straight Vs hypoid. Depending on the track....... Maybe .05 difference between the two.....And flip a coin as to which is faster. The hipoid is more consistent in a 10 lap run but-----------

OLPHRT
PHIL I.

[Tex]

I've leaned towards hypoid but have built non-hypoid too... mainly due to what motor brackets I could get at any given time. I've leaned towards hypoid because of the lower CoG mentioned. But at my last race, I went with my non-hypoid chassis instead of the hypoid chassis(YES, I now have TWO chassis'!). Both chassis' handled well but the non-hypoid was consistently faster by a tenth or more. I don't know that I ever did any serious back-to-back testing before... probably due to lack of a 2nd chassis of a different configuration to compare to. What I think I need to pay very careful attention to and test for is to make sure I keep hypoid gears separate from non-hypoid gears and to break both sets in properly. I think I was just swapping the same crown gear back and forth between the chassis' during testing; this may have been the cause of the hypoid's lesser performance, don't know for sure. Admittedly, I was pre-disposed to use the hypoid chassis but my testing showed me that it would be counter-productive to do so. For ONCE, I did the "right" thing instead of bull-headedly forging ahead with a lesser performing car just because that's the car I originally wanted to race.

[Pablo]

Use a Swiss Versa-Bracket and get the best of both worlds; fully adjustable.

[Rick]

The question has nothing to do with anyones specific product. It is a legitmate question as to builders/racers experience e.g. Katz.

[Mark Wampler]

While the performance comparison vs conventional bracket is inconclusive, this one is for SURE. A simple gear setup, with a conventional bracket, you’re guaranteed a good gear mesh.

My theory is that hypoid setup will tend to slide a car in the corners with .812" tires, while a conventional motor/axle configuration will give you better bite in the corners. The .050" rear clearance isn't going to allow significant low CG to make a serious impact on handling in a hypoid environment, IMO. Low CG is more proficient in mid to front of chassis.

And... while some of the hyper-poid addicts seem to be dogmatic, they are entitled to their opinion as much as mine.

Hypoids:

• Each hypoid setup may vary in offset degrees and thus gears have to be worn in to that specific chassis.
• There cannot not be any transfer of crown gears between cars unless the hypoid setup is exactly the same. Hypoid gears cannot be transferred to a conventional setup.
• It is more likely that there will be an increased power loss to the tires via hypoid as opposed to conventional.

Conventional:

1. Crown gears are easily transferred between chassis in a conventional setup

2. More power is transferred to the rear tires.

3. Smoother gear mesh equals longer life of the gears.

I’m super opinionated on this topic, but this is a friendly discussion

[MantaRay]

I like hypoid, lower CoG, easier to build.

[Cheater]

I’m super opinionated on this topic, but this is a friendly discussion.

And here's hoping it stays that way. I've already had to clean up a few things that didn't need to be posted.

[Hangtime]

I don't know. I'm guessing Hypoid is a chassis style or a new phone???

[Mark Wampler]

And here's hoping it stays that way. I've already had to clean up a few things that didn't need to be posted.

Thanks, Greg. I have nothing else to post here.

[Cheater]

Rick,

Hypoid refers to contrate (inline) gearing.

In non-hypoid gearing, the centerline of the pinion and the centerline of the crown gear intersect.

In hypoid gearing, the two centerlines do not intersect.

Here's a pic of a pair of hypoid spiral bevel gears:



Hypoid gears were first used by Packard to allow a car's driveshaft to be placed lower in the chassis.

[Hworth08]

Lowering the drive shaft is an advantage as there's less hump in the floorboard but hypoid gears are quite a bit stronger, especially the pinion gear, as the teeth are a lot longer than straight cut gears.

[Cheater]

True, and the downside is that hypoid gear teeth see a lot of relative sliding motion, much more so than non-hypoid gears. This is why hypoid gears (in cars and trucks) require special lubricants.

[Phil Smith]

I've leaned towards hypoid but have built non-hypoid too... mainly due to what motor brackets I could get at any given time. I've leaned towards hypoid because of the lower CoG mentioned. But at my last race, I went with my non-hypoid chassis instead of the hypoid chassis(YES, I now have TWO chassis'!). Both chassis' handled well but the non-hypoid was consistently faster by a tenth or more. I don't know that I ever did any serious back-to-back testing before... probably due to lack of a 2nd chassis of a different configuration to compare to. What I think I need to pay very careful attention to and test for is to make sure I keep hypoid gears separate from non-hypoid gears and to break both sets in properly. I think I was just swapping the same crown gear back and forth between the chassis' during testing; this may have been the cause of the hypoid's lesser performance, don't know for sure. Admittedly, I was pre-disposed to use the hypoid chassis but my testing showed me that it would be counter-productive to do so. For ONCE, I did the "right" thing instead of bull-headedly forging ahead with a lesser performing car just because that's the car I originally wanted to race.

Tex, there are too many variables for that comparison to have any meaning. There are a number of things that could cause one car to be faster than the other. Better chassis, better motor, better body, better set up, etc.

I'm deeply entrenched in the the lower CG the better camp. Not just the motor, everything needs to be as low as you can get it. There's a reason Hershman runs bodies lightly painted. The body and the paint is very high CG weight.

[Lucky Me]

True, and the downside is that hypoid gear teeth see a lot of relative sliding motion, much more so that non-hypoid gears. This is why hypoid gears (in cars and trucks) require special lubricants.

So,

In Retro inline as we currently know it, do we call it "almost" Hypoid? LOL... since the crown is not hypoid at all.

[Cheater]

Rick,

Well, the definition of hypoid is that the two gears' centerlines don't intersect.

The facts that we're using very crude toothforms on inline slot car gears and that the crown gears are made of a material with some level of self-lubricating properties is why hypoid works for slot cars IMO.

[Greg VanPeenen]

Gentlemen,

This is fact.

Hypoid gear sets have considerably more mechanical power loss during gear mesh than intersecting types of gears and as a result are less efficient. Period, end of story.

The straight cut gears we are trying to use in a hypoid set up make the above even worse. But that is what we have so we use it.

I myself use a non-hypoid bracket cut at an angle so the front of the motor is even with the bottom of the chassis. Or just use Mike Swiss's bracket; it does the same thing. Best of both worlds? Maybe, maybe not.

Hope you are working on those new brackets for me, Rick.

Regards,

Greg VanPeenen

[Brian]

I like the hypoid because of the low CoG.

I don't transfer gearing from chassis to chassis. I keep the pinion mounted on the motor, and the crown gears, 27t, 28t, and 29t, are kept in the box that houses the specific motor. When I have to replace a crown, I mount it, hook up the power supply, and use a lighter to run it in. I'm not a fan of slots in the motor bracket for adjustment, that's why ours don't have them.

Different strokes for different folks...

[Cap Henry]

I've built both, and used cars with both, and never noticed a performance advantage. In theory the lower center of gravity should benefit the car, but in testing there is no difference.

I've never noticed a motor seeming slower in a hypoid car then in a non-hypoid car. I prefer the hypoid brackets as they simply look nicer IMO with the motor flush on the bottom, plus it gives a little extra room to keep the lead wires out of the motor on low-mounted bodies.

[Rick]

Greg,

Nice illustration. I had entertained four years ago to have pinions made like that to mesh correctly in the non-centerline position, but finding that the tooling alone would be over $1,000 scrapped that idea fast. LOL.

[Duffy]

This is fact... considerably more mechanical power loss than... less efficient. Period, end of story.

Wo. Who let in the Buzzkill?

I'm not a fan of slots in the motor bracket for adjustment, that's why ours don't have them. Different strokes for different folks...

Slots are what we run our cars in, because they allow smooth motion along a prescribed track. This is why we don't want to put our motors into a slot. There, that sound stuffy enough?

Over the two years I've been back in this hobby I've been doing more homework than building, and more building than racing; makes me a poor racer and maybe a better builder. Something I regularly hear is, "A properly set-up so-&-so is just as good or better than a this-or-that." The gear mesh one's a perfect example, and a whole lot of the issue revolves around not what's best but what compromise you've convinced yourself is best.

Because, yes there is power loss in any gear mesh and measurably more as you go further away from simple sidewinder-style spurs; and on the other hand, a small percent of the motor's mass sits higher in the slanted, non-hypoid configuration, which disadvantage may be offset by less power loss...

... And, lacking real scientific testing with all variables isolated (including a machine as driver, to remove that big fleshy variable from the problem once and for all), we just won't know for sure. What we can be sure of is, the roller that we are most confident in is the one we'll drive the best; and whatever makes us confident makes us confident. It's Dumbo's "magic feather" in slots, and it is a very real thing indeed.

Does this statement add anything useful to the discussion?

I've been building with non-hypoid for a while now, and the reely-fast guys who try my cars say they perform as well as. I just don't know, but I suspect my misconceptions are no slower than the other guy's misconceptions, when the real battle is won between my trigger finger and his.

Duffy

[Lucky Me]

I prefer the 'power robbing" hypoid brackets myself. Just something about more mechanical power loss that I love.

[Cheater]

It's funny how the innate competitiveness of slot racers leaks out into different segments of the hobby.

Just as we all KNOW we're faster on the racetrack than anyone else (given the same equipment, of course) we also often insist our choices in design, body, chassis, controller, etc., are the best, the obvious choices, clearly superior, etc. LOL!!

The late Larry Shephard said the ultimate downfall of slot racing would be the inherent competitiveness of the participants. I still think the problem is manageable, fool that I am.

[Duffy]

The late Larry Shephard said the ultimate downfall of slot racing would be the inherent competitiveness of the participants. I still think the problem is manageable, fool that I am.

Damn! We SOOO need a "Like" button in the new format!!