17mm spindle / 40mm axle verse 25mm spindle / 50mm axle in lo206

Chassis Setup, Tires & Handling Forum
1

im sure this has been covered, but could not find anything. Is a 17/40 or 25/50 setup preferred for lo206?

I am seeing a migration from 17/40 to 25/50 in new chassis, and I’m chassis shopping so I’m just curious

We purchased a new CRG FS4 and is has 25mm spindles, 50mm axle. I see MGM has switched to this, and I know its an option on Coyote karts.

The comet eagle, Margays, and other still are running a 17mm spindle and 40mm axle.

For reference the 2 tracks I will be running are very different. 1 low traction, one high traction.

Is there a preferred setup? I will be running masters. Currently leaning towards a CRG or MGM, but keeping my eyes open for used as well

2

It’s all personal preference and chassis design.

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3

If someone had the answer to this question, they would make a lot of money :slight_smile:

Burpo is right. Its about what you want the chassis to do. Its about tuning style, tire choice, grip levels, track layout, chassis design, driver size, class weight, (and probably 50 other factors).

The two fastest MGM drivers I know:

  1. One of them switched to 25/50 a few years ago and never looked back. He wins at tough clubs and runs up front at national races.
  2. The 2nd one runs a 17/40 winning championships at the club level and cannot get a 25/50 set up further up than mid pack.
4

If we could get the Enginerds and Mathemagicians around here to come up with some kind of equation/function… :thinking: :money_with_wings: :moneybag:

5

Agree with everything else stated above.

Totally depends on how your kart is designed to work. A softer front end will reduce scrub and not work the tire as hard, but at the potential expense of front grip. But your specific kart may work best with a stiffer front end, so there is no general answer. Most karts have a specific philosophy in how they work best and how to tune them, and this can vary a lot brand-to-brand.

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6

What tracks are you running? What kart have you been on previously? Are you a big guy? Maybe someone here can at least point you in the right direction.

7

Will be running at Tulsa kart club and north Texas Karters.

I ran an older margay bra a in Tulsa. Never worked well.

Im 6’, 220 or so

8

For what it’s worth the kart I’m building at the moment is going to be a 17/40. If by chance the 17 spindle gets bent I will replace that with a 25mm stub.

I think 40mm is a good size for the rear and if I bent an axle I would replace it with another 40mm.

Main reason I see karts going 25/50 is when they pump out the power. Like a 30HP Rotax.

9

i was under the assumption of the bigger stuff for more power too, but I see so many lo206 chassis going to 25/50. for what its worth, our FS4 is 25/50 and running in Junior 2 and we are really liking it. May move to a soft axle next season to see how that changes it up, but its been a good kart and pretty east to tune

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10

Question is are the replacing 17/40 to go to 25/50 or is it the natural progression of 99% of karts are now 25/50 from the factory? So any new chassis will be 25/50.

If someone is buying new stubs, new axle, carriers, brake and sprocket, plus wheels to go 25/50 I’d be interested to find out.

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11

A bunch of the MGM guys bought all new 25/50 stuff to replace 17/40 setups 2-3 years and now they are shipping the majority of them with that setup.

Overall, you’ll see 90+% of a field on 25/50 in 206 now. The few exceptions are some leftover MGM guys who prefer the feel, Comet Eagles, Birel AM29, and VLR.

I HATE 17/40’s feel.

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12

I’ve not driven a proper race kart before. Just heavy rentals. Can you tell me what they feel like and how they compare between 17/40 and 25/50. I’m assuming the 17/40 feels more mushy?

And I just spent a few hours swapping parts from 25/50 to 17/40 chassis! lol