450 Axle recommendation

Ducats

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I'm running RWYB class with an Ultramax Excentrik and CRF450R. I'm going to be replacing the rear axle and was thinking chromoly 1 1/4 dia 1/4" wall. I was wondering if there were better solutions with this hp or just stick with 3/16" wall axle?
 
1/4 that’s a lot0 stiffness if that’s what actually looking for . With inboard chain pulling so close to a bearing hanger . I wouldn’t see any benefit of that thick of axle .
 
Thanks for the input. I haven't been on the track yet, it's 1/5 mile (by Mychron) clay hard packed track, and fairly flat. Track is primarily used for motorcycle flat track racing. Not sure if stiffer would be better or not?

Never thought of solid aluminum.
 
Thanks for the input. I haven't been on the track yet, it's 1/5 mile (by Mychron) clay hard packed track, and fairly flat. Track is primarily used for motorcycle flat track racing. Not sure if stiffer would be better or not?

Never thought of solid aluminum.
Alot of the outlaw kart running 250 and 450 platforms use the solid aluminum axle and say you can feel the track alot better. QRC sells the axle right on their site.
 
You can't translate almost anything from QRC driving style to ours, unless you plan to drive a UAS/RWYB style kart like a QRC through the corners. They use a completely different setup and driving style that does no translate to ours. If you drive like a QRC kart, you'll be lapped in a matter of seconds.

Stick with a stock axle and change it every season.
 
You can't translate almost anything from QRC driving style to ours, unless you plan to drive a UAS/RWYB style kart like a QRC through the corners. They use a completely different setup and driving style that does no translate to ours. If you drive like a QRC kart, you'll be lapped in a matter of seconds.

Stick with a stock axle and change it every season.
Understood, why don't you like the solid aluminum axle? Does it change the way weight transfers that much?
 
Just from the very very limited knowledge I have of material science, a solid aluminum axle is still softer than a standard thickness steel axle. Now, without getting into a lot of detail suffice to say that unless the track is a no bite track, loose dirt, where you're running treads and QRC style driving, an Aluminum axle is just too soft. At least from my very limited knowledge, and I could be wrong. But, I'd like to see hard numbers, and I don't know where to find them if they're out there.

Now, I'm not talking near failure, as NONE of the axles will ever be remotely close to failure at any point, so that's not even a consideration. It's all about handling.
For example he's looking at going to a thicker steel axle.
A thin wall kart axle is around .125 or an 1/8.
Standard axles are about .1875 or 3/16. A LOT of standard axles are .190 thickness.
Thick wall Axles are .250 or 1/4.

They don't mention the year of the Excentrik, but even the 10-11 are fairly stiff in the rear. My personal opinion from experience with an Excentrik, especially 12-13 models are very stiff, so when looking at things from a handling perspective, unless they're trying to "Fix" an issue, the standard axle is sort of the Goldie locks of axles. It's just stiff enough, but will degrade over the season if it's run hard on higher bite tracks. But, offers enough flex to still hook up on lower bite tracks too. So while a thick wall axle might not be a bad idea, it could potentially hurt on lower bite tracks, potentially to a point that it just will be very hard to ever get enough drive. I struggled with this a lot even with a standard thickness axle. So I opted to stick with the standard axle. If they choose to go with a thick wall axle I won't say it will be a bad idea.
 
Just from the very very limited knowledge I have of material science, a solid aluminum axle is still softer than a standard thickness steel axle. Now, without getting into a lot of detail suffice to say that unless the track is a no bite track, loose dirt, where you're running treads and QRC style driving, an Aluminum axle is just too soft. At least from my very limited knowledge, and I could be wrong. But, I'd like to see hard numbers, and I don't know where to find them if they're out there.

Now, I'm not talking near failure, as NONE of the axles will ever be remotely close to failure at any point, so that's not even a consideration. It's all about handling.
For example he's looking at going to a thicker steel axle.
A thin wall kart axle is around .125 or an 1/8.
Standard axles are about .1875 or 3/16. A LOT of standard axles are .190 thickness.
Thick wall Axles are .250 or 1/4.

They don't mention the year of the Excentrik, but even the 10-11 are fairly stiff in the rear. My personal opinion from experience with an Excentrik, especially 12-13 models are very stiff, so when looking at things from a handling perspective, unless they're trying to "Fix" an issue, the standard axle is sort of the Goldie locks of axles. It's just stiff enough, but will degrade over the season if it's run hard on higher bite tracks. But, offers enough flex to still hook up on lower bite tracks too. So while a thick wall axle might not be a bad idea, it could potentially hurt on lower bite tracks, potentially to a point that it just will be very hard to ever get enough drive. I struggled with this a lot even with a standard thickness axle. So I opted to stick with the standard axle. If they choose to go with a thick wall axle I won't say it will be a bad idea.
ABR thanks for the input.

It is a 2013, I have not had it on the track yet to know how it will handle. I just know that the previous owner ran the kart for a season and did not replace the axle and no idea when it was last replaced.

The primary track I will be running is a clay hard-packed track that is primarily used for motorcycle and ATV flat track. The clones are running Yellow Vegas and the RWYB class is mostly running treads. My goal is to run slicks going to start with Yellow Vegas.

If you want to humor your self start at 7:00; a video I found on YouTube.
 
Are the clones hooking up on the Yellows? If so, I'd definitely start there and if you can get it hooked up you'll be faster for sure. I'm going to say that a Standard axle is going to be your best bet.
 
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