Magnesium rims, what to buy

A guy crashed into me at my training session today, and smashed my rear rim.

The tecno rims are very expensive, so im looking for cheaper alternatives that are just as good/fast as the original magnesium wheels.

Does anybody have experience with different magnesium wheels and how they perform?

Thanks in advance.
Alex

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I DM’ed Alex with a more expansive answer but for those looking for a chart with the specifcs of the different wheels, I put a comparative chart here on my website - with most of the key details for the main wheels.

In the interest of full disclosure, I represent AMV kart components on the east coast, but I tried to provide an objective view of the key specifications in the table linked to above.

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Awesome chart, Paul! I’d be curious to know more about the different casting processes, and how that impacts the characteristics of each rim. Additionally, does the 67mm bolt pattern provide any significant difference in handling characteristics vs. the 58mm of the same wheel? What effect does wheel offset have on a) rigidity, and b) handling?

For context, I race in the shifter category aboard a DR Kart with an Iame SSE. Do the wheel recommendations change at all for the shifter category? Someone at AMV once told me (via FB message) that the Tiger is the ideal wheel for the shifter category due to it’s stiffness (more?). Thoughts? Very curious about the AMV line.

Great questions. I am in the process of doing a video on wheels differences with the guys at AMV. I will make sure these specific topics are answered in the video.

Here are the short answers. These are based on the information that I have received. As a disclaimer, I am not an engineer and I have not yet tested the different wheels first hand. I was hoping to do a vlog of track testing to provide some real-world information but Covid-19 has put that on hold.

-67mm v. 58mm PCD: I have been told there is no appreciable difference. Some kart manufacturers use the different bolt pattern so that is why AMV makes the different versions. You are not the first 175cc shifter pilot to ask this question

  • offset: a more inward offset provides more grip during the acceleration phase (center-off) of the corner. AMV state that the Tiger which has a more inward offset (63mm v. 58mm) and a longer 3 spoke design is more rigid.

  • wheel recommendations for shifter category: AMV recommend the Tiger as the starting point for shifter karts; for TAG the starting point is 3F. Matt Hamilton won G1 at the 2019 SuperNats with Tigers. Race Liberante ran both Tigers and 9Fs at the SuperNats. He had his fastest times on the Tigers and won the P2 final on 9Fs. I am in no way trying to suggest that Race or Matt won the SuperNats because of AMV wheels but simply they were one part of the overall puzzle. I don’t know Matt but I know Race liked the way 9Fs felt - he said he felt very confident on them.

The graphic uses TAG / OK karts as the starting point. For shifter karts, the ideal starting points move to the left a bit. Each wheel has a large performance envelope so don’t think of the wheels as discrete points but rather overlapping performance envelopes.

I hope that helps.

Forgot this one. Sorry.

The guys at AMV tell me the casting process is the biggest difference between their wheels and those of competitors. The AMV low-pressure casting process was specifically developed for kart wheels. The goal was to reduce the porosity of the wheel to alleviate the need for a coating to prevent air pressure loss. As you know, many companies either powder coat or put clear coat on their wheels. The paint/coating is an insulator and reduces the heat transfer properties of the magnesium wheel. The AMV wheels are not painted or coated. OXiTECH, as I am told, which is used to prevent corrosion is a fusion process which does not alter the heat transfer characteristics of the wheel. The gold wheels that preceded OXiTECH had a chromate treatment to prevent corrosion.

The rule of thumb is to start your cold pressures .5 to 1 psi higher with AMV wheels to account for better heat transfer and hence more stable tire temps over the course of the race.

Again I am not an engineer so this is a marketing guy’s dumbed-down version of what the guys at AMV told me so sorry if I got any of the technical pieces wrong. Please view this as a 30,000-foot explanation.

Thanks, Paul. Great info!

You bet. Any time :+1:

So I’m looking at it. And 9F for a 206? Harder tires use a higher grip wheel? Or I got that wrong?

9F is the free-ist wheel, optimal for the hottest days. Does your LO206 class run 11x6.00-5 or 11x7.10-5 tires in the rear?

I don’t know which tire compound you run + the tire width 6" or 7.1" but I have heard in 206 racing people are typically trying to free-up the kart. If this is your case, then I would go with 3F or 9F depending on how hot it gets in your area or how rubber get laid down on the track. If you are looking for more corner-off grip, then Tiger is the right choice.

3F is a great all-around wheel.

6.0 lecont red. In the Pacific Northwest. So heat isn’t to much ever. Haha.

And if the tracks don’t get too rubbered up, then I would go with Tiger. AMV_Wheels_Oxitech_Tiger_130%20212_v2_small