MG Yellow SM2 Observations

Raced at NCMP for the opening round of their club series yesterday. I practiced on some OLD MG Yellows for the two rounds of practice, and then put on new MG SM2 Yellows for qualifying. Unfortunately we had our heads up our asses and were late to qualifying, so I only got one flyer and went P13. However, in the main we had very good speed, but only went 0.2-0.4" faster (mychron-Race Hero) vs. what I did in practice 2 on the old old tires.

I did observe what others have claimed to be true, that being the difference in sidewall stiffness from the old compound to the new. The sidewall on the SM2 is noticeably softer, albeit in KZ application at 410lbs, so pretty high load. For me the new tire is more difficult to drive, especially in the early stages of a race, and it requires smoother inputs than the old tire to ensure it doesn’t get overloaded. I think chassis setup will need to be a little bit different in order to optimize, as will driving style.

I’m not sure who exactly was on what, but there was a mix of folks using SM or SM2 throughout the field. I was the fastest kart on track in the main FACT CHECK ME :wink: against the strongest shifter class the NCMP club races have ever seen. Sad that my qualifying debacle held back my race result potential, but it was a very fun race and I’m happy with the outcome. So the new tire seems to be working well enough.

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Your comment on the sidewall is interesting, as we, and everyone else we’ve raced or spoken with, feel the sidewall on the SM2 is quite a bit stiffer than the SM1. They are harder to mount, that’s for sure. Our experience is the tire isn’t much different to drive, but seems to last a bit longer. Speed-wise, no real difference. The new red, on the other hand, has a much softer sidewall and is a faster tire.

What weight have you been racing at? Things are usually a little different once you get into higher HP at 410+ lbs.

I did mount SM and SM2’s and found that the 2’s were more difficult, but they were also ice cold, where as the SM’s were sitting in the sun.

This is really only with one session of experience on the SM2, but I have thousands of laps at NCMP so even small differences are usually pretty obvious to me. Will report back after future tests though.

Just TaG and OKN weights, so 360 and 350. We’ll be racing them over the next 2 weeks, so we’ll be getting a lot more data.

What sort of cold pressures do you run at 410lbs in shifter? Did you change pressure new vs old?

I havent gotten to try them yet but i assume i will sometime soon when i can get my hands on them. Good write up @Muskabeatz. Ive been doing my fair share of tire research recently as theres been a big tire test going on from a guy on Facebook.

What is everyone seeing as far as tire life goes from the sm1 to the sm2?

Similar pressures for me so far between old and new. 9.0-12.0 cold pressures in front depending on the conditions.

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Thats good that you can use the same rough pressure range.

From the info received during the homologation period, i don’t believe the sidewall to have changed massively between the SM and the SM2 (i may be wrong).

The big change came from the compound itself, which is supposed to now lay down rubber (something the old homologation of MG never did) and be more consistent throughout its usable life (ergo, not have a 4/5 tenths drop between brand new and 1 heat cycle)

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I’d like to hear other peoples opinions of the new SM2 tire. I run TAG 125 SR on sprint tracks as well as road racing. The sidewall is definitely stiffer, the tire seems more consistent after the first few heat cycles.

Anyone else had to do set-up changes to their kart to compensate for changes in handling?

Whats your general opinion of the new SM2?

Hi Sean. Moved your question to the current topic on SM2

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