ASK TJ

JIM SILVERHEELS · Posted: Wed Mar 13, 2013 4:05 am Post subject: ASK TJ

Usually people move the seat forward as an option for push, seems moving the seat up or backwards would rotate the rear of the chassis making the inside tire lift higher and for a longer duration. correct?
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TJ Koyen · Posted: Wed Mar 13, 2013 6:19 am Post subject:

I pretty much never move my seat. Two reasons:

1. Factory settings are there to give you the best possible baseline to start from and will make all your other chassis adjustments react the way they are supposed to.

2. My seat weighs like 60 pounds and moving it sucks.

That's not to say it's not a legitimate adjustment. I know some guys who ONLY move their seat to tune.

We've had quite a few instances where we moved the seat up before trying to get higher CoG and get better lift.

I remember one national race in juniors, we were struggling to get front grip so we moved the seat forward. Then I qualified on pole. The next event, the kart was handling poorly again and we moved the seat back, past where we had it originally, and it came to life again.

As with anything in karting, it's a balance you need to find. Move it too far forward and you're just swinging the rear around and not getting any side bite. Move it too far back and you're not generating front grip and the kart is plowing. The factory settings are designed to get you close to that balance.
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Chris Livengood · Posted: Wed Mar 13, 2013 6:36 am Post subject:

Moving your weight forward or backward isn't as simple as people like to believe.

If your tire temps are low on one end or the other, it is likely they need mass, as greater loads will increase temperature and increase grip. If tire temps are maybe too high, then removing mass may lower temperature. Depending on the tire, it may increase grip because the tire was greasy in its overheated state. Or this may decrease grip if tire goes below optimum temperate. I have seen very few of the club style tires ever get so hot as to blister, so that makes them harder to read. Some of the softer tires are clearer on what is overheated and under-heated.

Then add in verticle C/G and things get crazy.

In my experience, I prefer to over work the rear tires a bit more than front. This typically required a a c/g a little more rearward, but as TJ mentioned, it can be totally dependent upon track conditions, etc. etc. etc.

Finally, "ASK TJ" is really crappy thread title as it doesn't add any meaningful information for future searches.
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Ray Lovestead · Posted: Wed Mar 13, 2013 9:06 am Post subject:

If you have a track with long fast sweepers and sharp corners, could you not physically move your butt (and upper body) forward in the seat on the sharp corners and lean back on the sweepers to get a chassis combo that works "everywhere" on the track?
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JIM SILVERHEELS · Posted: Wed Mar 13, 2013 10:00 am Post subject: EMM

To get back to the question about the seat. Shouldn't moving a seat up or back make the rea rend rotate better and make a higher and longer duration of lift? of course moving it back takes weight off the front but if it was pushing would it help? i know i have read this somewhere.
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Chris Livengood · Posted: Wed Mar 13, 2013 11:08 am Post subject:

You got your answer, Jim. There is no single answer. Go to the track and try some things.
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TJ Koyen · Posted: Wed Mar 13, 2013 11:39 am Post subject: Re: EMM

Rob Kozakowski · Posted: Wed Mar 13, 2013 12:25 pm Post subject: Re: EMM

JIM SILVERHEELS · Posted: Wed Mar 13, 2013 1:23 pm Post subject: GOT IT

Got it, will take your advice and leave the seat at factory recco's.. thanks very much guys !
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Tim Koyen · Advertiser Joined: 26 Nov 2002 Posts: 1556

I realize this is TJ's thread, but one more thing with regards to seat moving. I only move the seat when other changes aren't making a difference, or a significant difference. In other words, if the karts not responding, move the seat. Still no response, get a new kart. Wink

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Chris Parks · Posted: Thu Mar 14, 2013 2:17 am Post subject:

If you make a significant change to a kart and you can't feel the difference the seat is in the wrong spot, either the long CoG is wrong or perhaps the Vertical CoG but you need to fix it. why people get so wrapped up in seeing daylight under a rear wheel has always mystified me, all that is needed is to unload it so the tyre patch has such reduced friction it is ineffective. By lifting the rear too high you significantly load the opposite front and that is the last thing you need.
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