sprint kart adjustable cassettes

Legend

Site Supporter
I know some sprint guys run adjustable cassettes on their axles. What does the adjustment do for you? Say you have a track with mostly right turns, what adjustment would you make to improve your right turn speeds?
 

Ted Hamilton

Design Drafter / Racer
Most Euro sprint karts have slotted bearing hanger holes for adjustment, not adj. cassettes. The adj. cassettes skew the axle relative to the brake caliper and sprocket relative to the motor, so I don't like them in that regard. If you have one on each side, then the axle could be moved uniformly to avoid that issue. If I had to use one as a tuning band-aid for a RH biased track, I'd lower the right side of the rear, and raise the left. But it will cause alignment issues, for sure.

Most tracks are fairly balanced L to R. But if I had a track that favored rights, I'd slightly offset the rear to the right (axle goes LEFT of centered) to bias the weight in the proper direction. I'd leave the front end KPI/Caster/Camber geometry alone but I'd consider running the RF in against the spindle and LF out a few spacers. And if it was an option, I'd simply slide the hubs to bias the weight rather than shift the whole axle. YMMV.
 
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Gab507

Member
The adjustable cassettes make cross adjustments very quick to do. Careful because it will skew the axle so I use it to adjust cross and during the week I will make the appropriate adjustment on king pin washers and return the cassette to the "zero or neutral setting". I have also used them on both sides for quick ride height adjustment.
 

Legend

Site Supporter
Ted, in both of your comments, you are suggesting more right side or right rear weight on a right turn biased track. It seems that more right side or right rear weight would hurt exit speed because the inside tire will be more loaded and not 'picking up' as much. My understanding in sprint racing, the inside tire must pick up and slip the right amount to free a kart up on exit. How will more weight on that tire help? Maybe it's hi HP vs low HP on how this works. I'm talking about low HP (Lo206).
 

Ted Hamilton

Design Drafter / Racer
On a right turn biased track, you bias weight right just like you do on a left turn biased oval for a LTO kart. Only it's built in on the LTO frame. Oval karts unweight that LR too, just not as much as sprints. On a LO206, I doubt I'd change my setup at all unless it was the only track I raced at. When the Birel team came to North America from Italy to Charlotte for the 1996 North American Karting Championships, they brought specially built chassis that sold off after that race because the old Charlotte track was biased (right, IIRC.) The whole point of biasing is so that you can take more lateral G's before the kart bicycles. The only reason LTO's don't bicycle (often) is that there's not enough available grip to induce it with the ultra low Cg most LTOs are setup with. Concrete syrup ovals are the only place most oval racers get to see how a kart is really flexing.
 

rainman

Site Supporter
On a right turn biased track, you bias weight right just like you do on a left turn biased oval for a LTO kart. Only it's built in on the LTO frame. Oval karts unweight that LR too, just not as much as sprints. On a LO206, I doubt I'd change my setup at all unless it was the only track I raced at. When the Birel team came to North America from Italy to Charlotte for the 1996 North American Karting Championships, they brought specially built chassis that sold off after that race because the old Charlotte track was biased (right, IIRC.) The whole point of biasing is so that you can take more lateral G's before the kart bicycles. The only reason LTO's don't bicycle (often) is that there's not enough available grip to induce it with the ultra low Cg most LTOs are setup with. Concrete syrup ovals are the only place most oval racers get to see how a kart is really flexing.
Ted, sorry to tell you but that wasn't the main reason why the sold the chassis. Back on those days most European manufacturers rarely used their chassis for more than one weekend, much less when they raced abroad, even within Europe, because the price of flying the stuff back to Italy was way more expensive than what they could get out of them. It wasn't uncommon to find bare chassis abandoned or left after those races.
 

"J'-remy

Member
On a right turn biased track, you bias weight right just like you do on a left turn biased oval for a LTO kart. Only it's built in on the LTO frame. Oval karts unweight that LR too, just not as much as sprints. On a LO206, I doubt I'd change my setup at all unless it was the only track I raced at. When the Birel team came to North America from Italy to Charlotte for the 1996 North American Karting Championships, they brought specially built chassis that sold off after that race because the old Charlotte track was biased (right, IIRC.) The whole point of biasing is so that you can take more lateral G's before the kart bicycles. The only reason LTO's don't bicycle (often) is that there's not enough available grip to induce it with the ultra low Cg most LTOs are setup with. Concrete syrup ovals are the only place most oval racers get to see how a kart is really flexing.
I thought the FIA mandates the chassis manufacturers have to keep the chassis design for 5 years after getting approval?. they can only design a new chassis for sale every 5 years. wouldn't creating a new chassis for one race violate the FIA rules?
 

rainman

Site Supporter
I thought the FIA mandates the chassis manufacturers have to keep the chassis design for 5 years after getting approval?. they can only design a new chassis for sale every 5 years. wouldn't creating a new chassis for one race violate the FIA rules?
Unless rules have changed they can have several new chassis approved. Homologation periods usually open every certain number of years, but they can have several different chassis homologated for the same homologation period, and even in between homologation periods there has been modification approved. The real deal is you need to build a minimum (pretty high) number of chassis for every homologated chassis or even any modification to be approved. In theory yes, every modification should be approved and checked for homologation.
 

Ted Hamilton

Design Drafter / Racer
Santiago -- you've certainly gotten more argumentative these days. While your thoughts are true, in this particular case, I know what happened from people who were there. And, IIRC, the NAKC was a non-official world championship round. I don't think the circuit met FIA/CIK standards. I could be wrong on that 2nd part.
 

nobozos

Member
Right or Wrong they had some very fast DDrive karts that weekend. I never saw that much karting equipment anywhere. It was cheaper for them to sell off their equipment than ship back overseas. It was crash and burn pick it up run throw it down and go again lol. I'll probably never see anything like that again in my lifetime good times later Chuck.
 

rainman

Site Supporter
Santiago -- you've certainly gotten more argumentative these days. While your thoughts are true, in this particular case, I know what happened from people who were there. And, IIRC, the NAKC was a non-official world championship round. I don't think the circuit met FIA/CIK standards. I could be wrong on that 2nd part.
Not trying to start an argument, I know personally some of the chassis builders from Europe who took part in both big races at Charlotte, that particular one too, and I don't know of any of them shipping my chassis back to Europe, doesn't matter if they were according to FIA/CIK rules or not. Ted, I didn't reflect my thoughts, they are facts. Ask Mike Berg here for example. He was a dealer for a manufacturer from Spain who came for that race too. I don't even think they built a special chassis for that race. They did have the karts setup way different though but a kart has enough ways to set it up, even offset the setup, without building a specific frame. One of the things about most European manufacturers is that most they don't care about the US market. Maybe more now, but back then not at all. Of course that's a big mistake but it was like that. That's another reason why the Yamaha classes grew so much here, because Americas were tired of the crazy prices Italian stuff cost and the lack of customer support and reliability.
 

Ted Hamilton

Design Drafter / Racer
Birel was the company that made a special chassis. My recollection is that my dealer friend was at the races. He raced K135's against Haddock, Seay, Adkins, Lunati, and the others. He was offered a chassis, and also well acquainted with the product lines. I also understand and accept that they didn't want to ship everything back when it could be unloaded on American consumers. I'm not interested in arguing. I'm done with the topic. I hope to see you at the track sometime.
 

rainman

Site Supporter
Hope so. Just understand most chassis run at top level those years had low commercial value. People would buy them though because of who had driven them before, like big names, but the way they were built and flexed didn't make them good as a lasting frame. Don't get so upset anyway. I didn't say I knew just the dealers as you say, or one dealer, but builders, guys who actually designed and built those chassis. And yes, Birel used to try different things others wouldn't and would build protoype chassis for races where homologation wasn't a requirement, as all manufactures were allowed for the Super A class for example. I recommend you the vook in the picture.
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We'll leave it like this, no problem.
 
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nobozos

Member
Ted not trying to hen peck but as far back as I can remember there was no such engine as the K135. There was a K30, K35 plus plenty other K designated engines which were all 135 cc engines. later Chuck.
 

rainman

Site Supporter
Right, Chuck and for the 135 class those engines as well as for the class that replaced them, which was the Super A, they could run proto chassis, 6" wheels and big slide carbs, but not for the ICA (100cc Reed) or the JICA (PP).
 

nobozos

Member
I stand to correct myself just because they had a K designated didn't necessarily mean they were 135's most if not all Komet's were K then # later Chuck.
 
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