Period Correct Tire Widths, Engines and Rules

[steveohara]

Bill,

Good choice of tires for the Panther X. Joe's start to this conversation and my contributions to it are really not directed to chassis of the mid 70s or later when your chassis was built. That kart was designed to run on 6.00 Bluestreaks and it has the correct design elements to work well with that kind of tire... lower CG, wider rear axle and wider bearing spacing on the rear axle etc.
Where the safety problems really show up is when guys arrive with 6.00 or larger rears and 4.50 fronts on a Bug Sprint, A-Bone, Bonanza, Hornet or any number of other makes and models of early rear engine karts that shared certain common design features such as straight across dropped front axles, narrow rear axle bearing spacing, overall tread widths of 36" or less etc.
At every event except The Big One we see karts of the type I mentioned above show up with huge tires that make them unsafe and they don't look period correct. Some people think they look "cool" with the big tires and maybe they do, everyone has their own idea of what looks cool, but they are still a hazard if driven and all wrong if there to be entered into the showing aspect of the events.
Your chassis would have the same problem if you put it out on the track with 7.10 MG Yellows or any of the other modern kart tires designed to be used on chassis with 40 or 50 mm diameter rear axles and rear tread widths of 55 inches.
There are plenty of new tires available that are the correct size and design for the old karts so no one has to run on 20 year old tires. They are cheap and they last a long time so availability is not the reason for the choice of tires.
Here's a perfect example of the problem... ebay # 170684501063.... at least the seller is offering the kart with a second set of "vintage" wheels.... too bad it isn't pictured with the correct wheels, tires and rear axle.
Steve O'Hara

[Joe Drabicki]

Hi Bill,

Steve is right. We have been talking about rear engine karts from the 1960s, just like the name of this website. I like and have karts from all time periods of kart racing, but a guy could get shot talking about them there oddities some call sidewinders...SSSHHHHHHhhhhhhh!!! LOL

I use the Goodyear Blue Streaks rear 11x6.00-5 and front 11x3.5-5 as SHOW TIRES ONLY. I don't want to drive on 40 year old tires for safety reasons too.

Here is what I suggest for tires. I am big into Margays, have had and still have several of them, including the Panther X. Forget the Dunlops. The shoulders are too rounded to look right. Buy some rear Carlisle Super Slicks in 11x6.00-5 and some front Cheng Shins in 4.10/3.50-5. Both the Carlisles and Cheng Shins have the sharp square cornered edge the tires had in the 70s. Try buying from APS and/or Gokartgalaxy.

Kind Regards, Joe

[Jeff Campbell]

FYI - the VKA has moved to restrict tires on rear engine karts starting in 2012. Below are the VKA approved tires for rear engine karts for the 2012 season. Most of these tires are OK for TBO also, but I believe the Vintage Speed 11x3.50-5, 11x4.50-5, 11x6.00-5 have not been REAR approved yet? Rob?

Cheng Shin and Carlisle 4.10/3.50-4 / 3.40/3.00-5 /4.10/3.50-5
11-3.50-5 / 11-4.50-5 / 11-6.00-5
4.10/3.50-6 / 12-6.00-6

Duro 10x4.10/3.50-5

Vintage Speed 4.10/3.50-4 / 11x3.50-5 / 11x4.50-5 / 11x6.00-5

Kenda 4.10x3.50-4 / 4.10x3.50-5 / 4.10x3.50-6


Jeff

[Rob Voska]

Over the years we at REAR have worked hard at maintaining stability in the vintage karting world. We have not made any changes sense we first printed our rules so many years ago. We have maintained the “skinny hard” tire rule. It’s now time to approve a new product that is needed & has been reproduced to a high standard.

At The Big One 2011 onward we will allow the new 4” narrow (about 2” wide) Vintage Speed 4.10/3.50-4 front tires. No rear Vintage Speed tires or any other Vintage Speed tires are approved at this time.

This size tire was used on a lot of the early karts like Fox, Hornet, Dart, etc......

I tested them this past weekend. I mounted them up on a 4” front Go Power wheel & they have a nice profile. I ran 20 lbs of air in them & they worked well & didn’t roll over. They wore well.

Duro makes 2 styles of tires. One is a square corner tire like the Kenda, Cheng etc.... They are allowed. The rounded corner Duro tires are not allowed.

[david a luciani]

hurray,hurray, hurray,

the nasty tire tangle is finally getting unravelled.
after years of discussion and fierce debate and some false starts i see light at the end of the tunnel.

i have about a zillion 4" rims that were shelved because of the lack of rubber.

now if we could only get somebody to repop some new mcculloch cranks and con rods i'll be a happy boy!!!
maybe mcbob will get a giant pile to stem the hoards tillthat time.
dave