Effect of Stagger on Chute Speed

[Mike Walpole]

I Sprint Road Race in Yamaha Masters, basically SSX Can at 360# w/ Dunlop SL4s, and, while I think I have the answer to this, wonder what effect rear tire stagger would have on terminal RPM and how much stagger is too much. i.e. where do you draw the line in the sand.

[Jim White]

I also Sprint road race although I run a pipe and sl-3 tires here in Northern California. I go out of my way to minimize any stagger in my tires. I will run up to 5 or 6 lbs diferent in the rears to get roll out to be equal. You have to think that at 90 mph any bit of bind in the drive train is going to scrub speed, especially if your running a can exhaust. Try easing up your grip on the wheel going down the straight. If your kart starts pulling to one side...well you've got too much stagger. On tight tracks with a majority of turns in one direction a little stagger might be ok provided that the little speed you lose in the straight sections is offset by what you make up in the corners. But more often then not you want no stagger. Good Luck!

[Mike Walpole]

I had 5/16" stagger in the rear tires and the kart was pulling to the right on the straights. I figure if the kart won't roll straight, there has got to be some drag on it.

Stagger is probably a good thing under certain circumstances if it produces faster lap times. However, using stagger to tweek the kart to favor right of left hand turns is not the right way to do it. It's probably better to move the spindles up and down instead. I also believe that more power can handle more stagger. A can motor can't overcome the drag as well as a pipe motor can.

Now - I know of a track where I might try setting up stagger to turn left and tweek the kart to turn right.

[Jean Stafford]

Remember when we turned tires Mike?

We used to make them exactaly the same diameter and circumfrence. We found out that it's not possible to maintain the sizes as the tires heat cycle, and the things still grow unequally.

Also I hope you meant 5/16" in circumfrence, not diameter. I'm sure you did.

Next time you change tires, use a band to prevent the tire from swelling up too much as you seat the bead. You might find a little less diference in the size.

Sorry I've been too busy to talk to you on the phone, but I just have too much to do right now.

Later.

[Mike Walpole]

Yeah - I remember truing tires. You're giving away our age Jean. The other reason we used to do that was that BlueStreaks weren't always round.

I didn't say circumference or diameter, but I did mean circumference. I had 35 3/16 and 34 7/8. I got that set to with-in a 1/16th. kart worked better, but it's still not good enough.

[Frankie Schaffier]

Yes, Sometimes stagger is used on the long tracks with quicker lap times. More common in the high HP classes though.

Lets take Daytona for an example, How much time is spent on the straights VS. left hand corners ? How much time is spent on the infield (slow part of the track), VS. on the super speedway (fast part of the track). Can you make up more time on the oval that the guy tring to catch you, won't be able to make up in the infield?

Its not just as simple as stagger will cause to much drag, try it you may be surprised. Also have ran stagger on sprint tracks with improved lap times,Flatrock Mi. and Jacksonville are two tracks that come to mind.

Just someting to think about.

Frankie

[Mike Walpole]

Frankie - I agree. Under certain circumstances, stagger will make you faster. The question is how much is too much.

Daytona is a good example if a 1/16" or 1/18" or stagger frees the kart up in turns 1-2 and 3-4 of the oval and picks up 3 seconds there, so what if you lose a 1/2 sec on the back straight and another second in the infield. In this made-up example you are 1.5 sec. faster.

I think the amount of stagger depends on the track and the amount of HP. More HP means you can could potentually run more stagger.

I know a short sprint track that mostly turns left (3 lefts and 1 right); however, years ago, it was faster to stagger to turn right. The tires were harder than now and we had a lot more torque & HP. I don't believe that setup would work now because we have much more grip in the tires and it would make kart slow on the fast part of the track, which is a gentle left turn. What I think would work at this track now is a little stagger to the left, and to adjust the kart for a lot of grip in the right turn.