Q31

[Marc Miller]

Baseline set-ups for Birel Q31

[Marc Miller]

Baseline Setup for Q31

Q31 X was produced in 2000 as Garry mentioned in a previous post.
- spindles in the middle (one spacer on top, one on bottom)
- 75mm front hubs set with two thick and one thin spacer on the inside which should leave you with one thick and two thin on the out side
- 1.5 degree caster
- camber at 2mm positive and 2mm toe out
- You may have to turn the eccentric bushings slightly to create the 2mm of positive camber which will decrease the caster angle a bit, but, don't worry about that
- If you find that you need a bit more caster than you can add a second eccentric bushing
- Front bar in, F3.0 axle with 100mm rear hubs set 23.5 cm from bearing to the outside edge of the hub
- Seat should be at 59.5cm from the front rail to the front edge of the seat on the left side and 60.5cm on the right side
-Top of the axle to top edge of the seat 23cm if you are using a 40mm axle (which was standard in '00) and the bottom of the seat should be 5mm below the frame rails
- Start with one seat of seat stays on each side. Lower crash bar on the rear should be loose to begin with

[CH17]

I am using a soft 50mm axle. The axle is not a freeline. Is there an advantage to mounting the casets high or low in the carrier.

[Marc Miller]

CH....

I am not sure of your question. If there are no handling issues, then there is no advantage to changing anything. Keep in mind that the components and settings you place on your kart are to adjust balance and grip, not necessarily provide any "advantage".

Of course, we always recommend "FREELINE" axles and components. We have 20+ years experience with the company and can verify the parts and functions. A "soft" axle of another brand might not be actually soft, and we can not verify that.

What are the issues you are having and then maybe we can direct an answer your way. Thanks.

[Savoy]

Marc,

Any help with setup on a Q31 SP #410873? what year is that by the way?

6'-0", 215 lbs, Tillet T8 1/4 pad, Freeline 40mm x 2.5 x 1040- Mod 270, Mojo D2, Rotax Max.

Track is rather green and doesn't get very rubbered in. Andersenracepark.com for track layout if that helps.

I'm new to this and just looking to get a good baseline setup to start working from.

Thanks in advance
Scott

[Marc Miller]

Marc,

Any help with setup on a Q31 SP #410873? what year is that by the way?

6'-0", 215 lbs, Tillet T8 1/4 pad, Freeline 40mm x 2.5 x 1040- Mod 270, Mojo D2, Rotax Max.

Track is rather green and doesn't get very rubbered in. Andersenracepark.com for track layout if that helps.

I'm new to this and just looking to get a good baseline setup to start working from.

Thanks in advance
Scott

Hi Scott - and thanks for the question. The Q31SP is a 2004 model, I believe that was the final year for the Q-series karts. "SP" is the year designator and you can learn what the years mean on www.GoBirel.com at this link: http://www.mrpmotorsport.com/technical/howto-gobirel-chassis.pdf

I would certainly START with the baseline given above. You may have to make a slight seat movement adjustment if you are struggling with too much front or rear grip. It is possible at your height and weight you may have to move your seat back slightly. You might also consider an "M" axle, which is slightly stiffer as well if your kart is lacking of rear grip. You could always add eccentric caster bushings in the bottom of the spindle as well to obtain more caster.

Have you tried the baseline above yet? If not - try it out and then we can work from there. Best of luck!

[Savoy]

Marc,

Negative camber? tops out 2mm from bottom?

Also how do i measure the caster setting?

Thank you,
Scott

[Savoy]

Ok...so i found the thread on the camber/caster pills. I am assuming you mean that i would need a 1.0 deg pill on one side of the "C" and a 0.5 deg pill on the other. Bottom pill offset towards the front and top pill offset towards the rear.

[Marc Miller]

Marc,

Negative camber? tops out 2mm from bottom?

Also how do i measure the caster setting?

Thank you,
Scott

Scott....

Negative camber is when the top measurement is LESS than the bottom.

[Marc Miller]

Ok...so i found the thread on the camber/caster pills. I am assuming you mean that i would need a 1.0 deg pill on one side of the "C" and a 0.5 deg pill on the other. Bottom pill offset towards the front and top pill offset towards the rear.

Scott-

Typically you will want to add caster using the top pill. Caster is adjusted by moving the top of the spindle forward or backward. As mentioned, if you want MORE or LESS caster, you may add an offset caster/camber bushing to the bottom and also set that forward or backward. This will either stand up the kingpin or tip it even further back.

If you want to adjust CAMBER, you would adjust this by using an offset bushing in the bottom in the opposite direction, side to side to push the bottom of the kingpin out or in. Out would give you more negative camber, in would give you more positive camber.

Positive camber would give you more front grip, negative camber will take some front grip away. More caster will provide more mechanical grip and give a more weight jacking effect. It will also be harder to turn but make it easier to lift the inside rear tire. Less caster would be helpful if the kart is overstuck and is very hard to turn or the inside rear tire lifts too quickly and wants to set down before apex.

Hope this helps a bit.

[Jody Jernigan]

Marc,
I have a tillet t8 seat and I was checking over my seat measurements (Giessen installed it when I bought the kart) anyways when I measure from the front rail to the front of the seat on the left it's at 64.1cm, on the right it's at 62.2cm. the seat appears to be about 5mm below the frame rails and the back of seat (highest point) is at 24.8cm. I feel like the kart lacks a little in rear grip but from your baseline set-ups the seat appears to already be to far back?? I'm running the standard axle and have mostly been running the third bearing loose, rear width set at 54-54.5 inches. I also have an extended porch (don't know if all the cq's are that way??) thanks for any help.

[Marc Miller]

Jody-

You might want to email photos. It might be back far enough, but not leaned back enough. Try to post up a few photos.

[Jody Jernigan]

ok I should be able to do that in a day or so.. thanks, jody