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Old 03-24-2009, 07:51 AM   #1
Marc Miller
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Exclamation RY30 (2009 and newer)

Baseline set-ups for Birel RY30
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Old 04-02-2009, 09:18 AM   #2
Marc Miller
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Setup for RY30

- 1040 M axle up
- no middle bearing
- 100mm Freeline hubs at 54 1/2"
- standard cassettes
- 620x150 rear bumper with the crash bar loose
- seat at 62, 62.5, and 22 with the bottom of the seat flush with the bottom of the frame rails
- 2 seat stays each side
- standard front bar
- 17mm spindles in the standard position
- 75mm hubs with two thick and one thin spacer wide
- .5 caster in
- 2mm toe out.
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Old 04-08-2009, 12:29 PM   #3
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Additional set-up info for ROTAX JR or Sr. Classes

In all of our testing/racing that we have done with the RY30S1 we have found that the seat needs to be mounted much further back than "standard". 61.5-62 cm from the front rail to the front edge of the seat, 22.5 cm from the top of the axle to the top edge of the seat, bottom of the seat flush with the bottom of the frame rails. We have been running 5mm negative camber, spindles in the standard (up) position, 1 thick and 1 thin spacer wide, front bar in, side rail out, 1040x50x2 F or M axle depending on the track, 139cm wide. Obviously with the seat that far back you are going to have to make some adjustments to help make the driver more comfortable but you shouldn't have a problem with the addition of heal stops. Normally if you are lacking rear grip on high speed corners a harder axle or more narrow rear track will help but this might cause some problems in the slower corners. If this is the case after you try a harder axle you can try loosening the middle bearing off. Are you using the Freeline rear pod or the steel rear bumper? We have found the steel rear bumper that was introduced to the UK some time ago to create more rear grip than the plastic rear pod. When using the rear pod we have found more rear grip by adding a bar across the top of the pod supports. You will have to put a slight bend in it to accomodate the exhaust system but it mounts really nice under the 8mm hex head bolts that secure the bumper to the bumper supports. I will add a picture when I have a chance...I hope this helps and let me know if there is anything else we can do to assist.

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Old 04-08-2009, 05:47 PM   #4
dvcracing3
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Default Thank you

To Mark and Chuck,
Just a thank you, for what Alec and I thought was a very informative class on Saturday. Mark, keep up the good work on the forum updates. Very valuble information.
Regards, Dave Coates
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Old 04-09-2009, 02:44 PM   #5
Christopera
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So the first post says to set the seat at 62 and 62.5 and then the second post says to set it "much" further back at 61.5 and 62. I'm confused.
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Old 04-10-2009, 07:11 AM   #6
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christopera....

the first is a baseline.... the second is specific to Rotax Sr. and Rotax Jr. as specified in the first line of the post. Hope that helps.
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Old 05-08-2009, 08:51 AM   #7
Chris Lobaugh
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The difference in seat measurements also has to do with the difference in seat dimensions between a Freeline and Tillet seat. The Freeline seat measurements will be further back compared to the Tillet seat due to the fact that the Tillet seat is much "longer" than the Freeline. What Marc is attempting to do is pool all of the baseline set up posts in one area which will make them easier to locate on the forum. I would suggest that if you have a specific question about a set up simply ask and one of us will do our best to answer it in a timely manner. Thanks!
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Old 01-03-2010, 04:20 PM   #8
mav
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Dear Friends,

Somebody could help me about the basic set up for a RY31 (2009)?. I use it with a IAME PARILLA X30 and VEGA (green) tyres.

Thanks a lot, I will appreciate your comments
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Old 01-04-2010, 11:24 AM   #9
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Mav- You will want to look HERE: http://www.mrpmotorsport.com/communi...ead.php?t=1830
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Old 01-07-2010, 11:16 AM   #10
skyrone
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mark,
after daytona, with the ykc,do you agree the seat should be back further?
we used the r31, the last race helped with the 3rd bearing loose.
i thought for more rear grip you need the 3rd bearing tight
we will move the seat back further and try.
thanks for the help.
Ty
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Old 01-07-2010, 11:41 AM   #11
Marc Miller
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Quote:
Originally Posted by skyrone View Post
mark,
after daytona, with the ykc,do you agree the seat should be back further?
we used the r31, the last race helped with the 3rd bearing loose.
i thought for more rear grip you need the 3rd bearing tight
we will move the seat back further and try.
thanks for the help.
Ty
Hey Ty,
I believe our next step would have been to move the seat. Keep in mind that generally the stiffer, the more grip, but at some point the kart will be too stiff and flat slide. Daytona, with the bitter cold, sandy and overall no grip surface was a perfect example and once we allowed the axle to flex more in the middle, it created side bite that was much needed.
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Old 01-08-2010, 11:35 AM   #12
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Quote:
Originally Posted by Marc Miller View Post
Thanks a lot Marc
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Old 02-07-2010, 05:02 PM   #13
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Hi Marc, I have some questions about the chassis set up (birel ry-31s1 2009 with Iame x30 engine)

I have a lot of problems to get a good rear grip at the exit of the corner. What Can I do? My set up is:
FRONT: the big torsion bar anchored, 2,5 wheel spacers per side, 2 mm toe out, camber 5 mm.
REAR: 4th torsion bar not anchored, 139 mm rear width, central bearing hub loosed


Thanks
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Old 02-08-2010, 06:56 AM   #14
Marc Miller
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Quote:
Originally Posted by mav View Post
Hi Marc, I have some questions about the chassis set up (birel ry-31s1 2009 with Iame x30 engine)

I have a lot of problems to get a good rear grip at the exit of the corner. What Can I do? My set up is:
FRONT: the big torsion bar anchored, 2,5 wheel spacers per side, 2 mm toe out, camber 5 mm.
REAR: 4th torsion bar not anchored, 139 mm rear width, central bearing hub loosed


Thanks

Hi Mav. I have a few additional questions for you before I can give you qualified advice. I know that you run a IAME with Vega Green tires, but:

Where do you race?
What weight class?
Where is your seat mounted (measurements?) and who mounted it?
How tall are you and how much do you weigh?

This information may help us correct you to the best possible advice.

Thanks
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Old 02-08-2010, 08:30 AM   #15
mav
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Hi Mark

I race in Spain in the Open 125cc series (Iame x30 + Rotax Max), the minimum weight is 165 kgs. The seat is fitted with the standard 123,5 cms / 22 cms, as recommended by Birel. My weight is 78 kgs and my height is 169 cms

Thanks
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Old 02-10-2010, 06:18 AM   #16
Marc Miller
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Thanks Mav,

It is difficult to give you an exact solution to your problem. We don't use VEGA Green tires anywhere here, so we have no testing data on how the chassis handles with these tires fitted. Obviously though, you are having an issue with the chassis oversteering (or lacking rear grip) on corner exit.

You said that you had 5mm of camber... I assume you mean positive camber, which is a lot. If that is the case, try starting around 2mm of positive camber, or better yet.. 0-degrees. The added positive camber provides a lot of front grip to your kart, and in turn, makes it oversteer.

Have you tried the more rearward front bar (the straight one). That will provide more balance to the rear of the chassis as well and could assist.

If those other two things make little difference towards a positive change, then I suggest moving the seat back to see if that does not help.

Best of luck.
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Old 02-11-2010, 04:24 AM   #17
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Hello Marc,

The camber is 5 mm NEGATIVE, as recommended by Birel. Also I have some questions:
- If I anchore the staight front bar, What it happens?I will get more grip at the rear?
- What happens about the wide of the rear part? Less wide means more grip?
- And about the seat bars? These are provide more grip or less grip at rear?
- In general, set up the chasis stiffer provides more grip or less grip at the associated part (front or rear). Is it bacause I have listen that when you need to reduce grip (usualy at the race day due the rubber at runway) you have to make the chassis stiffer, but if is it true, why Birel recommend you choose a 30 diameter chassis for rubberized tracks if the ry30 is less stiffer than the ry31??

I appreciate your time to resolve my doubts, thanks a lot!!!
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Old 02-14-2010, 08:58 PM   #18
Marc Miller
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Hi Mav,

Recommendations are "max" 5mm negative camber.. but we typically run the range of 0mm to +/-2mm on camber.

Anchoring the straight bar will provide more balance to the rear of the kart, increasing rear grip.

As far as rear width, "yes and no". We typically use rear width as a small adjustment and begin between 54.5" and 54.75" (which is 1384mm to 1390mm)

Additional seat struts/stays create more rear grip. If you are not using these already, this is something you will want to add

Reagrding the 30mm chassis, keep in mind that just because the OD is smaller, it doesn't mean it is just not stiff. The 30mm chassis is thicker tubing so it might have similar rigidity, yet because of the smaller OD begin flexing easier, but holding the flex longer. That enables the kart to take a set longer and not try to bind the kart as quick.

Hope that helps a little.
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Old 02-22-2010, 05:25 PM   #19
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Many thanks again Marc.

Best regards!!
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