JPMKarting
Site Supporter
I would suspect you want to turn about 6600 peak RPM, with a 600-800 drop if there is any lifting
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I would suspect you want to turn about 6600 peak RPM, with a 600-800 drop if there is any lifting
racing promotor
Moderator
Most have there motor dynoed and that tell them target RPM to shoot for, Today's top builders are wanting them turning from 6800 RPM to 7000 RPM, If you do not have that info and it's not a fresh build as J.P points out 6600 to 6800 would be a good target, the Gearing you choose will dictate how close you hit that RPM target, Also as pointed out RPM drop is all track specific The tighter the turns more out of throttle the higher the drops, The More the track is gripped up combined with being a momentum track NO lift of slight burp drops will be in general 400 to 600, Once you prove your RPM drop if it's higher either your tires are to soft gripping up to much OR your set-up is tight thus less momentum which results in higher drops, Yes once you know the target RPM your motor likes the goal is to hit that, In general for time trialing turn it on the higher side, same goes for tight turn long straight turn it on the higher side as your only getting that reading the last little bit of the straight, on a bigger momentum track usually best to target RPM on the lower side, From early practice to qualifying and some even into the first few features the track will continue gaining grip getting faster so you will turn more RPM with out making any changes in gearing, It's VERY important to monitor this and learn what the track does, It's as important to know the RPM your motor likes and be confident with your gearing choice, because If you then find yourself chasing RPM it's a real good sign your off on tires as If tires are to far off you will chase RPM, Also don't buy into Ratio is Ratio EVERY track has the best size front driver being newer even IF you know say a 15 front driver is best start 1 lower until you feel your maximizing momentum 100% as the motor will recover little quicker, For the 1/8 th mile momentum slight burp throttle you mention for SR Clone you should be on close to 14/62 ish or 15/66 ish, What gearing combo are you using ? since you've used your tac what RPM have you been turning ? What are your drops ?
Plus you have a PM
racing promotor
Moderator
Short answer NO you cannot just add air to increase side wall stiffness, Air pressure is all track condition related you want to run as much as grip will allow however once you go past grip level on air it will just slide. Example of what you may be asking is can you just add enough air in an 11 & get it to hold up on a 33 track surface, That answer is NO, a harder 11 with more air in that case would hold up little longer but will not compensate for the 33.
Just like you cannot just run whatever air pressure needed to get proper staggers.
Perfect answer I was fishing for. Thanks
FotiRacing
Member
If you don't have a 4 ft level for toe, you can accomplish the same with a piece of string. Tie it around the bumper and wrap it around the outside of the RR wheel towards the front of the kart. I would usually tie it to a ladder or jackstand in front of the kart. Adjust the front of the string until it barely touches the front edge of the RR wheel. Then measure from the string to the front and back of the outside edge of the RF wheel.
Wynn Racing
Member
A prep man with good knowledge of your track is a plus. Provide all the info you can, track name, location, type of tires ran there, and if you can find out from people that run there a lot what the tires need to Duro from worst to best there.
SoCo Tire Treatments
Moderator
Im guessing youre calling someone and having an actual conversation. That person should know what that specific prep does and what questions to ask to help you to get the correct prep and/or usage of that prep.
racing promotor
Moderator
AS pointed out If your talking to someone that sells prep and even If they do not know your particular track If there a good prep person they should give different descriptions to you for you to confirm, Some key questions would be.
Which Tire your on tells them a lot, Is it wet slick but harder ? or Softer ( moves under your feet ), does it go dry slick ? Has enough moisture to Never roll dust BUT seals over and stays slick, Has enough moisture to get a good groove and makes good grip, For any lower grip situations does the dirt have any abrasive material mixed in it.
Which Tire your on tells them a lot, Is it wet slick but harder ? or Softer ( moves under your feet ), does it go dry slick ? Has enough moisture to Never roll dust BUT seals over and stays slick, Has enough moisture to get a good groove and makes good grip, For any lower grip situations does the dirt have any abrasive material mixed in it.
T-roy
Member
I have just been using what people tell me to because I don't know how to explain the tracks we go to.
I do searches on google and learn what people say about preps. I just haven't found out how to explain the diff tracks.
racing promotor
Moderator
Give it a try you might be better than you realize, tell us where which state and tracks, what Tire your on or most are on, which class and weight, and If it's wet or dry, harder or softer, If it rolls any dust, which preps you've been trying and application.
SoCo Tire Treatments
Moderator
Give me a call sometime, we can discuss.
JPMKarting
Site Supporter
Tracks (generally) come in the following ways:
-Wet/No Bite
-Dry Slick
-Hard/Fast
Wet/No Bite tracks are surfaces that have a lot of moisture, require an aggressive tire. These surfaces generally will take a softer tire, and an aggressive softening/bite chemical.
Dry Slick surfaces are tracks that have a harder base, but are dusty/dry and don't build a lot of bite. A sandy type of track would fall in to this category as well. This will generally take a harder tire to with stand the hardness of the track, but a tire that is wiped with a bite chemical (not soften), or rolled internally
Hard/Fast tracks are tracks that have a hard surface, and build a lot of bite by laying down rubber. These tracks call for a hard tire, minimal internal prepping, and a non agressive external wipe to light the tires off.
Again, a very general crash course, but this covers about 80% of it. Applications will vary based on the tire rule, time of year, etc.
Our Premier Blend prep that we make comes in 4 ways...Lite, Medium, Heavy, and Agressive. Our labels even instruct how to use the prep, and for which track conditions.
-Wet/No Bite
-Dry Slick
-Hard/Fast
Wet/No Bite tracks are surfaces that have a lot of moisture, require an aggressive tire. These surfaces generally will take a softer tire, and an aggressive softening/bite chemical.
Dry Slick surfaces are tracks that have a harder base, but are dusty/dry and don't build a lot of bite. A sandy type of track would fall in to this category as well. This will generally take a harder tire to with stand the hardness of the track, but a tire that is wiped with a bite chemical (not soften), or rolled internally
Hard/Fast tracks are tracks that have a hard surface, and build a lot of bite by laying down rubber. These tracks call for a hard tire, minimal internal prepping, and a non agressive external wipe to light the tires off.
Again, a very general crash course, but this covers about 80% of it. Applications will vary based on the tire rule, time of year, etc.
Our Premier Blend prep that we make comes in 4 ways...Lite, Medium, Heavy, and Agressive. Our labels even instruct how to use the prep, and for which track conditions.
Oregondirt
Member
Hello everyone I'm a total newbie. We picked up a QRC kart for our 9 year old son and I have some questions. For a box stock kart how wide of a rear tire should we run? With the low HP box stock is there a speed gain with the lower rolling resistance of a narrower tire? Thanks
racing promotor
Moderator
I was hoping one of the guy's that normally respond on this thread would have some experience with The QRC karts, because I have NONE but doesn't look like that's the case as NO response, I would look at what wheels are available for the rears you'll most likely find not many choices telling you that there the fastest ( If there are a lot of different choices then do more research ), So I doubt a narrower wheel would have any gain, with that being said with the lower H/P you should be able to run a lot higher air pressure so there is where you make up for the rolling resistance. If anyone knows I'm wrong please chime in !!
JM2Cents for what it's worth.
Good Luck !!
CarlsonMotorsports
Site Supporter
The bigger problem with the winged stuff is the lack of stagger tires in treads.
For instance, the Hoosier 9.00, or 9.50 (D50 or D30A) right rear that the bigger HP karts run, rolls out at 37 1/2". That makes for way too much stagger (and footprint) for a 206 or clone engine.
What we've done is use the left rear (6.50") tire on the right sides, and the 5.50" on the lefts.
This gets us back to the normal "flat kart look" and sizes (ie 34" right side tires) with treads. Now, you have to mount them on real wide wheels and they're a bugger to mount, but the effort is worth it in my opinion. This also get away from the "sprint car" look of running narrow front tires and big rears. BUT, it works. Remember, your winged kart is a flat kart under all that.
Not only is there speed in going to the smaller tires, but there is speed at cutting the tires (treaded) to half rubber.
When the tracks instituted a treaded tire rule, it did not make their racing any cheaper by eliminating cutting, quite the opposite. Tires are still being cut and prepped (yes, even treads.)
If you have any specific questions on winged cage karts, treaded tires, etc, please feel free to contact us at our shop number listed below, email, or PM me on here.
-----
Thanks and God bless,
Brian Carlson
Carlson Racing Engines
Vector Cutz
www.CarlsonMotorsports.com
Carlson Motorsports on Facebook
30 years of service to the karting industry
Linden, IN
765-339-4407
bcarlson@CarlsonMotorsports.com
For instance, the Hoosier 9.00, or 9.50 (D50 or D30A) right rear that the bigger HP karts run, rolls out at 37 1/2". That makes for way too much stagger (and footprint) for a 206 or clone engine.
What we've done is use the left rear (6.50") tire on the right sides, and the 5.50" on the lefts.
This gets us back to the normal "flat kart look" and sizes (ie 34" right side tires) with treads. Now, you have to mount them on real wide wheels and they're a bugger to mount, but the effort is worth it in my opinion. This also get away from the "sprint car" look of running narrow front tires and big rears. BUT, it works. Remember, your winged kart is a flat kart under all that.
Not only is there speed in going to the smaller tires, but there is speed at cutting the tires (treaded) to half rubber.
When the tracks instituted a treaded tire rule, it did not make their racing any cheaper by eliminating cutting, quite the opposite. Tires are still being cut and prepped (yes, even treads.)
If you have any specific questions on winged cage karts, treaded tires, etc, please feel free to contact us at our shop number listed below, email, or PM me on here.
-----
Thanks and God bless,
Brian Carlson
Carlson Racing Engines
Vector Cutz
www.CarlsonMotorsports.com
Carlson Motorsports on Facebook
30 years of service to the karting industry
Linden, IN
765-339-4407
bcarlson@CarlsonMotorsports.com
Oregondirt
Member
Oregondirt
Member
Thank you I'm sure I will be talking with you soon