New to nitro questions.

[BCbud]

Niel, I have various types. I will bring them next race, and figure out what you need. I normally use .21 like Blake mentioned, but again there are different types and sizes.   If you want to try them before race day then send me a pm and we can meet up for coffee.


Shawn.

Thanks but I am ok for now, I was just looking to get some as a needed consumable part.

Neil.

[BCbud]

I might need to buy a pair of front tires from anyone that may have a new or used pair that they can spare. The 2 pair I have are fairly bent up.

Thanks, Neil.

[Blake]

I might need to buy a pair of front tires from anyone that may have a new or used pair that they can spare. The 2 pair I have are fairly bent up.

Thanks, Neil.

Hi Neil,

I have a bunch of used tires you can look through.  None are huge - but will probably get you by.

Blake

[BCbud]

First off I would like to thank everyone for ther input and help at the track while I learn about this class.

Ok if with a 5 shore split the tire wear is the same front and rear, why not run the front with no overdrive and cut the front and rear tires the same diameter?

Neil.

[Shawn68z]

First off I would like to thank everyone for ther input and help at the track while I learn about this class.

Ok if with a 5 shore split the tire wear is the same front and rear, why not run the front with no overdrive and cut the front and rear tires the same diameter?

Neil.

Makes it easier to drive the cars out of the corner.  The front end is Pulling the rear of the car so you don't get loose when on the power.

I did find this explaination as well.

http://www.rctech.net/forum/7768633-post3.html


Shawn.

[BCbud]

First off I would like to thank everyone for ther input and help at the track while I learn about this class.

Ok if with a 5 shore split the tire wear is the same front and rear, why not run the front with no overdrive and cut the front and rear tires the same diameter?

Neil.

Makes it easier to drive the cars out of the corner.  The front end is Pulling the rear of the car so you don't get loose when on the power.

I did find this explaination as well.

http://www.rctech.net/forum/7768633-post3.html


Shawn.

But are you not eliminating that by cutting the front tiers smaller?

Neil.

[Blake]

First off I would like to thank everyone for ther input and help at the track while I learn about this class.

Ok if with a 5 shore split the tire wear is the same front and rear, why not run the front with no overdrive and cut the front and rear tires the same diameter?

Neil.

Hey Neil,

It's a good question - I would think your suggestion is valid.  All other things equal, it would seem that the car would behave the same with the overdrive pulley and 2mm smaller front tires as it would with the equal drive pulley and equal sized tires.

The difference might come down to getting more steering with the larger front tire setup.

Blake

[valk]

I think craig explained it to me best. with the 2mm split, as you race for 20 minutes or more, your start the race with the car a little pushy and as the rear tires wear down closer to the size of the fronts, it loostens up and by the end of the race has slight oversteer.

over 5 minutes you could easily run the tires the same size f/r with no overdrive, but over longer periods the rears just wear out faster. maybe with a center dif we could run tires the same size over long periods?

[Shawn68z]

First off I would like to thank everyone for ther input and help at the track while I learn about this class.

Ok if with a 5 shore split the tire wear is the same front and rear, why not run the front with no overdrive and cut the front and rear tires the same diameter?

Neil.

Makes it easier to drive the cars out of the corner.  The front end is Pulling the rear of the car so you don't get loose when on the power.

I did find this explaination as well.

http://www.rctech.net/forum/7768633-post3.html


Shawn.

But are you not eliminating that by cutting the front tiers smaller?

Neil.

Yes, by making the fronts smaller, and the rear bigger at the beginning of the race the drivetrain will be neutral. (Or atleast close) Until the rears wear down during the race, then it goes back to an overdrive situation again.  I really dont know the OD for the Serpernt, but if the car either gets to loose from small rears (to much overdrive), then its time for a harder rear tire.  The most important thing I learned was to never have the rear tires drive the car. (Underdrive) It will make it almost impossible to control out of the corner, and it will push so much going into a corner you probably wont make the turn.

Even the overdrive ratio would change as the our diameter of the wheel changes too.   A big front with a 2mm larger rear will have a different ratio then a small front with a small rear that is 2mm larger..  When I get home from work I had a spreadsheet that calculated overdrive/underdrive. I will post it for you to play with.

Shawn.

[BCbud]

Thanks for the replies. Another thing that is happening is the left rear tire is coning smaller on the out side and bigger on the inside. I have put the car on my setup station and the static camber is the same on both rear tires at 3.5* and I can not see any  visible damage or play in the suspension, any  suggestions?

Thanks, Neil.

[valk]

Maybe droop? An excessive amount will let the car lean a ton of weight to the outside in sweepers. Your car seemed to have a ton of traction there last I saw. 3-4mm down in the back, 2.5-3 in the front I believe is what you want.

[Shawn68z]

Thanks for the replies. Another thing that is happening is the left rear tire is coning smaller on the out side and bigger on the inside. I have put the car on my setup station and the static camber is the same on both rear tires at 3.5* and I can not see any  visible damage or play in the suspension, any  suggestions?

Thanks, Neil.

Yep. Its your Dynamic Camber.    You need to shorten the upper link on the rear suspension.   This might involve changing the angle of it (Which causes your roll center to shift.), but you need more "Camber Rise" as Hudy calls it. Page 29 of the Xray NT1 Setup Book.

Basically when the car is in the sweeper, and the suspension is compressed the car doesn't have enough camber, and its not keeping the wheel flat, so you get coning, in the wrong direction.    Ideally you would want no static camber, and all dynamic camber, but in slow corners the car is not going fast enough to compress the suspension and that's when its good to have alittle static camber.

Shawn.

[Shawn68z]

Here is the program for the Overdrive. Its for a 720, but you can change the gear ratios on the picture and play with the numbers. Calcs the overdrive/underdrive, for any size of tire.  Neat to play with.


Shawn.

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