Type R Woes

[swalker]

Hi guys,

My son and I have been running the earlier JRXS cars for many years now with great success. I bought my son a Type R when they first came out (Mainly to be able to use a LiPo). His car performs very well and handles great.

I recently had problems getting parts for my JRXS and decided to go to a Type R myself, but I have the strangest problem with mine. It is so loose at the back end that it spins out all the time. When I back off for a corner, it spins. If I power on in a corner, it spins out. It acts like there is something wrong, but I rebuilt the car a couple of times now and no different.

Any ideas???

[ctg1129]

softer spring in the rear,start there

[MaxRain]

softer spring in the rear,start there

I also suggest a longer camber link, I use lundsford, solved the loose back end.

[swalker]

Interesting, all the setup hints, for the cars I have, say shorter increases grip.

The next race day is a week away, I will try it then.

[da John Wee]

make sure droop is even or chassis is tweaked.

[swalker]

I also suggest a longer camber link, I use lundsford, solved the loose back end.

Max, Which Lundsford set should I use. The standard link always was too short, I have had several ends break through the years, even on the shortest link setting.

[da John Wee]

Max, Which Lundsford set should I use. The standard link always was too short, I have had several ends break through the years, even on the shortest link setting.

I m no t Max, but 1" is what you need

[SkyRocket]

I don't think it's any of that stuff, if he is backing off the throttle for a corner and it's spinning on and off power that to me sounds like there is something very very wrong w/ his drive train.

I'm going to run through the checklist, please don't take offense to any of the items posted i've been racing for 20+ years and some of these things aren't things even I used to do on a regular basis. Whit scooby and larry both berating me mercilessly because i don't do them ;).

A couple of things to check:

1) First take your rear diff apart (and your front too if you are running one) and check that the bearing in the center of the diff is loose and spins free in both directions. This was the culprit of my loose rear (no pun intended) at the Race of Champions and Fairtrace helped me figure it out.

2) Check the bearings in your layshaft, make sure they are **** in both directions.

3) Next check the bearings in all 4 of your hubs/steering knuckle.

4) check your belt tension are your belts tight enough? If they are slipping or skipping during braking you can spin

Oh and you may actually have a one way in your center layshaft, make sure your front end doesn't freewheel i did that once going from the jrx-s to the type-r.

5) check that you have proper diffing goign on, hold your car by one rear wheel (and one front wheel if you have a front diff) and lightly give it some throttle see if you diff correctly and the car feels smooth and ****.

6) With the car in the air give it a good bit of throttle and check all your wheels to be sure you are spinning freely, sometimes the outdrives bind.

7) put the rear wheels on a table or something and give it a little throttle is your diff too loose? that will cause weirdness to happen.

8) lastly if NONE of these things work, take some close up pictures of the car and either post them here or send them to me so i can post online so we can have a looksee.

Sounds to me like you have something binding, it may even be something simple like a loose pin in your cvd's. or a slipping dogbone in an outdrive.

Not sure why but there are ****'s in my post now where ever the word f-r-e-e was.

[swalker]

I don't think it's any of that stuff, if he is backing off the throttle for a corner and it's spinning on and off power that to me sounds like there is something very very wrong w/ his drive train.

I'm going to run through the checklist, please don't take offense to any of the items posted i've been racing for 20+ years and some of these things aren't things even I used to do on a regular basis. Whit scooby and larry both berating me mercilessly because i don't do them ;).

A couple of things to check:

1) First take your rear diff apart (and your front too if you are running one) and check that the bearing in the center of the diff is loose and spins free in both directions. This was the culprit of my loose rear (no pun intended) at the Race of Champions and Fairtrace helped me figure it out.

2) Check the bearings in your layshaft, make sure they are **** in both directions.

3) Next check the bearings in all 4 of your hubs/steering knuckle.

4) check your belt tension are your belts tight enough? If they are slipping or skipping during braking you can spin

Oh and you may actually have a one way in your center layshaft, make sure your front end doesn't freewheel i did that once going from the jrx-s to the type-r.

5) check that you have proper diffing goign on, hold your car by one rear wheel (and one front wheel if you have a front diff) and lightly give it some throttle see if you diff correctly and the car feels smooth and ****.

6) With the car in the air give it a good bit of throttle and check all your wheels to be sure you are spinning freely, sometimes the outdrives bind.

7) put the rear wheels on a table or something and give it a little throttle is your diff too loose? that will cause weirdness to happen.

8) lastly if NONE of these things work, take some close up pictures of the car and either post them here or send them to me so i can post online so we can have a looksee.

Sounds to me like you have something binding, it may even be something simple like a loose pin in your cvd's. or a slipping dogbone in an outdrive.

Not sure why but there are ****'s in my post now where ever the word f-r-e-e was.

Thanks SkyRocket. I will check it out tonight.

As I mentioned in the original post, this is a brand new car. I assembled it and everything seemed perfect. By the way, my son and I have been racing for 8 years now in a number of nitro and elect grades. I have assembled 17 cars in total, including 4 Losi JRXS cars.

I have adjusted just about every setting fully in both directions and have not been able to stop the loose back end.

Thanks for the help.

[Jaz406]

Sunday I had the very same issues with my type R.

Not knowing the track conditions and assuming that you checked most everything before you installed the electronics into the car.

Roll centers were my problem. front was too high and coupled with a stiff spring in front caused the car to have too much traction in front and not enough in the rear.

What is your set up like? Is it real "twitchy" like it's on the nose hard in a corner or on accel? If on accel then check the rear diff for tightness.

I went back to a low roll center setting plus a .030 shim in the front & rear. with 20lb springs and 50 wt oil in front and 17.5 lb springs with 35 wt oil in the rear. We have medium grip carpet and are running 32's for rubber tires.

[Jaz406]

Interesting, all the setup hints, for the cars I have, say shorter increases grip.

The next race day is a week away, I will try it then.

Shorter does increase grip in most cases by increasing camber gain provided that you have the correct amount of "roll" in the car when cornering. moving camber links also affects roll center.

[SkyRocket]

Thanks SkyRocket. I will check it out tonight.

As I mentioned in the original post, this is a brand new car. I assembled it and everything seemed perfect. By the way, my son and I have been racing for 8 years now in a number of nitro and elect grades. I have assembled 17 cars in total, including 4 Losi JRXS cars.

I have adjusted just about every setting fully in both directions and have not been able to stop the loose back end.

Thanks for the help.

You can also put washers under the ball studs on the rear hub carriers that will increase camber gain and give you more traction in the rear. Are you using the stock setup out of the manual or did you try one of the other setups floating around out there?

[swalker]

I started with the standard setup. Had problems. Then I set it up identical to my sons car. No better. Then I started changing each of the settings (one at a time) slowly to the limits in both directions and still have not found any setting that has solved my problems. I have made some additional changes not and will try on Sunday. I still have not found anything that I would expect to cause the problems.

Funny how you can have 2 cars that seem identical in every way and yet handle totally differently.

[SkyRocket]

I started with the standard setup. Had problems. Then I set it up identical to my sons car. No better. Then I started changing each of the settings (one at a time) slowly to the limits in both directions and still have not found any setting that has solved my problems. I have made some additional changes not and will try on Sunday. I still have not found anything that I would expect to cause the problems.

Funny how you can have 2 cars that seem identical in every way and yet handle totally differently.

Man that must be super frustrating!! I have a couple of these cars myself and i have them setup the same.

Would it be possible for you to take a couple photos of your car and post them? I can send you a login to my photo site or you can use flickr or something. I'd love to see how they look.

I'm sure it's something subtle. I've found that even the smallest setting can have a big impact on these cars if it's in the right place.

[jkirkwood]

Have you tried just changing tires between the two cars? I've put new tires on cars before and the car get really stupid, switch back to a known good setup and the car was on rails.

[swalker]

Guys,

Thanks for all of you have given input. I made many changes and so cannot gurantee which one fixed it, but for the first time since I built the car I am actually getting understeer. I can actually start tuning it now.

Once again thanks to all.