XB4 '15 tyre wear

[Hans Wynants]

Hello , i have gone from the XB4 '14 tot the '15 last month .

i mainly drive on an astro track ( Orra in Arendonk Belgium) . fully out of astro . and when dry with Schumacher minispike Yellow.

with my old 2014 i can race my tyre's untill they are almonst completely gone. the front tyres would also wear faster than the rear tyres . still have plenty of grip to drive fairly good lap times. less steering obviously butt still ok. the only times i would get in trouble was when driving brand new tyres...


now the 2015 is way different. i drive the new car in shorty setup , with at the moment extra weight on the chassis , under the rear mid axle . the difference i feel directly is that the car drives better with brand new tyres , but as soon the tyres are worn like approx 60% , the grip will dissapear in the rear! the rear of the car will slide faster and the bite when on throttle is nog good anymore...

cane someone tell me what i am doing wrong?

my setup is pritty soft . needs to be for the bumpy astro.

thanks .

[BentKa]

Hello , i have gone from the XB4 '14 tot the '15 last month .

i mainly drive on an astro track ( Orra in Arendonk Belgium) . fully out of astro . and when dry with Schumacher minispike Yellow.

with my old 2014 i can race my tyre's untill they are almonst completely gone. the front tyres would also wear faster than the rear tyres . still have plenty of grip to drive fairly good lap times. less steering obviously butt still ok. the only times i would get in trouble was when driving brand new tyres...


now the 2015 is way different. i drive the new car in shorty setup , with at the moment extra weight on the chassis , under the rear mid axle . the difference i feel directly is that the car drives better with brand new tyres , but as soon the tyres are worn like approx 60% , the grip will dissapear in the rear! the rear of the car will slide faster and the bite when on throttle is nog good anymore...

cane someone tell me what i am doing wrong?

my setup is pritty soft . needs to be for the bumpy astro.

thanks .

Post your setup and it will be easier to help you out :)

We run on astro using Mini Spike (control tires for the National Series) and Mini Pin as well and have never had any issues with the rear tires going bad before the fronts on either of the '13, '14 or '15 cars.

Bent

[dibble34]

I agree, if anything the tires are hanging on better with my 2015.

[Hans Wynants]

i hope the quality is a bit decent, i have pulled a print screen of the PDF file...


http://www.mijnalbum.be/GroteFoto-4Y4PCGUN.jpg

[Hans Wynants]

my car is completely in pieces at the moment, awainting for the 3mm chassis :-) so all the help is welcome. :)

[Hans Wynants]

maybe an important extra , i checked my diffs , becouse they are off the chassis anyway , and the rear diff was almost empty , i noticed in the race that i often had 'diff out' . maybe this had someting to do with the tyre wear , or the strange feeling off the tyres.

[dibble34]

Setup looks ok to me. Main difference to mine is you are a lot softer, i have been running 4 dot springs up fron, 3 on rear with a 1.6 roll bar up front and 1.2 rear. Also my oils have been 600/450 with kit 3 hole pistons. Not sure what affect that would have on tyre wear though.

[Hans Wynants]

This is the link of a movie , shot of me riding at my local track.?

https://m.youtube.com/watch?v=uKTIOQvdhGU

[dibble34]

Looks nice :thumbsup: I run 2 degrees antisquat at the rear as well which I find helps traction from breaking. You could try that?

[s22jgs]

Ure running hinge pins high with the chassis plate. Not surprised the rear is breaking traction easily.

Look at some of the team setups. Biggest different to yours is the Hinge pins. The 15 seems to like them being on the inside not outside. Especially running shorty

[dibble34]

Ure running hinge pins high with the chassis plate. Not surprised the rear is breaking traction easily.

Look at some of the team setups. Biggest different to yours is the Hinge pins. The 15 seems to like them being on the inside not outside. Especially running shorty

Can I ask what affect running the hinge pins inside has?

[BentKa]

Can I ask what affect running the hinge pins inside has?

Running the hinge pins on the inside towards the chassis or downwards gives more roll to the chassis.
Running them on the outside or upwards gives less roll.

We start with them on the inside and down, and if we need less roll we go upwards but keep them on the inside.
If this isn't enough we move them outwards as well.

Bent

[Hans Wynants]

is it also helpfull to put the hinge pins outwards to make the car as wide as possible to prevent grip rolling ? i also have placed the +0.75 hex front and rear , the car goed just in the testing box for maximum measurements .

yesterday i did some testing again on the track and had some changes on the dampers , and with sway bars installed. with a great result , had a lot of traction with tyres i have taken off on the race day becouse they had not enough traction anymore.

[dibble34]

is it also helpfull to put the hinge pins outwards to make the car as wide as possible to prevent grip rolling ? i also have placed the +0.75 hex front and rear , the car goed just in the testing box for maximum measurements .

yesterday i did some testing again on the track and had some changes on the dampers , and with sway bars installed. with a great result , had a lot of traction with tyres i have taken off on the race day becouse they had not enough traction anymore.

Could you post your new setup?

[BentKa]

i hope the quality is a bit decent, i have pulled a print screen of the PDF file...


http://www.mijnalbum.be/GroteFoto-4Y4PCGUN.jpg

is it also helpfull to put the hinge pins outwards to make the car as wide as possible to prevent grip rolling ? i also have placed the +0.75 hex front and rear , the car goed just in the testing box for maximum measurements .

yesterday i did some testing again on the track and had some changes on the dampers , and with sway bars installed. with a great result , had a lot of traction with tyres i have taken off on the race day becouse they had not enough traction anymore.

Based on your posted setup I would change this for the front:



Longer bushing: down
Shim on top of C-hub: 0
Shocks on tower: all the way in
Front toe -1
2* camber
Long wheelbase (2mm arm shim rear of arm)
Standard offset hexes
No graphite arm stiffeners
2x1.5 + 2x1.1 pistons / 700cst / 3 dot springs / 1.6mm swaybar / 1mm + O-ring uptravel limiter


For the rear I would change:


10' diff oil
No chassis plate under rear bulkhead (+2mm hinge pin holders)
Camber link inside hole on upright
Rear shocks outside on arms
2.5* camber
No graphite arm stiffeners
Standard offset hexes
2x1.6 + 2x1.1 pistons / 450cst / 2 dot springs / 1.6mm swaybar / 5mm + O-ring uptravel limiter
Remove 80g weight in rear and only use 10-25 grams behind motor to balance left to right weight of motor vs. battery.


Bent

[Hans Wynants]

thank you Bent, i will give that a try next time on track.

this is the setup i was driving yesterday, with already good result; my rear diff has changed to 10.000 also, but i forget to adjust the sheet...

http://www.mijnalbum.be/GroteFoto-L4GYLIN3.jpg

[dibble34]

Thanks that is interesting. Do you run 2wd spikes up front? Do you cut any spikes off?

[Hans Wynants]

i run the normal 4wd tyres normally, but am waiting for 3 sets of the 2wd slim minispike version. had a set once and they also do a pretty good job.

with the normal 4wd spike in yellow comp i cut away 2 rows on the outside and 1 row on the inside . als will glue the outher sidewall with thick glue . it will give less surprises in the corder.