B-MAX4 III Setup Thread

[gainsy]

As requested here is your setup thread

[Sylvain]

Hi guys here you can find my first setup...
http://imageshack.us/a/img818/9505/aep6.jpg
adydWCDj16E

[skyaflake]

And here is my setup http://teamyokomo.nl/setups/BMAX4III/B-Max4III_Dennis_vd_Waardenburg_MIO.pdf

Used in a tight indoor, medium traction track with some jumps.

[Raphalite]

Being new to Yoko, and new to 10th 4WD I thought I'd ask for thoughts and advice here on shock set up. It seems from what I can gather everyone tends to run with AE flat pistons, in 1.6/1.7mm x 2 hole variant.

It would be good to hear what people favour in piston and oil specification and where. I am currently building my kit and looking to run at on an outside Astro track. I am going to start with (as I have them) taper down AE 1.6mm x 2 in the front and 1.7mm x 2 for the rear and see how it goes.

Thanks Sylvain for posting your set up, I think I'll base oil weights around yours and tweak to suit the outside temp, once I've converted the weights for Losi that is..

[neallewis]

My current/latest setup for RHR astro:
http://courgette.jml.net/~neal/RC/Yokomo/Bmax4III_RHR_NL_2014-06-08.pdf

[neallewis]

Here is my latest BMAX4III Robin Hood Raceway Astro setup
http://courgette.jml.net/~neal/RC/Yokomo/Bmax4III_RHR_NL_2014-08-21.pdf

[minty]

Here is my latest BMAX4III Robin Hood Raceway Astro setup
http://courgette.jml.net/~neal/RC/Yokomo/Bmax4III_RHR_NL_2014-08-21.pdf

To use the 2wd slim spikes on the front I'm guessing you have to cut the wheels? Or do you run them on full width 4wd wheels?

[neallewis]

To use the 2wd slim spikes on the front I'm guessing you have to cut the wheels?

No, they fit on the regular Yokomo front wheels fine.

only stagger ribs or cut staggers need the rim cutting, but i didn't like those on the car.

[minty]

No, they fit on the regular Yokomo front wheels fine.

only stagger ribs or cut staggers need the rim cutting, but i didn't like those on the car.

Top stuff, I'll give some a try

[neallewis]

Top stuff, I'll give some a try

They feel a lot better than the regular balloony 4wd front mini spikes, which I found to give more grip roll and the car just wants to tip over in the corner, like it rolls onto the round tyre profile. I think a lot of the effect of grip roll comes from tyre sidewall gripping the astro, not just the spikes.

[minty]

Here is my latest BMAX4III Robin Hood Raceway Astro setup
http://courgette.jml.net/~neal/RC/Yokomo/Bmax4III_RHR_NL_2014-08-21.pdf

Hi

just having a look over your setup.

You have put on the sheet that on the front you used BM-S1270 Yok orange

And on the rear you have used YAS-700 Yatabe orange

looking at the spring chart on petit rc the YAS-700 is a front spring.

Did you use a front spring on the rear? :eh?:

[neallewis]

Hi

just having a look over your setup.

You have put on the sheet that on the front you used BM-S1270 Yok orange

And on the rear you have used YAS-700 Yatabe orange

looking at the spring chart on petit rc the YAS-700 is a front spring.

Did you use a front spring on the rear? :eh?:

oops, I made a mistake...

Should be the YAS-1025 orange rear.
http://www.rccarshop.co.uk/index.php/rc-accessories/buggy-springs/yokomo/yataba-arena-big-bore-shock-rear-spring-orange-for-astroturf-or-carpet-surface.html

Kit Orange front spring BM-S1270
http://www.rccarshop.co.uk/index.php/rc-accessories/buggy-springs/yokomo/bm-s1270-front-x-shock-spring-orange-soft.html
I kept coming back to this after testing.

The Orange rear BM-S12100 is also good.
http://www.rccarshop.co.uk/index.php/rc-accessories/buggy-springs/yokomo/bm-s12100-rear-x-shock-spring-orange-soft.html

I'll amend my sheet, cheers.

Edit. Done: http://courgette.jml.net/~neal/RC/Yokomo/Bmax4III_RHR_NL_2014-06-08.pdf

[Pedros20]

Hi guys, picked up a Bmax4 ||| with L/W shortie chassis, I'm looking for a good base set up to use on med/high grip carpet. I've ordered the YAS front & rear springs & hard roll bar kits, it's the rest I'm after. Do you all run kit roll centres & toe in etc?
Any advice would be great

Cheers

Here's the car so far. Really like it so far! 👍

http://i467.photobucket.com/albums/rr33/pedros20/E7E953E4-3E61-48EA-BB6E-DC8E0F8C0B3D_zpsuwuzl60k.jpg (http://s467.photobucket.com/user/pedros20/media/E7E953E4-3E61-48EA-BB6E-DC8E0F8C0B3D_zpsuwuzl60k.jpg.html)

[Allan1875]

Hi guys, picked up a Bmax4 ||| with L/W shortie chassis, I'm looking for a good base set up to use on med/high grip carpet. I've ordered the YAS front & rear springs & hard roll bar kits, it's the rest I'm after. Do you all run kit roll centres & toe in etc?
Any advice would be great

Cheers

Here's the car so far. Really like it so far! ��



High roll centre rear, low roll centre front. If its med grip, stick with the 3 degree rear toe, 2 degree anti squat however you can always go to 2.5 rear toe.

Yatabe Purple front, Yatabe orange rear. 550cst (roughly 45WT) front, 400cst (roughly 30WT) rear. 1.8 roll bar front and rear. 10k front and rear oil, however you could go 30k front and 20k rear as this is something the Yok drivers, mainly Lee, have been experimenting with lately and they like it.

Just PM if you want more info. :thumbsup:

Edit. I meant to add, we are using the 15 degree front caster blocks and the alloy rear.

[Pedros20]

Thanks for that buddy, much appreciated! I'll get the spanners out & it done! :thumbsup: can't wait to run it!

[eddscott]

Does anyone have a setup for grass for the BMax 4?

I'm close to building my shorty version BMax and have built it as per the instructions with 35 front, 30 rear and Yoke orange all round, 10K front and rear diff.

[CARB]

hi
Just bought a used BMax 4 III what a totally awsum car.
Neale

[Allan1875]

Does anyone have a setup for grass for the BMax 4?

I'm close to building my shorty version BMax and have built it as per the instructions with 35 front, 30 rear and Yoke orange all round, 10K front and rear diff.

If you look on petitrc, I just added a grass setup.

[eddscott]

If you look on petitrc, I just added a grass setup.

Thank you. There are quite a few changes compared to the kit build!

What benefits are there of running the YZ2 rear arms?

[Allan1875]

Thank you. There are quite a few changes compared to the kit build!

What benefits are there of running the YZ2 rear arms?

They are shorter so it adds rear grip. The geometry is also changed slightly which helps balance.

[ralphee]

Has anybody tried the YZ2 rear end on this car as yet? Raced mine Friday again and bagged a second overall, but found it over rotating a tad, and early on in the heat the rear was very loose.
Was running 650cst/Yatabe Purple front, 4mm droop limiters, 450cst Yatabe Orange rear on the shocks, but we run on Venoms, with 4WD cut stagger front tyres, so just wondered if the YZ rear arms and shafts i have lying about would bring up that rear bite somewhat?
On the whole though, what fantastic car, my first two meetings with this car, and in 4WD have gone down very well.

Lee

[neallewis]

What roll bars are you on?

YZ2 arms and shafts made it worse for me, but i'm not running on super high grip carpet or astro. if your track is med-loew traction, stick with kit or B4-008R1 arms.

[Allan1875]

What roll bars are you on?

YZ2 arms and shafts made it worse for me, but i'm not running on super high grip carpet or astro. if your track is med-loew traction, stick with kit or B4-008R1 arms.

Med-Low, the YZ2 arms should be better. That's why on high grip we go to the BMAX arms on the YZ2.

[ralphee]

What roll bars are you on?

YZ2 arms and shafts made it worse for me, but i'm not running on super high grip carpet or astro. if your track is med-loew traction, stick with kit or B4-008R1 arms.

Neil thanks for the reply, im running 1.8 front, 2mm rear, 10k diff oil all round, initially is struggle for lateral grip on the Venoms, when they kick in its not too bad at all, so was pondering the YZ2 option as i do have the parts, just didnt want to then, get into insane grip roll half way in the heat i guess?
Got a lot of front grip, just over rotates a fair bit on cold tyres!
Carpet is medium in grip if say, overall though love the car, 4WD seems to suit my driving way more TBH!

Lee

[neallewis]

Med-Low, the YZ2 arms should be better. That's why on high grip we go to the BMAX arms on the YZ2.

But it's not better? Car was a lot looser for me on rear in the low traction with them on. Returned to the +1 arms and it's good again.

[neallewis]

Neil thanks for the reply, im running 1.8 front, 2mm rear, 10k diff oil all round, initially is struggle for lateral grip on the Venoms, when they kick in its not too bad at all, so was pondering the YZ2 option as i do have the parts, just didnt want to then, get into insane grip roll half way in the heat i guess?
Got a lot of front grip, just over rotates a fair bit on cold tyres!
Carpet is medium in grip if say, overall though love the car, 4WD seems to suit my driving way more TBH!

Lee

Roll bars are fine, you could try 1.8 all round.
Try 20k front diff oil.

[Allan1875]

Neil thanks for the reply, im running 1.8 front, 2mm rear, 10k diff oil all round, initially is struggle for lateral grip on the Venoms, when they kick in its not too bad at all, so was pondering the YZ2 option as i do have the parts, just didnt want to then, get into insane grip roll half way in the heat i guess?
Got a lot of front grip, just over rotates a fair bit on cold tyres!
Carpet is medium in grip if say, overall though love the car, 4WD seems to suit my driving way more TBH!

Lee

How do you have your front hangar inserts?

You could also run -2 camber the front. Your fronts are gonna make the car over rotate in comparison to the rear tyres you are using. Try dropping your rear roll bar to 1.5 also.

[ralphee]

Thanks Allan, and Neal, ill try those options first, i can drop a 1.8 rear bar in first off. Front hanger inserts are as per kit too.

lee

[Allan1875]

Thanks Allan, and Neal, ill try those options first, i can drop a 1.8 rear bar in first off. Front hanger inserts are as per kit too.

lee

Kit front hangars are gonna give you extra steering also which may be what is pulling the car round. I tend to always run my front hangars in the low roll centre with the widest track. So, the inserts would be with the arrows at the bottom and facing outwards instead of inwards.

[ralphee]

Ahh so both front inserts bottom and arrow out? Allan thanks a lot for all the tips, really appreciate the help, ill try all this this coming Friday!

[Allan1875]

Ahh so both front inserts bottom and arrow out? Allan thanks a lot for all the tips, really appreciate the help, ill try all this this coming Friday!

Yeh give it a go, let us know how you get on.

[RDG 40]

Med-Low, the YZ2 arms should be better. That's why on high grip we go to the BMAX arms on the YZ2.

So standard bmaz rear for high grip
Yz rear for low grip

??

Just checkin as see lee ran yz rear end at rhr thats all

[ralphee]

Yeh give it a go, let us know how you get on.

Will do Allan, ill have to start messing with set up sheets so i dont lose myself lol!

Lee

[Allan1875]

So standard bmaz rear for high grip
Yz rear for low grip

??

Just checkin as see lee ran yz rear end at rhr thats all

Yeh let me clear this up as it's probably gonna start confusing things. That's my fault as it's in the bmax section.

On the bmax, we have run the yz2 arms everywhere, low and high grip.

On the yz2, we have been running the bmax arms on high grip. I think I'm the only one to have raced low grip, but I have been switching back to kit arms for low grip.

[ayske1]

With the +1 arms do you need to make any changes?

[neallewis]

Yeh let me clear this up as it's probably gonna start confusing things. That's my fault as it's in the bmax section.

On the bmax, we have run the yz2 arms everywhere, low and high grip.

On the yz2, we have been running the bmax arms on high grip. I think I'm the only one to have raced low grip, but I have been switching back to kit arms for low grip.

Confusing the issue, on the yz2 i run the bmax4iii arms and its excellent on both high, med and low traction tracks, I've found.

On my bmax4iii, i found the narrower yz2 rear arms to be worse on sandy medium traction astro, and Yorcc gym floor low traction, so i went back to B4-008R1 arms. I've not run yz2 rear arms at RHR though.

Allan, what's the technical reasoning behind the arm width for high or low traction?

[ralphee]

Allan, Neil, car was way way better last night. Changed the front hangers to arrows out, and i did leave the 2mm rear roll bar in, but swapped to Yatabe rear Purple springs, way better balance, managed to put it 2nd on the grid and came third due to driving like a right numpty, Finals arent my strong point lol, but for sure, car was great.
I will say on these 4wd staggers, the amount of front grip is bonkers, im running 4mm limiters in the front, may step that up to 5mm next week!

lee

[Allan1875]

Confusing the issue, on the yz2 i run the bmax4iii arms and its excellent on both high, med and low traction tracks, I've found.

On my bmax4iii, i found the narrower yz2 rear arms to be worse on sandy medium traction astro, and Yorcc gym floor low traction, so i went back to B4-008R1 arms. I've not run yz2 rear arms at RHR though.

Allan, what's the technical reasoning behind the arm width for high or low traction?

I only know about track width theory from go karts mate. Narrow = grip, wide = less grip. As for the actual theory, not a clue. You could be right though, these cars don't always behave as expected so it's always worth back to back testing.

Allan, Neil, car was way way better last night. Changed the front hangers to arrows out, and i did leave the 2mm rear roll bar in, but swapped to Yatabe rear Purple springs, way better balance, managed to put it 2nd on the grid and came third due to driving like a right numpty, Finals arent my strong point lol, but for sure, car was great.
I will say on these 4wd staggers, the amount of front grip is bonkers, im running 4mm limiters in the front, may step that up to 5mm next week!

lee

I run 5mm on high grip and 3mm on bumpy low-med grip.

Cut the outer row off the staggers, that will help a lot.

[timoxx4]

I am finding the same. Just bought a 4 III and first run on the weekend and it had a tone of steering and was also very loose and sliding in the rear. Kit setup basically with 2wd stagger ribs front and mini pins rear in yellow compound. Med/High grip indoor Carpet.

When you guys talk about 5mm of limiters in the front shocks are you saying 5 of the little Yokomo shock limiters ? Or an actual measured 5mm worth of shims ? As 5 of the Yokomo limiters would only be 4mm measured as they are only 0.8mm thick each. Kit has 2 in the front. I just put 5mm worth in and now I pretty much have no droop at all.

Is that right ? Seems like a very extreme droop reduction. Excessively so.:confused:

[ayske1]

Didn't want to start a new thread but I think I read that some people were reverting back to plastic shock caps, if so apart from weight what's the reason?

[neallewis]

I am finding the same. Just bought a 4 III and first run on the weekend and it had a tone of steering and was also very loose and sliding in the rear. Kit setup basically with 2wd stagger ribs front and mini pins rear in yellow compound. Med/High grip indoor Carpet.

When you guys talk about 5mm of limiters in the front shocks are you saying 5 of the little Yokomo shock limiters ? Or an actual measured 5mm worth of shims ? As 5 of the Yokomo limiters would only be 4mm measured as they are only 0.8mm thick each. Kit has 2 in the front. I just put 5mm worth in and now I pretty much have no droop at all.

Is that right ? Seems like a very extreme droop reduction. Excessively so.:confused:

Yes i use 5x 0.8mm yokomo droop washers in each front shock. I have also used 6x indoors on flat tracks, and 4x on bumpy outdoor, but preferred 5x.
Rear has 3x to stop shafts popping out.

It's not excessive. Ive seen similar amounts used on B44.x cars.

[timoxx4]

Ah I put too much in mine then. So 4mm is what it should be not 5mm. That explains a lot thanks. :thumbsup: Do you know what length the shock shaft is after you add those shims ? As the rod end can be screwed in more or less which will give a different droop setting also ? I have mine set at 19mm with the 5 limiters inside the shock but I could make it a lot less if I screw the rod end all the way in. I think 20mm is kit length.

[timoxx4]

Also while I remember. I see on Lee's setups he has the caster blocks modified and pushed back 2mm. Dose anyone know what that dose for the car exactly ?

[Allan1875]

Also while I remember. I see on Lee's setups he has the caster blocks modified and pushed back 2mm. Dose anyone know what that dose for the car exactly ?

Shortens the wheelbase and makes the car more stable on the low grip. I had an issue with the rear collapsing on low grip when turning and once I made this modification it was much better.

[Allan1875]

Confusing the issue, on the yz2 i run the bmax4iii arms and its excellent on both high, med and low traction tracks, I've found.

On my bmax4iii, i found the narrower yz2 rear arms to be worse on sandy medium traction astro, and Yorcc gym floor low traction, so i went back to B4-008R1 arms. I've not run yz2 rear arms at RHR though.

Allan, what's the technical reasoning behind the arm width for high or low traction?

Right, I was starting to seriously doubt what I believed to be correct after this thread and it was starting to get really confusing. I decided to do some reading on the subject and also spoke to Cockers about it.

After all that:

In theory, wider = more grip, however in reality it tends to translate as more stable. Narrower = more reactive, which gives the impression of more grip, however I believe in the grand scheme it will be less.

This now makes sense. If you try the YZ2 on Astro with stock arms, you will notice that it is extremely reactive. Stick the BMAX arms on and it is far more stable and much easier to drive.

This would also make sense with the YZ2 arms on the BMAX. Less grip without making the car too sensitive.

This also explains why you found the wider arms better Neal.

Now I need to get myself some track time for testing. I do love this stuff about racing, everyday is a school day.

[neallewis]

Right, I was starting to seriously doubt what I believed to be correct after this thread and it was starting to get really confusing. I decided to do some reading on the subject and also spoke to Cockers about it.

After all that:

In theory, wider = more grip, however in reality it tends to translate as more stable. Narrower = more reactive, which gives the impression of more grip, however I believe in the grand scheme it will be less.

This now makes sense. If you try the YZ2 on Astro with stock arms, you will notice that it is extremely reactive. Stick the BMAX arms on and it is far more stable and much easier to drive.

This would also make sense with the YZ2 arms on the BMAX. Less grip without making the car too sensitive.

This also explains why you found the wider arms better Neal.

Now I need to get myself some track time for testing. I do love this stuff about racing, everyday is a school day.

That's awesome, and explains it perfectly. I don't have Lee's thumbs, so less reactive is better for me ;-)

[neallewis]

Shortens the wheelbase and makes the car more stable on the low grip. I had an issue with the rear collapsing on low grip when turning and once I made this modification it was much better.

I've had the rear collapsing problem also, both on low and high grip.
I had it last the other week on batley astro when I went too low on the rear shock oil (to try and improve rear end over the bumps) but the car would just randomly hook. Going back up to 400cst made the car far more consistent again. It's fine balance of oils, spring and rollbar, but when you get the problem, the car become inconsistent.
I believe it's related to diff/outdrive height.

Did you also drill the steering block arms to move the ball end in?

[timoxx4]

Did you also drill the steering block arms to move the ball end in?

What dose that do ? I have seen it done also but never could figure out what it might be for ? Would make the steering more reactive I would have thought?

[neallewis]

What dose that do ? I have seen it done also but never could figure out what it might be for ? Would make the steering more reactive I would have thought?

Move Ackerman point back to where is is before the caster blocks are moved 2mm back.

I'm concerned that drilling them will weaken them?

[Adam F]

Move Ackerman point back to where is is before the caster blocks are moved 2mm back.

I'm concerned that drilling them will weaken them?

I've never broken a block and been running them drilled for a few months now.

There is a web underneath from memory which keeps them pretty strong.

[Allan1875]

I've had the rear collapsing problem also, both on low and high grip.
I had it last the other week on batley astro when I went too low on the rear shock oil (to try and improve rear end over the bumps) but the car would just randomly hook. Going back up to 400cst made the car far more consistent again. It's fine balance of oils, spring and rollbar, but when you get the problem, the car become inconsistent.
I believe it's related to diff/outdrive height.

Did you also drill the steering block arms to move the ball end in?

Yes, the arms are also drilled and made the steering far better.

[Squidzilla]

All interesting stuff, any chance of sharing a picture of where you have drilled and any other mods?

[Allan1875]

All interesting stuff, any chance of sharing a picture of where you have drilled and any other mods?

Will sort some tomorrow.

[Allan1875]

Pictures as promised.

I had the block machined and then I dremelled away the sharp edge to allow the block move side to side. I also dremelled the block to allow it to go even further back than 2mm.

With the steering arm mod, please note that the titanium turnbuckles are too short and just pull out the ball cup. You will see from the pic for the steering arms I am using kit, although these can be substituted for titanium YZ2 turnbuckles.

Edit: Noticed it's not very clear in the picture of the block fitted. There are 2 x 1mm spacers shown, and at the front there is 1 x 1mm and 1 x 0.8mm spacer. I will be switching the 2 of these to get the 2mm back at the front though.

[RDG 40]

Can anyone explain the bmax 4 steering link either front or back?

I notice on lees set up its shows back yet pics show feont position??

I presume ackerman setting? I know on yz2 its a big tuning aid

[Allan1875]

Can anyone explain the bmax 4 steering link either front or back?

I notice on lees set up its shows back yet pics show feont position??

I presume ackerman setting? I know on yz2 its a big tuning aid

Front = more aggressive steering
Back = calmer steering

Lee changes his dependent on where he is racing but majority of the time its in the front. I always run mine in the front now as the BMAX is fairly low on steering as standard.

[PJC]

I've never broken a block and been running them drilled for a few months now.

There is a web underneath from memory which keeps them pretty strong.

How far from the original hole should the new hole be sited?

[dikke hond]

Someone tried the DJC on the Bmax4?

[dikke hond]

Waiting for the setup sheet from Ryan Maifield:lol::p

[Arn0]

Waiting for the setup sheet from Ryan Maifield:lol::p
You will wait quite some time if for a Bmax4 III one.;)

[mes]

Maybe for the B-Max-4IV?! ;)

[dikke hond]

You will wait quite some time if for a Bmax4 III one.;)
:thumbsup:
Maybe for the B-Max-4IV?! ;)
:thumbsup:

I will keep my old, trustfull Bmax4 just a little bit longer :) I think it's a Bmax4 III with some YZ4 mods.

[purplenut]

Hi all
She good reading here about set ups, I'm running on polished floor and keep loosing back end, have tries taking the washers out of inner side nd made a little difference but wondered if anyone else race on these kind of floors.
Also I'm having big problems getting front arms, is it the yz arms will fit.
Sorry but all new to yokomo but loving the build quality and the car itself.
Thanks:thumbsup:

[Darrin70]

Any other bodies fit the Bmax4 III ?