Yokomo Yatabe Arena Springs for Astroturf/Carpet
 

Yokomo "Yatabe Arena" brand Springs for Astroturf/Carpet for B-MAX2/B-MAX4 III available now at MB models and teamyokomo.eu

I've put together a chart. No published spring rates. I'll do some measurements and calculations when I get mine.
As yet no idea where the rates sit compared to the existing Yokomo or AE springs, commonly used on these cars.

http://courgette.jml.net/~neal/RC/Yo...oYASprings.jpg


"Shin Adachi recommends:
For B-MAX2: front YELLOW - rear BLACK
For B-MAX4: front PURPLE - rear ORANGE"


Now available here: http://www.rccarshop.co.uk/index.php...sult/?q=yataba

Big rate difference by Shin if you ask me...

Please explain?


I've picked up all that MB models had in stock today, six of the nine springs.

He is talking about the spring advice from Shin Adachi.

2wd soft on the front and hard on the rear.
4wd hard on the front and soft on the rear.

And the big difference in the spring "rate" hardest to second to softest.
(Dunno if its all in propper English, but hey)

OK I see what you mean.

I run soft on front, hard rear(ish) on bmax2 already. The car likes this.

I run med/hard front and rear of my bmax4-III on the saddle chassis. I guess Shin's advice (quoted above) is for the newer shorty chassis setup they are running?

I've picked up 6 of the 9 rates today, all that were available. Missing the front Orange and Yellow, and rear Black.

The springs are good quality. I suspect they are X-gear made, like kyosho, but to Shin's spec?

I'll do some measurements and theoretical rate calcs later, to the equation that Arn0 gave me for his charts.

If anyone is at the Euros this coming week, please can they ask him for a proper spring rate chart?

What Paultje said. There is a big gap from purple front to orange rear (4wd), 2wd vice versa, if you know what i mean.
Still very confusing for me, but i'm not the smartest person! :thumbsup:

Btw Neal: keep up the good posts!

I talked to Shin about rates and he will probably confirm them later, but you are free to measure of course. I've them in stock (not tried yet since no time to wrench at the moment) and the springs feel very good and are indeed probably made by XGear.

Shin's advice is for the 'new' B-Max 4. It's slightly lighter than the saddle layout. :yawn:

Ok I've measured the springs I have and crunched the numbers. These rates are calculated and based on an assumption for the Modulus of Rigidity for the spring steel of 79000 GPa. That's a rough guess for spring steel (based on info found on Google), but not the actual value for the exact material used. I don't know that.

http://courgette.jml.net/~neal/RC/Yo...pringRates.jpg

If anyone could count the coils for the three springs I don't have, I could complete the data? If you want to know how to do this, PM me. Thanks.

Also if someone at the Euros could pass this under the nose of Shin to verify, that would be useful and also give me more of a clue to tune the Modulus of Rigidity to get closer to the actual real values.

Cheers.

Hey Neil, could you measure the kit springs?

I would like to know where they are to the Yatabe springs.

I've been working with Arno Petite who will be revising his spring calculations for the original Yok springs based on the maths I've done on these new ones, and putting out a new table. I'll check with him to see when it will be out.

I must say the new springs are very good, brown tempered wire colour, and a shorter length. Had my first run tonight at York indoor carpet/polished gym floor and they were awesome. Went purple front, orange rear as per Shin's advice and the car was great. Ran the new 1.8mm roll bar, then moved up to the 2.0mm and the car was better again. Still running the saddles/heavy car. I'll try get to RHR in the week for astro practice to get them dialled. So far so good anyway.

The new springs are a very different in terms of wire thickness and number of active coils, compared to the older Yok and AE springs. It's not just spring "rate".

Much appriciated, looking forward to the new table.

Hi Neil

The in regards of the spring rate Calc for a linear coil spring do not assume that the calc is correct/accurate with out checking the modulus of the steel.
Do this by testing the spring.

http://en.wikipedia.org/wiki/Hooke's_law

Regards

Sammy

I was looking for some springs for my Bmax2.

After looking at the springchart on Petit RC CLICK
I decided to try 2 sets of YATABE springs. Yellow front and Green rear.

I thought the Yatabe springs would all be harder than the Yokomo ones and extended the Yokomo spring range.

Once out of the pakkage the Yatabe springs didn't feel as hard as i thought they would be. So i mounted them up on the car and found the same.

This is what i "feel".

Rear: standard blue spring is harder than Yatabe green. (also have a set of Yokomo Purple and they are way harder than the Yokomo Blue)

Front: standard blue spring is close to Yatabe Yellow. not a big differance but seems to be harder.
Yokomo orange is harder than de Yatabe yellow (and Yokomo blue).

Also mounted up the rear springs and measured the sag.
Yatabe Yellow is softer than yokomo blue (and Purple)

So now it seems the Yatabe springs dont extend the Yokomo spring serie.
And the spring rates in the Sprinschart seem to be way off!

I wish Yokomo and Yatabe would give us a rating on the springs.

Has anyone compared the old purple and black springs to the Yatabe ones? Front oranges and rear greens seem to be slightly softer. I still have the old ones, which are quite good for a heavy truck on carpet. Now I wonder whether to get the full Yatabe set for the YZ-2 or not. The old ones would probably be too stiff for the YZ-2 on any kind of track.

Hi,

Just a quick question regarding these “Yatabe” Springs:
That is how long are they ( front & Rear ) ???
I know that the standard Big Bore Yokomo springs are a few MM in length shorter than other Big Bore springs like; Kyosho, Associated, Losi etc.
I just wanted to know how much shorter they are than the std ones ?

Cheers in advance for any info you can give.

Rob.

My front orange YTBs are the same length as my front orange B-Max springs, the same applies to my rear greens.

So what's special about the Yatabe springs vs the "standard" Yok springs anyway? Apart from the name, that is.

Having bought a BMAX4iii recently, I'm preparing it for the coming season and a set of springs is on the list so I was wondering what the difference is.

I don't understand how these can be sold with no spring ratings attached, or any indication of which does what? Surely this is a cock up somewhere?

I've seen this on petit rc:

http://www.petitrc.com/setup/yokomo/...ringsChart.pdf

Is this correct in what it's saying, or?

No that is wrong. We are working on it. I currently have a chart that i chucked together based on the N/CM ratings taken by Yokomo.eu that we believe to be closer but not fully accurate.

I haven't tried the YTB springs yet, but the wire used looks exactly as the wire of the X-Gear springs I had on my RT-6. The old Yokomo BM springs were coated with black paint, which is said to change spring characteristics and make them inconsistent as characteristcs are changed again with chipping paint. I can't say if the YTB springs are shorter than the new line of springs as I don't have any of these yet.

Although I'd prefer to have ratings on the spring packaging, I hardly really need them, the colour codes are sufficient for me in most cases. It is the colours that are written on the various set-up sheets out there, not the spring rate. ;)