BMAX 4 springs issue

[albertobdq]

Hi guys!

I've an issue with my BMAX shocks. I'm using champ package shocks with 30wt oil, stock pistons and green springs all around.

The car feels extremelly soft, specially at the front. It's not able of handling a 40cm droop without snapping the front end on the floor.

Any advice?

[bigred5765]

Originally Posted by albertobdq

Hi guys!

I've an issue with my BMAX shocks. I'm using champ package shocks with 30wt oil, stock pistons and green springs all around.

The car feels extremelly soft, specially at the front. It's not able of handling a 40cm droop without snapping the front end on the floor.

Any advice?

try 40wt all round thats what craggy had in at the weekend at worksop

[DaveG28]

Originally Posted by bigred5765

try 40wt all round thats what craggy had in at the weekend at worksop

Do you know what springs be was running? Looked like none Yok ones as far as I could see?

I've used Greens too, it is very soft at the front that way, but still very quick!

[bigred5765]

black front, pink rear, both yok and the champ kit piston 2 and 1

[albertobdq]

According to Yokomo spring chart, pink ones are just softer than the green and black are the hardest ones.

What kind of surface was it running on? Here we only had dirt tracks.

[DaveG28]

Originally Posted by albertobdq

According to Yokomo spring chart, pink ones are just softer than the green and black are the hardest ones.

What kind of surface was it running on? Here we only had dirt tracks.

very low traction track, so far I've found I need to keep the rear quite soft spring wise to get grip.

Although, for next time was planning on removing all the lead (I run Lipo), dropping to green (or maybe now try pink!) rear springs, putting the stiffer anti rol bar on, and going for thicker oil (I have been on 25wt rear, may try 35 or 40). It may be a terrible idea, but a theory my dad came up with on how to cope with the changed weight distribution from Lipo and the traction issues I've had!

For the front, if you want to go slightly harder on the front, try Orange springs, then the black. Like I say though, I actually went quickest I've been with it while using the front greens and driving around the diving under braking.

[DaveG28]

Originally Posted by bigred5765

black front, pink rear, both yok and the champ kit piston 2 and 1

If they were Yok springs in the back, he'd had the pink removed from all but the very bottom!

Pink is very soft, he had a 1.4 roll bar on the back, and I think was running Lipo (looked it), wonder if it's a way of dealing with the lower weight?

[bigred5765]

paint was removed

[sosidge]

I've managed to work a few things out about the Yokomo springs.

First of all, the spring chart from Petit RC is a great resource and gets a big from me - http://www.petitrc.com/reglages/BuggySpringChart.pdf

Secondly, Yokomo's coloured BX springs are very close in rate - they have only 0.25 coil difference between them. This may be a good step for a short touring spring but on a buggy it is far too small to make any difference. A 1/4 coil is worth 2-3% on the rate at these lengths, the AE and Losi springs are at closer to 10% difference between each rate. So as suggested above you need to go right down to a blue or pink to notice any real difference.

Thirdly, the front black springs are quite a lot stiffer than the nearest rate, at 0.75 coils stiffer than the next coloured spring. And are still at best a "medium" spring, similar to an AE silver.

[albertobdq]

Thank you very much, this weekend I'll try some kyosho springs.

[DaveG28]

Originally Posted by sosidge

I've managed to work a few things out about the Yokomo springs.

First of all, the spring chart from Petit RC is a great resource and gets a big from me - http://www.petitrc.com/reglages/BuggySpringChart.pdf

Secondly, Yokomo's coloured BX springs are very close in rate - they have only 0.25 coil difference between them. This may be a good step for a short touring spring but on a buggy it is far too small to make any difference. A 1/4 coil is worth 2-3% on the rate at these lengths, the AE and Losi springs are at closer to 10% difference between each rate. So as suggested above you need to go right down to a blue or pink to notice any real difference.

Thirdly, the front black springs are quite a lot stiffer than the nearest rate, at 0.75 coils stiffer than the next coloured spring. And are still at best a "medium" spring, similar to an AE silver.

Does your, or anyone else's experience, bear out the petit chart? Just wondering cos if so it could well be worth dropping below the yokomo softest spring on the rear, or harder than the hardest on the front? Say up to AE blue up front, down to AE silver/kyosho yellow at the back?

[sosidge]

I tried some AE springs last time out and it pretty much agreed with the Petit chart. Going up to AE blues definitely took the edge off the steering, this was running AE silvers on the back too.

[DaveG28]

Originally Posted by sosidge

I tried some AE springs last time out and it pretty much agreed with the Petit chart. Going up to AE blues definitely took the edge off the steering, this was running AE silvers on the back too.

On the chart the AE silver is softer than any Yok rear, does that fit in with what you found too?

[sosidge]

To be honest I just threw the silvers on to have consistency of brand on the car. Didn't notice anything specific about them, except that the balance of the car was a lot smoother with less grabby steering with the AE setup.

I later returned to kit springs but with the fronts on the outer wishbone hole, had a similar balance but also felt a shade faster overall, not sure how much of that was the decreased front droop and different shock angle though. More testing required.