333LikesXray XB2 2WD Buggy Thread
05-04-2019, 06:44 PM - Wikipost
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02-05-2016, 01:26 AM
#1306
Tech Initiate
I have always found the Xray handling characteristic descriptions to be a little ambiguous.
Moving the shocks to the rear definitely helps in lower traction conditions. Be sure to adjust the droop to compensate for the wishbone angle though. This is a worthwhile tuning aid, but it is not a one size fits all fix for all low grip situations.
Moving the shocks to the rear definitely helps in lower traction conditions. Be sure to adjust the droop to compensate for the wishbone angle though. This is a worthwhile tuning aid, but it is not a one size fits all fix for all low grip situations.
02-05-2016, 06:28 AM
#1307
Bent
02-05-2016, 07:03 AM
#1308
He is right... Theoretically.
But sometimes theory doesn't play out in the real world.
I can't really explain this to someone without drawing a picture.
Regardless, it would seem that most are finding more grip with the shocks in back. It's just counter intuitive to everything we know about weight transfer. Maybe a long wheel base would help this car too, in low grip, as it seems slowing rotation is a greater benefit than adding weight transfer to rear.
But sometimes theory doesn't play out in the real world.
I can't really explain this to someone without drawing a picture.
Regardless, it would seem that most are finding more grip with the shocks in back. It's just counter intuitive to everything we know about weight transfer. Maybe a long wheel base would help this car too, in low grip, as it seems slowing rotation is a greater benefit than adding weight transfer to rear.
02-05-2016, 07:38 AM
#1310
He is right... Theoretically.
But sometimes theory doesn't play out in the real world.
I can't really explain this to someone without drawing a picture.
Regardless, it would seem that most are finding more grip with the shocks in back. It's just counter intuitive to everything we know about weight transfer. Maybe a long wheel base would help this car too, in low grip, as it seems slowing rotation is a greater benefit than adding weight transfer to rear.
But sometimes theory doesn't play out in the real world.
I can't really explain this to someone without drawing a picture.
Regardless, it would seem that most are finding more grip with the shocks in back. It's just counter intuitive to everything we know about weight transfer. Maybe a long wheel base would help this car too, in low grip, as it seems slowing rotation is a greater benefit than adding weight transfer to rear.
02-05-2016, 07:40 AM
#1311
The rear shocks are the fulcrum point for the lever that is the whole car. The further forward they are, the easier it is for the rear of the car to squat. Move them back, and it takes more effort for the car to squat.
The further forward they are, assuming the same spring rate, the more weight they are supporting, and they effectively get softer, letting more weight transfer rearward under power. Move them back, they support less weight, and become effectively stiffer, and the car won't squat as much under power.
Maybe getting rid of that weight transfer is helping to drive the wheels into the ground more, instead of letting the energy pass into then over the rear, it just keeps driving down.
Looks like the shocks are on the back of the dirt car... so... guess I'll be moving mine next time out
02-05-2016, 07:50 AM
#1312
Bent you tease!
02-05-2016, 08:41 AM
#1313
Tech Adept
Moving the shocks from the front to the back changes the static weight distribution to further rearward as you are moving mass rearwards, this gives more traction. It really is as simple as that (assuming you use equivalent droop). However, some of the explanations are quite funny, so carry on!
02-05-2016, 11:17 AM
#1315
The rear shocks are the fulcrum point for the lever that is the whole car. The further forward they are, the easier it is for the rear of the car to squat. Move them back, and it takes more effort for the car to squat.
The further forward they are, assuming the same spring rate, the more weight they are supporting, and they effectively get softer, letting more weight transfer rearward under power. Move them back, they support less weight, and become effectively stiffer, and the car won't squat as much under power.
Maybe getting rid of that weight transfer is helping to drive the wheels into the ground more, instead of letting the energy pass into then over the rear, it just keeps driving down.
Looks like the shocks are on the back of the dirt car... so... guess I'll be moving mine next time out
The further forward they are, assuming the same spring rate, the more weight they are supporting, and they effectively get softer, letting more weight transfer rearward under power. Move them back, they support less weight, and become effectively stiffer, and the car won't squat as much under power.
Maybe getting rid of that weight transfer is helping to drive the wheels into the ground more, instead of letting the energy pass into then over the rear, it just keeps driving down.
Looks like the shocks are on the back of the dirt car... so... guess I'll be moving mine next time out
You're describing the impact the weight of the car itself has on the performance of the rear shocks, based on the location of the shocks. IE: You're saying the further forward the shock is, the more weight it bears, thus the softer it is overall it feels given the same springs and such. The only thing I'd suggest is that the shocks are always tied to the same suspension arms and same shock tower. I believe the deltas you're describing would exist only if there were significant flex on the arm or shock tower, or both.
On the other hand, I'm saying that the location of the shock has an impact on how the overall car's weight is distributed front to rear. That weight bias would also have impact on shock performance as you describe, but I think it's due to different dynamics.
Like anything else, you still have to go by what you experience on the track.
02-05-2016, 11:22 AM
#1316
Moving the shocks from the front to the back changes the static weight distribution to further rearward as you are moving mass rearwards, this gives more traction. It really is as simple as that (assuming you use equivalent droop). However, some of the explanations are quite funny, so carry on!
Maybe I was wrong, but I still am having a hard time picturing the piston moving up when a car landed. However, I still enjoy these random conversations.
02-05-2016, 01:09 PM
#1317
(plus the order-2 effect of droop because of anti squat that was discussed a few pages back)
edit: Goehm had answered already.
02-05-2016, 01:42 PM
#1318
Interesting.
You're describing the impact the weight of the car itself has on the performance of the rear shocks, based on the location of the shocks. IE: You're saying the further forward the shock is, the more weight it bears, thus the softer it is overall it feels given the same springs and such. The only thing I'd suggest is that the shocks are always tied to the same suspension arms and same shock tower. I believe the deltas you're describing would exist only if there were significant flex on the arm or shock tower, or both.
You're describing the impact the weight of the car itself has on the performance of the rear shocks, based on the location of the shocks. IE: You're saying the further forward the shock is, the more weight it bears, thus the softer it is overall it feels given the same springs and such. The only thing I'd suggest is that the shocks are always tied to the same suspension arms and same shock tower. I believe the deltas you're describing would exist only if there were significant flex on the arm or shock tower, or both.
I see what you are saying though... it really isn't as simple as I am making it out to be... for one, the front of the car doesn't pivot on a fixed point.
I'm not arguing for one way or the other. I am a firm believer in throwing theories and numbers out the window.... I just want to understand what is happening.
I also agree that moving the weight(of the shocks) back certainly doesn't hurt... But I still think it's a little more complex than just that. Maybe not...
02-05-2016, 02:07 PM
#1319
I really want to hear X-Rays logic to this, because they are saying the opposite of what everyone is finding.
Dirt car has them on the rear though, so that says a lot...
02-05-2016, 02:23 PM
#1320
Question regarding the ball differential: is this using 1/8 diff balls? I tried to look at some replacement parts, and only see full diff sets and the diff gear so I couldn't tell. I counted the openings in the diff gear and see 12, so it leads me to believe they're 1/8 balls - which I think is a great thing. I love how the diffs build and last on my SRX2 which also uses 1/8 balls.