22 replies to this topic

[Exmantaa]

I'm not a suspension guru, as most of us, but is there a certain ideal bump vs. droop travel on the VX shocks? Not talking ride heights here...

Just fitted some NTR's 425/550 and without helpers or pre-load there's not a lot of spring compression going on... So probably lots of bump travel left, but not much droop.

 

I probably need some helpers to get there, but should static ride height ideally be somewhere in the middle of the shock travel for our plastic cars? Or maybe 1/3 droop - static height - 2/3 bump?

 

 

 

Edited by Exmantaa, 10 June 2013 - 05:39 PM.

[JohnTurbo]

if they are old ones they are designed for running normal ride heights with 22" wheels only.

[Scuffers]

for a road car, between 50/50 and 33/66 is about right (bump/rebound)

[2-20]

for a road car, between 50/50 and 33/66 is about right (bump/rebound)

 

So 2/3 droop 1/3 bump is acceptable !!

It's going to be very low (at the rear) with standard Nitrons.

 

Anyone could post a rear Nitron open length ?

[Exmantaa]

for a road car, between 50/50 and 33/66 is about right (bump/rebound)

 

So static rideheight should be somewhere in te middle or up to 2/3 shock travel used... I'll never make that with the current 425/550 springs alone and the 50/85mm NTR travel (no soft helpers yet)

 

I assume sufficient rebound is travel is most important on the rear to keep traction? (Slight deja vu here from another shock topic... )

 

Thxs

[alexb]

My Nitron NTR's are 395 mm long (rear) and with 350 lbs/inch rated springs and no preload, I end up about in the middle (50% droop, 50% bump). Ride height is very low, about 115 mm. I've increased ride height to about 125 mm, compromising on droop. Not a good thing, but with my wheels, 115 mm is just too low. In your case, the spring rating is a lot higher, so you end up in 4WD territory To even get to the middle, you will need to lower the car like 20-25 mm, which means that in full droop you have a considerable gap between the spring and the collar. Solved by using a helper.

 

From what I remember Arno mentioned once that having more droop than bump on the rear is a good thing, as one rear wheel losing traction due to not enough droop (lifted in the air), leads to drivers thinking they need LSD. I assume he meant the mechanical and not the chemical version.

[techieboy]

 leads to drivers thinking they need LSD. I assume he meant the mechanical and not the chemical version.

 

[siztenboots]

if memory serves me well, according to the autocad drawings shown to me at Nitron by Guy, all Lotus and VX standard dampers have a length of 420mm ( from both bolt centres )

[Scuffers]

 

for a road car, between 50/50 and 33/66 is about right (bump/rebound)

 

So static rideheight should be somewhere in te middle or up to 2/3 shock travel used... I'll never make that with the current 425/550 springs alone and the 50/85mm NTR travel (no soft helpers yet)

 

I assume sufficient rebound is travel is most important on the rear to keep traction? (Slight deja vu here from another shock topic... )

 

Thxs

 

 

85mm travel on the rear shocks is very much at the low end of usful (ideally, ~100mm covers the full wishbone articulation range)

 

what this means in reality is that your very much limited to a specific ride height to keep in the working window of the damper, and it's likely you will need some kind of helper/tender to do this without having a spring-gap on full droop.

 

and yes, without sufficient droop, you end up unloading the wheel and loosing traction, as well as (in bad cases) screwing up the road ride because the wheels can't move enough to follow the road surface.

[Exmantaa]

The 85mm rear travel is without bumpstop compression, but it's more that the std 60mm Bilstein travel I measured on my rear 111R shocks. (these must ride the bumpstops a lot.)

 

My NTR's were 2nd hand units and they maybe had some helpers in the past (but probably not), but all this still makes me wonder how they can supply shocks with 425/550 like this. There's not much room to add a helper spring up front, so why not develop some nice progressive spring to go with these?

[Scuffers]

The 85mm rear travel is without bumpstop compression, but it's more that the std 60mm Bilstein travel I measured on my rear 111R shocks. (these must ride the bumpstops a lot.)

 

My NTR's were 2nd hand units and they maybe had some helpers in the past (but probably not), but all this still makes me wonder how they can supply shocks with 425/550 like this. There's not much room to add a helper spring up front, so why not develop some nice progressive spring to go with these?

Ah ok, (you should include the bump rubber in the travel measurement!)

 

so realistically, you probably have 100mm stroke, and yes you really need tender springs with that... what length springs have you got?

[JohnTurbo]

Count yourself lucky. I wind a good bit of preload onto my Nitrons and get an eerily precise 100/110 ride height, and bugger all droop travel.

 

It handles very well actually compared to 110/120 on GAZ, but bumpsteers like yo mutha.

[JohnTurbo]

 

(For the sake of education- bumpsteer demo)

[Exmantaa]

 

The 85mm rear travel is without bumpstop compression, but it's more that the std 60mm Bilstein travel I measured on my rear 111R shocks. (these must ride the bumpstops a lot.)

 

My NTR's were 2nd hand units and they maybe had some helpers in the past (but probably not), but all this still makes me wonder how they can supply shocks with 425/550 like this. There's not much room to add a helper spring up front, so why not develop some nice progressive spring to go with these?

Ah ok, (you should include the bump rubber in the travel measurement!)

 

so realistically, you probably have 100mm stroke, and yes you really need tender springs with that... what length springs have you got?

 

 

OK, so I'll add 15mm bumpstop compression to the available shock travel .

 

With almost no preload my rear 550's are 200mm. Just measured the loaded static height: ~175mm, so only 25mm compression. ( that's 25% of my ~100mm stroke) 

 

Front 425's are about 176mm open. Static height ~155mm, so 20mm compression. (that's 30% of the ~65mm front stroke)

 

@JohnT, how can you add lot's of preload tension with those ride heights and have no droop travel. Are your shocks very short with soft springs?

[Scuffers]

you need tenders or helpers... looks like you have 8 inch years and 7 inch fronts, so you are probably going to struggle to get 2 inch tendered on the shock. what ride height is it at on zero preload?

[Exmantaa]

My current height with no pre-load is about 120-120, but it's on 235-40-17 and 215-40-17's so a bit lower than std wheels.

 

Rear looks OK, but it needs more droop so besides a helper that implies a longer shocklength.

Front simply needs more spring compression to get it right. Although the 7"spring leaves little room for a helper...

 

(Progressive springs anyone??  )

[JohnTurbo]

Mine are too short, that's the issue for me.

[Bumblebee]

Are all Nitrons like this? (Sorry I'm not up on all the technical stuff like suspension so most of this goes over my head lol)

Edited by Bumblebee, 12 June 2013 - 08:24 PM.

[2-20]

Are all Nitrons like this? (Sorry I'm not up on all the technical stuff like suspension so most of this goes over my head lol)

Good question.

My rears are less than 400 mm when fully extended (bott eye to bolt eye) and are too short.

I wonder if the new Nitrons have a different length

Edited by 2-20, 12 June 2013 - 08:41 PM.

[JohnTurbo]

A little bit Aimy, by the sounds of it. From what i've heard mine were designed to run 100/110 and there aint much I can do about it (without having longer rods fitted anyway!)

- Though of course its nonesense to think that handling suddenly collapses to sh*t below 110/120 - this is just a popular line in the sand. With that said it really corners!

 

Newer NTRs should be much better as is evident by comments in this thread.