whats the different between adjustable rebound rates and adjustable bump rates?

and which one do i want.. looking for some coilovers. would rather not spend silly money but the only make i feel i can trust is KW

 

adjustable bump means you can adjust the damping rate of the damper on the compression stroke

rebound is as the damper extends again

 

any decent shock will adjust both bump and rebound - sometimes this is only with one adjuster knob though (both are adjusted simultaneously at a ratio of approx 3:1)

Cheaper shocks will only have rebound adjustment

Top notch shocks will have separate adjusters for bump and rebound, and really really top ones sometimes have 4 adjusters, for high and low speed bump and rebound

Edit - forgot to say - the problem with lots of adjusters though is how to adjust them.......personally I am a fan of getting a simple system right rather than a fancy system wrong

 

And a damn sight cheaper too.

Is this for the rally project?

 

If this is for the rally project Bodge, as Chris asked?

You may want to consider a Bilstein kit (think it is the B12 one). The one i am thinking of has the inverted front insert (groupA) which is very stong and the back shocks come with a thicker piston rod too.
It is not a coilover kit though but as a result it is if fitted with dirt gaurds that protect the shocks from the gravel and stones that blast them during a stage.

 

nope this is for the stripped out daily VR for the odd cheeky track day. Been looking at KW AVO and Weitec

The KW V2s are apparently only rebound adjustable.

Would love to spend around the 600- 700 mark and think i was getting a good performance gain with a bit of adjustment, with something that will last longer than 2 years but everything seems to be over the 1000 mark

I wouldn't want to put a 1000 worth suspension on the rally car, more 300 springs and shocks as it could end up been replaced few times a year

 

not trying to influence but something to keep in mind is when you get the KW kit they provide springs and also they recommend suspension setting.

All i had to provide was corner weights of car and a cheque of course

 

Why do you feel this? KW is basically a Koni clone and Koni do some excellent twin tube dampers (road & competition) that can be re-built and/or re-valved.

Once again I would suggest Koni twin-tubes or Bilstein mono-tubes (H&R also) though Avo's have got better over the years and I think Nige (Avo UK) will re-valve and / or re-build for you.

With dampers (more than anything else) you really do 'get what you pay for'

The nice thing about getting something with some quality is the ability to re-biuld / re-valve / re-furb there are loads of places you can get Koni, Bilstein or Ohlins worked on and the parts are not prohibitively expensive either.

Ironically a competition car that sees rough surfaces NEEDS the best dampers you can afford, more so than a vehicle that only sees smooth race tracks. In fact I'd go so far as to say they are one of the most important components on a rally car, try getting a quote for a WRC damper

100% agree, a set of Bilstein mono-tubes with a professionals 'best-guess' damping rates is (IMO) MUCH better than a novice playing with bump & rebound adjustor's, not having a clue!

And lets face it, the title of this thread is "what's the different between adjustable rebound rates and adjustable bump rates?" I would humbly suggest that if you have to ask that question then you shouldn't be purchasing adjustable suspension

 

you might want to give Leda a call also - top notch, rebuildable, near Derby

 

thanks for your input.

the rally car wasn't of a WRC level. I was talking about budget level having fun as not to get arrested level of rally. and the class i was looking at "BWM 325i" from the pug cup and all that and they run standard suspension.


KW have got the best name for them self i don't here a lot about the other companys.


My car is a stripped out VR6 with a near 50/50 weight distribution but its LOW which is bad for handling.

I want a suspension that i can have stiffer for the track but softer for the road. Ive had very hard suspension before and the car did what ever i told it to do. but was horrible day to day. plus feeling the limits was hard


so my car is far from set up properly for a track. its to low.. but it does still handle much better than it did standard. and its quicker due to been light.


All i want from my coilovers is to know there good quality. can go low. can have them hard or soft and give me the best handling/ fastest cornering with the ride height i run

sorry but comments like this are COMPLETE rubbish. take your self back to before you new about suspension set ups. Infact think about before you could drive. Learning is easy and your not born with information. how do you think people learn. when i came out of school i new nothing about cars.. now im a fully qualified mechanic.. and now a fully qualified floor fitter. done 2 years in a body shop and do all my paint myself. 1 year as an auto electrician. plaster myself.


If i want to buy suspension with adjustable rebound rates and adjustable bump rates and learn how to set it up then i will. If it takes me 2 years of playing around with it on track days and reading information and asking questions then thats what it takes


but all in all thanks for your recommendations...

Im going to look into the "Koni twin-tubes or Bilstein mono-tubes"

 

Multi adjustable suspension is fine, as long as you keep a note of the settings that work, and go back to them when it feels worse.

Sadly - not aimed at you personally - many people have no idea which way to go, or if things are improving or getting worse. As long as you can be impartial, and describe the differences you feel...adjusting is an easy - if long - process.

I've set many cars up for people who thought it handled well...but was - in my view - dangerous.
A couple of hours later, it's spot-on....and significantly easier to drive fast, and hence ultimately faster.

Suspension set-up is as much about getting the car to behave as you want it to, in order to give you the confidence you need to go fast...what you like and are quick with, may be awful for someone else.

I know my driving style and likings aren't to many of my mates cars...and I know mates can get VR6s round tracks where I only get understeer, due to their driving style.

I say fo for as much adjustment as you can...put the hours in, and learn the set-up.
It's invaluable.

Personally, I want independant rebound, low speed bump and high speed bump on my next set of dampers...as I can't seem to find a 'perfect' setting. So, i'll have to spend the cash...and start all over again!

 

thanks for your input Ess Three. very useful

My problem is not wanting to spend more than 600 on suspension.. if i could spend what I wanted then it would make it much easier.


I think ive decided on the avo GTZ coilovers. I can get them for 500 which isn't bad. they state that there damper adjustable but doesn't say if its rebound or bump. and they can go as low as 120mm. all though at a guess mines about 90mm.

Only problem is they don't recommend going below 60mm (so why make them go lower lol) Im not sure if this is because anything lower than that makes your car handle worse or if its that the life of the coilover will be reduced or that they will get damaged at this ride height (again why make them go this low)


But im hopping that this set up will be better than the cheep ebay coilovers, jom, ect and better than AP, FK, supersport ect as they have more of a track/ race background.

Had a look at the Koni twin-tubes and Bilstein mono-tubes H&R mono/ twin tube but there all a bit expensive or don't go low enough (probably for a good reason)


Does anyone know anything about turret extensions? this way id be able to use all the coilovers in there safe limits and get the ride high I want.

add ball joint extensions and id have a slammed car that handles pritty good as well

 

I was just trying to illustrate the relative value of dampers compared to 'other' components you may choose to uprate/change

Is it a Corrado or Golf VR6? I'd be interested in how your achieving (& measuring) this as we have Corrado VR6's (about 63% front) and though it's easy to remove weight from the rear, the front axle is MUCH harder!

(Fully) adjustable will certainly help, though I would say that (as a generalisation) more expensive dampers tend to 'ride' better than cheaper units.

OK that comment was not to be taken 100% seriously (hence the double ) nonetheless the 'teach yourself' method is not always the best way, especially with something like vehicle dynamics.

However, if you do choose this route I would strongly suggest studying some book's (Alan Staniforth is a good start) rather than consulting 'internet experts'

edit (before I upset anyone else lol..) there are people 'worth' listening to (eg Ess Three) BUT as Ess Three says in his post, it's about getting a vehicle to feel good but also to be safe.

Without access to a closed course and low μ surface this is not always easy even for a professional.

Perhaps I should expand this, "twin tube" is a damper construction method used by Spax, Avo, Jamex, Koni, Bilstein and numerous others (usually for struts). The damper piston runs in a tube with is in turn mounted inside another (larger) outer tube - Hence "twin tube"

As a generalisation twin tube units tend towards the budget end of the market. However, Koni make some very nice (and good performing) twin tube units (some of which are multi adjustable), indeed I myself have a pair of competition double adjustable (i.e. bump & rebound) front (twin tube) "coil-over" struts that I re-valved for road spring rates.

"Mono-tube" refers to units were the piston runs inside the main damper body, thet only have one tube (hence "mono"). Again it's a generalisation but these units tend to be of higher quality (not to mention cost!).

 

ah sorry mate I took that the wrong way.

thanks for the info on mono/ twin tube sets ups.

the AVOs are pritty much mine now.. just waiting for an email back about the problems I might get running around 90mm.

I think for the money they can't be bad and defo an improvment over my old supersport coilovers (rock soild)



Its a mk3 golf.. ok "near 50/50" might be a bit of an exaggeration. I haven't done any corner weighting or anything like that (although I would like to one day) buts its defo closer than when I started.


So far ive fitted a carbon bonnet, slim line fans, slightly heavier battery to the boot, water res for the wipers in the boot, ABS removed, aircon removed, sun roof motor removed, aftermarket de badged grill (1/3 of the weight of the OE one lol) manual mirrors, one horn removed, inner archs removed, metal cut out of front cross member, chopped a lot of the dash out (just the skin to the glove boxes left, no airbags, half the vents cut a lot of the hard plastic off the back of the dash bla bla bla bla, you get the idea.


Its not a proper set up track car. but as a daily and for the odd track day it doesn't handle to bad. feels like ive made an improvement anyway

 

My pleasure.

The price is the main problem to getting the quality and adjustment to do 'the ultimate' job...
600 won't buy you a single, multi-adjustable, monotube damper unit without spring or top mount!
Although bespoke height, low speed bump, high speed bump, rebound, camber and caster adjustable set-ups are available...how many will suffer the 3000min cost? [:^(]

 

It does not HAVE to cost this much, sure if you spec a new units then yea, 2k upwards BUT there are alternatives.

I have H&R (Bilstein) mono-tubes on my MK2 at the 'mo, I got a complete set at an auto jumble (GTi international IIRC) for 25 (yes 25). I was expecting them to need a re-build, re-valve & new DU bushes (the bush the stop's em 'wobbling' in the casing)... Got em home and stripped em, perfect but even if they had need a complete re-furb it's only 70 a corner!

The double adjustable Koni competition units were 125 (again that's a complete set F & R inc springs).

OK these were valved for 750 lb/in springs so I had to re-valve em, which I did myself for 0 BUT even if I'd paid for it, it's only 70 a corner! (So for "anyone else" would be 280 for the car set plus the original 125 means 400 for a car set of double adjustable Koni's, very affordable!)

Last year I found/brought a pair of Ohlins (4 way adjustable with remote reservoir, mmmmm ) front struts from Holland for 450 (delivered), I was going to use em on the Corrado (VR6) but decided they were 'overkill' for road use (and left the PSS9's on there). So I sold em on (for an obscene sum )...

What I'm trying to say with all this boasting is that there are plenty of 'bargains' out there to be had, you just have to keep your eyes open (and be prepared to 'drop everything' to go collect something)

 

Bodge, why do you need the car dropping by 90mm?
The wishbones and steering arms will be so far out of their designed operating range that no suspension (adjustable or not) will correct the damage done to the suspensions geometry.
Turret extensions will not help either as this is just allowing the fitment of a strut that is too long.

Is it 4 or 5 stud hubs out of interest?
Still reckon Bilstein mono tube none coilover is a good well designed kit.
If you run proper dry and wet tyres depending on conditions this will be adequate for most circumstances.
In rallying every corner and bump is different where as on a race circuit they are repeated each lap so trying to set low and high speed bump and rebound becomes impossible to be right for every cicumstance.

 

Dan I just love the way low cars look. But just as much i love to drive them hard so its a bit cock really.
ill probably grow out of it (hopefully lol)
Yep i know about the wishbones, roll center and bump steer all and all that. ive lived with it for years lol. Tbh if your suspension is as rock solid as my last set up you hardly notest it as the geometry wishbones dampers ect doesn't move lol. so as long as the camber and tracking is spot on its not to bad. but as ive probably said before you have no feel for the limits.. so its not as fun as it could be.

Id get to much grief off people i know if i was to raise it up. im not as bad as some though stretched tyres, 13" wheels 120mm down, subframe dragging on the floor.


The turret extensions where more to keep the coilovers in there usable safe range so i wouldn't have to wind them most the way down to get the look im after.

I was hopping that they might ride a little better because of it. Kind of a handling improvement of some kind.


"In rallying every corner and bump is different where as on a race circuit they are repeated each lap so trying to set low and high speed bump and rebound becomes impossible to be right for every cicumstance.[/QUOTE]"

This is a good point, all i really want it to be able to do is make mine hard or softer. last time it was way to hard so i just want a bit of adjustment. Its still a daily driver but will see track days thought out the year. saying that id like to make it as good as i can.

can always wind the coilover up at track days. should be pritty well set up then.

Ive been looking at them KW lifters. they lift the car like 3" to go over speed bumps. fit inside your coilovers. Only thing is id want to use them the other way round drive hard when there up lol don't think there designed for that though

 

What you're forgetting is that when you adjust your height, you also effect your geometry.
So it takes a while to change your ride height ie; Construct perfectly level platform, set ride height, do corner weights, do camber, do wheel alignment then do it all again just to make sure.
Do you fancy doing that in the car park before the session?

 

Low car = Scene points but crud handling

I personally cannot see the point in wanting to lower the car to the point where it means the steering and suspension geometry is compromised. Especially as you intend to you use the car on track.
This is a bit off topic with regard to adjustable suspension types, but it is relevant if folk want to have a car that handles.
I have spent alot of time looking at various suspension kits and found that i could not get what i wanted without going custom due to the design of the mk1 & 2 suspension. And even then i would be taking a chance on spring rates and valving as every car and driver is different.
In the end i made my own suspension with a hacksaw, lathe and welder!

Getting an LSD will have a more beneficial effect on handling.

Again, is your car 4 or 5 stud? If you are not sure why i am asking this there are things you could do.