Leon Cupra R bushes Question

[ARO]

Hi there, after reading so many posts concerning leons bushings i am still confused. Can a fellow Leon Cupra R mk1 owner or forum suspension guru confirm the following for me.

Leon cupraR front rear wishbone bushes are exactly the same as audi tt, tt roadster & s3 8l bushes, is this true?

Leon cupraR rear beam ones are exactly the same as audi tt, s3 is this true?

So i have the best oem bushes on my lcr already? Would front rear wishbone polybushs & rear beam polybush make a big improvement or introduce to much road vibration for a daily driver?

I am soon to fit the following, hopefully resulting in a car with better turn in, flatter cornering and less understeer but still a smooth daily driver.

Eibach 22mm front arb & 25mm rear arb
Replacement oem shocks
Oem lcr top mounts & bearings
S3 front strut brace
Full alignment

I was thinking of h&r hub centric 10mm front spacers to further counter understeer, would this be to extreme?

Look forward to your reply, Thanks, Aron

 

[Ape]

Hi there, after reading so many posts concerning leons bushings i am still confused. Can a fellow Leon Cupra R mk1 owner or forum suspension guru confirm the following for me.

Leon cupraR front rear wishbone bushes are exactly the same as audi tt, tt roadster & s3 8l bushes, is this true?

Leon cupraR rear beam ones are exactly the same as audi tt, s3 is this true?

So i have the best oem bushes on my lcr already? Would front rear wishbone polybushs & rear beam polybush make a big improvement or introduce to much road vibration for a daily driver?

I am soon to fit the following, hopefully resulting in a car with better turn in, flatter cornering and less understeer but still a smooth daily driver.

Eibach 22mm front arb & 25mm rear arb
Replacement oem shocks
Oem lcr top mounts & bearings
S3 front strut brace
Full alignment

I was thinking of h&r hub centric 10mm front spacers to further counter understeer, would this be to extreme?

Look forward to your reply, Thanks, Aron

I can't answer all of it, but I'll have a go at the bits I've experienced. I've polybushed the front of my LCR, it's got AP Coilovers, Vibratechnics Competition Mounts, Polybushed DogBone Mount, 28mm Rear Anti Roll Bar (Neuspeed adjustable). Adding the modifications has vastly improved the handling over stock.

I found the LCR understeered too much for my liking in standard form (as all FWD stock cars are designed to do) , the Rear ARB (set on the middle setting) balanced this out (having it set to the rear made it a tad tail happy). The polybushed wishbones etc helps turn in and the AP coilovers helped handling overall. The mounts transmit vibration as you'd expect but they stop tramping and reduce wasted torque.

 

[ARO]

Thanks for that ape

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[ARO]

Hi there, after reading so many posts concerning leons bushings i am still confused. Can a fellow Leon Cupra R mk1 owner or forum suspension guru confirm the following for me.

Leon cupraR front rear wishbone bushes are exactly the same as audi tt, tt roadster & s3 8l bushes, is this true?

Leon cupraR rear beam ones are exactly the same as audi tt, s3 is this true?

So i have the best oem bushes on my lcr already? Would front rear wishbone polybushs & rear beam polybush make a big improvement or introduce to much road vibration for a daily driver?

Is anyone able to clarify these couple of questions for me?

Sent from my Nexus 7 using Tapatalk 2

 

[JoeBrooke]

I have recently fitted Powerflex rear beam bushes to my R. The back end is much tighter, and more predictable than before, and I've noticed very little, if any, increase in road noise. I strongly recommend buying these over standard ones!

 

[ARO]

I have recently fitted Powerflex rear beam bushes to my R. The back end is much tighter, and more predictable than before, and I've noticed very little, if any, increase in road noise. I strongly recommend buying these over standard ones!

Thanks for the reply Joe, powerflex rear beam bushes sound good, do you know if the LCR has the stiffest OEM bushes already?

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[JoeBrooke]

I believe it does yes. Although they may be the stiffest fitted as standard, they aren't actually that stiff

 

[ARO]

I believe it does yes. Although they may be the stiffest fitted as standard, they aren't actually that stiff

Thanks for that Joe, looks like something else to add to my upgrade list!

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[towcester vag]

yes they are the same
i only fit these now as they last longer than all the others inc power flex
as for rear axle bushes only use genuine as they are designed to give some rear steer through bush
power flex dont give you that feature

 

[JoeBrooke]

Rear steer?! That's rediculous. I noticed a marked improvement in handling characteristics after fitting Powerflex rear beam bushes, because the standard ones are slack and allow the axle to wander. This has nothing to do with seat designing a "rear steer" feature.

 

[ARO]

yes they are the same
i only fit these now as they last longer than all the others inc power flex
as for rear axle bushes only use genuine as they are designed to give some rear steer through bush
power flex dont give you that feature

Ah right, so powerflex maybe a bit extreme for the road then, the integra typeR i had previously had a similar design on the rear trailing arm bush to aid braking stability. So I didn't change those as i wasn't tracking the car. Cheers for that info.

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[Muttley]

JoeBrooke wrote

Rear steer?! That's rediculous. I noticed a marked improvement in handling characteristics after fitting Powerflex rear beam bushes, because the standard ones are slack and allow the axle to wander. This has nothing to do with seat designing a "rear steer" feature.

Ridiculous or not, the LCR design incorporates what was claimed to be Agile concept suspension in anti-roll bar, springs and bushing over standard (see Page 12). If you were able to improve yours, the originals must have been worn out with age, or that is what will be claimed by the manufacturer.

 

[JoeBrooke]

Having read that, suggesting the R has "rear steer" designed into it is still doesn't make sense. How can a car that has constantly variable rear suspension geometry handle predictably?

Seat fitted stiffer rear bushes to the LCR than any other model that uses this axle, because that makes the handling sharper and more predictable.

 

[towcester vag]

i will have to dig out the self study book on rear suspension (VW)
THE BUSH IS DESIGNED TO GIVE A REAR STEER CAPABILITY
it allows the rear axle to move slightly by a degree or 2

 

[Muttley]

Towcester, is that a general description of the Mk.4 rear beam axle, or something specific to the LCR and similar cars (whatever they may be - Audi TT?).

The Golf Mk.4 SSP says "The large-size rear axle mountings are positioned at an angle of 25° to the transverse axis of the vehicle. This reduces the self-steering effect of the rear axle."

Yet in the Audi TT coupe SSP, it says
"– Track-correcting axle bearing
The self-steering effect of the rear axle is more favourable thanks to the bearing inclination of 25°.
Due to the rear axle inclination, the side forces which occur when cornering are transmitted favourably to the bearing and from the bearing to the body."
(here the term "bearing" actually means the mountings, where the bushes are.)

Nothing about stiffer bushes, but there is now a claim for beneficial self-steering, wheras previously exactly the same layout is claimed to reduce the self-steering. The only conclusion I can reach is that reduced self-steering is beneficial . . . .

 

[ARO]

Well Mutley I am glad i went with the OEM shocks now! haven't fitted them yet but sounds like there's a lot more to this suspension tuning with so many small details that will get spoilt by slapping on some lowering springs or cheap coil covers. Thanks for the info guys.

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[Muttley]

The voice of reason! There are indeed an awful lot of variables to consider in suspension tuning, something I've no great experience of, just enough to know that I don't know the half of it, if you see what I mean.

OEM suspension on the LCR is not too shabby at all, not surprising as it was a premium "racer" sports saloon variant meant to be top of the range. Shocks are Bilstein as far as I know.

It will always be possible to improve on the OEM handling, so long as you're prepared to sacrifice in some areas to achieve improvements in others. Possibly the best starting point is improve anti-roll measures at the back, which means fitting an add-on ARB, as the beam axle has its anti-roll bar fitted inside the beam, where it can't be removed.

I've been known to be rude about lowering on this forum before. In almost all cases, lowering a car may result in a better look (although I don't think so, but it's your car) but will make handling worse. The best racetrack handling with a Golf Mk.4 platform is achieved by raising the front end a little and lowering the back - according to those in the know. Of course this looks terrible, but if you're building a track car then you can modify the bodywork to suit,especially as you won't have to worry about speed bumps or potholes.

On the roads that we have to deal with day-to-day, lowering makes very little sense. It can make an improvement, as long as springs, shocks and ARB's are all changed together and tuned to work together - my TDI 150 Sport has the Sport variant suspension which is 15mm lower all round than the standard Comfort setup, yet this car handles much better than my previous TDI 110 Toledo - that is it goes round corners faster without breaking a sweat, lifting a wheel or tripping the ESP. I put that down to stiffer anti-roll front and rear and properly matched springs and shocks to deliver a firmer ride (less comfortable in absolute terms) but one that keeps the tyres in contact with the road better.

Tyres are the main thing to be wary of though. I'm sure that poor tyres are responsible for most of the handling problems we see complained about.

 

[ARO]

Great info there Mutley, I have got a set of 22mm/25mm eibach arbs to go on and S3 front strut brace, already got a black forest dogbone.

I think that will be my lot as now I have to replace some dimpled & slotted discs that the previous owner fitted... Really noisy under hard braking, today i saw micro cracks all over the front discs!

According to the service history they are supposed to be Brembo's but I reckon the garage tucked him up. Going to fit standard discs from TPS, the pads are good ds2500 front and mintex rear. It will give me a chance to replace the brake fluid with rbf600 anyway... perhaps a gearbox oil change as i cant see that the LCR has had one.

Then hopefully I can enjoy driving the car for a while, which is why i bought it!

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[towcester vag]

muttley
the 2 wd tt has the same rear axle as the golf/leon/A3
the bearing as they say is the bush itself you may find the TT ssp you have is a newer issue
when i went on the 4wa course at VW they were going on about the set up on the golf etc and saying the design of the rear bush was for enableing a rear steer design to help handleing

 

[Muttley]

I've done a little research. I'm only an amateur mech. eng. (most of my hands-on engineering was done in electronics and optics), and any real engineers are welcome to correct me.

Beam rear axles have a tendency to lateral force oversteer due to trailing arm distortion. The golf Mk.4 design, angling the mounting bush axis outwards, reduces that tendency and improves handling. Stiffer bushes can also help, but at a cost in comfort and road noise transmitted to the car body.

I suspect that the wording of some of the self-study programs has been edited with a view to presenting everything in a positive light. I sense a PR man behind this, and disapprove most strongly at tampering with the accuracy of engineering texts.