363 replies to this topic

[siztenboots]

gy gsd3 have a utqg wear rating of 280 , compared to a R888 = 100 utqg , you would expect the former to last 2.8 times longer in test conditions

[anz3001]

track tyre vs road tyre simples

[Dave E]

I must be doing something wrong. In 2 1/2 years and approx 14 track days, a couple being wet, I'm still on my original set of r888 medium fronts, which are still road legal. Also I'm only on my 2nd set of rears which are also road legal. Obviously not trying hard enough.

[Scuffers]

I always thought that it was generally, the more agressive the greater the tyre wear, but this also applies if the set up is not suited to that particular tyre as well?

thing to consider here is that if you are on OEM suspension and then stick sticky tyres on the car, whatever geo you have on it becomes somewhat variable as the suspension parts all have some compliance in them, more load, more compliance, less accurate geo.

in bad cases (like very old wishbone bushes/work ball joints, etc) I have seen cars that end up going slower over a lap with softer tyres.

[Scuffers]

gy gsd3 have a utqg wear rating of 280 , compared to a R888 = 100 utqg , you would expect the former to last 2.8 times longer in test conditions

in general yes, but UTQG ratings are somewhat hit/miss, they are only really a guide

[anz3001]

they are only really a guide

And a very poor one at that

[siztenboots]

its not an indicator of performance, only tread depth vs distance against the benchmark tyre doing the same test . But as an official specification stamped on the side, marketing people will abuse how consumers trust any system. So I don't think the testing is faulty.

[TheRealVXed]

track tyre vs road tyre simples

I wasn't comparing the wear of the R888 against the GSD3s, just that both lasted longer than I thought/have heard from others that they would

I always thought that it was generally, the more agressive the greater the tyre wear, but this also applies if the set up is not suited to that particular tyre as well?

thing to consider here is that if you are on OEM suspension and then stick sticky tyres on the car, whatever geo you have on it becomes somewhat variable as the suspension parts all have some compliance in them, more load, more compliance, less accurate geo.

in bad cases (like very old wishbone bushes/work ball joints, etc) I have seen cars that end up going slower over a lap with softer tyres.

I am fully poly bushed and on fairly new gaz golds so things should be pretty tight down there.

Edited by VXRed, 20 March 2013 - 10:15 AM.

[Scuffers]

I am fully poly bushed and on fairly new gaz golds so things should be pretty tight down there.

shockingly bad assumption.

my experience of poly bushes is that they are more compliant than (new) OEM ones (for the VX)

I'll not comment on the other bit!

[TheRealVXed]

Not a gaz man eh? They haven't been on the car long, and I was comparing to the ones I took out.... That's interesting though the the OEM would be better. Does that mean you would recommend the OEM bushes over powerflex?

[VXT Tim]

or Ertacetal !

[chris_uk]

I like the exige bushes.

[Mike (Cliffie)]

I am fully poly bushed and on fairly new gaz golds so things should be pretty tight down there.

shockingly bad assumption.

my experience of poly bushes is that they are more compliant than (new) OEM ones (for the VX)

I'll not comment on the other bit!

I have to disagree Simon. I have a lot of experience with Poly Bushes and all are far less compliant than OEM Lotus ones and have the added advantage of being sleeved rather than relying on clamped twist. On the downside, the poly ones can be a bitch to fit and will be quite tight until bedded in.

IMHO the poly bush option is a better one for road cars. For a race car it would be Rose Joints or Ertacetal.

Edited by Cliffie, 20 March 2013 - 12:14 PM.

[Scuffers]

I am fully poly bushed and on fairly new gaz golds so things should be pretty tight down there.

shockingly bad assumption.

my experience of poly bushes is that they are more compliant than (new) OEM ones (for the VX)

I'll not comment on the other bit!

I have to disagree Simon. I have a lot of experience with Poly Bushes and all are far less compliant than OEM Lotus ones and have the added advantage of being sleeved rather than relying on clamped twist. On the downside, the poly ones can be a bitch to fit and will be quite tight until bedded in.

IMHO the poly bush option is a better one for road cars. For a race car it would be Rose Joints or Ertacetal.

need to look at this another way...

I have 'tested' (as in put on a press, and measured deflection vs. load) OEM Lotus ones and poly (in this case Powerflex) and in radial load, the OEM ones are stiffer, in axial the Poly ones were stiffer.

now, in cornering loads, it's the radial loads your dealing with, under brakes/power, it's axial.

either way, I would either go with new OEM or Ertacetal (unless we start to talk about going spherical etc etc).

[chris_uk]

We need to see laptimes for the differences between oem and poly bushes... Only way to tell.

[techieboy]

But it doesn't matter if they're tested on wildly different cars with massively different drivers. It's still proof.

Edited by techieboy, 20 March 2013 - 01:39 PM.

[Scuffers]

We need to see laptimes for the differences between oem and poly bushes...

Only way to tell.

ultimately, yes, but with things like bushes, it's an easy thing to empirically measure and quantify.

with most cars the OEM bushes are way more compliant than Poly, Elise/VX is odd in this respect, not that this stops people selling them as stiffer.

other issue is the OEM ones now on cars are some what? 6+ years old, so they will be far from 'as new', ie. anything will be better.

for road only cars I like the OEM ones, only issue is with higher powered cars being able to 'push' the wishbones axially, although this can be delt with by making up packers for the sides.

edit..

for example, this cars on new OEM bushes (and old A048's)

http://www.youtube.com/watch?v=Rq_WbFBwBrE

Edited by Scuffers, 20 March 2013 - 01:43 PM.

[techieboy]

this can be delt with by making up packers for the sides.

As in some big washers, like we'd do to replace the castor "shims" and snubber washers with poly bushes? Going to be hard work getting those into the wishbone mounts though.

I've got a full set of OEM bushes to go back onto my car, to replace the poly bushes, so might look at doing something along those lines.

[Scuffers]

As in some big washers, like we'd do to replace the castor "shims" and snubber washers with poly bushes? Going to be hard work getting those into the wishbone mounts though.

I've got a full set of OEM bushes to go back onto my car, to replace the poly bushes, so might look at doing something along those lines.

kind of...

think like a thick washer with a hole big enough to clear the bush tube...

easy enough to fit them, as you slide the bush into the mount with them held in place (and use some sticky thick grease)

[fezzasus]

Let's clear one thing up Polyurathane bushes and Ertacetal are essentially the same thing in terms of physical properties, the only difference in this application is the grooved metal inserts to retain grease. so why are they being recommended for different applications?