Antnicuk
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| posted on 25/4/10 at 11:56 AM |
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The stylus doesn't use a watts linkage, good old pan hard rod
how muchbeer for the springs and are they 8 inch?
[Edited on 25-4-10 by Antnicuk]
600 BHP per ton, Stylus Brought back from the dead! Turbo Rotary Powered!
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Steve Hignett
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| posted on 25/4/10 at 12:54 PM |
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quote:
Originally posted by mookaloid
quote:
Originally posted by MikeRJ
quote:
Originally posted by mookaloid
with a live axle it is much simpler - the rear roll is entirely a function of the spring rates.
quote:
on the live axle Striker/Fury etc. They have built in roll stiffness due to using a watts linkage for longitudinal location of the axle at
each side instead of the standard 4 link setup. In roll the linkages try to twist the axle and the deflection of the rubber bushes in the linkages
determines roll stiffness (+ springs obviously).
I didn't realise that the striker uses a watts linkage. So thinking about it - it would be a bad idea to make a watts linkage using rose
joints then?
quote:
OP's picture remind me very much of Mk1/Mk2 Escorts that I see on local tarmac rallies; for some reason they always seem to have far too
much roll stiffness at the front and end up with the inside front wheel way up in the air.
I have seen many escorts doing this too - they seem to get round the corners ok 
This is the point of my question, I would think that they would be too stiff for that design of rear end.
Obviously the comments above re reducing stiffness of front ARB and rear spring rates are still v true, but I'd be taking a good look at the
back ends links to the chassis again...
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iank
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| posted on 25/4/10 at 03:13 PM |
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Miglia's can do it as well.
--
Never argue with an idiot. They drag you down to their level, then beat you with experience.
Anonymous
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Hellfire
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| posted on 25/4/10 at 03:46 PM |
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We had the very same problem on our Indy. It always lifted the inside front wheel on one particular corner at Teeside. Fitted some heavier springs on
the rear which sorted the issue.
Phil
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Antnicuk
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| posted on 25/4/10 at 04:54 PM |
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thanks guys, even with the 275's on the back it doesnt seem to hard on the road, especially with the shocks softened a bit and it still
squates loads under power so i could probably try 300's and it wouldnt be too stiff.
600 BHP per ton, Stylus Brought back from the dead! Turbo Rotary Powered!
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bigfoot4616
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| posted on 25/4/10 at 04:57 PM |
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quote:
Originally posted by Hellfire
We had the very same problem on our Indy. It always lifted the inside front wheel on one particular corner at Teeside. Fitted some heavier springs on
the rear which sorted the issue.
Phil
this corner
its the only corner i've been told mine does it so it doesn't concern me to much.
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MikeRJ
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| posted on 25/4/10 at 08:16 PM |
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quote:
Originally posted by Antnicuk
The stylus doesn't use a watts linkage, good old pan hard rod
We aren't referring to lateral location, the Striker and Fury also use a panhard rod for this.
The Watts linkage in this case is used instead the two trailing arms at each end of the axle that more traditional chassis use. I don't know if
the Stylus uses this though.
quote:
Originally posted by mookaloid
I didn't realise that the striker uses a watts linkage. So thinking about it - it would be a bad idea to make a watts linkage using rose joints
then?
Very bad idea, you would be breaking the brackets of the axle/chassis for a pass time.
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Hellfire
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| posted on 25/4/10 at 08:17 PM |
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Yep, that is the one. Or maybe I should say 'that was the one........
Phil
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Antnicuk
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| posted on 25/4/10 at 08:53 PM |
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quote:
Originally posted by MikeRJ
quote:
Originally posted by Antnicuk
The stylus doesn't use a watts linkage, good old pan hard rod
We aren't referring to lateral location, the Striker and Fury also use a panhard rod for this.
The Watts linkage in this case is used instead the two trailing arms at each end of the axle that more traditional chassis use. I don't know if
the Stylus uses this though.
quote:
Originally posted by mookaloid
I didn't realise that the striker uses a watts linkage. So thinking about it - it would be a bad idea to make a watts linkage using rose joints
then?
Very bad idea, you would be breaking the brackets of the axle/chassis for a pass time.
Sorry, i didnt know the sylva method of front and rear facing arms was also referred to as a watts linkage although i see the relationship. Yes, the
stylus uses the same system.
I replaced the chassis end of the arms as mentioned with rose joints but left the axle brackets bushed. I have abused the car on track on slicks with
lots of power and torque and not had any problem (yet). I dont understand how there is more stress on the chassis brackets with a rose joint as it
swivels where the bushed joint wont. I can see the stress on the axle bracket, although these are very heavy duty and the axle is an atlas
I still dont fully understand the exactly the issue of the bushes making the whole system work.
600 BHP per ton, Stylus Brought back from the dead! Turbo Rotary Powered!
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MikeRJ
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| posted on 25/4/10 at 09:14 PM |
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quote:
Originally posted by Antnicuk
I still dont fully understand the exactly the issue of the bushes making the whole system work.
The Watts linkage has to twist the axle slightly one way or the other as it rises and falls. You can see this on a traditional watts linkage (panhard
replacement) since the linkage attached to the axle is supported by a bearing in the middle to allow it to rotate.
As the body rolls, each side of the suspension is trying to twist the axle in opposite directions; the system therefore resists roll, and thus roll
stiffness is added. The top and bottom links are of unequal length to enhance this effect.
Obviously a big axle is not going to twist very easily, so some compliance must be provided, which comes in the shape of the metalistic bushes. If
these are replaced with rod ends, you remove all compliance from the system, and the only way the car can now roll is by bending something. This puts
very large cyclic forces onto the suspension brackets which inevitably will crack and fail at some stage.
Cracking isn't unknown even with the metalastic bushes, especially on track cars.
[Edited on 25/4/10 by MikeRJ]
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Steve Hignett
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| posted on 25/4/10 at 09:50 PM |
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I won't bother repeating the above, but it's why I asked the Q's I did of you in this post. The above is correct - With your setup,
something has to give, be it the bushes, the brackets or the prop, something HAS to give.
You fitting RJ's can only exacerbate the situation IM(humble)O...
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Antnicuk
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| posted on 26/4/10 at 07:41 AM |
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Thanks for the info, I still have bushes at the axle so there is some compliance.
I'm not sure about something having to give. Most mounting points on a car have various stresses and strains, from suspension and engines to
seat belts, but we make the points strong enough to with stand the amount of stress the car will give it, rather than identifying a week point and
using bushes to compensate and give the mounting an easy life.
A chassis takes stress and wants to flex but we triangulate them and reinforce them untill it is prevented from doing so.
Am I missing the point some where? Is there some other reason for wanting compliance? Does it improve geomitry under load or something?
If it wasn't for comfort we wouldn't use bushes anywhere, surely?
These are just my inexperienced thoughts
[Edited on 26-4-10 by Antnicuk]
600 BHP per ton, Stylus Brought back from the dead! Turbo Rotary Powered!
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zilspeed
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| posted on 26/4/10 at 05:52 PM |
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The sylva setup - two trailing arms / two leading arms.
Never ever liked it, for the reasons described above.
When I first saw it on a striker, I couldn't get my head around it, the trailing and leading arms are describing different arcs, so even in a
straight line, there has to be compliance in the bushes to make it work if you take axle rotation out of the equation.
I'm as much a JP fan as anyone, but I honestly can't think of what he was smoking when he thought that this was the best solution.
Then again, that's car designers. The courage of your convictions and all that.
How it shoudl be, I guess.
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MikeRJ
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| posted on 26/4/10 at 06:24 PM |
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quote:
Originally posted by Antnicuk
Thanks for the info, I still have bushes at the axle so there is some compliance.
I'm not sure about something having to give. Most mounting points on a car have various stresses and strains, from suspension and engines to
seat belts, but we make the points strong enough to with stand the amount of stress the car will give it,
If you made the suspension brackets/linkaged/chassis strong enough to resist the forces the axle would provide in roll, then your roll stiffness would
approach infinity, i.e. it wouldn't roll. It would be the same as having an anti-roll bar so stiff that it wouldn't twist at all under
normal use.
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iank
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| posted on 26/4/10 at 06:41 PM |
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quote:
Originally posted by zilspeed
The sylva setup - two trailing arms / two leading arms.
Never ever liked it, for the reasons described above.
When I first saw it on a striker, I couldn't get my head around it, the trailing and leading arms are describing different arcs, so even in a
straight line, there has to be compliance in the bushes to make it work if you take axle rotation out of the equation.
I'm as much a JP fan as anyone, but I honestly can't think of what he was smoking when he thought that this was the best solution.
Then again, that's car designers. The courage of your convictions and all that.
How it shoudl be, I guess.
Then again his cars have a reputation for handling better than the opposition and winning a lot of races.
So he must be doing something right.
[Edited on 26/4/10 by iank]
--
Never argue with an idiot. They drag you down to their level, then beat you with experience.
Anonymous
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