blakep82
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posted on 22/4/07 at 08:33 PM |
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what is anti tramp and axle tramp?
or indeed axle tramp...
is this the same as anti squat?
been buying some axle brackets from rally design and they call the anti tramp brackets
[Edited on 22/4/07 by blakep82]
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amalyos
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posted on 22/4/07 at 08:43 PM |
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Tramping is normally caused by the windup of the rear axle under acceleration. The tramp bars stop the axle winding on the springs.
A typical set up on an escort would be 4 link bars that stop the tramp, and a panhard rod that locates the axle sideways.
Steve
http://stevembuild.blogspot.com
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blakep82
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posted on 22/4/07 at 08:46 PM |
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do you mean like the prop shaft trying to twist the axle (lifting one of the wheels and pushing the other down)?
how do the link bars stop it?
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amalyos
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posted on 22/4/07 at 08:55 PM |
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No, normally a live axle is mounted on leaf springs only, so when you accelerate the wheels push the axle forward, but as they are only connected to
the springs, they start to twist the springs. The wind up of the spring is what causes the tramp effect.
By locating the axle with bars you transfer the thrust straight to the body.
http://stevembuild.blogspot.com
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blakep82
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posted on 22/4/07 at 09:36 PM |
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i see!
so, since we're all using 4 link systems we shouldn't be too concerned then should we?
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DIY Si
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posted on 22/4/07 at 09:41 PM |
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With the 4 link set up, tramp disappears. With a 5 link set up, axle movement should be totally controlable, but you'll need a Watt's link
or similar to do it properly. BUt you sound as if you know that anyways
“Let your plans be dark and as impenetratable as night, and when you move, fall like a thunderbolt.”
Sun Tzu, The Art of War
My new blog: http://spritecave.blogspot.co.uk/
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blakep82
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posted on 22/4/07 at 09:56 PM |
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i'll be working on my watts linkage very soon
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DIY Si
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posted on 22/4/07 at 10:01 PM |
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I take it then that you now know the difference between anti tramp and anti squat? I'm guessing you knew the two set ups, but were unsure as to
the names?
“Let your plans be dark and as impenetratable as night, and when you move, fall like a thunderbolt.”
Sun Tzu, The Art of War
My new blog: http://spritecave.blogspot.co.uk/
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blakep82
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posted on 22/4/07 at 10:11 PM |
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anti squat being a set up that prevents the back of the car pushing down on acceleration? (similar to anti dive on the front, to stop the front of the
car dropping under braking?)
I'm not too good on suspension geometry, but really need to get the basics sorted in my head before building a car which will be horrible to
drive
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DIY Si
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posted on 22/4/07 at 10:19 PM |
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Yup, you got it right. Anti-tramp to stop the axle bouncing all over the place, and anti-squat to aid traction off the line.
“Let your plans be dark and as impenetratable as night, and when you move, fall like a thunderbolt.”
Sun Tzu, The Art of War
My new blog: http://spritecave.blogspot.co.uk/
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Ivan
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posted on 23/4/07 at 09:11 AM |
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quote: Originally posted by DIY Si
Yup, you got it right. Anti-tramp to stop the axle bouncing all over the place, and anti-squat to aid traction off the line.
Actually in my view the more squat you have the better traction and acceleration you have off the line because whieght is tranfered onto the rear
driven wheels - but it's really bad news accelerating out of a corner as it unloads the front wheels and causes control problems - so if
you're building a straight line dragster go for squat but if you're building a track racer limit squat.
Like all things in car's suspension setting "squat" is a compromise.
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DIY Si
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posted on 23/4/07 at 01:57 PM |
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My understandinsg is simialr, but varies in one detail. The anti-squat tries to force the car up at the back, thus putting the weight plus the
reaction force through the wheels, thus increasing grip. Lots of anti-squat will see the back of the car rise on launch. I may however have the wrong
term for it, but I know it as anti-squat.
As you rightly say though, it will remove all/most of the front wheel grip, so flooring it mid corner wil see you understeer into a tree.
“Let your plans be dark and as impenetratable as night, and when you move, fall like a thunderbolt.”
Sun Tzu, The Art of War
My new blog: http://spritecave.blogspot.co.uk/
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Ivan
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posted on 23/4/07 at 03:12 PM |
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quote: Originally posted by DIY Si
The anti-squat tries to force the car up at the back, thus putting the weight plus the reaction force through the wheels, thus increasing grip.
That's interesting thanks - I have learn't something but will check it out in the literature as you don't seem sure - guess
that's what this site is all about
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DIY Si
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posted on 23/4/07 at 03:31 PM |
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I'm sure about how it works, just unsure on the correct term. As you apply the power the axle will try to twist. This twist normally squats the
car down by pushing the top trailing arm forward and pulling the bottom one backwards. However, if you angle the trailing arms up, this then decreases
the effect of the twist and thus squat, eventually reaching 100% anti-squat as the car sits level at a full launch. 100%+ will see the car rise.
That's probably badly explained and makes not much sense, but it should get some of what I mean across.
“Let your plans be dark and as impenetratable as night, and when you move, fall like a thunderbolt.”
Sun Tzu, The Art of War
My new blog: http://spritecave.blogspot.co.uk/
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locost_bryan
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posted on 24/4/07 at 04:04 AM |
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A 4 or 5 link rear can still allow axle tramp if it's not well designed, or the bushings allow too much movement - the Triumph TR7 was an
example.
The old Chevette with it's torque-tube 3 link rear had so much anti-squat, it would visibly rise up at the rear (even with a modest 57hp!)
Almost impossible to get wheel spin, but still very neutral handling.
Bryan Miller
Auckland NZ
Bruce McLaren - "Where's my F1 car?"
John Cooper - "In that rack of tubes, son"
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Ivan
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posted on 24/4/07 at 06:12 AM |
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Thanks for the clarification I am planning to re-design the suspension on my Cobra which currently has tons of squat off the line giving me quarter
mile times of around 13.5 seconds which is much better than my motor deserves due to almost zero wheelspin off the line.
The car also handles a bit like a barge due mainly (I think) to rediculously heavy unsprung weight and very soft springs giving a wheel rate of around
75.
I will seriously concider building in a little anti-dive (another problem I have) and anti-squat.
All the above to go with twin turbos and homemade EFI to give around 650 hp (We can dream can't we)
Now if only I could find a cheap sequential box to go with it - will have to stick with TH400 for the meantime
[Edited on 24/4/07 by Ivan]
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procomp
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posted on 24/4/07 at 07:08 AM |
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Hi some rather rash comments regarding the use of anti-squat above.
If interested in anti-squat then try some research on mallock clubman cars.
It is somthing that if you have a live axle is certinaly worth looking at if looking for better acceleration.
cheers matt
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