Bumpsteer mod
#3
They shim the steering rack to eliminate the changes in (castor ??? ) wheel steering angle when the wheel to chassis distance changes, like going over a sudden bump, i.e. bumpsteer and then reset the alignment.
No piccies, sorry
No piccies, sorry
#4
It isn't really something you can photograph, the shims are only a few millimetres at the rack end of things. No external signs.
Main benefit is that understeer is reduced because the geometry in a turn doesn't change for the worse when the outside wheel is compressed and the inside wheel is uncompressed. I had it done on my MY98 a few years ago and the effect is particularly impressive.
Main benefit is that understeer is reduced because the geometry in a turn doesn't change for the worse when the outside wheel is compressed and the inside wheel is uncompressed. I had it done on my MY98 a few years ago and the effect is particularly impressive.
#6
Scooby Regular
Join Date: Aug 2003
Location: Epsom
Posts: 5,832
Likes: 0
Received 0 Likes
on
0 Posts
Originally Posted by Wonder Wagon
So how do they know how much to shim it??
They have done so many they can roughly guess straight away how big the shim needs to be
HTH
Trending Topics
#9
Scooby Regular
bum steer mod? pmsl, the most expensive bit of garabage know.
whole point is they remove some of the pressure on the sterring rack and alow it to move slightly, normally done with a pair of 4mm washers!!!!
my question is this, y the hell would you want to remove some of the feel of the steering?
o and by the way if you uprate evrything else, anti roll bars, drop links, anti lift kit etc it has same effect (although admitedly more expensive) and makes car handle better not just slightly feel better.
whole point is they remove some of the pressure on the sterring rack and alow it to move slightly, normally done with a pair of 4mm washers!!!!
my question is this, y the hell would you want to remove some of the feel of the steering?
o and by the way if you uprate evrything else, anti roll bars, drop links, anti lift kit etc it has same effect (although admitedly more expensive) and makes car handle better not just slightly feel better.
#16
Scooby Regular
Join Date: Feb 2003
Location: Zed Ess Won Hay Tee
Posts: 21,611
Likes: 0
Received 0 Likes
on
0 Posts
Originally Posted by Tidgy
bum steer mod? pmsl, the most expensive bit of garabage know.
whole point is they remove some of the pressure on the sterring rack and alow it to move slightly, normally done with a pair of 4mm washers!!!!
.
whole point is they remove some of the pressure on the sterring rack and alow it to move slightly, normally done with a pair of 4mm washers!!!!
.
my understanding is this
your rack is not the same height as your wheels
therefore when you hit a bump your toe in/toe out changes which affects handling, standard car is set for numptys
adjustment of bumpsteer can help change the handling while the suspension moves up and down
#17
Scooby Regular
i've been told, cos i asked the very question, the extra washers remove the presure on the steering rack alowing it to move if impacted aka bumped.
dont think anything to do with the handeling is left standard on mine lol
dont think anything to do with the handeling is left standard on mine lol
#18
Scooby Regular
Join Date: Feb 2003
Location: Zed Ess Won Hay Tee
Posts: 21,611
Likes: 0
Received 0 Likes
on
0 Posts
who told you this answer?
the washers are only part of the "mod" the rack still needs shimmed down by the same amount as the washers, other wise your just driving around with a slack steering rack???????
#21
Scooby Regular
yeah kinda, heard it from a couple of other people as well though, when they were explain about what they'd had done. so dunno mate, can only go on what i've been told it is and what does
#22
Scooby Regular
Join Date: Apr 2003
Location: South Bucks
Posts: 3,213
Likes: 0
Received 0 Likes
on
0 Posts
Originally Posted by Tidgy
i've been told, cos i asked the very question, the extra washers remove the pressure on the steering rack alowing it to move if impacted aka bumped.
dont think anything to do with the handeling is left standard on mine lol
dont think anything to do with the handeling is left standard on mine lol
Ummm who did you ask and was it Impreza specific?
My understanding is that it is an adjustment of the steering rack height to minimise understeer on bump or particularly, cornering. I haven't got it done but if it does what it says on Powerstation's tin, it means slightly less arm twirling to take corners and less adjustment to get the car through. Also means if you lose the back end there may be less arm un-twirling and re-twirling required to recover the situation.
J.
#24
Scooby Regular
Join Date: Feb 2003
Location: Zed Ess Won Hay Tee
Posts: 21,611
Likes: 0
Received 0 Likes
on
0 Posts
im not taking mine apart to take pics
my explanation above tells you what to do anyway??
i cant remember how much i shimmed mine now, i done it about 2 years ago
my explanation above tells you what to do anyway??
i cant remember how much i shimmed mine now, i done it about 2 years ago
#27
Scooby Regular
Join Date: Jul 2002
Location: Under your bonnet
Posts: 9,173
Likes: 0
Received 0 Likes
on
0 Posts
LOL at this thread. I think Tidgy's mate needs to go learn something.
He took out the washers hope he took out the shims too then (cos you can't see them)
It doesn't loosen the rack allowing it to move PMSL
Standard cars are set up to understeer for Mr average and therfore for safety in the event of the driver running out of talent.
Bumpsteer removes this tendancy so the front wheels actually point where you want to go instead of pointing towards the hedge.
You can't just shove washers in it has to be measured on an alignment rig and if you don't know what you're looking for then you are pissing in the wind.
Yes it re-positions the rack to a lower position so that the track rod arms follow the travel of the lower suspension arms, that way when the suspension is compressed or extended the toe part of the alignment stays the same throughout it's travel.
nothing to do with castor vulnax
And no I aint showing you how to do it.
Oh yea and price is around £70 quid for the alignment and another £70 for the bumpsteer.
You can have an alignment without the bumpsteer
but you cant have the bumpsteer without an alignment.
Andy
He took out the washers hope he took out the shims too then (cos you can't see them)
It doesn't loosen the rack allowing it to move PMSL
Standard cars are set up to understeer for Mr average and therfore for safety in the event of the driver running out of talent.
Bumpsteer removes this tendancy so the front wheels actually point where you want to go instead of pointing towards the hedge.
You can't just shove washers in it has to be measured on an alignment rig and if you don't know what you're looking for then you are pissing in the wind.
Yes it re-positions the rack to a lower position so that the track rod arms follow the travel of the lower suspension arms, that way when the suspension is compressed or extended the toe part of the alignment stays the same throughout it's travel.
nothing to do with castor vulnax
And no I aint showing you how to do it.
Oh yea and price is around £70 quid for the alignment and another £70 for the bumpsteer.
You can have an alignment without the bumpsteer
but you cant have the bumpsteer without an alignment.
Andy
Last edited by Fuzz; 16 May 2006 at 11:49 PM.
Thread
Thread Starter
Forum
Replies
Last Post
Mattybr5@MB Developments
Full Cars Breaking For Spares
28
28 December 2015 11:07 PM
Mattybr5@MB Developments
Full Cars Breaking For Spares
12
18 November 2015 07:03 AM