Hi,
In the last week, twice I have come up to a (different) roundabout and the car would suddenly want to veer to the right for a split second s:scared: :scared: s:scared: . Today, I was driving slow round a flat righthand corner and the car suddenly felt like it wanted to veer left for a split second! s:crazyeyes: :crazyeyes: s:crazyeyes:
Anybody had this or can think what may cause it? Brakes/ABS/Power Steering ...
Dave
start with teh obvious
what tyres are you running?
probably tracking the road. normally happens when the front tyres are starting to wear low.
Bridgestones on the front and embarrassingly different cheapish on the back .. (times were hard a few years ago s:oops: :oops: s:oops: ). Yes, they are all getting fairly low but more importantly they are pretty old (rubber hardening?).
I have had dodgy handling with tyres before but this felt far scarier than normal. Maybe I just havn't got to this level of 'dodgyness' before.
Do Bridgestones get this bad when fairly low?
most brands do as far as i know. guess its down to more grip as the tyre wears low. when replacing try and get all tyres the same,
mixed rubber, and most of it old and wearing
i'd fix that first then look elsewhere its the most likely culprit.
mr2 is incredibly sensitive to tyres
Will do, was hoping to wait a little while and get wheels and tyres, can't afford wheels as well at the mo.
I think I'll go and me a set of Toyo T1Rs, they seem to be all the rage and quite affordable.
Thanks for everyones replies. s:D :D s:D
Have you checked whether one of your brake calipers is seizing / seized..?
Mine was like this a few weeks back: I had refurbed all my calipers last summer, so it didn't cross my mind they could be faulty...any of them..! s:D :D s:D
However, car failed the MOT last month and the NSR was seized. I refurbed it last week, using a new piston, grease and seals, and the car is TOTALLY different now... s8) 8) s8)
I very much suspect that some of the handling "problems" people have reported here over time wil have been due to this, rather than the much-maligned, but mis-understood mis-matched tyre makes /stagger.....?
Its very hard to accurately diagnose stuff like this in the real world, as you also get side-winds, tramlines, etc, which cloud things considerably.
After dismantling an EHPS pump, I do believe it is possible that this MAY have some profound effect on handling on our cars..? Perhaps its effect varies randomly at various speeds, giving the impression that the steering is "wandering"....? (Yes, I DID have the correct stagger tyres when I experienced this! s:wink: :wink: s:wink: )
This is just a theory currently, but time will shed more light on this...... s:wink: :wink: s:wink:
One final thing which may be worth noting:
I can report that with the 100mm space-saver tyre on the NSR, and a 225/45/16 on the OSR, the car felt remarkably stable at 60mph...
..in fact, FAR more so than when I had 225's both sides but with the binding caliper.......
..for what its worth!
Hi Dyn-Evo,
Brake binding was a thought with me but I've had a veering right AND left ... unless both are binding!
Can binding be diagnosed without the brakes currently bound? ... if you see what I mean. Or do have the calipers refurbished and hope it's cured it?
I hate intermitent problems, had a Porsche 911 SC (1979) once that kept failing to start. Everytime the car was transported off to a garage, the car started ok after getting there! Grrrr! Found out eventually that it was an engine cut-off switch that activates upon the car being upside down! The switch is also engaged when the ignition is off. It was sticking s:twisted: :twisted: s:twisted:
Thanks,
Dave
misunderstood tyre effects?
really?
some peoples stupidity knows no bounds if they think mismatched tyres aren't a problem
Have to say that i have today felt the benefit of fixing tyre mis-matches.
My car had a fairly significant pull to the left since i got it, feared it might be chassis bend since it was a cat D write off in 2003 (Non-recorded for some reason, but admitted by the seller). It was running 185/55/15s all round, with 3 different tread patterns (NSF - Goodyear Eagle NCT, OSF - Pirelli P6000, Both rears - Hankook K105 Ventus Prime)
Today the fronts reached the legal limit, or more accurately they reached the legal limit a few weeks ago, i reached the limit of my nerve and more importantly, pay day.
Put some Lassa Impetus on both fronts, and even with a different pattern front to back, and an incorrect stagger the car handles 100% better now, its cured that nasty understeer and completely fixed the pull to the left. Drives straight and true now.
As for your veering without experiencing the pull its different to understand exactly how bad we're talking, but if we assume for a moment its not tyres i'd say bushes would be my next suspect, maybe allowing too much play when the weight shifts. My brothers 320d had worn bushes on the back and you could see the back end shifting about something eeerie when he put the hammer down.
Ok, so it happened again last night. This time I was doing 2mph and it felt like I was driving through a deep puddle or the left front caliper came on. Each time it happens I'd say it last for about 1 second then everythings back to normal.
Can't be tyres at that speed. ABS? Can ABS apply the brakes or can it only de-apply the brakes.
s:? :? s:?
Dave
I cant imagine it being tyres at anything like 10MPH or less.
I'm fairly confident the ABS system on the MR2 isnt sophisticated enough to be able to apply the brakes, that would be more of a job for EBD or something of the sort, applying braking pressure to whichever wheel has traction, could malfunction i guess. But either way the 2 doesnt have it. What really confuses me is that its doing it in both directions, a seized caliper would do it in one direction - constantly or intermittantly.
I'm out of ideas i'm afraid.
don't see why tyres cant affect at low speed?
your right the abs can't apply the brakes
I'm glad you can both see my confusion!
Hopfully taking my car to my local garage today. I'll see what they say.
I've read the MR2 has BA (Brake Assist) on the SMT, I guess it should have it on the manual aswell.
dont think we have any form of traction control except an lsd which is mechanical.
Nope - no BA on the SMT. Facecelift SMT cars did get VSC which used the ABS pump to apply the brakes on individual wheels to stop the car going too sideways. Made for great safe fun on roundabouts (until I discovered the technique for overcoming it!)
No BA on SMT? Not according to this.
"In addition, the MR2 Roadster SMT incorporates the innovative features of Vehicle
Stability Control (VSC), Traction Control (TRC) and Brake Assist (BA), which
automatically aid the driver to control the effects of wheel spin, correct any understeer
or oversteer and supplement braking force if required."
m http://www.toyota.co.uk/bv/1024-heritag ... _Aug03.pdf (http://www.toyota.co.uk/bv/1024-heritage/Brochures/MR2/MR2_Aug03.pdf) m
Quote from: "markiii"don't see why tyres cant affect at low speed?
your right the abs can't apply the brakes
Generally i would bow to your greater experience and perhaps you are right but my early learning center understanding of physics says that tyre slip occurs when the inertia placed upon the contact area in any direction is greater than the resistance the tyre generates against the tarmac at any given moment, for this problem to be tyre related it would have to be either uneven sizes causing a difference in rotational speed (ruled out), a massive difference in the rolling resistance of the tyres on one side (n/a because the problem would be constant, not intermittent) or some sort of loss of traction, probably on one wheel, causing a directional change.
But i cant believe that any modern tyre, even a bald one from an old bus generates so little resistance as to be overcome by the force of a lightweight car like the MR2 travelling at 10MPH on plain tarmac, even if wet.
Plus any directional change caused in this way would effectively be a diversion of kinetic energy from forward acceleration, at 10MPH i dont understand where the energy required to cause such a "veer" would come from. Not through a tyre slip anyway.
Alternatively, and i say this in all seriousness, i could be talking out of my rear...
Quote from: "dcod"No BA on SMT? Not according to this.
"In addition, the MR2 Roadster SMT incorporates the innovative features of Vehicle
Stability Control (VSC), Traction Control (TRC) and Brake Assist (BA), which
automatically aid the driver to control the effects of wheel spin, correct any understeer
or oversteer and supplement braking force if required."
m http://www.toyota.co.uk/bv/1024-heritag ... _Aug03.pdf (http://www.toyota.co.uk/bv/1024-heritage/Brochures/MR2/MR2_Aug03.pdf) m
as steve said only post facelift
Quote from: "dcod"No BA on SMT? Not according to this.
"In addition, the MR2 Roadster SMT incorporates the innovative features of Vehicle
Stability Control (VSC), Traction Control (TRC) and Brake Assist (BA), which
automatically aid the driver to control the effects of wheel spin, correct any understeer
or oversteer and supplement braking force if required."
m http://www.toyota.co.uk/bv/1024-heritag ... _Aug03.pdf (http://www.toyota.co.uk/bv/1024-heritage/Brochures/MR2/MR2_Aug03.pdf) m
I've done 45k miles in my '53 SMT over that last 2 years, it that REALLY surprises me! it certainty doesn't drive like it has BA.
Edit: I think I may be confusing BA with EBD however s:? :? s:? ?
Quote from: "markiii"as steve said only post facelift
Steve said no BA, facelift got VSC.
What's important is that I don't have BA. I just can't think what is causing this.
Quote from: "dcod"Quote from: "markiii"as steve said only post facelift
Steve said no BA, facelift got VSC.
What's important is that I don't have BA. I just can't think what is causing this.
he said post facelift have vsc which uses the abs pump, sounds like BA to me?
If you've got BA that would certainly be a likely culprit.
In fact as Hugh Laurie once said, its "As guilty as a puppy sitting next to a pile of poo"
ABS / BA / traction control are all basically reliant on the ABS sensors.....
Perhaps you have one (or more?) generating some sporadic info...not enough of a fault to throw a code on the dash, but enough to make the ECU respond unfavourably to the signal....maybe..?
Having said that, though, that would indicate a (possibly fatal) major design flaw on Toyota's part, if the system CAN perform this way, making the car dangerous to drive without a code being generated and a CEL being thrown..... s:? :? s:?
I must say, my similar experiences over the last 2 years, running many different tyre makes, staggers and under different road conditions, seem to indicate that there are things going on that CANNOT be related to tyres (especially stagger), due to the low running speeds (on occasions), and the fact the car is running dead straight on a dead straight road in zero wind conditions.....?
I reckon either the active BA or the PAS systems MAY be throwing a spanner in the works for us, somewhere.....?
Tyres seem to get the blame for virtually everything on this forum?? s:roll: :roll: s:roll:
Rarely a mention of driver error, driving too fast into a corner...or maybe even an ongoing mechanical problem with our cars that we're not actually aware of yet........?
Quote from: "markiii"misunderstood tyre effects?
really?
some peoples stupidity knows no bounds if they think mismatched tyres aren't a problem
Mismatched ON THE SAME AXLE.....obviously THAT is a no-no...... s:roll: :roll: s:roll:
but different makes front/rear..THATS not gonna kill anyone anytime soon...as long as they're matched side to side.
Sure it will affect the handling...but it wont be dangerous as long as you get used to the difference BEFORE trying to be Seb Vettel on a public road....
THEN you may find that elusive ditch......!! s:wink: :wink: s:wink:
Quote from: "markiii"he said post facelift have vsc which uses the abs pump, sounds like BA to me?
Hmmm, think I'm going to research on how to findout whether I have BA or not. I can't really go by UK specs because my car was imported from Holland.
I agree with you, BA seems the most logical conclusion.
Dyn-Evo, I wouldn't put anything past Toyota anymore ...
I thought brake assist was the technology designed to interpret how hard you were pressing the brake pedal in order to determine the need for an emergency stop. If the inputs appear to indicate an emergency stop is required, then the ECU will apply the brakes fully in order to bring the car to a stop as quickly as possible. As far as I know, this technology was introduced because modern braking systems are so well assisted, most drivers don't need to press the pedal hard to pull up in normal driving conditions, they are therefore conditioned to not have to press the pedal hard ever, and therefore rarely apply sufficient pressure to effect a good emergency stop, thus warranting the introduction of more electronics to 'aid' the driver.
I don't think this is fitted to my facelift. The braking is too progressive for BA to be interfering with what I want to do.
And on the other hand, everyone I know who has ever had this fitted on a car has pretty much hated it. Apparently, it is very difficult to control when and by how much BA will interfere, it is therefore pretty much impossible to judge braking distances accurately.
Going back to the OPs original problem: worn tyres will cause the '2 to tramline (esp. Bridgestones). This can be felt at low speed if there is sufficient disturbance in the road surface for the front wheels to start following something. The best course of action is to address the tyre situation, put the standard ('book') pressures in and work it out from there.
If you've got ramps or another easy way to get under the car, I'd check for play or signs of wear in any of the suspension arms. I'd imagine a knackered ball joint or bush could cause this kind of issue?
Tyres or brakes do sound like the most likely culprit though.
Hi filcee,
I am certain, in my mind, that the issue isn't tyres. However, I will be changing them very soon s:) :) s:)
If BA has such an effect that people hate it then I would say that I don't have it. My brakes have always done exactly what I wanted and never surprised. Thanks for the info though. s:) :) s:)
Hi jaik,
Good point but I had my wheel allignment done 2 weeks ago and watched the guy pull away at my suspension. He told me everything was cool.
Of course having 20-30mm of stagger front to rear is only going to make the overall tramlining effect worse, whatever speed we go at....
Doesn't matter how worn the tyres are: if you drive along 2 ruts in a motorway lane there will be points where either the front or rear tyres are on the edge of one or other of the ruts..this will cause one end of the car to pull.
Not a very nice effect....
You'll only really notice it at speed on a dual-carriageway / motorway, though, to the point where it'll feel dangerous.
Add to this the buffeting of gusty side-winds and the instability some suffer at 70+, and you may feel your car is trying to kill you.....!
..and thats WITH the correct front/rear stagger.... s:wink: :wink: s:wink:
Quote from: "dcod"Good point but I had my wheel allignment done 2 weeks ago and watched the guy pull away at my suspension. He told me everything was cool.
Did the problem start before or after the alignment? If after, perhaps something has worked itself loose since being adjusted.
Quote from: "Jaik"Did the problem start before or after the alignment? If after, perhaps something has worked itself loose since being adjusted.
Started about a week after. I've already booked my car in at my local garage for Tuesday to check the whole suspension out.
Does anyone hear/feel a scraping noise just after starting and pulling away? I believe it's something to do with the braking system taking on air. Is this BA? My car has done this from new, 10 years ago. Has been doing it a fair bit more recently.
Brake Assist: p169 of the owners manual specifically mentions brake assist for vehicles fitted with VSC - which is the post-facelift SMTs (i.e. mine). I can't say I've ever noticed the effect I described above. Maybe this was another aspect of a sports car that Toyota got right.
you have said yourself the tyres are low so rule them out and change them, hell you got to do it anyway. also mine does yours it because it is tramlining my tyres are low and it even will turn some corners for me it trams so well. now this is not because of a ba or traction system as i know for fact that it dont bloody well have it. and at the end of the day if it not your tyres which you ruled out because you changed them it will be a ball joint etc as it throughs out the alinement. either way its not a sodding ba
rant over
Quote from: "dcod"Quote from: "markiii"he said post facelift have vsc which uses the abs pump, sounds like BA to me?
Hmmm, think I'm going to research on how to findout whether I have BA or not. I can't really go by UK specs because my car was imported from Holland.
I agree with you, BA seems the most logical conclusion.
Dyn-Evo, I wouldn't put anything past Toyota anymore ...
you can, as mechanically EU cars are identical
Tramlining is a well known problem with well worn Bridgestones, and I'd agree with all those above who suggest getting some new tyres. I woudn't look for any other cause until you've changed them.
It's all been said really and some good stuff.
The golden rule for any form of problem solving is to only change one variable at a time so that it can be eliminated from the equation.
You have identified a problem variable. If you alter something else and the problem is still there then you still don't know whether or not the tyres are the cause of the problem. (Although you will know that what you changed isn't).
Update:
I cancelled the garage check for last Tuesday, I decided to change the tyres first (as logically suggested earlier).
Car has not shown the problems I was getting since last Thursday. I hate intermittent problems! s:x :x s:x (car does bounce around, tramline and feel like its made of jelly though)
Should be getting a full set of Toyo T1Rs today. s:D :D s:D
Then?
a) Car feels great; play the waiting game ...
b) Car still feels wrong or scary problem comes back; get car checked at garage ...
Thanks for all your replies.
Quote from: "dcod"Good point but I had my wheel allignment done 2 weeks ago and watched the guy pull away at my suspension. He told me everything was cool.
First and most obvious question, did the problem start after the alignment?
If so, is the alignment correct?
Was it a proper 4 wheel alignment correcting toe and thrust angle so front and rear track match?
If the rear alignment was adjusted, are the lock nuts on the rear toe adjusters fully tightened?
I had a problem after some work was done recently and it turned out to be a rear control arm mount bolt only done up to around 15lb/ft. You could pull on it and no free play was evident, but when driving, it was all over the place.
The RE040 do tramline really badly when worn, it is just a function of camber wear, stiff side walls and geometry as far as I can tell. The softer sidewall tyres seem not to have so much of a problem with it, but I am running R888 and they are similar to the RE040 in this respect. With the RE040 the tramlining can be at very low speed.
Hope your tyre change fixes it, let us know how it goes.
PS, remember to take it easy on new T1R as they are greasy for the first 500 miles or more.
Chris
Quote from: "ChrisGB"I had a problem after some work was done recently and it turned out to be a rear control arm mount bolt only done up to around 15lb/ft. You could pull on it and no free play was evident, but when driving, it was all over the place.
The RE040 do tramline really badly when worn, it is just a function of camber wear, stiff side walls and geometry as far as I can tell. The softer sidewall tyres seem not to have so much of a problem with it, but I am running R888 and they are similar to the RE040 in this respect. With the RE040 the tramlining can be at very low speed.
Hope your tyre change fixes it, let us know how it goes.
PS, remember to take it easy on new T1R as they are greasy for the first 500 miles or more.
Chris
So far the car has felt great. I forgot how new tyres can breathe fresh life into a car. s:D :D s:D
Unfortunately, the problem I had seemed to stop 4 days before I had the tyres fitted so I don't 100% know whether the problem has been fixed.
New tyres has fixed the following though:
1. Sliding around on bumps even in the dry s:shock: :shock: s:shock:
2. General tramlining.
3. Bone shaking ride.
4. Cornering feel.
Current problems:
1. Tyres don't feel too sure in the wet (probably need wearing in as you said).
2. Car vibrates above 70 (balancing weights fell off or were falling off! Half fixed by kwikfit on Sunday but will get all wheels done again very soon)
What have I learnt? Just because you have plenty of tread on your tyres, don't think they are ok! If they are over 4 years old and don't get used much, change them!
what pressures are you running?
Quote from: "markiii"what pressures are you running?
26 front, 32 rear. They feel fine but any suggestions are welcome s:) :) s:)
i would say they low as i believe the toyo tyres should be run 5 psi higher to normal. for me i would probably run 30 front 35 rear but its all depends on mods and tyres and finding the right balance
Need to know specific sizes to give a definitive answer on pressures as some sizes are xl rated, some not.
Chris
Standard OEM wheels 185/55/15 and 205/50/15. Mods? Flaky paint and bubbles s:D :D s:D
I had a similar problem with mine.I had Toyo T1Rs and only replaced the rears because the 2 year old front tires still had half the tread left.It drove terrible and an alignment made no difference.Replacing all 4 tires at the same time works best.
Quote from: "dcod"Standard OEM wheels 185/55/15 and 205/50/15. Mods? Flaky paint and bubbles s:D :D s:D
Looking across the load index tables, I would say you are pretty much spot on with stock pressures.
Chris