Thanks P. You read my mind because I was going to ask that very question about over/understeer, but couldn't figure out how to word it correctly! :smile: B

 

First off if you jerk the wheel you'll likely just loose control and probably squish the squirell. If you don't lose control and experience understeer you'll probably still squish the squirell because your car doesn't turn as much as you are trying to make it go.

In a front wheel drive (FWD) car understeer is when you the combined force of acceleration and turning exceed your tire's maximum grip. Because a front wheel drive car accelerates with the front wheels understeer is far more common in FWD. Conversely RWD cars tend to exhibit oversteer.

Part of the reason understeer is preferrable to oversteer in production cars is your natural reaction to let off the gas is the correct one to correct the problem. This reaction decreases the acceleration demand on the tire so more traction can be used for turning while it also can transfer more weight to the front wheels to increase their total grip.

About sway bars, I found a very informative article I thought all here would find interesting: http://www.mercurycapri.com/technical/suspen/hasbw.html

Never mind that it's on a Capri site, physics are physics and it's pretty well written.

The jist of it is that while the sway bar improves the contact patch of the tires by maintaing better camber under heavy cornering manuvers it also speeds the load transfer rate putting additional demands on the tires. This makes the car feel more responsive, reduces body roll and ultimately induces slight oversteer giving cars with a factory tendancy towards understeer to feel more "balanced". This could be accomplished with stiffer springs and dampers but they will severly impact daily ride quality while the sway bar does not.

There are other specifics in the article but I thought some here would appreciate the summary.

Regards,
Jim

 

BMINI to answer part of your question... both the Driver and the Car can contribute to over or understeer...

if say you go way too hot (fast) into a very sharp corner... a huge rear anti roll bar is not going to help much... the car will understeer. the driver in this case is the issue, now if you hit the same corner at the proper speed, and the car still wanted to go straight then it could be a car setup issue. MINIs like all factory suspension setups dial in a bit of understeer for saftey... a larger rear swaybar will take some of this factory tuning out and makes the MINI a more neutral car (one that does not under or over steer).....

I do belive some people new to performance driving (like autocross) try to tune the car first before tuning the driver...

In a FWD car only in rain or like conditions would a big aftermarket swaybar induce unexpected oversteer... and even then if it happened driver error contributed...

SO yes a car setup can cause under or over steer, ans yes the driver can cause under or oversteer...

Hope that helps a bit I am about to get off work and thus kept this short.... Motor on my friends...

 

Okay, new topic: removing a wheel.

Last week I had some time and wanted to prepare myself in case I ever needed to change a tire. Roadside assistance is good and all, but there may be a time when I get a flat and don't have my cell phone or don't want to wait around forever just for some GUY to come and change my tire. I'm glad I took the time to do this trial. The instructions in the manual SUCK!! The MINI jack is like none that I've used before. It took me a few tries just to figure out how the darn thing cranked!! I got the car jacked up fine, had already loosened the lug bolts and then was stuck on how to remove the center cap. The MINI tool kit has a little tool for this, but I couldn't figure out how it worked and didn't want to risk scratching the center cap. Help guys, I was this close to getting the wheel off. I got frustrated and decided that I'd save the "retrieval of the space-saving spare" trial for another day.

 

HARMINI: you were closer than you thought. Since you have wheels with exposed lug bolts and you had already loosened them, you should have been able to remove the wheel without removing the center caps. The only time you would need to remove the center caps is if the lug bolts were behind the cap.

BTW, I would break the lug bolts loose *before* you jack the car up. Leave the bolts fairly tight until it's jacked up in the air. This way you won't have to put too much force onto the lug bolts while the car is perched on the emergency jack (which may or may not be on the most stable footing if you're on the side of the road changing a flat).

 

I agree with dave... on the 7 holes there is no need to remove the center caps...

one issue you may hit is having the wheel "stuck" to the hub. esp since you are up north (corrosion).... IF!!!! ( a BIG IF ) the car is stable on the jack my method for getting stubborn wheels unstuck is to sit on the ground by the wheel/tire feet facing the rim and pushing on each side on the tire (don't want scratched rims) to rock the rim back and fourth till it is loose. then when you put the wheels back on use an anti size greese to keep them from getting stuck again.

 

>>BTW, I would break the lug bolts loose *before* you jack the car up. Leave the bolts fairly tight until it's jacked up in the air. This way you won't have to put too much force onto the lug bolts while the car is perched on the emergency jack (which may or may not be on the most stable footing if you're on the side of the road changing a flat).

That's important, something you should write down or burn into your hand or something. I *KNEW* this and once when I had to change a flat for a friend I jacked the wheel up and said "DOH!" I forgot to loosen the nuts. I can laugh now but I felt like an idiot especially since I've changed a tire before and I knew what I was supposed to do. Also, don't take the bolts all the way off, just loosen them so you don't have fight with a spinning tire.

Also, when you're putting a new one on (or if your just testing how to do it, the old one) tighten it down as much as you can while it's in the air and then when it's back on the ground finish tightening it. It's really not that hard to do... I don't have any sort of hubcap as I have the S-Lite wheels so I con't tell you how to remove those but if the nuts are exposed, you shouldn't need to remove it. (Like the others have said)

Normally I wouldn't recommend using the jack that comes with your car as they are usually flimsy and only for emergencies but the one that comes with the MINI seems like it's a lot better than some of the other ones I've seen. Though if you plan on doing work on your car, I'd suggest getting a hydraulic jack of some sort as they are more durable and usually easier to jack up the car with.
-Chris

 

Thanks guys. You would be proud to know that I DID loosen the lug bolts before jacking up the car. Once up, I removed them all the way and then rocked the tire to try to remove it. When nothing budged, I assumed that it had something to do with the center cap. Damn NorthEast corrosion to blame, I guess. I didn't rock too hard because the car was not super stable. I used the brace in the toolkit under the opposite front wheel, but things were still not too stable as there is a slight downhill grade to my street. I know these little jacks aren't the best, but I wanted to simulate a real life situation.

What is this anti size grease? Where can I get some and how often do I need to apply it? I am planning on changing wheels very soon and want to make sure the new set-up is one that I can get the wheel off if I need to. I've gotten flats on every car that I've owned and have never had this much trouble changing a tire before. I've changed a tire uphill on gravel, on the narrow shoulder of the NJ Turnpike (record time of 12 minutes), and plenty on city streets. I am sure that the MINI will be no exception and want to be prepared to change the tire when the unavoidable happens.

EDIT>> TEEHEE!!!! (to borrow a giggle from Clo) My girlfriend just nicknamed my practice session a "tire drill".

Oh, and one more thing: this corrosion stuff.....it looks nasty in there and I was thinking about painting the calipers. How do I prep them/remove the corrosion before painting?

_________________

 

>>Thanks guys. .....
>>What is this anti size grease?
>>
>>
... that should be anti-Seize .. .. and there are some with names like NeverSeize and they come in tubes or tins with brushes to apply them ... in a pinch, you can even use pipe thread goop that can be found in the plumbing section of your local hardware store; Once it's on, you don't need to re-apply - unless it gets wiped off ...

 

>>Thanks guys. You would be proud to know that I DID loosen the lug bolts before jacking up the car. Once up, I removed them all the way and then rocked the tire to try to remove it. When nothing budged, I assumed that it had something to do with the center cap. Damn NorthEast corrosion to blame, I guess. I didn't rock too hard because the car was not super stable. I used the brace in the toolkit under the opposite front wheel, but things were still not too stable as there is a slight downhill grade to my street. I know these little jacks aren't the best, but I wanted to simulate a real life situation.

Good, it's always good to practice because when it happens you are most likely going to be shook up because of whatever caused you to get a flat in the first place.

>>What is this anti size grease? Where can I get some and how often do I need to apply it? I am planning on changing wheels very soon and want to make sure the new set-up is one that I can get the wheel off if I need to. I've gotten flats on every car that I've owned and have never had this much trouble changing a tire before. I've changed a tire uphill on gravel, on the narrow shoulder of the NJ Turnpike (record time of 12 minutes), and plenty on city streets. I am sure that the MINI will be no exception and want to be prepared to change the tire when the unavoidable happens.

most auto stores should have it. Just look for an Anti-Sieze compound

>>EDIT>> TEEHEE!!!! (to borrow a giggle from Clo) My girlfriend just nicknamed my practice session a "tire drill".

Just be sure to not get confused and grab the drill... that could be bad.

>>Oh, and one more thing: this corrosion stuff.....it looks nasty in there and I was thinking about painting the calipers. How do I prep them/remove the corrosion before painting?
>>

I've been planning on doing likewise. I just ordered a brake caliper paint kit which includes caliper cleaner and high temp. paint from Moss MINI (A MCO sponsor). There is a howto over at http://www.tech-esq.com/mini/main.htm but I haven't done it yet. Once I get the paint and some free time I should be able to post some pics but I haven't taken the brakes apart yet.
-Chris

 

THanks for info Chris and 8ball. I'm learning so much from you guys :smile:

 

Real Minis don't have spares! And a lot of them don't have runflats anymore. Get a couple cans of tire sealer/inflator. They even fit in those little compartments on the side of the trunk (boot) (hatch) so that the red cans won't clash with the interior decor. At least one in every car I own.

 

>>Real Minis don't have spares! And a lot of them don't have runflats anymore.


No Cooper bashing on the Girlie Performance thread, please. I am too tired right now to defend my reasons for buying my car.

So I guess that makes my car UN-REAL!!! I can get with that!

I do have a spare and do not have run-flats. Fix-a-flat doesn't work for blow-outs which is the situation I want to be prepared for most. And the information I learned here will also be needed when I remove the wheels to paint the calipers, or is that something only Real Mini owners do?

 

Go get 'em, Harmini!! ... and while some MINI's do not indeed have spares, All real Mini's did ... and it does my heart good to see anyone wanting to know more about how their car ticks ...

 

>>Real Minis don't have spares!

I thought this sounded silly, so I looked around and found this:
'70 Morris Mini, white with burgundy roof
[/edit]

 

>>Real Minis don't have spares! And a lot of them don't have runflats anymore. Get a couple cans of tire sealer/inflator. They even fit in those little compartments on the side of the trunk (boot) (hatch) so that the red cans won't clash with the interior decor. At least one in every car I own.

Come on now, was that necessary? Cooper, Cooper S... does it really matter? I have an S but we're all MINI owners.

For an AutoX course, lighter wheels and tires will certainly help (and the runflats are heavy) and a spare certainly adds uneeded weight but unless your racing it doesn't really matter. I like to have more power in my MINI and I will probably get rid of my runflats and get regular tires when they wear out but that's a risk I am going to take... some people don't want to take the risk that they will get a blow-out or something. Let's not forget the intent of this thread, to educate MINI motorists who want to learn. There is nothing wrong with having a spare or a non-S, we're all here to have fun.
-Chris

 

Thanks everyone for the over/understeer info. Great help understanding!

HARMINI - haha, I did a tire drill on my previous car too! I wanted to know if I could do it by myself, versus having to figure it out on a dark night in the middle of nowhere with only scary weirdos driving by! It's nice not to be a completly helpless/hopeless chick! :smile:

Even though I have the runflats and no spare, I will do the tire drill on my MINI too. Can't hurt anything to know how to best change the MINI tire if I had too. Perfect example: I blew out a runflat in the middle of nowhere. No one in Smalltown USA had the right size tire for me to replace the flat, so I had to buy 2 brand new tires for the back because I can't drive 400-500 miles with 2 different size tires on the rear. So, I threw the healthy runflat in the back (cool - spare!) and drove with the 2 new non-runflats to get home. The whole way home I kept thinking (just my luck) "what if I get ANOTHER flat on the NON-runflats!?" I didn't have any fix-a-flat, nor did I know anything about how to change the tire, where's the jack, etc etc... since I'd only had the MINI for a few days. A previous "tire drill" in this situation would have certainly given me some peace of mind! :smile:

As for the corrosion being mentioned, I have little rust colored dots/specks behind my wheels. (ppsstt..is that my caliper?) Is that what you are seeing on yours?

Oh I love the Morris Mini pictures! The tires are so tiny - like donuts on big cars!

 

dbwilldo, you can hi-jack any thread when you show us pics of such a beauty!!

db, Daytona and 8ball, thanks for backing me up.

BMINI, let's hear it for us girlies girls that can change our own tires! I love your example of when a girl might need to know these things (what a creative mind you have). You asked: "As for the corrosion being mentioned, I have little rust colored dots/specks behind my wheels. (ppsstt..is that my caliper?) Is that what you are seeing on yours?"

My calipers have more than specks, there is a thick layer of crud, whitish corrosion from driving in snowy/salty NJ roads this winter. Here is a picture of some calipers painted red, so you can see the difference between them and the brake discs (also visible behind the wheel).

 

I did a quick search on the web to find some pictures and found these: (They aren't MINIs but they look the same)
Brake caliper:


In this next picture you can see the rotor: (The big round thing)


The rotors are what gather that gunk... if you do a couple of hard brakes, the crud on the rotors should go away. They tend to look rusty when you get them wet. The top and the center do get rusty but it's nothing to really worry about, just a little unsightly. Calipers however are the things that attach to the rotors and they can get quite dirty too. The EBC Greenstuff brake pads are supposed to reduce the ammount of brake dust and hopefully keep your wheels looking cleaner. Also, as a side note, to keep your wheels clean try waxing them (when they are clean). That way they clean up a lot easier.

If I could afford it, I would probably upgrade the rotors and pads when I paint the calipers since you do basically the same thing. In fact if you want more info on getting the calipers on and off you can check out Randys HOWTO: Brake rotor/pad change How-to. He doesn't paint them but describes how to remove them and put them back.

HARMINI: always here to help

Remember, no question is a stupid question in the girly performance thread... and no making fun of anyone!!!
-Chris

 

just another note of followup to this: "Also, when you're putting a new one on (or if your just testing how to do it, the old one) tighten it down as much as you can while it's in the air and then when it's back on the ground finish tightening it. It's really not that hard to do."

After you have driven a while (~50 miles) check the tightness of the bolts again because the wheel can settle a little in use loosening the bolts (The tyre stores should and usually do tell you to do this).
Another "tip" while on the tyres, the recommended inflation pressure is on the door pillar and in the owners manual NOT the sidewall of the tyre. The value on the sidewall is the MAX pressure the tyre can take, not the recommended pressure. On my other car I have twice had the tyre shop overinflate (by double the recommended pressure) a tyre. This is not a good idea on a rim that was not designed for a tubeless tyre . Even with the runflats you should regularly check the tyre pressure.

 

Wow, I think I may have the opportunity here to tie in the 3 main topics of this thread in one post! :smile:

Let's look at our topic of changing a tire. In order to remove the wheel bolts, you have to apply a torque to them to loosen them. To do so, you get out your trusty lug wrench. Why? Well, you haven't had much success just grabbing the bolt and trying to loosen it by hand, right? You can't apply much torque that way. You need LEVERAGE. So let's say for the purpose of this discussion that the wrench you are using is 2 feet long. Let's also say that you weigh 100 lbs.

You try to loosen those bolts but they just won't budge. You intuitively know that the farther out on the wrench handle you apply force, the more force you can apply because of the greater leverage. You don't think about it, you just instinctively do it when you grab the wrench (no one grabs the wrench close to the center, everybody goes for the end).

So you orient the wrench so that it's parallel to the ground and you attempt to gain max leverage by standing on the wrench with your full body weight.

So you can figure out here just how much torque you're applying. Let's say you stand on the wrench exactly at the 1-foot mark. If you weigh 100 lbs., you are now applying 100 ft-lbs. of torque (twisting force) to the bolt. Well, that still doesn't do it so you move outward so that you are standing right on the end of the wrench, at the 2 foot mark. You don't weigh any more but since you are standing twice as far out on the wrench, your leverage is greater and you are now applying 200 ft-lbs of torque to the bolt.

If it still doesn't give (and it should have given at the 100 ft-lb point if it was not overtightened) then you might start bouncing a little on the end of the wrench, which can apply severe torque to the bolt (if you are bouncing, your effective weight is no longer 100 lbs, since you are using gravity to help you apply more force). If you really go nuts that's the point where you snap your wrench in half or you twist the head of the bolt right off. D'OH!

You can see that sometimes you have to apply rather high torques to wheel bolts in order to remove them, which is why the initial breaking loose of the bolts should be done with the car firmly on the ground. It's possible with the car on a jack to apply enough force to roll the car off the jack!

The same torque theory works in reverse when tightening the wheel bolts, though for improved accuracy you should use an actual torque wrench :smile:

Torque as it relates to an engine is the same general idea, except many more factors are involved, including things like bore and stroke, compression ratio, engine displacement, number of cylinders, intake manifold design, forced induction, camshaft profile, etc.

howstuffworks.com is a great site for getting the basics of how an engine ticks, especially with their cool animations. Definitely check out the How Engines Work article. They also have lots of great articles about how transmissions work, how clutches work, etc etc. Tons of good automotive stuff.

 

It's the curious girlie back again! I've been hearing lots of technical terms lately, but I don't really know what they mean. Help me out guys......

My car has a stalling problem. First trip to the dealer, they applied stabliant to connectot. (what/where are these?). Didn't fix the problem. Next trip, they upgraded the ECU. Didn't fix the problem. Third trip, they only checked for fault codes (is this when they hook up a laptop to a connection that is behind a panel under the driver's dash?). No fault codes=no fix. After speaking with someone in the know at MINIUSA, it seems that the problem may be with the wiring harness. So I got to wondering, is a wiring harness something that keeps all the wires tidy and allows them to attach to another something? I've seen the term used for audio as well. Now, if the wiring harness is the problem, what is it doing that makes it faulty? Does it not allow the wires to reach their destination? Does it pinch the wires in such a way to impede a good connection? What wires are held by this harness? And, does this have anything to do with "drive-by-wire"?

 

Great thread! Thanks cdconsor for the How Stuff Works Site. I could spend all night on that site. I esp. like the exploded views. The question I have is in regards to shifting. I tend to be a little lead footed and I've noticed when I motor with passengers I tend to make them move forward a bit when I'm shifting. I've tried different techniques and I've noticed when I let the clutch out slower it is less apparent. Is letting out the clutch slower going to cause it to wear out faster? I'm wondering about my general motoring habits...

If anyone can pass on a few tips it would be much appreciated!

 

>>Great thread! Thanks cdconsor for the How Stuff Works Site. I could spend all night on that site. I esp. like the exploded views. The question I have is in regards to shifting. I tend to be a little lead footed and I've noticed when I motor with passengers I tend to make them move forward a bit when I'm shifting. I've tried different techniques and I've noticed when I let the clutch out slower it is less apparent. Is letting out the clutch slower going to cause it to wear out faster? I'm wondering about my general motoring habits...
>>
>>If anyone can pass on a few tips it would be much appreciated!
>>
>> :smile:

 

>>It's the curious girlie back again! I've been hearing lots of technical terms lately, but I don't really know what they mean. Help me out guys......
>>
>>My car has a stalling problem. First trip to the dealer, they applied stabliant to connectot. (what/where are these?). Didn't fix the problem. Next trip, they upgraded the ECU. Didn't fix the problem. Third trip, they only checked for fault codes (is this when they hook up a laptop to a connection that is behind a panel under the driver's dash?). No fault codes=no fix. After speaking with someone in the know at MINIUSA, it seems that the problem may be with the wiring harness. So I got to wondering, is a wiring harness something that keeps all the wires tidy and allows them to attach to another something? I've seen the term used for audio as well. Now, if the wiring harness is the problem, what is it doing that makes it faulty? Does it not allow the wires to reach their destination? Does it pinch the wires in such a way to impede a good connection? What wires are held by this harness? And, does this have anything to do with "drive-by-wire"?

I have insomnia, so I might as well try & be of some use. I am not 100% sure so I won't speculate what "stabliant to Connectot" means. I'm guessing you're reading some semi-legible service advisor's notes off your service ticket. "Upgraded the ECU". There is a recent software upgrade the dealer can 'flash' your Electronic control unit (ECU)with that allegedly alleviates some of the cold start & low RPM stumble . There have been some recent threads in 'Under the bonnet' on this. The owner concensus seems to be mixed on if this most recent upgrade helps or in some cases might cause additional drivability issues. You are right about the fault codes. If they find no fault codes it means " no trouble found" = no fix. Wiring "harness" is basically jargon that describes the vehicles' wiring as a whole unit. The "harness" they refer to IS the actual wiring rather than something that holds the wiring in place. If you saw the entire wiring harness out of the car you'd probably describe it as wiring spaghetti. The wiring for all electrical componants is incorporated in the "harness". They are probably refering to that specific part of the harness that has to do with the ECU/engine management. If portions of the wiring harness are damaged or cut it could definitely pose a problem. I'd be really interested to hear where they go with the troubleshooting. On a new vehicle there shouldn't ordinarily be issues with the wiring harness unless it's been physically damaged. Keep us posted.
The MINI has no accelerator cable. In a nutshell,When you depress the gas pedal, a potentiometer is involved, & a signal sent to the engine management system that tells it how much throttle opening is needed based on the gas pedal position, hence the term "drive by wire". There was a much better,minutely detailed description of how this works courtesy of Andy Ross & others in a Performance thread about two months ago. Search on 'drive by wire'. Hope this is of some help & best of luck with resolution of the stumbling issue. must-go-to- sleep ......ZZZZ