Okay,

I recently (over a month ago) replace my stock 16" wheels with 17" lo pro tire/wheel package. I've since noticed the car "hops" at the 20-30 MPH range. Seems it's coming from the rear driver side. I have since taken it in and had several things checked.

1. Alignment is okay. All is green and as it should be
2. The tired have been balanced and rotated. (I would guess this factors out an out-of-round tire or a bent rim)
3. Took it in to MINI and although they weren't able to get the tire off the car (because I didn't have the lug key with me) they looked underneath at control arms and such and said that the only thing he noticed is that there is an aftermarket part there. (Forgot which part it was) He said it has "part stickers on it."

I'll be bringing it back in when I get my lug key- but I was wondering if anyone has any ideas what would cause this that I may offer as suggestions when he looks at this issue again. It's EXTREMELY annoying to me.

The only odd thing about it is that I didn't notice it with the factory wheels/tires. The factory wheels were the "horseshoe" type, and they were normal tires, not lo-pro.

Any takers on this one?

 

Is there any tire wear yet?
Also what tire is it (brand and name... Pirelli Pzero)

It sounds like the tire has internal construction issues...

But, you mentioned aftermarket parts... what suspension work was done?

Also is this on the same section of road at 20-30 or any piece of road at that speed?

 

None

My car is not near me so I am unsure of the tire. I'll check and get back on this one...


It was the Rear Control Arm.

No not the same piece of road. It's all over.

 

A worn trailing arm bushing maybe?

 

when you say "it hops", is it a constant, rhythmic hop relative to the speed of you car?

 

Also, Why was the rear control arm replaced? Only one side?

Have you tried switching back to the 16" rims?

Also, are the hub-centric rings installed (correctly?)

I'm assuming that the 'hopping' is on the same corner, and does not move when you rotated the tires... is this the same corner as the replaced arm.

(I'm wondering if the wrong arm was installed for your year.)
I'm also wondering if what ever caused you to replace that arm hasn't damaged the shock as well...

 

Along those same lines, I've seen water inside the tire too, although it's kind of a rare cause.

 

Definatley relative to the speed of the car.

 

I'm assuming it was damaged. I am the 2nd owner but to my knowledge there is no Carfax report.

I have not tried this yet.

They're pretty tight and from when I put them on, I couldn't remember there being a wrong way for them to go on.

Yes.

 

Well, I'd guess that your tires and wheels are fine.

I'm going to go out on a limb... I'd guess that the problem has something to do with the history of that part... either the part itself, (defective or incorrect) or why it was put on (accident bending something else).

Carfax misses A LOT... like my friend who rolled his Exploder... he filed a police report and insurance claim, and it was not on the carfax report.

I'd check VERY CAREFULLY the rolling diameter of your 16" and 17" setups (I have a spreadsheet that may help, PM me w/ your email if you want it).
I'd also check the width and offset to make sure that you have not shifted the suspension geometry, but I'm guessing its the stiffer sidewalls of the 17s that let you feel this issue.

While your at it, DEFINITELY, try the 16s... the same issue might still be there, but the larger sidewall may cushion the affect... use a spotter outside the car (do a drive-by) and see if they can see the hopping on both 17s and 16s...

You might need to put a Mini control arm in, but first (as prev. noted) I'd check the bushings, dampers (shocks), bump-stops... get teh info off the arm, call the mfg. and make sure its the right one for the year and model.

If you can contact the PO, do it to find out the history of why that part was changed.

Also goto your local BMW/Mini dealer and have them pull the history of the car. (All you need is your key or call with the VIN)... it will list every visit to every dealer. (you can also get your options listed).

In the mean time, try to spend as little time at the speed that causes the hopping as possible. And don't do any track time until you get this resolved!
You will see wear patterns in the tires if you just ignore it (and prematurely wear other components).

Good Luck!

 

if the car started hopping with the 17" wheels, then that's where the problem is. put the rear of the car in the air and spin the tire. look for a bent rim, out of round tire. if you can't see anything, replace that one wheel with the 16" wheel and see if it goes away. are you using hubcentering rings?

rolling diameter, offset, suspension geometry, blah blah, all that will not cause this.

 

Thanks for the info! I'll look into this as soon as I can.

P.S. What's a PO?

 

But as I said, I've had the tires rotated and the hopping still happens from the same location. The driver rear side.

I would think that rotating the tires would cancel out the thought that it would be out-of-round or a bent rim.

 

Unless you have 2 bent rims... both on the same side (like someone hit a deep pothole with both passenger side wheels)

 

Okay so if this is the culprate...

Stupid question... Can a rim be "unbent?"

 

Maybe, depends on how bent the wheel is and where it is bent.

Don't know where in Fla you are, but there is a Wheels America in Miami. If at all like the Dallas shop they have it's a great place. They can fix if fixable. In Dallas they offer us Mini Club owners a discount too.

 

sorry, missed that on original post.

 

PO = Previous Owner (the one who took the depreciation hit)
EPO = Evil Previous Owner (the one who replaced the entire wiring harness with blue wire)
DPO = Dumb Previous Owner (the one who never changed the oil, ever.)