Skipping with wider tires?
12-29-2013, 09:10 PM
#1
Thread Starter
Skipping with wider tires?
Recently went from stock AP1 sized tires to 225 and 255 tires and noticed that the rear tends to skip around more on bumps like cats eyes and expansion joints. Is this a normal characteristic of running wider tires? In the corners on a smooth road everything is fine, however at highway speeds it's not the most confidence inspiring trait!
Perhaps skipping is the wrong adjective, maybe more of a shimmy?
Perhaps skipping is the wrong adjective, maybe more of a shimmy?
12-29-2013, 09:36 PM
#2
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That sounds like a case of bump steer, which is a common problem in our cars. Idk why it would start happening with wider tires though. Maybe because you're pushing it harder than when you had the 225's?
Anyway, you can solve this problem with adjustable toe arms in the rear aka an anti-bumpsteer kit. I know that megan racing and J's Racing sell them, but there are probably other companies out there that make them too.
Anyway, you can solve this problem with adjustable toe arms in the rear aka an anti-bumpsteer kit. I know that megan racing and J's Racing sell them, but there are probably other companies out there that make them too.
12-29-2013, 10:12 PM
#3
Are you running adjustable coilovers? Check your tire pressure and make sure its consistent with where you ran the 225. Sidewall construction and air pressure can make a noticeable difference in how the car behaves over irregularities in the road. This doesn't sound like a case of bump steer, it sound like simple tire deflection. Stiffer sidewall or higher air pressure can pronounce this effect. Actual bump steer is when the suspension moves through the stroke far enough that the actual wheel geometry changes, causing the car to exhibit unpredictable behavior. The typical is more what your likely experiencing, when you hit a sharp bump and it causes the tire to deflect and actually leave the road, making the car skip off track, the sensation can feel similar but its a very different thing and usually more abrupt like freeway expansion joints and potholes etc, the suspension may have only moved a fraction, not enough to cause any geometry changes. Don't start throwing money at something until you can properly diagnose what your experiencing.
12-30-2013, 07:35 AM
#4
Thread Starter
That sounds like a case of bump steer, which is a common problem in our cars. Idk why it would start happening with wider tires though. Maybe because you're pushing it harder than when you had the 225's?
Anyway, you can solve this problem with adjustable toe arms in the rear aka an anti-bumpsteer kit. I know that megan racing and J's Racing sell them, but there are probably other companies out there that make them too.
Anyway, you can solve this problem with adjustable toe arms in the rear aka an anti-bumpsteer kit. I know that megan racing and J's Racing sell them, but there are probably other companies out there that make them too.
Are you running adjustable coilovers? Check your tire pressure and make sure its consistent with where you ran the 225. Sidewall construction and air pressure can make a noticeable difference in how the car behaves over irregularities in the road. This doesn't sound like a case of bump steer, it sound like simple tire deflection. Stiffer sidewall or higher air pressure can pronounce this effect. Actual bump steer is when the suspension moves through the stroke far enough that the actual wheel geometry changes, causing the car to exhibit unpredictable behavior. The typical is more what your likely experiencing, when you hit a sharp bump and it causes the tire to deflect and actually leave the road, making the car skip off track, the sensation can feel similar but its a very different thing and usually more abrupt like freeway expansion joints and potholes etc, the suspension may have only moved a fraction, not enough to cause any geometry changes. Don't start throwing money at something until you can properly diagnose what your experiencing.
However, it does feel like something is off, almost as if the subframe is moving around in the rear...hmmm
12-30-2013, 08:02 AM
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No coil overs, just simple Spoon springs on OEM dampers. The tires are Hankook RS3's which do have a stiffer sidewall than the previous DZ101's which may be, as you stated, the contributing factor. Currently thinking about switching to a more all season (live in the PNW) and 245. If I do end up doing this I'll report back with the changes.
However, it does feel like something is off, almost as if the subframe is moving around in the rear...hmmm
However, it does feel like something is off, almost as if the subframe is moving around in the rear...hmmm
12-30-2013, 08:58 AM
#6
Thread Starter
Assuming this thread Loose bolts. The symptoms described by others sound very similar.
No one mentioned this, but wouldn't it be better to tighten on an alignment rack if they are indeed loose?
No one mentioned this, but wouldn't it be better to tighten on an alignment rack if they are indeed loose?
12-30-2013, 08:58 AM
#7
Site Moderator
So you just put larger tires on the AP1 wheels? It could be that the wider tire is to wide and thus the sidewall is now softer due to this. Also are you sure the rs3's have a stiffer sidewall because I thought I had heard the opposite.
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12-30-2013, 09:08 AM
#8
Thread Starter
Sorry, should clarify, 17x8 and 17x9, 45 offset all around...
12-30-2013, 09:12 AM
#9
Site Moderator
Ah ok. I really seem to remember someone saying the RS3's had a softer sidewall but I am not sure how accurate that is but if it is true it could be the cause. I have stayed away from those tires as the amount of rain we get here is WA makes them the most dangerous to attempt to run regularly here.
12-30-2013, 09:55 AM
#10
Ah ok. I really seem to remember someone saying the RS3's had a softer sidewall but I am not sure how accurate that is but if it is true it could be the cause. I have stayed away from those tires as the amount of rain we get here is WA makes them the most dangerous to attempt to run regularly here.