# 18 inch + 225/40/18 = BUMPY RIDE. How do I fix?



## ador (Jun 12, 2001)

I have a 2003 GTI that have sport suspension (w/c I heard is stiffer than the regular suspension). I just purchased a set of 18 inch wheels with 225/40/18 tires. After installing them, I noticed that the ride changed drastically. I can feel the bumps on the road. The over all feeling is that it is bumpy. Is there a way to fix this? If so, do I change the springs? If I have to, I may as well buy something that will lower the car by at least 1 1/2 inch. Any suggestion? (Brand and Model Number). How much will they cost?


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## U n i o n 0015 (Sep 10, 2000)

*Re: 18 inch + 225/40/18 = BUMPY RIDE. How do I fix? (ador)*

If you're on stock shocks, you'll want to change them. I've found that is the worst part of the "sport suspension" on VWs. A set of Konis or Bilsteins will have much better rebound control than the stock ones, so that would probably help with the bumpiness. Either way, you're going to feel more of the road coming through with 18s.


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## ador (Jun 12, 2001)

*Re: 18 inch + 225/40/18 = BUMPY RIDE. How do I fix? (U n i o n 0015)*

Do I just change the springs or the entire suspension? I'm not that familiar with suspensions. Thanks. quote:[HR][/HR]If you're on stock shocks, you'll want to change them. I've found that is the worst part of the "sport suspension" on VWs. A set of Konis or Bilsteins will have much better rebound control than the stock ones, so that would probably help with the bumpiness. Either way, you're going to feel more of the road coming through with 18s.[HR][/HR]​


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## ajchenmph (Aug 20, 2001)

*Re: 18 inch + 225/40/18 = BUMPY RIDE. How do I fix? (ador)*

Your suspension is comprised of mainly three components: springs, shocks (aka "dampers), and the control arms. Most of the time, the springs and the shocks are the parts that you swap out.
You need to be more specfic: "bumpy ride" = ? Does the car bounce all over the place (i.e., you hit a bump and it jars your teeth loose, and the car starts moving all over the road)? Or you hit a bump and the thing wallows up and down for a mile after the bump? I'm assuming it's the first case -- a simple thing to try is simply LOWER the tire pressure until the cold pressure is on the low end of normal/acceptable (say, in the low 30's or high 20's). Failing that, you can try changing out the shocks to something a bit more compliant. As s/he said above, you do end up with more road feel and noise on 18's than on stock tires/rims, you can't avoid that...


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## f1forkvr6 (Jun 10, 2002)

*Re: 18 inch + 225/40/18 = BUMPY RIDE. How do I fix? (ador)*

You're stock suspension wasn't designed to handle the weight of 18" wheels and tires. That combination can add quite a bit of unsprung weight for your springs and shocks to control - this can make the ride rough, and cause a reduction in handling capabilities. If you wanna go big, you really should upgrade your suspension to handle the additional mass ... or you can just accept the consequenses as a trade-off for "looking cool".


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## ador (Jun 12, 2001)

*Re: 18 inch + 225/40/18 = BUMPY RIDE. How do I fix? (ajchenmph)*

I guess I just need to get use to the ride of having 225/40/18 tires. When I'm on the freeway and I run over some small potholes or even if I'm driving on an "uneven" freeeway, I feel a hard "bump" each time. The car is not going sideways or anything like that. It's just that I feel my head being shaken each time I go over small potholes or road bumps. I will try to lessen the air and see if it makes a difference. Thanks for the advise. quote:[HR][/HR]Your suspension is comprised of mainly three components: springs, shocks (aka "dampers), and the control arms. Most of the time, the springs and the shocks are the parts that you swap out.
You need to be more specfic: "bumpy ride" = ? Does the car bounce all over the place (i.e., you hit a bump and it jars your teeth loose, and the car starts moving all over the road)? Or you hit a bump and the thing wallows up and down for a mile after the bump? I'm assuming it's the first case -- a simple thing to try is simply LOWER the tire pressure until the cold pressure is on the low end of normal/acceptable (say, in the low 30's or high 20's). Failing that, you can try changing out the shocks to something a bit more compliant. As s/he said above, you do end up with more road feel and noise on 18's than on stock tires/rims, you can't avoid that...[HR][/HR]​


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## f1forkvr6 (Jun 10, 2002)

*Re: 18 inch + 225/40/18 = BUMPY RIDE. How do I fix? (ador)*

quote:[HR][/HR]I will try to lessen the air and see if it makes a difference. Thanks for the advise.[HR][/HR]​Careful ... your sidewalls are pretty short at this point. Make sure you don't go too soft or you'll bend a wheel if you hit a good size bump.
*edit for spelling


[Modified by f1forkvr6, 1:52 PM 3-6-2003]


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## ador (Jun 12, 2001)

*Re: 18 inch + 225/40/18 = BUMPY RIDE. How do I fix? (f1forkvr6)*

The wheels that I got is much lighter than the stock ones. I bought the CenterLine which are 15lbs a piece. The stock Lon Beach weighs 22lbs. I would think that the additional rubber for the 225/40/18 tires will just make the weight almost the same as the stock. But you are absolutely right. I just have to take the consequences of looking "cool". But if there is a way for me to make the ride the same as the stock, then I would rather have the same feeling and look cool. Thanks for the info.


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## ador (Jun 12, 2001)

*Re: 18 inch + 225/40/18 = BUMPY RIDE. How do I fix? (f1forkvr6)*

Any advise on the highest and lowest air pressure for the 225/40/18 tires?







quote:[HR][/HR]I will try to lessen the air and see if it makes a difference. Thanks for the advise.
Careful ... your sidewalls are pretty short at this point. Make sure you don't go too soft or you'll bend a wheel if you hit a good size bump.
*edit for spelling

[Modified by f1forkvr6, 1:52 PM 3-6-2003][HR][/HR]​


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## f1forkvr6 (Jun 10, 2002)

*Re: 18 inch + 225/40/18 = BUMPY RIDE. How do I fix? (ador)*

No experience with 18s (just not my thing), but personally, I would go no lower than the 1/2 load pressures recommended by VW, and probably a couple of pounds higher than that. You have a much shorter sidewall now - your ride will be harsher ... there is no changing that fact.


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## a2lowvw (Dec 17, 2000)

*Re: 18 inch + 225/40/18 = BUMPY RIDE. How do I fix? (f1forkvr6)*

i run 32 psi in mine 225/40-18 at 35 psi i was getting a hint of wear in the middle of the tire after dropping it down the wear hasn't gotten any worse


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## mdeleo3 (Jan 29, 2001)

*Re: 18 inch + 225/40/18 = BUMPY RIDE. How do I fix? (ador)*

Hmm I'm going from the BBS RXII's (I think at 24lbs) to the 18" BBS CH (I think at 30lbs). The model car I drive is a Jetta WE w/sport suspension. Do you think that will hold me off okay until I upgrade the suspension? I'm not sure if this weight difference is really all that bad? Any ideas?


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## Marty (Jul 14, 2000)

*Re: 18 inch + 225/40/18 = BUMPY RIDE. How do I fix? (ador)*

Your bumpy ride is from your tiny sidewalls. Live with it if you want the "look."


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## mdeleo3 (Jan 29, 2001)

*Re: 18 inch + 225/40/18 = BUMPY RIDE. How do I fix? (Marty)*

Do you think getting 18", (the BBS CH about 30lb) would be okay temporarily with the vw stock Sport Suspension that is on the 01 WE jettas?
Mike


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## f1forkvr6 (Jun 10, 2002)

*Re: 18 inch + 225/40/18 = BUMPY RIDE. How do I fix? (mdeleo3)*

quote:[HR][/HR]Hmm I'm going from the BBS RXII's (I think at 24lbs)[HR][/HR]​If you were really running those pressures .... man, pretty brainless.








That is at least 25% underinflated














... remember all those Ford "Exploder" rollovers? That was due mostly to underinflated tires ... not to mention at that pressure handling pretty much sucks a$$.


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## mdeleo3 (Jan 29, 2001)

*Re: 18 inch + 225/40/18 = BUMPY RIDE. How do I fix? (f1forkvr6)*

quote:[HR][/HR]Hmm I'm going from the BBS RXII's (I think at 24lbs)
If you were really running those pressures .... man, pretty brainless.








That is at least 25% underinflated














... remember all those Ford "Exploder" rollovers? That was due mostly to underinflated tires ... not to mention at that pressure handling pretty much sucks a$$.[HR][/HR]​No no no!!! I meant each wheel weighs about 24lbs not the air pressure. That's what my question was.. If the VW sport suspension can handle the 18" BBS CH's which weigh about 30lbs / wheel without rubber.


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## f1forkvr6 (Jun 10, 2002)

*Re: 18 inch + 225/40/18 = BUMPY RIDE. How do I fix? (mdeleo3)*

Oh -- cool ...








30# seems pretty heavy ... add another 22-25 # for tires, and you are asking a stock suspension (yes the "sport" suspension isn't much beefier than the non-sport version) to handle quite a bit of unsprung weight.
Will they fall off your car? Nope ... but handling, acceleration, and braking performance will all take a hit.


[Modified by f1forkvr6, 9:38 AM 3-8-2003]


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## mdeleo3 (Jan 29, 2001)

*Re: 18 inch + 225/40/18 = BUMPY RIDE. How do I fix? (f1forkvr6)*

So that 6 lb difference/wheel (compared to the BBS RXII 16" now) and difference in weight / tire really will make that big of a difference in handling, acceleration, and braking?
If I were to upgrade my suspension, would I simply need to upgrade the shocks and springs to "get back in the game"?


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## f1forkvr6 (Jun 10, 2002)

*Re: 18 inch + 225/40/18 = BUMPY RIDE. How do I fix? (mdeleo3)*

quote:[HR][/HR]So that 6 lb difference/wheel (compared to the BBS RXII 16" now) and difference in weight / tire really will make that big of a difference in handling, acceleration, and braking?[HR][/HR]​Yes -- a BIG difference.
quote:[HR][/HR]If I were to upgrade my suspension, would I simply need to upgrade the shocks and springs to "get back in the game"?[HR][/HR]​That's exactly what you'd need to do. Stiffer springs & shocks would help handling. Unfortunately, there is nothing you can do to overcome the degredation in acceleration and braking ... just one of the trade-offs for going big.


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## ubercrap (Feb 18, 2003)

*Re: 18 inch + 225/40/18 = BUMPY RIDE. How do I fix? (f1forkvr6)*

Yes, any change in unsprung weight makes a big difference!


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## Sheep (Dec 21, 2000)

*Re: 18 inch + 225/40/18 = BUMPY RIDE. How do I fix? (ubercrap)*

I'd never install a wheel that weighed over 23lb...mine are under that. I also have to keep 40-42psi in my RE730's (rated at max of 51psi) on 8" wide wheel or the it wears outside edges too fast. When you go an aftermarket tire which differs significantly from OEM tires and wheels in size, speed rating, etc you must go by the tire manufacturer's recommendations, not what's in your manual. If you run a z-rated 40 aspect ratio tire with too low a pressure, you'll get poor wear patterns, hotter running tire which is more prone to failure, poor handling and high rate of wheel damage on potholes etc since the sidewall will compress too much to keep wheel's edge off the sharp part of hole.
My car had the optional sport susp pkg new and it stunk compared to the present setup....especially the dampers/shocks. The only "bumps" which are a nuisance I experience are pronounced road dividers with these tires/wheels and there is no way around it with tires requiring higher pressures. I am considering 235's next but not really for sake of reducing road noise. Incidentally, several tire specialty stores/Tirerack say 40psi on a Mk4 is about right on a Z-rated tire of 51psi max.


[Modified by Sheep, 11:20 AM 3-10-2003]


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