Fitting 18" wheels with 35mm offset

[Zuk]

I am looking at getting some Racing Hart C5's (incredible deal!!), 18 inch 215/35 front and 225/35 rear but I am concerned about the low offset (he can't remember exactly but said between 35-38mm).

Has anyone had problems (rubbing, excessive wear on the joints, bearings etc) running big wheels with low offsets?

I know our cars (mine is a AWD 2g) come with higher offsets, so thats why I am asking.

Thanks for your replies, in advance.

Mike

 

[cait sith]

Any sort of bearing wear crap is when you start getting into the negative offset range, which if you're actually getting into on DSM's you're probably not too worried.

35 offset is NOT a low offset at all.

 

[jtmcinder]

I am looking at getting some Racing Hart C5's ... 18 inch 215/35 front and 225/35 rear but I am concerned about the low offset ....

You should be more concerned about the mis-match in tire diameter. (The offsets are fine for those widths of tire.)

- Jtoby

 

[Zuk]

Cait sith - Nice car. I took a quick look at your wheels, they seem to fit the car nicely. What is your offset? How far is the drop?

JTMcinder - Can you elaborate a little bit please? Most people I have talked to say the difference is negligible.

 

[c5chris]

+35mm offset will be ok BUT your wheels will tend to be more towards the outside and at the edge of your fenders, you might have to roll or trim it. Make sure your rear camber settings are RIGHT or else your negative camber will be more pronounced and will eat up your inner tires.

 

[Zuk]

C5 Chris - Is there any way to make sure my camber is set up correctly...what offset are your wheels?

 

[jtmcinder]

+35mm offset will be ok BUT your wheels will tend to be more towards the outside and at the edge of your fenders, you might have to roll or trim it. Make sure your rear camber settings are RIGHT or else your negative camber will be more pronounced and will eat up your inner tires.

Buzz! Camber and offset have zero to do with each other. Thanks for playing.

As to whether the difference between 225/35/18 and 215/35/18 is enough to trash a center VC, there is no definite answer. I would love for you to volunteer to be the test subject, but I can't in good conscience suggest it.

- Jtoby

 

[Zuk]

Buzz! Camber and offset have zero to do with each other. Thanks for playing.

As to whether the difference between 225/35/18 and 215/35/18 is enough to trash a center VC, there is no definite answer. I would love for you to volunteer to be the test subject, but I can't in good conscience suggest it.

- Jtoby

...I just called SBR and they said I couldn't go with any rubber over 50...so I should be good with 35's. He also said bad idea to put 215's on the front and 225's on the rear...so I guess I will be getting new rubber.

As per the offset they firgured it shouldn't be a problem.

I am glad to hear I won't have camber issues with the this offset....whewww.

 

[c5chris]

Buzz! Camber and offset have zero to do with each other. Thanks for playing.

As to whether the difference between 225/35/18 and 215/35/18 is enough to trash a center VC, there is no definite answer. I would love for you to volunteer to be the test subject, but I can't in good conscience suggest it.

- Jtoby

Are you sure about this? If the center of the wheel is away from the centerline and more towards the outside (as the case of a +35 offset), negative camber that setup and you have the inner contact patch of the wheel pressing harder to the ground.

If you have a +45 offset which has the centerline of the wheel biased toward the inner side, negative camber that and you have less tire wear on the medial side.

 

[wret]

You may be confusing your terminology when you “negative camber” this and that. Negative camber is the usual result of compressing the suspension, either under jounce or by shorter springs. It is not typically induced by changing wheel offset. A 10mm difference in wheel offset does not have quite enough leverage to do that.

 

[housegsx]

Without you giving us the width of the wheel it is hard to tell you a definite answer. I am assuming, as well as other I'm sure, that you are talking about a 7.5 inch width. On my car with a 7.5 inch width wheel, a tire size of 225/40/18, and a 38mm offset the rear fender lips just barely rub on the outside of the tire if I am cornering hard or hit a PA pothole. With everything being the same except for having a 35mm offset the fender lip would dig into my tire more. One thing I have to point out is that I had no rubbing until the camber kit was installed and pushed out the top of the tire slightly. With 215 instead of 225 you may be fine with a 35mm offset. Otherwise you may have to roll or cut the fender lip.

 

[Zuk]

You may be confusing your terminology when you “negative camber” this and that. Negative camber is the usual result of compressing the suspension, either under jounce or by shorter springs. It is not typically induced by changing wheel offset. A 10mm difference in wheel offset does not have quite enough leverage to do that.

Ok, but when I do decide to install shorter springs...does that mean I will run into camber problems?

 

[jtmcinder]

Yes, changing ride height can change camber, because we have non-zero bump-camber curves. But offset has nothing -- absolutely nothing -- to do with camber. Camber is the angle between the ground and the tire and this angle does not change when you switch tires or wheels.

- Jtoby

 

[snox135]

I have 18x7.5 with a 35 offset. I don't know my tire size right off hand(I think they are 235's). But since I installed the JIC's they do rub the front fenders on hard corners and bumbs even after having the fenders rolled.

I do know a guy who cut 5mm off of the inside of his rims with a Bridgeport to increase his offset to 40mm. I don't know how safe this is. But it's probably not a huge deal. I personally find it hard to believe they make a different rim for every different offset but they might.

 

[c5chris]

You may be confusing your terminology when you “negative camber” this and that. Negative camber is the usual result of compressing the suspension, either under jounce or by shorter springs. It is not typically induced by changing wheel offset. A 10mm difference in wheel offset does not have quite enough leverage to do that.

Let me get this straight. Im was not implying that a different offset will cause negative camber. NO. It is caused by lowering by over 1.5 inches.

I was saying that if you had the car lowered and has already too much negative camber, the +35 offset will cause more inner tire wear than if your car is +45 offset. Why? The wheel gets tilted more inward since the +35mm offset is closer to the centerline than the +43mm stock.

It is recommended to stay closer to stock offset. Your +35mm offset will work but make sure to fix your negative camber first. On that +35 offset, you can only go 225/40/18 since you will rub the fender.

 

[wret]

Let me get this straight. Im was not implying that a different offset will cause negative camber. NO. It is caused by lowering by over 1.5 inches.

1. You are not straight yet. Lowering 1.5 inches will increase negative camber by about 1°.
2. Zuk said nothing about lowering.

I was saying that if you had the car lowered and has already too much negative camber, the +35 offset will cause more inner tire wear than if your car is +45 offset. Why? The wheel gets tilted more inward since the +35mm offset is closer to the centerline than the +43mm stock.

1. You are still confusing offset and camber. Maybe you should avoid using them in the same sentence.
2. Camber, offset, or distance from the ceterline will not increase tire wear.

It is recommended to stay closer to stock offset. Your +35mm offset will work but make sure to fix your negative camber first. On that +35 offset, you can only go 225/40/18 since you will rub the fender.

1. Yes, it is recommended to stay close to stock offset. Below +35mm may increase bearing wear.
2. Maybe you know more about Zuk's suspension set up than the rest of us but a lowered suspension is not part of the equation (yet).
3. Fender rub can be an issue but not necessarily a limiting one.

 

[Zuk]

For the record, my suspension is STOCK. Naturally, I plan to lower it once I get the wheels, probably 1.5-1.75".

I guess I will try and get some 18" wheels closer to the stock offset, perhaps 40mm.

Thanks for all your comments.

 

[DOHCTA]

I need to bring this thread back to life.

I'm about to purchase a full set of 235/40/18's on my 7.5" wide rim with a 34mm offset. I hate tire shoping, but at the same time, need to learn more about our cars in terms of fitment and rubbing issues. And my car is riding on the Eibach Pro-Kit lowering it by 1.5 inches.

I realise there is a thread dedicated to a spreadsheet style explaination of "what wheels/tires fit my car" in the newbie forum but my SIZE isn't listed.

I got a great deal on the rims and I love the look and aggessive stance it gives the car, the current 215's are a little to narrow for my liking but I need to decide asap on whether or not I should go with 225's or 235's.

Help is appreciated.

DOHCTA

 

[jtmcinder]

Well, a 235/40/18 is about the same diameter as 215/50/17 and, at most, you'll only need to a little fender-lip rolling in the rear to run them on a +34-offset wheel. But that's a terrible set up for anything other than sitting still and looking pretty.

 

[ed1380]

it'll fit fine. This is 245-40-18 with a 36 offset.

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[DOHCTA]

that's a terrible set up for anything other than sitting still and looking pretty.

How is it a terrible set up if the stance of the car is wider? Woudldn't a wider stance promote better cornering and steering response? I don't just always 1/4 mile, I like lapping too, so I figured the wider, the better and I don't suspect I'll run into premature bearing wear or ball joint failure given it's only 34mm offset. I could be wrong in all of this, like I said, I'm no good with tires and wheels but give me a wrench and a block, I'll have it apart and back together in a day

it'll fit fine. This is 245-40-18 with a 36 offset.

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This is very helpful, I appreciate the picture aswell. Thank you!

 

[jtmcinder]

It's not terrible because of the offset. The offset is the one thing I agree with. But 18s on a car that doesn't need them because of the brakes is bad, and 235s when you can easily fit 245s or more is also sub-optimal.

 

[DOHCTA]

235's can't exceed a 7.5" wide rim....from what I've heard and read on line.

 

[ChunkyLover53]

235's can't exceed a 7.5" wide rim....from what I've heard and read on line.

Could you clarify this statement? Maybe I'm not interpreting it right, but I can think of a couple members running 235/40/18 on 18x8.5 +40mm wheels.

 

[ed1380]

245 tire is 10" wide. - 8.5" rim = 1.5" size difference
235 tire is 9.5" wide - 7.5" rim = 2" size difference

A 245 on a 7.5 will be just an extra half inch, but if you're getting a great deal on 235's go for it.