Topic: How crazy is changing wheel offset by 50mm?

In our quest for faster cornering in our crap FWD car, I found some 11" wide wheels we want to try.

Our stock 7" wheels have +41 offset/ET, getting the 11" to fit will require spacers to balance this out to about -10 offset / ET to avoid rubbing the suspension.

It's Lemons, so we are good for bending and cutting the fenders to avoid rub there.

My concern is from reading, common 'wisdom' is not to change from factory offsets by more than 5mm. Our system would change this to about 50mm.

I know there is additional stress on the wheel bearings, and some talk of lack of ability to 'feel the road' with much wider tires.

It's quite a commitment to get wheels, tires, hub adapters to make this all work - so I'd love to (at least think I can) get this right he first time.

Does anyone have experience with radically changing their wheel offsets they can share?

2 (edited by OnkelUdo 2021-09-16 06:00 PM)

Re: How crazy is changing wheel offset by 50mm?

I am not even going to comment on the offset, I am going to ask you search your soul to think about the forces you are adding to your FWD car by going up 57% or 36% depending on how you calculate it in effective contact patch with the ground.  Are anyt of the these going to suffer so greatly your time on track will suffer (hint, at least one, likely all):  Ball joints, front end bushings, tie rod ends, strut bearings, wheel bearings?

This is not a +1 or +2 change...this is a +4 or more increase if grip.  The damage you can do is immense.

3 (edited by majo 2021-09-16 06:34 PM)

Re: How crazy is changing wheel offset by 50mm?

Also, depending on the weight of the new tires, wheels, spacers, you may actually go slower. 

I love how fat tires look on race cars, so I say go for it -- who cares how much slower you'll be.  You will look cooler, and that's really what matters.

COM ( Chief Operating Moron ) of Burnt Rubber Soul Racing
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Re: How crazy is changing wheel offset by 50mm?

Don't do it.  Not based o0on anything but my gut.

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Re: How crazy is changing wheel offset by 50mm?

OnkelUdo wrote:

I am not even going to comment on the offset, I am going to ask you search your soul to think about the forces you are adding to your FWD car by going up 57% or 36% depending on how you calculate it in effective contact patch with the ground.  Are anyt of the these going to suffer so greatly your time on track will suffer (hint, at least one, likely all):  Ball joints, front end bushings, tie rod ends, strut bearings, wheel bearings?

This is not a +1 or +2 change...this is a +4 or more increase if grip.  The damage you can do is immense.

I'm by no means a veteran on the track, but I've seen enough FWD crapcans ripping up ball joints, half-shafts, and wheel bearings on a 205/50/15 to feel like I wouldn't want to add a whole bunch of tire than a stock-ish size under one.

That said, an 11" tire is immense and even if it doesn't rip up your suspension, it will completely change most things about your car. Maybe better, maybe worse—probably both in various ways—but you're going to spend at least one race weekend relearning the car's dynamics completely.

Edit to add: It's your car and Majo makes a very salient point about looking cool mattering as much as anything.

Eric Rood
Everything Bagel, 24 Hours of Lemons
eric@24hoursoflemons.com

6 (edited by derekste 2021-09-22 08:46 AM)

Re: How crazy is changing wheel offset by 50mm?

you will need a lot more than 50mm of spacer! you're adding 4 inches of wheel per side! also bear in mind that whatever wheel/tire you go with must be covered by a fender.

you didn't mention wheel diameter. what were you thinking as far as that goes? 15x11 tires aren't exactly easy to come by wink

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Re: How crazy is changing wheel offset by 50mm?

It’s a great idea for style points. It’s a really, really bad idea if you want to turn laps. You’ll destroy everything attached to the hub in short order.

Also what kind of problems are you having now? Turn in? Mid corner? Track out? Depending on where in the corner you are having problems the recommendations can change.

Share your setup. Geometry and suspension config. What are you running? What do the tires look like after a run?

I bet there is a much better solution to the problem than giant rubbers.

Re: How crazy is changing wheel offset by 50mm?

We did this, but not to the degree you are thinking. We went from 9 to 10s and 30mm offset from none.  It did alter the grip, ALOT. From 225-50/15 to 245-40s. I'm not sure what you are putting it on, but like the other guys said, really think about geometry and how much force you are adding. Be religious about wheel lug torque, and look around every pit. We were all ready to sent a guy out when we noticed a wheel with two lugs broke off. We had parts on hand, so he was out in 20 minutes.  No more problems in the remaing 10 or 12 hours. 
        It does look great,  and that is part of the fun. Being able to take advantage of all that grip , now that might be a challenge.  We were much better one year to the next with the wider track and tires, but there were other changes as well so the tires don't get all the credit.
Reminds me- i need to put up an add for the old tires and wheels  4x100 or 4×114.3  15x9s

Good luck

9 (edited by DelinquentRacer 2021-10-08 09:35 AM)

Re: How crazy is changing wheel offset by 50mm?

You'd be better served by moving weight off of the nose of the car to the rear.
Have you corner balanced your car?
Do you know how much weight is on the front tires?

Miatas handle great (so I've been told many, many, many times) on 205 width tires.
This is because they start with an effective design, and have very good weight distribution.
IM<HO this is what you should strive for.

http://www.tuneruniversity.com/blog/201 … e-matters/

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