How will having 30+ offset rims on an integra affect handling charactristics? Ive been searching all over and it just talked about wheel bearing and spongier suspension feel. There is no info on understeer, oversteer, stability, during a corner at the limit of the vehicle. How will having an lsd vs. open diff affect it? The 30+ offset i have sits like 10mm outside my fender and it makes me worry if i were to track with them.

 

1) Offset without width is rather meaningless I have 16x7 +32 wheels on my Integra, and they don't even come close to the fenders, much less poke out.
2) I'd worry about about changes to the scrub radius and ackerman than the fact that they stick out affecting handling.
3) We do have a dedicated Wheel and Tire forum for questions regarding wheels and fitment.

 

Wow...Im learning alot goes into building a track car.

Anyway, through my light research, am I correct in understanding this can be corrected with an alignment?

 

hmm good point. here is the info

kosei K4R 15x7 30+ on toyo proxes R1R 195/50/15R
the car is an 2000 integra LS 2dr. no alternations to fenders, don't plan on it either
suspension mods are KYB AGX on eibach prokit
here a pic



i posted in this forum versus the wheel/tire forum because my main concern was in regards to cornering and handling characteristics of the car at the limit of the car especially on the track. I understand why you would suggest the wheel/tire forum but i know there are more people who have wheel/tire questions to confirm clearance for cosmetic purposes more than performance. I just thought I would get better response in this forum. I also extended a similar thread in the integra forum because my concern as far as I know is relevant to a DC2 chassis only. I am unsure if the civic has the same geometry.

I am also familiar with scrub radius and thus will indirectly affect performance as well. I worded my concern vaguely as opposed to something specific like how it would affect "scrub radius" because I wanted to have a more open discussion to encompass everything that can be affect with having a less positive offset.

Thanks for your reply, you have helped reassure me that 15x7 should fit fine and not rub all over the place. however, i guess i still have yet to know how it will affect handling between a 30+ and a 45+ when the car is pushed [bold]at the limits[/bold] where weight transfer, traction is vital (like on the track)

for the below discussion, normal= 45+ OEM offset:
i guess the thing with scrub radius and lower than normal offset is that the car will probably increase cornering sensitivity? because the outer wheel will pivot forward more than normal while the inner wheel will pivot backward more than normal. on the contrary, it also means the outer wheel needs to travel an EVEN LONGER path than the inner wheel. since the speed/torque of both wheels are unchanged because it is determined by the differential, it means the car will tend to understeer more than normal because the outer wheel now needs to travel a longer path while travelling at the same unchanged speed. at the same time, if the rear wheels are also lower offset than normal, the rear will have more grip due to a wider stance and won't want to oversteer as much. ultimately, you will gain a good amount of understeer with running a lower offset setup?

please correct me if i am wrong.


scrub radius has to do with the angle of your shock tower and the center contact patch of your wheel. when you draw along the long axis of your shock tower and extend it down/outward, it should intersect the floor somewhere, but it can meet the floor on the inside of center contact patch of the outside. our double wish bone suspension usually has a positive scrub radius which will put more leverage stress on the suspension components when the wheel is spaced outward versus the same setup on a suspension design with a negative scrub radius.

in theory, you can change the scrub radius if you can mount the top part of the shock tower either more towards the side or towards the center of the car. moving them out will give you a more positive and moving them in will give you more negative. however, i don't think anyone makes a kit and even if that was possible, there really isn't a lot of room for you to do so without suspension components rubbing on each other during load. Also because the knuckle is outward from the shock tower, even if you can change the angle, it doesn't change geometry outward from the knuckle (can't use wider wheels).

 

Neither of those can be corrected with an alignment.

 

thanks for the clarification guys. so basically stick with +45 offset to match the stock wheels and adjust handling with suspension and alignment?

also...im guessing 15x8 w/225 tires would mess up the scrub radius and ackerman as well?

 

It depends on what you are doing with the car? Some things will out way others.

I have to run a wide wheel for grip and a low offset to clear the inner fender and suspension. I for one would never go back to anything less than an 8 if for auto x or track...

 

The center of the contact patch being moved further out than stock is what changes the scrub radius.

That said, and to provide a bit more information than I did before, I haven't observed any issues with by 16x7 +32 wheels with 205/45-16 or 205/40-16 tires during auto-x use. Playing with camber and toe settings has done much more than wheel offset to change the handling of the car.

I also don't understand why your tires stick out so far past the fenders. Mine tuck without any rubbing issues on un-rolled fenders without additional negative camber added.