Suspension Theory/Chat Thread

[Sirbelch]

for answer from the man that still knows more than me

[aki]

Originally Posted by Highrev1

EVEN if you were to run a 195 you want to go with as WIDE of a wheel as possible....I know, once I get my new wheels I am going to calclulate exactly the offset for the width that I will be running that will allow proper clearance...Probably 9" wheels....BUt I will also probabhly run 245's or more/up front....Now enough about me...Generally ou want to run the closest offset to stock as you can to fit what tires you can run without rubbing...THere is a formula..I don't recall it off hand but will sooner rather than later..

Regardless of wheel width, the ideal offset always stays the same. The only thing is, the wider you go the closer the wheels get to the suspension components, hence people going to lower offsets.

As for wheels going as wide as possible, are you talking about stretching the tires for wide tires/smaller tire width?

[Highrev1]

Originally Posted by aki

Regardless of wheel width, the ideal offset always stays the same. The only thing is, the wider you go the closer the wheels get to the suspension components, hence people going to lower offsets.

As for wheels going as wide as possible, are you talking about stretching the tires for wide tires/smaller tire width?

I said that "Generally ou want to run the closest offset to stock as you can to fit what tires you can run without rubbing." Just said it differently

The width of the wheel determines the width of the tire your able to run. In general its always better to have a wider wheel than a skinner one. This has been discussed alot on another forum and the general concensus is that a A heavy wide wheel will always be better than a light skinny one.

For Max performance, You want the smallest lighetstt wheel that will fit over your rotor, that is as wide as possible without rubbing the dampers or fenders, and that doesn't unduly stress the wheel bearings. Also the widest tires that you can get int her that doesn't rub under extreme cornering.

[Sirbelch]

Revy did tell me that he fit a 245 tire on a 7.5 in wide wheel (i think thats the stock width). So with a 9 in wheel, a 245 won't be to much of a stretch. I have read on CRSX that a guy ran 275 up front and 245 in the rear for auto x. We have simular cars but i think that the wheel well is bigger on the rsx. So if measured right, it could fit.

I had a tire rub on the suspension. When i first put my Flex's on, they were wayyyyyyyyy to low and the 235/40/17 on a 8 in wheel with a +45 off set rubbed the spring on the coilover. When i raised it, the rubbing went away.

[aki]

Originally Posted by Sirbelch

Revy did tell me that he fit a 245 tire on a 7.5 in wide wheel (i think thats the stock width). So with a 9 in wheel, a 245 won't be to much of a stretch. I have read on CRSX that a guy ran 275 up front and 245 in the rear for auto x. We have simular cars but i think that the wheel well is bigger on the rsx. So if measured right, it could fit.

Well the calculation is .85(tire diameter) for ideal wheel width. So for 245 width 8" would be best. If you plan on going 9" then that'd be for a 275 or 265 width tire. The more you deviate from the intended rim/tire width, the less optimal your tire wear will be.

For 9" and 265/35/17 you'd need a 35-ish offset.

My concern though was more with how much 10mm lower offsets exactly impact suspension geometry. You could always find creative ways of sticking gigantic tires under the fender. The question is whether the stability/traction benefits outweigh all the negatives.

[Highrev1]

jmercado567 does run a 275 up front with a pretty darn low offset...I would be concerned as to how long his wheel bearings will last...as he does track days and Autox..The rear arm is pretty intrusive on the rsx I haven't seen that as of yet on our cars but may come to find out it is also. I have experienced and seen a couple of instances where the rear wheels from hard cornering will flex enough to acutally rub the rear arm. Alothough when installed there was absoutly no indication of rub and there was clearance...could be bushing's but I even had it on my Full poly car so I doubt its bushings.

[Highrev1]

Originally Posted by aki

Well the calculation is .85(tire diameter) for ideal wheel width. So for 245 width 8" would be best. If you plan on going 9" then that'd be for a 275 or 265 width tire. The more you deviate from the intended rim/tire width, the less optimal your tire wear will be.

I am going to have to politly dissagree with some of this

I ordered R-Comps and my wheels from tire rack and they refused to put them on cause they weren't within spec....BAH...Somtimes you learn more with going outside of the calculation.
I ran a 245's up front on a stock width wheel...THese where R compunds so really they were problaby a street tires equlivalnt of a 265. I got them on there and had no rubbing and the car did MUCH better than when I was running the 225s all around. THen I started to run a staggered setup due to the regulations and ran 245's front and 205's rear this greatly increased rotation....Still not enought to best the mini's but allowed for a fun fast G-stock car.
There are rules and there are some that should be followed to the T and others that can be stretched slightly...Wheel to tire width sizing can be one of those stretchable rules...

[Sirbelch]

I had a little experiment that showed the value of proper suspension frequencies today. California roads are rougher than most dirt roads. I had my suspension set at full soft in the front and full stiff in the rear. On the rare smooth road, the car handled great. It had lots of stick and ok rotation. However, when the road got a little rough, the car just couldn’t stick. It would just bounce around all over the place and was really scary at *cough cough 125 cough*. So, I’m driving on the freeway today, and I realize that the back end of the car is, or feels like its coming off the ground. Sooooo, I thought back to the things that Revy taught me and came to the conclusion that I need to soften the rear end up to make for a better street car. So, before I got back on the road, I set the rear to full soft and took a couple of well known turns and one on ramp. Low and behold, the car handled better that it ever has on those roads. There was a little less rotation, but a lot more stick. It made the car a lot more fun to drive on the streets.

[aki]

Originally Posted by Highrev1

I ran a 245's up front on a stock width wheel...THese where R compunds so really they were problaby a street tires equlivalnt of a 265. I got them on there and had no rubbing and the car did MUCH better than when I was running the 225s all around.

Oh I'm sure the 245s handled better. My point when saying "the less optimal your tire wear will be" was that you get extra stress buildup with incorrect tire/rim width ratios. If the rim is a lot more narrow than the ideal spec, then it can cause stress that prematurely wears out the tires. Tires are designed to flex, but if the rim width is off then the tire flexes in weird areas that it wasn't designed to. In short 1-2 minute spurts of autocrossing this isn't much of an issue, but in the long run it will make an impact. I think that's why tracked Si's use at least 17x8 for 245 width tires.

[LucasBlack]

Originally Posted by Sirbelch

I had a little experiment that showed the value of proper suspension frequencies today. California roads are rougher than most dirt roads. I had my suspension set at full soft in the front and full stiff in the rear. On the rare smooth road, the car handled great. It had lots of stick and ok rotation. However, when the road got a little rough, the car just couldn’t stick. It would just bounce around all over the place and was really scary at *cough cough 125 cough*. So, I’m driving on the freeway today, and I realize that the back end of the car is, or feels like its coming off the ground. Sooooo, I thought back to the things that Revy taught me and came to the conclusion that I need to soften the rear end up to make for a better street car. So, before I got back on the road, I set the rear to full soft and took a couple of well known turns and one on ramp. Low and behold, the car handled better that it ever has on those roads. There was a little less rotation, but a lot more stick. It made the car a lot more fun to drive on the streets.

application at its best

[Sirbelch]

Yeah, this thread kicks ass.

[LucasBlack]

Originally Posted by Sirbelch

Yeah, that would be nice, but we would have to record the whole conversation and dictate it on to the forum so that everyone could learn from it. Plus the whole NJ TX CA location thing would be kinda hard to work out.

How do pushrod suspension work? Like the ones found in open wheel cars. I don't see how vertical movement can be dampened by something that is perpendicular to the rod and the movement of the rod.

geography was never a strong subject for me...i'm not seeing a problem.


pushrod suspensions are cool. the actuation of the dampers/springs works off the pushrod which is on a fulcrum setup with the actual direction of compression of the tire.

benefits: moves weight of damper/spring inward away from edges/corners of car, and also clears up space in the wheel well for wider tires or for more adjustability on selecting a preferred wheel offset/size/tire size and possibly allowing for more travel without threat of interference.

[Highrev1]

Why not try a conversion for your civic

We should setup like a MID-Ohio track day for all us FG guys...

[LucasBlack]

Originally Posted by Highrev1

Why not try a conversion for your civic

We should setup like a MID-Ohio track day for all us FG guys...

dang, FA not getting any love?

[Highrev1]

NO WAY!!!!!!!!! Why Bother

[LucasBlack]

Originally Posted by Highrev1

NO WAY!!!!!!!!! Why Bother

....then i guess i'm not invited. ya jerk

[Highrev1]

Don't feel bad Sirbelch or AKI aren't invited either, I don't want anyone who may acutally give me a hard time out on the track

NOT THAT THAT WOULD HAPPEN

[Highrev1]

I will look into somthing like this maybee we can get alot of Cars out to an event like this..

Teach you noobs about car control

I see Blueroadster!!!! He is DEF!!! NOT invited

[Sirbelch]

I would be looking and Revy's tail lights just like everyone else. I like to race, but I never said I was any good at it. I have a good G meter in my butt and a good processor in my head but my hands and feet aren't smooth or coordi