who has tracked w/ 225/45 15s?...

[JRKOUPE]

15x8 kosei w/ 225/45 ra1 here. m20- 3.73
Didnt feel like i ran out of revs at all, but redline was pushed past stock.
Car was predictable with that setup, could toss it wherever i wanted with no worries.

15 x 8 koseis.....now that is a rare species.....congrats

what spring/shock set up?

[JRKOUPE]

225/45

great responses/info......thanks.

running an 8 or 9 on the 225/45 is the way Id like to go.......

I had a lead on some lightly used closeouts at this size and thats why I posted the question.

now thats its friggin snowing in NY!!!!!!!!!....it seems like track season is years away.

BTW...PSA!!!!!!!!

if any1 ever wants barely used r tires like RA's or even Kumho v710s and HoHo r6's?....always ask/pm/e me?.......I get great deals usually.

u guyz rock

[Jonny Cash]

15x8 kosei w/ 225/45 ra1 here. m20- 3.73
Didnt feel like i ran out of revs at all, but redline was pushed past stock.
Car was predictable with that setup, could toss it wherever i wanted with no worries.

[bmwguy325is]

:stupid:

I run my 225/45 rs3s on 15x8s

AN 8.5 or 9 would be great too.

[Balleristic31]

I run my 225/45 rs3s on 15x8s

[Emre]

You guys running the 225/45/15 on 7's or 8's?
I'm thinking about getting R888s in this size.

Most of us run 15x7" wheels just because they're more common. But 15x8" would be ideal for those tires.

[Fusion]

You guys running the 225/45/15 on 7's or 8's?
I'm thinking about getting R888s in this size.

[Skafrog]

I just ran back to back days at the track, one running 225/45/15 NT01's and 205/50/14's. The 225/45/15's feel much much crisper at turn in, and do not not have the same amount of slip angle. If the 205's weren't free, I would have gone right back to 225/45/15s. Cant beat the shorter sidewall and larger contact patch.

[Wanganstyle]

Does decreasing the overall wheel/tire diameter have the same affect as a shorter differential ratio or a shorter gear ratios in the transmission?

Is it better to increase your gear ratio through the transmission choice, differential choice, or wheel/tire diameter choice?

I'm guessing the only difference is more stress on the parts in the transmission or differential if it's a shorter ratio.. I'm just wondering terms of performance though, not considering how hard it is to find a certain ratio differential or use a different transmission (ZF vs getrag) or have an inaccurate speedo.

if a full rally support shop was at your disposal, you would pick best handling wheels/tire for weight/fit for the chassis, and gear the individual gears 1/2/3/4/5/6 and final drive to be perfect for the course. BMW went to a close ratio with 1:1 final in the ZF style gearboxes to be more efficient, cut down driveline losses.

Larger tires usually allow for larger area of tire (if you cut and laid flat a 18" 245/40 it would be more total area of rubber than a 245/40/17). usually the more tire mass helps with heat, but this can be accounted for be higher temp rating/higher grip tire.

differential does not really care about tire size or abuse as long as its not over its working zone. if you are breaking the ring and pinion on power its another story.

Overheating the stock LSD in stock config(i.e.going to a drift day) will make the unit = open diff quickly, I did this in my e36m.... oops :P

[Emre]

I've got a stock M20B25 in my E30 track toy. I run a medium-case 4.10:1 LSD and 225/45-R15 tires. Between the smaller tire diameter and the shorter rear-end ratio, the overall gearing is noticably shorter compared to stock.

On the highway, it sucks. But on the track, it really helps with acceleration out of the corners. The car really pulls hard in 4th gear. At Tremblant, Mosport, and Watkins Glen, my gearing is perfect: I'm well into 5th at the end of the main straights and the gearing is spot-on for all the major corners.

[VinniE30]

Does decreasing the overall wheel/tire diameter have the same affect as a shorter differential ratio or a shorter gear ratios in the transmission?

Is it better to increase your gear ratio through the transmission choice, differential choice, or wheel/tire diameter choice?

I'm guessing the only difference is more stress on the parts in the transmission or differential if it's a shorter ratio.. I'm just wondering terms of performance though, not considering how hard it is to find a certain ratio differential or use a different transmission (ZF vs getrag) or have an inaccurate speedo.

[Fooshe]

I just did a 3 hour enduro on 225/45/15 Nittto NTO1's and they were steller! I did the sprints on my 205/50/15 spec tires (toyo RA1's) and I will say this, Spec E30 really should embrace using this tire size. MUCH better tire for this car's track set up.

[Wh33lhop]

Im wondering if it was obvious that the tire is a wee bit short?..did you run out of revs often and go to the next gear?...



Im used to 225/50s....but am considering 225/45s..

tia


Jrk

This is an easy calculation to perform if you remember where you're at at the end of most straightaways (although obviously you are not staring down at the tach when you reach your braking point :p).

I run 225/45r15s, there is very little sidewall flex. I run a 3.73 and my overall effective gearing is about halfway between a 3.73 and 4.10 with stock tires. So it is there, but not super noticeable.

[Jean]

I've done most of the season on 225/50 and last few events switched the rears to 225/45....I did that mostly because my 225/50 were done, and 225/45s were free.

[dude8383]

hey..pm sent..


about LRP....bring snow tires....ya never know.

EEK! If it snows my RS3's will be useless!!