225 tires on an AE86

[BosoHachi]

I was just curious as to know how an AE86 would respond to 225/50r15 tires on 15x8 (-10ish offset) wheels. The car will be a daily but will also be autocrossed. I've searched on other forums but no straight answers, some people are saying that they are too big for an AE86 and will affect the performance negatively and apparently an AE86 is too light to even warm the tires up. I will be driving on roads which you could say aren't in the greatest condition but are still pretty decent. If the 225s are too much, should I just go with some 195/60r14s on a 14x7? Thanks!

[nohachi]

Which 225s? The answer to that question makes all the difference.

225-50 might rub the towers, 225-45 is a better match for both fit and gearing. The people talking about how light the AE86 is are talking out of their asses, go to any autoX and you'll notice why in about 10secs.

[BosoHachi]

I was thinking of going with the hankook ventus v12 evo k110 for summer and maybe the Falken ziex ze912 for all seasons. I'm open to suggestions for summer and all season tires if anyone has any!

[nohachi]

You won't be competitive on either of those tires, so it doesn't matter much. If the last few tenths of performance are not an issue, you would be better of with much cheaper and easier to fit 205-50's.

[SidekickChuck]

I am about to throw on some 225/45-16 on my ae86. I have 16x9+0 fronts and 16x10+0 with 20mm spacers all around, so the current 205/45 and 225/40 are too stretched IMO. I hope I like how the 225/45 tires sit and feel over the current configuration.

In the OPs case, with a 7 inch wheel, I would think the 195's would be a better choice over the 225.

[BosoHachi]

^Please let me know how that works out for you!

And if it helps, I will be running tires like 225/50r15 Toyo Proxes R888 when autocrossing. I just want some good feedback on how an 86 would react to them. I might end up just trying it for myself and then making a review thread for anyone else who may be making a similar build.

[gaijin_rokurunner]

If grip is what u want then u will get it but i suggest putting a panhard re enforcement rod on the rear if u run tires that fat as its going to put a lot more stress on that one panhard mount thats connected tot he frame when u corner hard...

[nohachi]

@ gaijin_rokurunner
Any pics of that panhardrod failure? I've never heard of or seen any panhard mount failures on rolla's. Sounds a lot like the myth being spread about rear-coilovers. Lots of people repeating claims, zero failures.

[MisterJerk]

My panhard mount was cracked and rewelded by one of the previous owners. it is unknown if they curbed it or what. though it is the first and only time i have actually seen it damaged. It could have been stress related, flexing in either direction or whatever, but i doubt it. When i rebuilt the rear end, the axles looked original and were the hardest to get out. 40 lbs of brake lathe weights on an axle puller is what it took to get them out.

[BosoHachi]

Thanks for the input fellas, definitely gonna have to look into that panhard reinforcement rod!

[fiveten]

I run 225/45/15 Toyo RA1s when I road race. For autox, I run 215/50/13 Victoracers. The 225's are great but doesn't make a big of a difference compared to 205/50/15 RA1s on a mildly modded AE86. I bet It would benefit me more if my car was more powerful.

[gaijin_rokurunner]

nohachi, its not the panhard that fails its the mount behind the rear tire that fatigues and cracks...can happen during drifting if u get some wheel hop, going offroad side ways or just the weight of the car pushing the rear on that mount...its not very sturdy for hard track use....Ive had about 12 ae86's and only 2 of mines have ever cracked ...one was my N2 flared track car the other i think it was cracked when i got it...anyhow heres a reenforcement bar on my current setup for those that want to see what it looks like

[HASport AE86]

@ gaijin_rokurunner
Any pics of that panhardrod failure? I've never heard of or seen any panhard mount failures on rolla's. Sounds a lot like the myth being spread about rear-coilovers. Lots of people repeating claims, zero failures.

Never seen any failures due to grip driving, but tons due to drifting. We make a brace similar to the one above that we sell. The rear strut mount failure I have seen. Mostly on rusted corollas. That mount was not designed as a load bearing surface. On a 2000lb corolla let's say 500lbs are on each corner, the springs hold the weight of the car. The stock location of the perch is a good 6"+ in diameter versus the 1" diameter of the strut mounting point. I trust 500lbs of weight spread over a 6" mount versus a 1" mount all day. I just dont see the benifit in running a coilover conversion in the rear vs a stock configuration. They are both doing the exact same thing, one just looks cooler i guess?

This weekend ran Streets of Willow with my friend, our cars are setup very similar:

Him
20v TE72 on 225/15 RS3's iirc
1:29.6 (Previously a 1:29 on 195 Azenis without cams)

Me
20v AE86 on 195/14 Azenis 615k
1:30.4

He was having a hard time heating the tires up. I would say the difference between 195 and 225 is about 1sec lap time. I think it's something you can easily make up with a change in driving or different brand of tires in the same size. I felt that the 195s were perfect for my car weight at 1850lbs. Tires heat up into the second lap and stay consistent until the end of the session. Much different from the old Azenis 615 that would grease up after about 7 laps. But like I said, unless you are making 200hp+, I think you can make better lap times by tweaking your driving style and tire brand than going increasingly wider on tires. I dropped 5.1 secs off my lap time just by changing my shifting points and braking spots.

FRS/AE86 Challenge times this weekend:
Robispec Supercharged FRS 1:27.4 (235 Hoosier Slicks)
Random dude stock class FRS 1:28.8 (235 Hankook)
Friends TE72 20v 1:29.6 (225 RS3)
Random dude FRS 1:29.8? (225 idk)
Me AE86 20v 1:30.4 (195 Azenis)

[Mr.Fujiwara]

why would you even want 225 on an 86 that isnt N1 tunned??

Just curious

[fiveten]

why would you even want 225 on an 86 that isnt N1 tunned??

Just curious

It was free for me. If I were to buy a set of tires, I would have bought 205/50/15s.

[Mr.Fujiwara]

why would you even want 225 on an 86 that isnt N1 tunned??

Just curious

It was free for me. If I were to buy a set of tires, I would have bought 205/50/15s.

yeah thats the biggest i would personally go
ive driven an 86 with 225 and it doesent feel natural
it doesent allow the traction loss that i use in cornering
not talking about drifting just grip driving

[gaijin_rokurunner]

i will be using 225s in the back and 205 on the front of my setup for the track but if youve seen my post in the build log section you will know my engine is not an average setup...and thats the smallest tire i can fit on a 11.5j rim

[nohachi]

The rear strut mount failure I have seen. Mostly on rusted corollas. That mount was not designed as a load bearing surface. On a 2000lb corolla let's say 500lbs are on each corner, the springs hold the weight of the car. The stock location of the perch is a good 6"+ in diameter versus the 1" diameter of the strut mounting point. I trust 500lbs of weight spread over a 6" mount versus a 1" mount all day.

The corner weight load of the car is nothing compared to the dynamic loads the suspension sees. And those loads are generated mostly by the shocks. The springs simply store and release energy, the energy is dissipated in the shocks.
Now take a look at some shock dynos to see which forces are generated. Tokico HTS go to 900lbs no problemo. What's worse is that they generate those forces over impacts, so you should multiply that by a dynamic load factor (2 or 3).
The shocks work against the springs to control their movement. The forces generated by both are always opposing. In a coilover the load paths of those forces are short and direct. With externally mounted springs, you have to add whatever the springs are generating at the time to the load on the shock tower. The forces are BIGGER with external springs! AKA coilovers are fine. Not a must have, but any failures occurring with them would have happened on normal cars too.

People that can't slide a car around on 225 tires need to go faster Grippy/peaky tires are more difficult to drive though. The problem with AE86s is that everyone mounts very low offset rims, so the tires are hanging out there in the air stream creating lotsa aero drag. I could see that being a factor on a stock powered AE86. 205 tires on the highest ET rim you can get away with would work best in that situation.

The panhard rod reinforcement I'm still not sure off. No-one that has any pics of failures (genuine interest). I'd rather not add weight there. a tiny reinforcement plate right where the problem occurs would be better, but need pics to see where they fail.

[gaijin_rokurunner]

Heres a posting of a failed panhard mount although mines didnt fold like this it cracked along the seam where it was connected to the body...u can re-weld them but the metal is pretty thin so adding metal would probably be best..then again the reenforcement bar probably weighs the same or maybe a little more and is the difference between taking everything off, prepping and welding or bolting the support on...convenience always wins over labor especially when the average guy on this forum probably doesn't own a welder..

http://forums.club4ag.com/zerothread?id=16622&page=3

[4agshoob]

only thing i can contribute here, is when i bought my celica supra wheels for my current 87' gts, they had 225-60-14's cooper cobra radials on them. the car handled like absolute ass..... period. way too much tire for the car. electric fan, and de-power steering/no a/c, cone filter adapter, other wise stock.

on the other note of the panhard bar mount......ive had 6 ae86, all drifted hard, including the last one there in my sig, up to 90 mph entry speeds, and never, ever had i ever bent, broke, cracked, etc. a panhard mount. but in that defence , all of my ae86's have been rust free cars from TN, GA, and FL.

[HASport AE86]

In a coilover the load paths of those forces are short and direct. With externally mounted springs, you have to add whatever the springs are generating at the time to the load on the shock tower. The forces are BIGGER with external springs! AKA coilovers are fine. Not a must have, but any failures occurring with them would have happened on normal cars too.

How do you figure a 500lb spring on a perch will generate more stress than a 500lb coilover sitting on the diameter of a dollar coin? A MacPherson strut applies no load to a chassis' mounting points but a conventional setup does? Even if you look at other coilovers, they sit on a tophat/camber plate to disperse the load over a large area. On a normal car, like a civic, coilovers are fine because the car is a MacPherson strut design to start (or like the front shock tower of the AE86). Those shock towers are designed for that setup, the towers are thick. If the corolla was meant to be coilover in the rear they would have made it that way. I'm talking about the strength of the mounting surfaces. Its the same reasoning behind snow shoes. 500lbs spread over a greater distance means less stress in PSI on the chassis. It makes more sense to spread out a load over a greater area than an area 1/7 the size of that originally designed.

Do coilovers work in the rear? Yes.
Would I feel good running them? About as at ease as shaking hands at an Adult Entertainment Convention.

[nohachi]

Did you read any of the above? The static 500lbs load is peanuts.

Edit: sorry if that comes over as harsh. English isn't my mother tongue and explaining engineering stuff in simple terms can be difficult for me. I'm an engineer and I did the calcs since the Trueno I bought ages ago came with a fresh set of T3 coilovers. You need look at the peak loads as those are the critical case and static loads are in no way part of that critical load case.
I'm not arguing for or against coilovers since I could care less. But from the calcs they seem a little bit better at everything. Lower forces and stresses (except when the car is standing still), wider spring base, better ratio between spring rates in roll and two wheel bump etc. So there is no substantial reason for me to go back to the stock setup.

@gaijin: Thanks for the pic. Weird. It almost looks as if the mount was hit hard from underneath or the front.

[HASport AE86]

....No, this NEVER happens.....I mean....peanuts and all...

[HASport AE86]

[Deuce Cam]

[nohachi]

It happens, but that's the case both with and without coilovers.
Come on, you come with this whole theory about stress concentrated in one point and then show a pic where the whole wheel well is ripped out? The shock tower is fine in that pic, and it was a BIG hit that ripped that **** apart. That hit would not have been less with external springs.
Deuce cam's pic looks closer to what you would expect, if that was a set of coilovers. Have any more?

[Deuce Cam]

To be fair the pics hasport posted show a lot of corrosion which likely further weakened those areas, still...

The pic above is a coilover. (The alignment collar and spring top hat can bee seen peaking through the hole.) I've seen at least one other example of the shock tower failing like above, but I couldn't find any other pics after doing a quick search. I've never seen or heard of anyone blowing out the rear shock tower without coilovers (I'm not saying it's never happened). Not only is the oem rear spring seat spread over a larger area than the shock tower, but there's a lot of reinforcement around the spring seat and almost none on the shock tower.

It's probably an uncommon failure, but still a risk (ymmv). I personally wouldn't feel comfortable using rear coilovers without reinforcing the tower and tying a roll cage into it.