Streching Tires... The truth behind them?

[iownju]

Well, my dad and i have been having this argument about tires and what streaching or putting a smaller tire on a larger rim actually does. Now my dad when he was my age worked at good year, but that was a long time ago and tires have changed. But he knows more about tires than i do so...

Anyway, i was curious what are the Pros and Cons of streching your tire. Ive heard that hey give you better grip, but ive also heard that its more for show and a lot more stuff. Also what application are they better suited for: drifting, track racing, street, track? And how far can you go on streching? I know that there not streching the tire its self, just pulling it to fit. But i was just curious about it. I tried searching and didnt really come up with anything that explained it.

So thanks for any info.

[Ris4drift]

basically it eliminates sidewall flex by stretching it to where theres no room for the tire to move.


but in all honesty, if i can stretch a 245 on a rim designed for a 275, id run the 275. people would be amazed about this thing you can adjust called "air pressure" to reduce sidewall flex.

imo its more a style thing. although you can fit some crazy rims on cars and it does look cool, and it is kinda funny to run 195's on a 15 inch wide rim (i know thats stretching the truth but you get my point)

it also kinda comes in handy if you have wide rims and get used tires, you can put a lot of sizes on wide rims.

also fwiw. every car that won FD this year didnt stretch the tires, but then again they had pushrods too :P

[SidewaysGts]

And whats wrong with push rods

[Dead Roman]

for real, they are less outdated than the overhead cam!

[Velvet]

Hmmm, I've been wondering about this for a while too. So I have three questions:
1. Whats the Japanese name for tire streaching?
2. Can someone show me what this looks like?
3. Are rims more prone to damaging with the road when using this technique?
Thanks.

[SidewaysGts]

STRETCHING PEOPLE! ITS STRETCHING! I thought this thread was "Screeching" at first.. oi anyways.

It looks like a normal tire except the sidewalls are thinner, ever see a low profile tire? kinda like that.

[BooZTT]

Originally posted by Velvet
Hmmm, I've been wondering about this for a while too. So I have three questions:
1. Whats the Japanese name for tire streaching?
2. Can someone show me what this looks like?
3. Are rims more prone to damaging with the road when using this technique?
Thanks.

Answers to your questions:

1. It's called "hipari" tire.
2.
As seen on my boy Mike's S14 (in progress)
3. Not necessarily, if the pressure is too low then the tire can unbead itself, but even with a larger tire running low pressure can damage the tire in it's own right. As far as the rims themselves..if you like to drive over deep potholes..ANY tire set-up will not enjoy it.

I personally run hipari tire myself...although not as extreme as some people do. I run a 215 on an 8" and a 235 on a 9".

[CrazyHawaiian]

From my experience it makes the kick/re-grip a little smoother. Somebody got all technical about it last time it came up, slip angles and whatnot, but I'll be honest I dont know why it makes everything feel smoother. All I know is that it does. I started doing it because (like Ris said) I run all used tires and I gotta make due with what I got. Alot of times you'll end up with tires that are mismatched to the wheel sizes you got. Slap em on and see how it slides. Its also cool to experiment with different contact patches and see which ones you like the best. Whenever I run stretched tires I always run high psi (40+). Depending on how stretched the tire is, it is possible for the wheel to get damaged if the tire fails. No sidewall to drive on. All the wheels I use to drift are cheap/free anyway so who cares hahaha. For my 16x8's I've been running between 205 and 235 widths (mostly 50-55 sidewalls). For my 17x9.5's I've been running between 225 and 255 (mostly 45-55 sidewalls). This is all on the rears. For the fronts I dont run stretched stuff, just a smaller sidewall than I would on the street.

[Ris4drift]

you know one thing ive really always wanted to do was find some *Censored**Censored**Censored* 10x15 wheels for a foxbody that were out of style in 1981, redrill them and put a 195/65r15 on there just to see if the sidewall was big enough to stretch tthat far. if you have any poop rims that wide find some used tires see if you can do it haha.

but as to the making it more smooth its basically because tehre is no movement in the tire at all if its stretched jdm style . if you stretch it the sidewall simply cannot flex, neither can the tire. if you dont tighten your lugnuts however....

[Wayne]

Originally posted by BooZTT
Answers to your questions:

1. It's called "hipari" tire.
2.
As seen on my boy Mike's S14 (in progress)
3. Not necessarily, if the pressure is too low then the tire can unbead itself, but even with a larger tire running low pressure can damage the tire in it's own right. As far as the rims themselves..if you like to drive over deep potholes..ANY tire set-up will not enjoy it.

I personally run hipari tire myself...although not as extreme as some people do. I run a 215 on an 8" and a 235 on a 9".

damn mikes car is looking awesome. any new pics of it?

[amejin_japan]

stretching basically (as noted above) reduces sidewall flex. This is somthing you DON'T want on a drift car. Sidewall flex reduced the handling response when you want to kick the *Censored**Censored**Censored* out because your car has to first overcome that extra flex. Cars with hippari tires act stiffer than one's without. People run them either way though and most people stretch them just cause it looks good.

[Reckless Hero]

I do agree with all the above statemens, it just feels so much better and smoother.
lol i might need new tires soon, lol now to convince another guy to mount my tires.

[GRiDRaceTech]

I am against hipari, but thanks to BoozTT and CH, I do see the advantages... for rear tires and for used tires.

The origin of hipari, as far as I know, is twofold. One: drifters/touge drivers wanted a way to get great steering feel out of normal street tires. Thus, they stretched them to make the sidewalls stiffer, without having to pony up the cash for more expensive tires. Two: drifters/touge drivers want to run as low as possible, and with the current trend of big, wide, low-offset wheels, stretching the tires and running tons of negative camber is the only way to get the necessary clearance.

In the front, giving up contact patch for feel just doesn't seem to be a good tradeoff. I must point out that I am giving a racing-biased point of view, however. Notice the tires that are being stretched... they're by no means true performance tires. (No, ES100s are not true performance tires.) The Falken Azenis RT-215 has an extremely stiff sidewall already and does not facilitate stretching, nor does it really warrant stretching. As far as I know, the Falken drift team doesn't run RT-215s on the front of their cars. (If someone could enlighten me as to what they run or even prove me wrong that would be great... *edit* See next post. Thanks!) As to why, one can speculate that they may be concerned with overall car balance or maybe Falken just wants to sell more ST-115s.

I see plenty of Japanese amateur drifters (that doesn't mean they suck, they just aren't in D1 for any number of reasons) who run 15s and 16s with hipari. Most are relatively low-horsepower, and therefore balance would not be so much of an issue. I have no problem with hipari in the rear, in fact I'll probably run hipari in the rear after I get some 15x8s... it's just the front tires that I don't understand. In January, the new Falken semi-R-compound tire, the RT-615, will be coming out with wider sizes. Therefore, there will be almost no reason to run hipari in the front, as the RT-615 is reasonably priced and will have a sidewall just as stiff as the RT-215. (Again, fitment issues can be exempted... but why go so low that you have trouble fitting 225/50R-15s or 215/45R-16s?)


Cliff's Notes: I don't do Cliff's notes. Read the whole thing, you lazy bum.

[The sheriff]

yea you made some good points, the falken team do run the rt 215 in the front, but not all the cars. calvin wan has them, jr had them, ben schwartz has them as well. Koguchi has some, but in a special fittment. and the only reason that most people use the st115 in the front as opposed to the 215 is simply size availabilty. as we all now the 215 is not availble in most sizes. but the 615 will remedy that for sure. the grip is need in the front and the 215 does that much better than the st115, but you made good points on the stretching theory and all that, and i against strecthing the tire like in that picture....that is crazy and unsafe...so if sides are picked on if that is cool, put me on the side that says "no,no that aint cool" lol

[Ris4drift]

the azenis sports htey have made in a 245/45r17 for a long time. thats the exact size used on the falken cars.

also the only car i saw them on the front of was calvin's car. i never saw them on jr or koguchis car and was puzzles as to why. (by me saying i didnt see it i am NOT saying it didtn happen, i was just stating what i noticed, and i also foudn it kinda odd)

but one reason im sure they didnt use them in the rear b/c the st215 or whatever the sports were tended to get greasy when hot. i do know alex used to run them on his corolla at all 4 corners. and i personally have drifted with them at all 4 corners. i liked it but then again i could justify the tire life after seeing their demo runs and how they can kill off brand new st115 in one outing.

as to the hipari , i still think theres no need for the excessive stretchigngion gon. like noted earlier, most real performance tires have a stiff enough sidewall to where you dont need to do it to that extent. but in the rears i understand and will probably do it next year to an extent. but not the running 215 tire on a 10 inch wheel. the contact patch lost is completely retarted.

[GRiDRaceTech]

The RT-215s don't get greasy in one lap of a really short track, such as at the Drift Showoff. Even in two or three laps the performance difference would be negligible.

I don't think Alex ran RT-215s in the back of his Corolla, they're too grippy to spin well and tend to respond poorly to excessive drifting.

[f8ldzz]

This has been covered before.
It's going to erupt in a war.

I've been through too many real racing venues to find the argument of sidewall stiffness total *Censored**Censored**Censored**Censored**Censored**Censored**Censored**Censored*.
You want stiffer sidewalls?
Run lower aspect ratio...
Run more tire pressure...

All tire manufacturers have a recommendation chart for all their tires sizes and appropriate wheel widths.
I dunno anyone else who would know tire to wheel fitments than the tire manufacturers themselves.
I know I'd follow the manufacturer recommendations then some Joe Schmoe on the street.

Liking hipari is also a subjective thing.
Driving style and suspension geometry has a lot to do with it.
If you're a good driver, you can adapt your driving technique to handle (small) variances in your set-up.
Certain geometries will work better with hipari tire set-up's: double wishbone suspensions do not roll the tire over as much as Macpherson strut designs.
I just don't like the idea of having the sidewall so "horizontal" with the possibility of tire rollover.
Now, it could be the tire (grip) is so low that the tire would slip rather than roll over on the sidewall - this is a valid point, but it's not a valid reason for best performance.

I'd rather run the biggest tires matched with the widest wheels I can fit under my car.
Street tires have very limited grip.
Race tires are a whole nother matter.
And no, I don't run a "drift" set-up on the street - I don't drift on the street in the first place.

So, it comes down to it's a style thing...
Or, you are broke and can't afford the wider width...

[CrazyHawaiian]

Just some food for thought ... go bust out any D1 Option Video and pause each time one of the D1 guys gets the car sliding. You'd be supprised how many professionals stretch their tires, front or rear, tire sponsor or not. Of course this dosnt mean they do it for purely tech reasons (maybe it is the look) but it sure seems like it works out good for them.

[CrazyHawaiian]

Also, consider that this sport is not all about performance. I mean, yeah the cars are in performance situations, but remember that the slide is the goal, not better grip, not faster times. So you cant really compare racing situations to drifting, different goals mean different theories. What creates the optimal grip situation might not be the best setup for a sport like drifting. What creates the optimal drifting situation is what we're after.

Also, consider liability. Tire manufacturers list acceptable sizes because they need to protect themselves from stupid people. Remember the lady that spilled Mcdonalds coffe and burned her legs, or the guy that picked up the lawnmower to trim the hedges and lost his fingers? There are a bunch of stupid people out there in this world. Anyone that releases products in this day of lawsuits and crooked lawyers has to protect themselves from liability. I'm sure acceptable wheel width specs are an extension of that thought.

[Reckless Hero]

Originally posted by CrazyHawaiian
Also, consider that this sport is not all about performance. I mean, yeah the cars are in performance situations, but remember that the slide is the goal, not better grip, not faster times. So you cant really compare racing situations to drifting, different goals mean different theories. What creates the optimal grip situation might not be the best setup for a sport like drifting. What creates the optimal drifting situation is what we're after.

yep ive met all too many racers that "over think" everyting and just try to hard to "get" drifting. check your ideas at the door and just have fun with it, i have fun with my car, if u think my choice of tires look stupid, i say thanks cause i dont care what u think

[tonesdef]

ok well i've read most of the posts and i ran on stretched tires on my rolla for about a year. It was awesome the first time out i had less roll in my body and 10x the response when drifting. For drifting i suggest it but for anything else i would just get a lower profile becuase stretching usaly means running a small tire and thats no good with grip. But for drifting it works and its great. My car responded much better and i had a lot more feel of what i was doing. While drifting with unstretched 50 series i could feel the tire roll befor i got out and that just made it harsh.


And yes the pros do stretch not as much as we do. The low HP hahcis stretch a lot. UEO use to runa 185 neova in the rear on his 8.5's.


what i use to run was a 15x8.5 with es100's 195/50/15

i suggest stretching to any one that is intrested in drifting it makes such a big differnce and you can't knock it till you rock it.

[Ris4drift]

Originally posted by GRiDRaceTech
The RT-215s don't get greasy in one lap of a really short track, such as at the Drift Showoff. Even in two or three laps the performance difference would be negligible.

I don't think Alex ran RT-215s in the back of his Corolla, they're too grippy to spin well and tend to respond poorly to excessive drifting.

i have several pics of alex's hatchi with sport on all 4 corners. i have drifted on them all the way around with a stock ka in my 240 (215/45r16). the grip levels these tires allow drifting is insane, and you can carry a ton mroe speed than with crappy tires. they dont last very long though, and after the 1st corner or so they do get hot, and a little easier to drift on. the grip level is still extremely high though, and they do produce a TON of smoke (with my ka you have to be full throttle to keep them going almost) . his junkyard turbo kit i am sure was putting down more power than my stock ka. not to mensino i thik he was running 14's all the way around. which are 195.

reckless hero and tonesofdef, those are some nice thought out posts.

but just to get another of my .02 in on the "grip level" comments. i personally like to have too much rear tire to where its extremely difficult to keep the rears spinning . i have noticed much much higher cornering speeds due to the grip level being increased, and the amoung of wheelspeed i require to hold the slide. same angle, just a lot faster, and it tends to lead to a huge amount of smoke since i am at full throttle most of the track minus transision (even then sometiems) but then again i do have a stock ka, so i dont hve a ton of power. but 215/45r16 falken azenis sports are almost perfect for the car imo. absolute insane amount of grip. i would like to try khumo mx or even a bigger size es100 possibly. but i for one tend to like having a huge contact patch (considering power) with as much rear grip as i can get and still be able to have enough power to hold the drift.

[stuntman240]

Originally posted by Ris4drift
but i for one tend to like having a huge contact patch

stretching small tire over wide wheel gives you more contact patch per tire size i.e.

a 205 on a 6.5 will have less contact patch then 205 on a 9 (what I run) KA!!!

[tonesdef]

personaly i will never run falken sports on any of my cars. There great for auto x than they turn into mud and seem to be really unpredicatable.

My freind was running sports on his sr20 240 all the way around and being in his car i could tell how unpredicatable they were. They would either go or grip or some time like when he nailed that curb they would spin than grip sending the car into a not so fun direction. I love es100's for drifting and the grip is great on the front. I ran fm901's for a while and well wasn't impressed at all.

[f8ldzz]

Originally posted by CrazyHawaiian
Just some food for thought ... go bust out any D1 Option Video and pause each time one of the D1 guys gets the car sliding. You'd be supprised how many professionals stretch their tires, front or rear, tire sponsor or not. Of course this dosnt mean they do it for purely tech reasons (maybe it is the look) but it sure seems like it works out good for them.

I'm sorry, but I don't consider D1 to be the absolute authority on tire performance.
Yes, I agree, the parameters are slightly different for drifting.
BUT, the front tires for drifting should work similarly to grip driving.

Also, be careful with using D1 as a benchmark.
There's a lot of sponsor money in the whole sport.
This usually implies money-talks and not necessarily the BEST components (i.e. tires) are being used.
D1 is also about appeal.
Running a 245 hipari tire on a 10.5" wheel will probably get as much grip as a proper 225 wide tire on a 7.5" to 8" wide wheel - there was ways to fudge the combination to suit your needs.
You need to look at the chassis (i.e. vehicle weight), suspension design, and tire sizes.
You can get an approximation of what minimum tire size versus vehicle weight pretty easily.
Having a D1 Hachi running 225's, even hipari, is overkill in terms of tire width versus vehicle weight.
It's still all about the "balance"...

If you want to talk about ultimate tire performance without the excess baggage with sponsorship (well, to a point) check out what the SCCA National Run-Off guys are running...