Sidewall flex is actually a major part of the equation in the suspension of a car. A small amount of give is a large amount of error-proofing. Half a tenth of a second lost per lap is worth not having a DNF. In drifting you can’t have flex, you need instant response. You’ve already gone past the limit and now you need to keep it there.
There should be no mechanical need to stretch your tires. All it is is cosmetic or a tribute to the practice that began in Germany (IIRC) where people wanted to run a wider rim, but were limited to a legal limit that stated that a tire’s tread could not be wider than the fender… or something like that.
I’m putting 185/45/16’s on my 7" wheels all around. Its fucking hot, I don’t care what anyone says!
-1
are the tires stretched on your FWD euro car?
My idea of “responsible” stretching putting a 225 tire on a 9" rim when the manufacture recommended is 7"-8" (just throwing random numbers out for an example).
Euro stretching, i.e. 185 tire on a 9" rim.
When designing a car you design the suspension around the tire, it characteristics, and its spring rate. You do not pick the tire to act as a suspension component (although it does) that should ultimately be the job of the springs and dampers. Obviously a tire needs to deform to road conditions to maintain traction, but the spring rate of a tire when compared to the total mass system of a vehical is three to ten times that of the suspension spring.
My idea of strecthing wouldn’t end in a DNF, euro-stratching yes.
And why wouldn’t you want instant response in racing?
So are you saying a 225 tire would perform the same on a 5.5" rim as it would as on a 9" rim?
Really stupid example to follow: Think of it this way. You have a size 9 foot (rim). A big fluffy wool sock represents sidewall flex. Put on a size 10 shoe, move your foot left to right, same with a size 9, same with a size 8. Size 10 has a nice big contact patch, but too much sidewall flex negatively affecting turning. Size 9 a little tight,but still a little flex. Size 8 gives you blisters and cramps up your pinky toe, but no flex.
You have it all backwards.
Stretching does not help handling. A proper suspension setup, tire and rim combo do that.
You sacrifice your tires and not the rims. The rim is still exposed in a non stretched app. You hit something either way the rim is fucked… makes little difference
Am I the only one that buys a better tire when I want a stiffer sidewall?
Exactly.
So are you saying that you never driven a car with a rim width at the upper end of the tire manufacture’s suggested rim width?
I have never put a tire that was too skinny on. Too wide of a tire - that’s another story…
Nope.:wiggle:
Doesnt a stiffer sidewall help handling?
It allows less flex, which would make it easier for the car to lose traction. The tire can’t really roll with a stiff sidewall therefore it would be a better drift setup rather then a better handling setup.
Edit: at least thats what I’ve always thought.
pardon me if my thinking is flawed, but the most important thing is getting the most rubber to contact the ground. it the tire it too large and the tire can roll off to the side less would be contacting the pavement. If you stretch it too much what the point when you can fit a slightly larger tire to give you that little more width to sit flat on the ground.
suspension adjusts the movement of the car so it orients the rim and tire to sit flat on the pavement when turning agressively or in a straight line.
More rubber to the ground = more traction. Less flex will affect the contact patch and weight transfer. Compound also affects grip. Look up pics of race cars and look at the tires.
Holy shit there is so much wrong in this thread I really don’t know where to start.
The stiffer sidewall allows the tire to produce more grip at lower slip angles.
I really would rather arguee calculus to a class of 2nd graders than get into it. So the extremely digested version is this:
NEGLECTING THE BENEFIT OF COMPOUND;
Take a $30 Walmart all season, a really good performance street tire, and a race compound tire. Purely as an example it takes 10* of tire input before max lateral force to be produced, 5* for the performance tire, and 3* for the r-comp.
So going through a 15:1 steering ratio you have to crank on the wheel when autocrossing on a cheap all season, on r-comps you don’t need to be so agressive and can produce more grip with less steering input.
I’m not a huge fan of it and I think some people take it to the extreme. It does look good on certain cars…
Some decent info…
it seems as of late there is a metric assload of hate directed towards those of us who run stretch or about stretch in general. thought i would throw this up to educate or help out those of you with questions.
what is stretch?
- “stretch” refers to stretching a narrower tire over a wider wheel, the sidewalls stretch from the lip to the tread
why do stretched tires?
well the whole thing started in germany/belgium, local laws required that the tire tread be within the fender line. well that doesnt allow one to run wider or lower offset wheels, so they put narrower tires on the wheel to maintain legality
when you would like to run really wide or low offset wheels and keep the tire tread at the fender
when you would like to go really low and not rub
isnt this unsafe?
- there hasnt been any soild evidence that running a stretched tire is any more dangerous than a regular tire.
where can i get tires stretched?
-any reputable wheel/tire shop should be able to do it. i know when i did a 215-45 kumho on a 8.5" wheel, it took one shop 90lbs to pop the bead. getting a 225-45 on a 9 and a 245-40 on a 10.5 took another shop 50 lbs
can’t you afford the right tire size?
- the tire that stretch the most tend to be at the top of the price list, so it isnt an issue
what tires stretch best?
- from what i have seen, the best tires with regards to stretch are:
toyo t1-s
dunlop sp9000
dunlop sp8080e
falken fk451im sure there are more, but look for a tire with a rounded shoulder and a lip protector, they tend to give the “desirable” look
but staggered wheels are stupid on fwd cars, arent you worried about handling?
- its all about looks, you wont see anyone with low offset deep dish wheels flopping around the autox course.
what size/offset wheels are the best for a staggered look
- its all about personal preference. me, i have 17x9et26 and 17x10.5et26 and i couldnt ask for a better setup. some may not like the look but thats why people build their cars for themselves
arent you worried about curbing a wheel?
- take a look in the classifieds and count the number of wheels on regular tires compared to those on stretched tires with damage.
Quote, originally posted by 02blkgtivr6 »
what if you get a puncture in the tire from a nail and you’re going 65mph and the tire loses air rapidly, will it stay beaded (proper term?) as long as a regular sized tire would? do stretched tires need to have above a certain tire pressure to stay beaded?
one thing about running stretched tires, the driver tends to be a bit more careful because of the cost of the wheels, i definately drive more alert with the tramonts than i do my stock wheels.
and as far as loss of pressure is concerned, i tested my wheels the other day after putting them on, i drove around one day (~60 miles mixed highway/city) and one tire was at 10psi, no visual or performance cues.
the main reason for a tire popping a bead is sidewall flex, not internal pressure. like i said, it took ~90lbs to mount my one set, there is no way taht driving forces would add to exceed that pressure, let alone the 40lbs it took to do this set
Quote, originally posted by LA20 »
From my understanding, stretching tires is just putting smaller tires on a bigger rims, like 215 on a 19"x8.5 or something like that. But to get that tire outside the fender, dont we need spacers or something? or as long you have stretch tires, you will achieve “the look” on the rear wheels?-you can do one of 2 things: 1- use spacers, 2- pick a wheel or have one made that provides an offset such that when mounted it will have the look you want
Quote, originally posted by LA20 »
oke, it seems clear now. what et usually gives that kind of look? and with that kind of offset or by using spacers, wont the tire tread falls under or outside the fender just like that? It it is, then why we need to stretch the tires again??answer:
Quote, originally posted by tivs31 »
the thing is that in most cases people are running a wide, low offset wheel, which would allow them to run a large amount of dish…the proper offset for a mark 4 front fender is about 30-32 with an 8.5" wheel, but with the strech idea, one could run a 20-25 (would poke outside the fender about 1/2") without rubbing and without being against the law.
the addional 1/2" outside the fender would also allow you to run a 9" wide wheel in the front as well