hardon85

hey guys I was reading an earlier post that someone was talking about stretching tires (narrower tires on a wider rim). I was gonna reply there but the thread got locked but I just wanted to say that when I raced go-karts we stretched tires all the time and the reason was to lower the circumference for stagger reasons eventually we stretched all the tires I never really understood why we did all the tires but we did, we were dealing with so little horsepower that I'm sure the lower circumference helped somehow. Now I thought on the go-karts it looked very cool but I'm not sure about a street car. One thing you have to remember is these tires were designed to be stretched an unmounted tire had nowhere near the same profile as a street tire. As far as hurting handling performance on a street tire, it most definitely will with the center of the contact patch not meeting the road. Maybe there is a street tire that is made to be stretched but if it is not designed to I would think you would also be setting yourself up for failure somewhere else as you would be stressing the tires in places they weren't meant to be stressed. I don't mean to stir up problems but I just wanted to say stretched tires do have a place and a purpose but I agree they do not belong on street cars

87tpi350,6spd

iTrader: (12)

Not sure what the op was about but this reminded me of a kid I knew who was into hydralics and the would get really skinny tires and mount them on wider rims so they would have a more rounded shape and made jumping easyer or something. Now I belive he ran tubes and the cars were not built for anykind of performance driving but the tires were "streached" and on a car so I thought I would share.

basiccamaro

When I raced dirt track we had to run 8" wide towel city retreads in our class. No exceptions. They were a recapped street legal D. O.T. tire. This kept everything equal and kept costs in line. And since varying the circumference between the inside and outside tires (stagger or rollout) drastically affected cornering performance, we tried everything to get the stagger we wanted. It was hard to do with those D.O.T. casings.
When you measured the circumference of the tire unmounted on the tire truck rack , it would usually not match up to what it would be when inflated. So we would put a LOT of air in them and set them out in the hot sun and they would grow, to get the stagger we were looking for. One guy even worked at a lumber yard and they put their way over - inflated tires in a kiln to make them grow! And it worked.

We raced them sideways, spinning and burning, forcing sidebite into them with heavy body roll, and at fairly high speeds side by side and never had any problems whatsoever. Some of the top class Late Model guys did it with racing tires too. This was all back in the bias- ply days, before the metric size designation system.

When I built a new tube frame car, I still wasn't running as well as I wanted to. One day I watched a top running competitor from our class go over the track scales and get weighed and inspected. I looked at his tires and thought, man! is he moving up a class tonight? His tires look waaayyy too wide. The inspectors had a go- no go, 8" tire width guage that everyone's tires had to fit inside of. I watched in amazement as this guy passed inspection, easily making it through th go- no go guage. I knew right then if I didn't figure this out, I wasn't going to run very well.

A little while later I went over and took a better look at his car. I finally figured out that he was using 10" wheels with the 8" tires and it was bulging the sidewlls out a little and flattening out the tread to where he was getting the full width of the tire on the track.
So I did the same thing, went out and bought 10" wheels and re- mounted my tires. It was like night and day, the car took off! Soon I was running better, top qualifier one night, winning helmet dashes and fast heat races and main event features. It put me right in the middle of the top cars and made my car fun to drive.

Acouple of years later, due to car counts going lower and lower, they opened up the rule and allowed 12" racing tires in our class to make cars from a different track legal in our class. It made me instantly uncompetitive since I didn't have the money for new tires and wheels, and I didn't have a big hp engine to push them anyway. I did manage to win a fast heat one night with my old 8" retreads against all of the other guys with the racing rubber. But I soon quit after that. The racing tires took it out of my budget. There were now guyscoming in with high dollar engines and able to hook them up with expensive racing rubber and beadlock wheels to run them at low pressures, just old Late Models. But it was a BLAST while it lasted!

Even back then, every tire was not a candidate for either one of these treatments. Every kind of tire has a different sidewall and tread and relationship between the two. I don't think you would ever find anybody to recomnd this for a street tire or road driving due to safety and durability concerns. But I have seen it done!

hardon85

In this thread https://www.thirdgen.org/forums/fabr...flush-3rd.html they were talking about stretched tires, that's where this current thread came from as the other one got locked because the op got pretty rude. I was just trying to say that there is a place for stretched tires but not on a street car. 87tpi350,6spd that's interesting that he used them for bouncing cars I wouldn't think it would work to well for that but who knows. And thank you basiccamaro for chiming in I think we both agree that it works in racing but were not exactly sure why, and I think we both agree this is not something that belongs on a street car. Also I realize you're out of racing now but a quick question did airing the tires up and setting them in the sun actually work I know it works temporarily but in my experience the tires would usually shrink back to their original size within a day or so, but another trick I heard was to put the tires in the oven just on warm for a little while then pull them out and submerse them in water I never did it but a lot of people swear by it.

Also to 87tpi350,6spd I do realize you weren't being rude I just thought I would explain it since I'm sure a lot of other people were probably thinking the same thing you were. Thanks for the replies guys.

basiccamaro

Yeah, the too much air/out in the hot sun did work, but the Towel City Retreads (Towel City is an old linen industry town very near Kannpolis, North Carolina where Dale and Dale Jr. Earnhart are from) were made by recapping all different brands, sizes and types of medium performance street tires and there was no consistency in any part of the equation. What worked on one of their tires one time usually did not work on another, or at least not in the same way.
The good part was that they wore really well and you didn't have to buy new tires too often. This was the only way I could afford to race.
And you could run side by side with people and rub fenders and you usually didn't cut one since they were a heavy sidewall street tire and not a paper thin racing tire. They were a hard tire (they came in three hardness/softness compounds but you couldn't tell the difference in any of the three!) and the only way it worked was that everybody was required to run that brand and size of tire.
It really was a lot of fun and was where I learned a lot about chassis tuning. I went from running poorly and goofing around between my races to winning a few and working my butt of the whole night. I had a tape measure in my hand mesuring tire circumference constantly!
If you watch the NASCAR or INDY Car races on TV and hear them talking about adding or taking out 1/4 of a pound of air pressure, you'll see how it works. Air pressure not only affects circumference, and thus stagger, but also spring rate (the tire is actually another spring).

hardon85

that's exactly right about the tire being another spring. I don't know if you have ever listened to different crew chiefs in nascar talk about things they did before are completely backwards of what works today and I think a big reason is due to the move to radial tires which have a lot softer sidewall therefore the springrate of the tire is affected a lot more by tire pressure. Most people (including what I was taught) believe that if you take air pressure out then you are adding grip but well you are doing that you are also softening the springrate of the tire making it react slower so they kind of contradict eachother. It's good hearing from someone so knowledgeable about racing.

JimmyDavidson

Heh, flush mounted tires is acceptable, imo as far as looks go tire bulge(aka taller or wider tire) > flush or stretched(smaller tire on wide rim).. I have seen plenty of people in the import crowd with excessively stretched tires. I can only assume they think this is to help them break the tires loose for drifting. My only response to that is: "Get more torque."

If it's for the looks of it, then I believe it's just a fad, either way I don't like it.

blackbmagic

Bringing this back because this is really becoming popular.

The reason people really stretch tires is to get lower without tucking the wheel and rolling/pulling fender.

The arc on the stretched tires allows the fender to get close to the rim lip without digging into the tire. With the right about of spacing it can be done right to get the flush look.

We stretch tires all the time at the shop for customers cars. Its definitively not a look for certain cars like ours as well as early muscle cars but it does look really nice with the right stance on some of the imports ESPECIALLY retro imports and "jdm muscle" I have seen quite a few datsuns, 70's celicas, rx7's, corollas, with some very nice looking stretch....

Zach/90\irocZ

iTrader: (6)

A lot of info is being thrown around here .. I'll try to clear it up

Running a slight stretch tire increase side wall rigidity and increases performance and feel

First thing first a lot of racers and German and Japanese see positive performance gains and feel from running a slight stretch tire and come from factory as such

The new 1LE Camaro runs a slightly stretch rear tire 285/35ZR20 on 20x10fronts 20x11 rears do to better turn in and performance

Stretch tires do have there place on the street and track ..

Then there's the hellaflush scene which is the extreme side and is just a fad and lifestyle and looks but it's deeply rooted from the racing performance scene but taken to the extreme

All tires are not the same some are wider then others, have thicker sidewall etc etc

Go karts prob run stretch tire for the same reason .

With the reduce diameter that would affect the gearing of a vehicle to include go karting but I don't think that people run stretch tire for that reason

Diesel truck guys or truck guys that drag race run tire combos with smaller dia. For mainly for gearing performance gains at the track

lmidden

i still think its because they cant afford the right tires