Tyre Choice - 195/55 or 195/50

[frost]

I have run 195/55's on 15x8 rims in the past with zero problems - the sidewall is virtually vertical, and was certified that way. Even prior to the new legislation there was still a cert requirement for the right section width tyre to be fitted to the rim, now it is clearly defined by way of a table.

However I think it is aimed more at people stretching 185's on a 9.5in rim or similar, but a line has to be drawn somewhere and the manufacturers 'recommendations' are probably a good place to start.

agreed.

[pc]

i dont think an 80s corolla is going to be at the pointy end of any field, unless the field is otherwise made up of 70s corollas. many, many cars have been running stretched tyres for many, many years. i have seen a few examples of it causing problems, but it seems to be only in extreme cases, both usage and stretch.

whatever benefits or penalites it may impose on your lap times are largely irrelevant imo, unless its a dedicated track car and you care about tenths of a second. if the owner likes it and has fun, whats the problem?

the old fogeys comment was largely tongue in cheek

Kind-of like "I don't need to wear a seatbelt cos i've never had a problem yet"?
I've seen 80's corollas at the pointy end of many fields. I haven't seen any problems with stretching tyres on rims, but then again i've not seen anyone race with stretched tyres.

Why not follow manufacturers recommendations instead of risking doing something that is generally thought to be dumb and dangerous? (google stretched tyres/tires dangerous)

[Simon86]

Kind-of like "I don't need to wear a seatbelt cos i've never had a problem yet"?
I've seen 80's corollas at the pointy end of many fields. I haven't seen any problems with stretching tyres on rims, but then again i've not seen anyone race with stretched tyres.

Why not follow manufacturers recommendations instead of risking doing something that is generally thought to be dumb and dangerous? (google stretched tyres/tires dangerous)

I would almost guarantee that you have seen people racing with tyres that are stretched on according to the LVVTA's table. According to the table a 215 tyre on an 8.5in rim would not pass certification and I don't believe it would be possible to tell just by looking at the rim/tyre that it was outside of the range that manufacturers specify.

[shihad]

lol googling stretched tyre dangerous comes up with a whole lot of threads about people saying they havent seen any proof that its dangerous.

I have 195 40s on a 8inch 15 on a ae85 i didnt buy the tyres for their stretch they came with the rims and i dont see the point in taking them off seeng as they are dam near new (i will buy 195 50s next set).but why is a stretched tyre lets use mine as an example soooo ghay and dangerous.

[rx7guy]

195 on 8.5 is a bitr of stretch

[RomanV]

I always lol when hearing people's technical justifications for irrational decisions.

People put 195s and what not on wide rims because they think it looks cool, end of story.

I've got no problem like that, it's just when they try to reverse engineer all sorts of reasons why they're doing so, apart from car fashion.

I reckon it can look cool on the right sort of car.

But seeing some hillclimb car with wide as $&#$% semislicks barely stuffed under the gaurds is just as cool in my opinion, even if it's out of vogue at the moment.

[Simon86]

195 on 8.5 is a bitr of stretch

http://www.tyrestretch.com/8.5_195_45_R ... 1R.jpg.php

Agreed, however that particular photo they are using a 195/45 which will appear more stretched than a 195/50

[frost]

I always lol when hearing people's technical justifications for irrational decisions.

who's getting technical? if anything all the posts have pretty much said "its for looks not for performance"
there is no technical justification for stretch,

i like my wide dish rims, i can only fit 215/50/15 under the guards, if i could fit 225 under with no mods to the body i would, but i cant with out jacking the car up, and i hate the look of guards rolled completely out to a peak, like you see on most ae70's
i don't even like stretch look that much.

[rollaholic]

umm about a zillion drifters in a billion countries 'race' on stretched tyres all the time. if thats not hard work for your tyre sidewalls what is?

and its totally different to wearing a seatbelt!

[Malcolm]

I would imagine the biggest issue is the risk of de-beading your tyres. Apply a lateral force to a tyre that's already sitting against the safety bead, maybe coupled with low tyre pressure and I can definitely see a tyre getting pushed over the safety bead and then you're buggered.

The other thing is that sidewalls are designed to be able to flex, and this is a very important part of the way tyres behave. Stiffening up the sidewalls to lateral deflectiion (which is what happens when you stretch a tyre) will tend to increase the responsiveness of a tyre (at a vehicle dynamics seminar I attended it was recommended to run slightly wider wheels on the front for exactly this reason), but it will be at the cost of ultimate grip and you make the tyre a lot more unpredictable. I doubt this would affect drifters because the tyres aren't being used in their adhesion range, they're being used more like skis and the behaviour of the carcass probably has little effect on the way they perform.

[DRFTIN]

People put 195s and what not on wide rims because they think it looks cool, end of story

im sure a 195 on 8.5 would work in this case, just dont let the pressure get low as thats when they pop off in my experience
it does depend on the wheel and tyre though, i've found some hold on to the bead better than others
55 profile if you're worried about the stretch and 50 for better gearing

and as much as people like to think its not, drifting as all about grip. it just happens that its more about the look

[pc]

lol googling stretched tyre dangerous comes up with a whole lot of threads about people saying they havent seen any proof that its dangerous.

I have 195 40s on a 8inch 15 on a ae85 i didnt buy the tyres for their stretch they came with the rims and i dont see the point in taking them off seeng as they are dam near new (i will buy 195 50s next set).but why is a stretched tyre lets use mine as an example soooo ghay and dangerous.

Depends what parts of the threads you find that you choose to read.
Not wearing a seatbelt is perfectly safe and there is no need to wear one to get from A to B. You won't magically crash and die by not wearing a seatbelt... But it would be dumb not to use one.
You won't magically crash and die with a stretched tyre... but you are operating it in a sub-optimal configuration that it is not designed for, and there are manufacturer guides that say so.
It's not a complicated discussion.

[rollaholic]

drop the seatbelt thing seriously, its a terrible comparison

seatbelt keeps you safe in the event of a crash, has no effect (as you noted) on your chances of being in one.

potentially dangerous tyre fitment (though anecdotal evidence suggests its fine, or at least not unsafe in moderation) CAN cause a crash. its not magic, its a bead popping off cos you stretched the sidewall too far. but sub-optimal (i havent seen anyone suggest that stretch is anything but) does not mean its dangerous.

manufacturers recommendations will be well inside the safety margins to cover their asses. how many cars have you seen with 150km + on their original cambelts?

[Mr Revhead]

Have a good hard think about a tyres design, what certain parts of it are for, and how they are designed to act.

Stretching the sidewall decreases grip. Instead of having some sidewall flex to allow the contact patch to move a little and stay in contact with the ground, no flex means when the wheel leans the contact patch will lift. Add in lots of air pressure, and you have a hard inflexible and quite possibly misshapened contact patch that lacks the support it was designed to work with. No extra grip there.

It would be quite interesting to see some data re temps across the tyre on a stretched tyre. I bet you there will be some awfully hot sections.

[pc]

seatbelt keeps you safe in the event of a crash, has no effect (as you noted) on your chances of being in one.

nope, doesn't keep you safe at all. It can help reducing injury in most types of crashes.
I don't think it's a terrible comparison at all.

[metal_sean_head]

nope, doesn't keep you safe at all.

When mum wrote off her car I was pretty glad we were all wearing our seatbelts TBH.

[frost]

Have a good hard think about a tyres design, what certain parts of it are for, and how they are designed to act.

Stretching the sidewall decreases grip. Instead of having some sidewall flex to allow the contact patch to move a little and stay in contact with the ground, no flex means when the wheel leans the contact patch will lift. Add in lots of air pressure, and you have a hard inflexible and quite possibly misshapened contact patch that lacks the support it was designed to work with. No extra grip there.

It would be quite interesting to see some data re temps across the tyre on a stretched tyre. I bet you there will be some awfully hot sections.

again i come back to "its a fashion thing not a performance mod"
having tints can be dangerous,
super low profile tires can be dangerous
open headers can be dangerous
open wheels can be dangerous
cheap Chinese wheels can be dangerous
but you do it cos you like it,

thats the problem with toyspeed its too closed off, instead of sounding technical and helpful its become "do it my way cos im king"
anyone else notice the numbers on toyspeed have been declining?
more members have been subing over to other forums cos of this pool.
(not directed at u rev)

[Mr Revhead]

Fashion is for girls
I was trying to get technical, instead of saying "it looks shit and is gay" I was trying to get my (and others) point across in a logical manner about a valid point.

And no, I have not noticed numbers declining.

[FLAWLES]

i do giggle when these threads get started on forums

99% of the time they end up in a completly different direction that what was started apon

amusing i must say

but it comes down to this

each to there own, some like it others well

haters goina hate lol

but please let the debate continue, with constructive info, to help the chap out

[holden_fan2005]

I don't like stretch. I think it's gay.



The worst part is I have to run stretch to get the tyres to sit in my guards. and when you hit curbs, it ain't tyres ya grinding up......



FML......