Tyre Size Acceleration?

30th January 2010, 22:07

I bought a set of 195 50 15 R888's - Good Buy

"but" when i put my 195 45 15 road tyres on the car seems a lot quicker!??

Any one used the 185 65 14 R888's? looking at going to 14" VTR rims with the above tyres on but before i buy them looking for the advise - the 750 cc race cars use this size of tyres but is that because they have to as per the rules

Not getting into 5th properely at Oulton, only just on the longer straights then gearing down instead of leaving the car reving in 4th

Long storey short the wheels would be smaller meaning better acceleration / handling but just asking if anyone has noticed the same??? Cheers in advance

Plus anyone done a day on the Mich Pilots which are standard on the 14" VTR rims?? what you think

30th January 2010, 22:28

Sure a 195/50 R15 tyre is wider than a 195/45 R15 nearly 1cm, so you earn more rolling resistance + the 195/50 R15 also got more circumference + extra weight of the stronger loadindex!

Robert

31st January 2010, 02:57

They're the same width, the 50 has a higher profile.

Yes, you might be loosing out slightly on the straights although you'll be gaining ten fold in the corners. Although personally i'dve not thought that 5% difference would be that noticeable, surely?

31st January 2010, 08:32

Cheers - What about the 14" rims?

What do you run on tracK?

31st January 2010, 09:21

lol at 195 vs 195 is increased width.......another sax-p noob pretending to know it all!

iv driven with 15/195/50 r888 whilst using 45 profile on the road.
i didnt notice any difference between the 2 with regards to lack of speed down the straight.Felt a tad,and i mean a tad slower pulling out of the corners,but the increase in grip would be so much better it makes up for itself.

the reason most people use 15 inch is to get bigger brakes under the wheels,if your using standard sized brakes then use 14's.but still use a good quality motorsport type wheel for weight saving and extra cooling.

comparing our cars to full race cars is stupid,as they can virtually run any gear ration to make up for any other changes.

the slowness you felt is due to you changing the final gear ratio.

31st January 2010, 11:36

Too true abount comparing to race cars! I will just try the 14" VTR wheels on the next track day to see how they feel before jumping into another set of 14" 888's and like you say find minimal difference.

Race VTRs in the 750 championship use the 14" wheels - A048 tyres

Talking about ratios what box does suit track conditions best?

Cheers

31st January 2010, 12:28

Quote:

Originally Posted by littleracer

lol at 195 vs 195 is increased width.......another sax-p noob pretending to know it all!

Sorry littleracer you are wrong!

Even a 195/45 R15 Michelin is not the same width like a 195/45 R15 Bridgestone for example, its just a value with a little room for tolerance.

Tyres are always a bit different depending on the brand, the model, application, profile height.

So there is a convention that a tyre with more profile, nearly always used to be a bit wider as the model by same tyre with less profile height.

A good example are the 195/50 R15 tyres.

If you don't belive go and measure.

There are people who would feel a difference from things like that and many who won't notice.

But of course with semi slicks, the roundtimes should be better.

Robert

31st January 2010, 13:57

cant get 888 in 185/65/14. Dont think you will gain alot by reducing wheel size, If anything go down to 13 inch and run used slicks, Can get them for pretty much free

Plus new tyres are cheaper aswell....

31st January 2010, 15:19

Quote:

Originally Posted by Oxas16V

Sorry littleracer you are wrong!

Even a 195/45 R15 Michelin is not the same width like a 195/45 R15 Bridgestone for example, its just a value with a little room for tolerance.

Tyres are always a bit different depending on the brand, the model, application, profile height.

So there is a convention that a tyre with more profile, nearly always used to be a bit wider as the model by same tyre with less profile height.

A good example are the 195/50 R15 tyres.

If you don't belive go and measure.

There are people who would feel a difference from things like that and many who won't notice.

But of course with semi slicks, the roundtimes should be better.

Robert

lmao,them manufacture tolorences are neglible.
your not even gonna be talking the difference of 1mm.
the manufacture is advertising a tyre at 195 it is going to be 195.cant have less as thats false advertising,a saftey hazard from not fitting the rim properly.
its not going to be over 195 as the manufacture isnt going to give you something for nothing.
tyre size is a measurement,pure measurement theres nothing else to it.
one mile is one mile,any difference is going to be down to manufactures measuring tolerence being out of calibration,moulds differing in calibration.
a tyre has to fit the rim perfectly,its a standard fom the j rating of a rim to the tyre size to fit.
profile is exactly the same.
there isnt any magical numbers or big secret in it,just basic mathamatics tbh.
you have aspect ratio,which is a percentage of the width of the tyre = the height.but its a tiny amount and unoticable.

31st January 2010, 16:35

Take a 195/45 and a 195/50 put them together measure and you will see, belive it or leave it.

Enough OFF TOPIC but yes 50 profile accelerates lamer as a 45 profile, that was the topic

31st January 2010, 17:38

Side wall height has increased.... therefore rolling circumference has increased... Resulting in lower torque force exerted by the wheels.... thus lower acceleration.

You're not imagining things man, the 45 profile will cause you accelerate quicker.

31st January 2010, 18:07

Quote:

Originally Posted by littleracer

lmao,them manufacture tolorences are neglible.
your not even gonna be talking the difference of 1mm.
the manufacture is advertising a tyre at 195 it is going to be 195.cant have less as thats false advertising,a saftey hazard from not fitting the rim properly.
its not going to be over 195 as the manufacture isnt going to give you something for nothing.
tyre size is a measurement,pure measurement theres nothing else to it.
one mile is one mile,any difference is going to be down to manufactures measuring tolerence being out of calibration,moulds differing in calibration.
a tyre has to fit the rim perfectly,its a standard fom the j rating of a rim to the tyre size to fit.
profile is exactly the same.
there isnt any magical numbers or big secret in it,just basic mathamatics tbh.
you have aspect ratio,which is a percentage of the width of the tyre = the height.but its a tiny amount and unoticable.

But there's still a difference. So really you've just made yourself look like a child calling that other guy a "sax-p noob", just so you could look like you know what your talking about.

31st January 2010, 19:45

195= 195mm
50= 50% of the width (195mm in this case)
15= 15inch diameter of the wheel it fits.

Surely it is that simple? Can a tyre be sold as 195mm wide if it isn't?

31st January 2010, 20:55

Quote:

Originally Posted by col101

195= 195mm
50= 50% of the width (195mm in this case)
15= 15inch diameter of the wheel it fits.

Surely it is that simple? Can a tyre be sold as 195mm wide if it isn't?

there are variances (which is why wheels have to be balanced and that)... but they're 1-2% if that...

31st January 2010, 23:21

Quote:

Originally Posted by Saaamon

But there's still a difference. So really you've just made yourself look like a child calling that other guy a "sax-p noob", just so you could look like you know what your talking about.

maybe you shuld re read my first post,it said there wold be only slight differences and would be negligible.which is basicly what adsayer has said.

Quote:

Originally Posted by col101

195= 195mm
50= 50% of the width (195mm in this case)
15= 15inch diameter of the wheel it fits.

Surely it is that simple? Can a tyre be sold as 195mm wide if it isn't?

top and bottom yes

Quote:

Originally Posted by adsayer

there are variances (which is why wheels have to be balanced and that)... but they're 1-2% if that...

saamon take no of abovequote!!!!!!noob!

31st January 2010, 23:29

may i add another dimension to this.
without any noobs flaming me down.....if you dont know,cant contribute to the thread you should kindly f'ck off!

the r888 and similar tyres are of a softer,stickier compound compared to normal road going tyres.
This can also increase rolling resistance slightly as it will need more energy to overcome the extra stickiness.id say that would be the most biggest single contributer to rolling resistance.

as a side note,the vtr wheels do not offer much in the way of cooling,and could overheat standard brake set up especially on a tight twisty track or a track which has hard braking from high speeds (rockingham for example)

just take it easy.

1st February 2010, 01:04

The overheating brake point is a good one, and something to consider is that if a wheel does look as though it's not going to offer much cooling, brake ducts might be a good consideration, but on the other hand, not overcooling the brakes too much if you've got a pad that's got no bite from cold...

1st February 2010, 10:11

I done a day at Bedford on Michelin Pilots
They were all brand spanking new 195/45/15
I was very surprised they gripped very very well! There was only one corner i noticed the difference over r888's and that was a 120mph chicane at the end of the main straight.
They didn't wear bad either i done 4 hours out of 7 on track and there was plenty of meat left on them from 21runs at Santa pod. Then sold the wheels and tyres with 3mm tread left on them.

For the price of them you might aswell get r888's but it was just the fact they were already on the wheels when i picked them up.

1st February 2010, 15:41

Are you talking about the Exalto PE2?
I know some people, who say that these are next to good semislicks.
I use them also, and they are gorgeous. They are one of the best road tires in 195/45R15.

Robert

1st February 2010, 15:51

Exalto PE2... I've got them too. I've had them on my car for 10,000 miles and they look like they've lost about 0.00000001mm of tread since then. My rears are originals from my old car and they've done close to 60k... no lie. And on top of that they grip stupidly well

1st February 2010, 15:58

Before I get my Ultras with the new PE2 I got the Michelin SX GT s the pair on the rear hat about 150.000km.

Michelin is known for that less treadware!

1st February 2010, 16:02

PE2's are excellent, just a shame they cost so much.

I had SX GT's all round on my VTR and I rated them just as highly - tread never seemed to wear down. Unless you drive like a total mad man, you'll probably find the sidewalls crack before you can get the tread down to borderline legal limits.

1st February 2010, 16:41

Quote:

Originally Posted by littleracer

may i add another dimension to this.
without any noobs flaming me down.....if you dont know,cant contribute to the thread you should kindly f'ck off!

1. you've made yourself sound like a right cock. if you think someone is incorrect it is possible to correct someone without insulting them.
2. you were a noob not so long ago. just because you have been a member longer or have more posts doesnt mean you know more than them. also if you jump down someone's throat just for contributing to a thread its not exactly going to make a good impression and new members will be less likely to stick around.
3. your wrong. a 195 tyre doesnt have to be 195mm wide. go and measure a load of tyres yourself. they do vary and by more than 1mm or 2mm.

e.g. http://www.jaxquickfit.com.au/blog/2...pecifications/

a 280 tyre thats actually 302mm wide

from my personal experience 195/50 tyres are generally a bit wider than 195/45 tyres

having said that i do agree that people should be corrected if they are wrong in an attempt to improve everyone's knowledge but there are ways to do it and ways not to i.e. telling people to f**k off.

3rd February 2010, 09:27

Quote:

Originally Posted by Curran

1. you've made yourself sound like a right cock. if you think someone is incorrect it is possible to correct someone without insulting them.
2. you were a noob not so long ago. just because you have been a member longer or have more posts doesnt mean you know more than them. also if you jump down someone's throat just for contributing to a thread its not exactly going to make a good impression and new members will be less likely to stick around.
3. your wrong. a 195 tyre doesnt have to be 195mm wide. go and measure a load of tyres yourself. they do vary and by more than 1mm or 2mm.

e.g. http://www.jaxquickfit.com.au/blog/2...pecifications/

a 280 tyre thats actually 302mm wide

from my personal experience 195/50 tyres are generally a bit wider than 195/45 tyres

having said that i do agree that people should be corrected if they are wrong in an attempt to improve everyone's knowledge but there are ways to do it and ways not to i.e. telling people to f**k off.

thank you the best bit of advise i've heard in ths tread

3rd February 2010, 13:52

anyone that says all 195 tyres are the same width is a "n00b"

as you can see the toyo with the 195 profile on the left is wider than the faulken with the 205 profile

Also to agree with ads, michelins as road tyres are freaking awesome, my rear tyres have been there from new. and are pretty perfect

3rd February 2010, 14:11

bloody awesome example...! I didn't think it varied that much though!

3rd February 2010, 14:16

Quote:

Originally Posted by adsayer

bloody awesome example...! I didn't think it varied that much though!

From what toyo say it's a new "wider footprint" design being used on this tyre to increase contact patch on the roads

im looking forward to trying these out, i held one up next to my michelin and it does seem a fair ammount wider

3rd February 2010, 14:20

but it's not a '195' then is it really???

I'm confused

3rd February 2010, 14:21

Quote:

Originally Posted by adsayer

but it's not a '195' then is it really???

I'm confused

I thought the same, not really sure on how it all works

they sell a 205 version too, so that mush be very wide on a 15" wheel

3rd February 2010, 14:26

oh hang... I just saw the rim size... there's 12.6mm difference... that'll push the tyre out slightly - making it wider.

3rd February 2010, 14:28

Well spotted

i never noticed that

that'd make the tyres of the same witdh (if on the same 6.5" wide wheel (or 7"))

so still a wide tyre for a 195, proving that not all tyres of the same width are the same