Why do 15's make the handling better?

[jack_kemp]

So I understand the idea of having minimum unsprung weight, and a smaller wheel being lighter.
But weight aside, why would a 15'' wheel with a 50 profile tyre be better than a 16'' alloy with a 45 profile tyre? When the overall diameter of the tyre/wheel combination is almost identical?

 

[lindleyp]

depending on the alloy the main reason is shedding weight reducing unsprung weight, reducing this makes the car more nimble and sharper also the pick up is some what quicker. reason most go 195/205 50 15 is the HUGE saving in money for tyres, also depending on track rubber the tyre side wall is alot stiffer which is good because it reduces tyre ''roll'. hope thats hit the nail on the head. utilisation of the cheapness of a common tyre size. pluss it fills out empty arches

 

[jack_kemp]

So the only reason to get a 15'' Ultraleggera over a 16'' is the price of tyres really (discounting the few grams of weight difference as they're both stupidly light)
Thanks for the reply.

 

[lindleyp]

Putting weight saving aside and looking at tyres then in my own opinion Yes 100%, tyres are so much cheaper and not only that, were spoilt for choice as theres ALOT more tyre options available for 15''.

 

[jack_kemp]

Cheers for the reply mate.
That just makes my decision all the more difficult....

 

[lindleyp]

dont forget i myself am selling up my much loved turinis ha, as much as i love them i like 'go' more than 'show' and its hard to envision a cup with anything but turinis, take the dive and try something different..

 

[john lloyd]

i have ran 15s and 16s as well and loved it on the 15s felt it was the extra play in the tyre side walls just took the harsh edge and twitch out of the fairly hard oe suspension and reinforced pe2's

 

[Kam.]

The other benefit is the larger sidewall allows the tyre to absorb more vibration and bumps through the tyre carcass

 

[Malachi]

Do reinforced tyres have any real benefit when cornering? Or would you corner just as well with "normal" non-reinforced tyres?

/noob

 

[Kam.]

yes. The tyre is more likely to stay on the rim under high loads for a start! It will also control the tyre contact patch better.

 

[TheEvilGiraffe]

Say a wheel has a mass of 10kg when you measure it on your bathroom scale...

When that wheel is rotating, it's equivilent mass is actually higher. Some homework ...:

http://daliracing.com/v666-5/info/article_read.cfm?articleID=401

 

[Malachi]

Shame the Rainsports aren't reinforced then... anyone used the Rainsports and PE2s? Any opinions on their differences?

 

[lindleyp]

depends what tyres your using to be honest, with rubbish economy tyres you wont benifit so much in handling, with good sticky rubber you will benifit 10 fold! its the only thing thats keeping you in contact with the road so never ever skimp on tyres, things like handling, braking, turn in etc will be drastically compromised using rubnish tyres.

Using the correct tyres for what your using the car for i.e track, then youl want some dedicated track compound rubber. Dont get me wrong road tyres can be used but wont last very long of give enugh grip for a serious driver.

thers 100's of threads on what tyres to use for road, track, winter etc, just search.

 

[.Kev.]

Its mass whilst rotating may be 2x or 3x of that whilst static but the lighter wheel will accelerate faster.

 

[.Kev.]

888's all year around

 

[jack_kemp]

Shame the Rainsports aren't reinforced then... anyone used the Rainsports and PE2s? Any opinions on their differences?

I've got rainsports on the back of mine and pe2's on the front ( bought it like that) but I swapped them round a couple of weeks ago, just for a little experiment, and found the rainsports to be a lot better, not as much overall grip, but more predictable. I only tried them in the damp and cold though and the rainsports are newer, so don't take that as gospel.

 

[jack_kemp]

Its mass whilst rotating may be 2x or 3x of that whilst static but the lighter wheel will accelerate faster.

I've read up about relative masses a few times, Figures anywhere between 3x and 5x are quoted... Considering each ultraturismo is nearly 4kg lighter, it's going to have to be done I think.

 

[Malachi]

I currently have PE2s all round on the standard 16s (which so far have served me well whilst caning it around bends and corners), I just wondered what it would be like moving to Rainsports on 15s.

 

[jezcharger]

Shame the Rainsports aren't reinforced then... anyone used the Rainsports and PE2s? Any opinions on their differences?

I used a brand new set of 15" Rainsports on track on saturday, and they were excellent. I was a bit worried because before I got them fitted the side walls looked comically flimsy. but running 29psi front and 32psi rear they were spot on. Loads of feedback and very little wear after 200+ track miles. It was cold tho so maybe not as good on a hot day. Never used PE2 but they are twice the price.

 

[Malachi]

Thanks jez, that's nice to know :approve:

Need to raid my savings account now...

 

[jezcharger]

Thanks jez, that's nice to know :approve:

Need to raid my savings account now...

Pity you don't live near Stoke I can get them fitted for £38 each...

 

[The Boosh!]

I prefured the handling on my turinis than I do to the 2118's.

15" with 195 tyres feels more 'playful' but imo 16" with 205 tyres felt more planted.

 

[Kam.]

I prefured the handling on my turinis than I do to the 2118's.

15" with 195 tyres feels more 'playful' but imo 16" with 205 tyres felt more planted.

Grip and handling are two separate entities. The wider and lower profile tyres will probably give a better contact patch when cornering, but the lighter smaller alloy will change direction faster and help with acceleration and braking etc, and of course allow the suspension to react faster.

 

[jack_kemp]

Having looked around for Ultraleggeras, I don't seem to be able to find them in 15'' and 7'' wide.... Which I believe is the width of the standard turinis? They only make them up to 6.5'' wide as far as I can tell....

 

[ripp]

not true^
a friend has 15x7" ultras on his 172. maybe they are harder to get right now

 

[jack_kemp]

Any idea where he got them from?

 

[ripp]

he bought the car with them on so couldn't tell
edit: you could email here: info@ozracingltd.co.uk
according to the official website they're the UK distributor

 

[Malachi]

Pity you don't live near Stoke I can get them fitted for £38 each...

I need to get some alloys first! Having said that, there is a small tyre shop in Essex that usually are pretty good on price... sorted out a few Kwik-Fit nightmares for me too >_>