15" v 17"

[Šįk]

can sum1 explain y 15" is so much better than 17" even though you can get lighter 17" alloys than the average 15"...?

Surely if you had either a set of 17" weighing in at 6.2kg and 15" weighing in at 7.5kg, surely the 17" would be just as good if not better on a long straight!??

Isnt it all to do with rotational weight?

 

[Inactive]

I think people mean 15 look better... dont get 17 to fill the gaps.

I have 17s wish i had 16 an springs

 

[Bazzon]

its not only about weight though.

 

[MikeyK18]

17"'s would have a slight more unfortable ride

 

[White16valver]

15s give you a more flexible limit too due to higher sidewalls - 17s will naturally be more grip/slide due to stiffer, smaller sidewalls.

 

[mini-valver]

A 15" wheel turns 1 rotation quicker than a 17" wheel, so power is transferred into motion quicker. Thats my understanding anyway.

 

[joebristolgym]

I had 15's on until recently and it just seemed like the car was more lively - turned in quicker, and seemed to accelerate a tiny bit quicker.

Got the standard 16's back on now and ride is less comfy, and less lively.

15's all the way for me - I'd never put bigger wheels on a CLio, only smaller ones (with a decent drop on coilovers of course)

 

[c__w]

A 17" alloy wheel at 6.2kg is extremely lightweight for that size. If they are really lighter and you can fit tyres that are the same rolling radius then they would be beneficial but unless they're made of magnesium they tend to be heavier than smaller sizes.

 

[ForceIndia]

I believe it's due to rotational inertia, more to overcome with a 17inch wheel.

 

[Šįk]

ok some good fair points there, but I'm sure extra light 17's with the perfect offset and awsome tyres (correct tyre wall etc ) would become just as good, and better mid/top range speeds through the gears.

Also In my opinion 15"s just look too small for the arches on the car but can just get away with a massiv drop on coilovers then they look ok but then ends being an expensive option..

What is the perfect offset and what would be the best tyre wall size on 17"s, 45,50?

 

[drhowser]

iirc. a 50/15 has the same rolling radius as a 45/16, so to get the same with a 17" wheel i'd assume you would need to go down to a 40.
this is why you will have a less comfortable and snappier ride with 17"s. you could run higher sidewalls, but then you are increasing the gearing.

 

[iimushroomzii]

and better mid/top range speeds through the gears.

Explain?

 

[drhowser]

Explain?

longer gearing.

sadly also 1980's diesel acceleration:dapprove:

 

[Šįk]

well surely bigger wheels will make the gear ratios bigger (not massivly) slower accel but higher gains later on through the gears 3/4/5 (4k rpm onwords) which would should be quicker if your already rolling fast in 3rd and maby top speed.... plus the lighter kg the bigger wheel will vastly improve accelleration. .....Correct me if I'm wrong..?

 

[iimushroomzii]

I see what you mean now yeah! Although surely thats top top speed, which is pretty much never seen? Be better off getting the 15's for better acceleration, or go half way with 16's.

 

[drhowser]

thats correct,

but i have you ever managed to hit the limiter in 5th?

 

[Šįk]

Yea but then again 15"s I'm sure will cause alot more chance of wheel spin and loss of traction in the wrong weather which is most the time in the uk..

Light alloys act in the same way a light fly wheel does. And if u have both (light flywheel and alloys) then you will get alot more power to the ground, ubwont lose as much.

Ktec do a light fly wheel (30% lighter iirc) and the standard 172 wheels way about 18kg each (with tyres) and you can get light alloys which become about 40% lighter minimum. If u had both then you have saved 70% weight thru rotational weight which heavier than sitting weight (car) so intact I rekon instead of getting 145bhp to the ground you could acheive maby 155bhp, thats a rough guess througj theory mind...

 

[drhowser]

so you are calculating that longer gearing will put more power down? if so would that not increase the chances of wheelspin..
why not get a set of lightweight 15's and save 100% weight thereby creating the worlds first zero-g car.
why not put 20" wheels on a caterham and break the speed of light?

yes, a greater radius does increase the top speed in theory, but there are quite a few other factors that are going to have a bit more of an effect, how about transmission losses, aerodynamics, and still having exactly the same power output?

yes.
rotational and unsprung weight has a greater effect than dead weight.

no.
17's will not make your car faster, not even a little bit.

(and no, the world isn't flat)

 

[White16valver]

Yea but then again 15"s I'm sure will cause alot more chance of wheel spin and loss of traction in the wrong weather which is most the time in the uk..

In standing water and snow, thinner tyres (as usually found on a 15" rim when compared to a 17" rim) are better as they cut through to the surface better due to increased pressure on a given area.

 

[mini-valver]

Bigger wheels will extend your gearing slightly, yes. But you have exactly the same torque output so not only will you get to the terminal speed slower, the terminal speed will always be the same.

 

[Šįk]

so you are calculating that longer gearing will put more power down? if so would that not increase the chances of wheelspin..
why not get a set of lightweight 15's and save 100% weight thereby creating the worlds first zero-g car.
why not put 20" wheels on a caterham and break the speed of light?

yes, a greater radius does increase the top speed in theory, but there are quite a few other factors that are going to have a bit more of an effect, how about transmission losses, aerodynamics, and still having exactly the same power output?

yes.
rotational and unsprung weight has a greater effect than dead weight.

no.
17's will not make your car faster, not even a little bit.

(and no, the world isn't flat)

well done to u for the gr8 attitude :star: !! , i love ppl like u!

....:nono: tutut!

 

[Šįk]

ok well thanks for all the comments and imput guys

 

[DannyR]

Had 17's on my valver when i bought it changed them for 15's on 45's smaller than standard and the difference with accelration were un real!

 

[drhowser]

its not only about weight though.

17"'s would have a slight more unfortable ride

15s give you a more flexible limit too due to higher sidewalls - 17s will naturally be more grip/slide due to stiffer, smaller sidewalls.

A 15" wheel turns 1 rotation quicker than a 17" wheel, so power is transferred into motion quicker. Thats my understanding anyway.

I had 15's on until recently and it just seemed like the car was more lively - turned in quicker, and seemed to accelerate a tiny bit quicker.

Got the standard 16's back on now and ride is less comfy, and less lively.

15's all the way for me - I'd never put bigger wheels on a CLio, only smaller ones (with a decent drop on coilovers of course)

A 17" alloy wheel at 6.2kg is extremely lightweight for that size. If they are really lighter and you can fit tyres that are the same rolling radius then they would be beneficial but unless they're made of magnesium they tend to be heavier than smaller sizes.

I believe it's due to rotational inertia, more to overcome with a 17inch wheel.

iirc. a 50/15 has the same rolling radius as a 45/16, so to get the same with a 17" wheel i'd assume you would need to go down to a 40.
this is why you will have a less comfortable and snappier ride with 17"s. you could run higher sidewalls, but then you are increasing the gearing.

In standing water and snow, thinner tyres (as usually found on a 15" rim when compared to a 17" rim) are better as they cut through to the surface better due to increased pressure on a given area.

Bigger wheels will extend your gearing slightly, yes. But you have exactly the same torque output so not only will you get to the terminal speed slower, the terminal speed will always be the same.

Had 17's on my valver when i bought it changed them for 15's on 45's smaller than standard and the difference with accelration were un real!

i'm sorry if i sound harsh, but what is the point asking questions if you won't listen to the answers?

 

[Šįk]

I have, im just getting my thoughts/opinion accross to argue the point, I haven't said anything any1 has said is wrong, false etc... What I have said is what I originaly thought and to try and understand other peoples posts. I made the thread to see if my opinion was correct or not, which in parts i wasnt, I admit that. So the thread achieved it's purpose, basicly to double check my theory on the whole subject...

So how? please explain...?

 

[c__w]

The two big concerning factors as overall weight (both tyre and wheel) and overal diameter (or rolling radius). If the 17" wheel and tyre weighs the same and is the exact same rolling radius then there should be any noticable difference in performance (ignoring stiffer sidewall from lower profile tyres).

 

[drhowser]

no worries at all fella.

basically, if you had limitless power, you are correct. increasing the wheel size (gearing) will give you a higher top speed, but at the cost of reduced acceleration.
if you have sufficient power, then the reduced acceleration will not matter- you would just open the throttle further and overcome it.

unfortunately, there is not any excess power with a 1*2, so people go the other way and reduce the gearing. not just by using 15's, but also with the gearbox.
hissingsid had a sadev straight cut box for sale, and iirc top speed was close to 110.
you might loose out slightly on long straights, but what you gain through and out of corners means that you would be quite a bit quicker round a circuit.

there are a lot of other pro's and cons, a 17" wheel means you would have a slightly larger tyre print, but at the cost of increased rolling resistance,
then you have the issue of radius, you can fit low profile tyres and keep the original gearing, at the cost of snappier handling. or you can use a slightly higher tyre wall for a more forgiving limit, but at the cost of acceleration.

there is more to it than that, but you get the picture?

what are you aiming to achieve with the car?

 

[Bash]

There is very little difference on a clio, if you dont believe me I'll give you a race.

 

[Šįk]

what are you aiming to achieve with the car?

well i want it to drive good, better than standard, but also look good as i only use it for general day to day use and have the odd thrashing down some gr8 b roads... :S

 

[Tigger]

The first thing I put on my previous Clio was a set of 17s - loved them

I spent ages deciding as I was only "getting into modifying cars" and didn't really get what it was all about lol. So discussed it on so many threads/forums and decided to go ahead and get a set, despite some people putting me off with horror stories like;

MPG will suffer
Bearings will go more often
Wears out your Power Steering
The tyres will rub the arches
You won't get full lock - at all
Will void your warranty (my car was 6 months into a 3year warranty)
Renault won't look at it if anything goes wrong, even if it's not related to any modifications

I had 17s on for over 3 years without any major problems -

Only thing I had to do was remove my mud-flaps, which looked better anyway
It did catch at first on full lock, but only because there was something making my arch-liner pop out, easily sorted

I needed to replace one rear bearing and I had the car for almost 4 years from new!

Hope the above helps
Trev