17’s slow you down - fact

[geordiepaul]

After my first encounter with the Clio Cup and CTR when I got cained by them both - they both pulled about 10+ car lengths on me. I met up with Paul (Cuppy 172) in his cup again this morning - same place, same roads everything but this time with the 16s back on albeit with very little tread left!!

This time there was nowt in it kept up all the way to a tonne. No 10 car lengths this time round!! The Cup is definatley slightly quicker but not noticeably on the second run I missed third slightly and he pulled up along side .

So there you have it, I knew I was right.

 

[McBunny]

well we will have to see at run what ya brung wont we its the only way we are going to find out

 

[JJ172]

Not surprising really!

195/45x16s are 582mm diameter

205/40x17s are 597mm diameter i.e. 15mm bigger

 

[McBunny]

yes but that isnt 10 car lengths !!! anyone who was on the euro trip can say that my car wasnt a slouch against those with 16s on

 

[geordiepaul]

To be fair both runs were on a slight incline which wont have helped either but 10 car length is what it was Paul will hopefully post and confirm what Im saying.

 

[JJ172]

Increasing the rolling diameter will definitely slow you down....but is supposed to increase top end speed by a fraction.

 

[Steveold]

17s also have wider tyres so more rubber is touching the road slowing u down..... 17s also are heavier than 16s so that also slows you down.. 17s have a bigger diameter and that slows you down....

But 17s look good and enable you to corner faster because of the extra rubber.....

 

[Fred@BTM]

Try my SuperLs on your car against him, i reckon its all to do with weight

 

[jasonjz]

Its common fact, the bigger the wheel, the more rolling radius there is. this means the acceleration wll be slower, but the top speed will not be effected unless the speed rating on the tyre is below "v" (150mph).

 

[Steveold]

Quote: Originally posted by Fred2001Dynamic on 28 April 2003

Try my SuperLs on your car against him, i reckon its all to do with weight

So what about the 40mm of extra rubber thats touching the road?

 

[jasonjz]

All goes with the rolling radious, its as clear as a glass of water that because the wheel is bigge the radius is going to be also. Im getting 17" K2s for my RT, i know about the accelaration problem, so im gonna have to deal with it i suppose!

 

[Adams_16v]

i have 17s on and its definately slower...... booooooooooo!

 

[geordiepaul]

Its got nothing to do with weight the 17s I have a are fractionally lighter than standard 172 16s. Im looking into getting different tyres 215/35R17 they are exactly the same diameter as the 16s but slightly wider

 

[Fred@BTM]

and more expensive!!!!

 

[Sport182]

£1000 for an extra inch is ok if it in the right place!! But personally i cant see the point in spending it for a 1" gain on the wheels!!

 

[McBunny]

mine were free

 

[Sport182]

Yeah, thats probably cause you left your neighbours car up on bricks!!! lol

 

[andysport]

ive got 17" super turismo on mine and it doesnt feel any different apart from I reckon i get more grip from standing starts.

 

[McBunny]

nope previous owner put them on and as i only payed 10500 for the car with 12700 miles on id say thy were pretty much free

 

[Sport182]

Result!!

The whole reason i first joind this forum was to decide whether to go for 17 or 16s on my MKI 172 there must be near on a 50 50 split here, So i am still none the wiser!!!

Personally i cant see it not having some sort of effect on the performance, just look at that rules of physics, but the bottom line is you have weigh up the style factor against the Affect on performance.

If it was that much better with 17s the manufacturer would have supplied them as standard.

 

[McBunny]

if you put all the figures into cartest (nice program) there is naff all between them but hey ho it might be wrong but its not been far out yet

 

[Paul16V]

Manufacturers only put small wheels on in case you carry like 3 people weighing loads in the back. If you dont it doesnt matter if you have bigger rims. Its not that much difference between a 16 inch and a 17 inch rim anyway. On turbo cars its actually meant to be better having bigger rims and can make em accelerate faster cos they have better traction. Get your car turboed! hehe