How much do 17’s slow a valver

[_Tom]

How much do 17s slow a valver down by? When i swapped at first i didnt think there was a difference but i now appear to have lost power. Do they make much of a difference? Everyone i spoke to seems to think the power loss is the wheels!

 

[cliopower]

yes, because they are heavier and have to cover a longer distance. Its only a few bhp but you can regain that by adding an air filter or something, plus you get the looks and grip of a 17" wheel.

 

[_Tom]

Well heres the full story.....I got my car on 17s and lowered. Drove it for a week and then it went to the garage for a full service,head gasget, Timing belts and cam belt. I got it back and from then it seems much slower! Ive taken it to a few garages and they say the engines fine and that the 17s slow it down. I bought a ram air IK which helped a tad but do you lose much power with 17s? Cus i didmt think i lost any before it went to the garage.

 

[Smokey]

I dont think i lost any power fella when i changed from 15s to 17s!!

Its not noticeable anyway!!

Its like removing your back seats, you hardly notice any gain either!! All phsycological IMHO!!

 

[_Tom]

i noticed no change either at first! Just Clutchin at straws to find where me power has gone! Gunna Get a new fuel pump anyway cus i think mine f**ked! Who knows, that be where my horses are hidin!

 

[u33db]

Id say theyd make a hellova difference! I had 16s on my valver until a few months ago then changed back to phase 1s and i noticed a difference immediately....

 

[Scott Wood]

My mate, stuck 17" on his RS2000, he then went back to the 15" for a week, and the difference was mad! id like to go back to 15" on my valver just to see what difference it would make to mine.

 

[_Tom]

Ive still got me phase 2 satndard 15s. May pop em on again for a while and see what happens! Havent had em on whilst its been lowered either, Should look nice and authentic.

 

[iPap]

The extra width slows cars down as well!

 

[Daz.]

Surely if the 17s are lighter than the wheels theyre replacing then it wont be such a dramatic loss?

 

[chip16v]

17s do make a difference! well top end anyway. like most of you i couldnt notice the difference but when i tried a max speed run with 17s on it struggled to make 130 mph but with 15s on the car will hit around 140 mph(at the limiter) quite easily. the 17s are now off and wont be goin back on even thou they look so good

 

[Clio16vPaul]

your changing the gearing... so you lose acceleration and gain top speed, put tiny wheels on it and you would accelerate quicker and have a lower top speed. thats why your meant to keep the rolling radius the same.

yes, the weight and width of the wheels will create drag, and the heavier the wheel the harder the car works to spin it, but they aint going to be heavier than the phase 2s if thats what you have.

you arent losing BHP... thats at the engine end, just changing your gear ratios....

 

[_Tom]

All the answers seem very varied! I seem to have lost a bit of acceleration and defo top end (not gettin much more than !20) Im gunna have to put me 15s on and test!

 

[Adams_16v]

15s all the way. mine was loads slower with the 17s on! loads!

 

[_Tom]

My cars in the garage as we speak tryin to have its power loss sorted. i asked bout me 17s slowin it down but the bloke at Renatec said 17s should increase acceleration at first but then kill your top end! Its all down to gearing which makes sense if you put your mind to it!

 

[Tom_16v]

Hes got that the wrong way round.

Smaller wheels - better acceleration

Bigger wheels - better top end

Simple solution to this is go and stick some 15"s on it and see how she goes!

 

[_Tom]

Yeah im just waitin for the right weather! If it stops rainin sometime this weekend ill put me standards on!

 

[Cord-172]

Dont forget that the speedo readout is affected by the size of your wheels anyway., It may look like you are getting slower top speed but the sppedo is not to the right configuration anymore anyway!

Plus, all speedos are fairly inaccurate past 100mph