OK, am I right in assuming that if you go from 16" to 17" wheels that your speed/mileometer needs to be adjusted accordingly.
Reason I ask is that in the new sillycar we covered 120 miles in 2 days, which is great, but we have sort of worked out that we dont think we actually did cover that amount.
I would "presume" that when Mr T put the 17" on the car they would have fiddled with the dials, but I have learnt not to assume anything with them. I need to call them to ask for my holding deposit back, will I look stupid asking the question about the miles?
bigger wheels usually means lower profile tyres, which keeps the rolling radius the same.
so yes you would look silly.
I'd be a bit stunned if they'd not sorted this... but you never know.
m http://www.miata.net/garage/tirecalc.html (http://www.miata.net/garage/tirecalc.html) m
As Markiii said the tyre is usually lower profile consequently the rolling radius is the same ie no effect. Any changes will be marginal and if and dealer/garage said they had made any changes to the dials I would laugh in their faces s:wink: :wink: s:wink:
Only factor honestly worth considering when upgrading to larger wheels is the additional weight of the wheel(if applicable) and or the harder ride of lower profile tyres, other than that any changes to be quite honest are negligable and un-noticable
You often read wild negative statements regarding changing wheels to a larger size and decreased acceleration etc, these statements are usually made by the "leave your car looking like everybody elses" brigade and to be honest are more to justify their own course of action (or lack of it) s:wink: :wink: s:wink:
(stands back awaiting incoming fire )
Cheers boys for the valuble advice as normal.
I wont say anything to Mr T then s:lol: :lol: s:lol:
I will however be installing the B2 at the weekend, and would obviously expect the usual 4mph outage in relation to the speedo...anything more than this would point to a problem...but I am now satisified based on your advise that all is well and happy.
You are of course all correct, the new 17's do in fact have lower profile tyres on than the stock 16's
Quote from: "perry190"You often read wild negative statements regarding changing wheels to a larger size and decreased acceleration etc, these statements are usually made by the "leave your car looking like everybody elses" brigade and to be honest are more to justify their own course of action (or lack of it) s:wink: :wink: s:wink:
(stands back awaiting incoming fire )
OK - you wanted flaming so here you go
s:flame: :flame: s:flame: s:flame: :flame: s:flame: s:flame: :flame: s:flame: s:flame: :flame: s:flame: s:flame: :flame: s:flame: s:flame: :flame: s:flame: s:flame: :flame: s:flame: s:flame: :flame: s:flame: s:flame: :flame: s:flame: s:flame: :flame: s:flame: s:flame: :flame: s:flame:
A little applied maths ('A' level stuff) quickly shows why the acceleration is slower with the larger rims - even when the total weight is the same, the mass is further out on the larger rims, and hence requires more energy to get it moving.
Another (really nasty) side effect is the wheels act more like gyroscopes when you move the mass so far out, so when you try to change direction the wheel is fighting you by trying to stay in a straight line.
Impirical research with markiii's car shows that the 17" wheels and tyres (despite being only marginally heavier overall) robbed him of nearly .5 second to 60 (mind you that's not as bad as the 1.0 second he lost by using the decat pipe s:oops: :oops: s:oops: )
not quite sure where the figures came from, but there definately was a difference.
However, that was with a couple of kilogram weight increase and a slightly larger rolling radius, both of which are bad.
While the theory regarding weigth placement is accurate, it also depends upon the weigth of your tyres, S)3 fr example are much heavier than Proxies.
Of course getting all the relevant weigths together and doing the math. is a little like hard work.
Now try and find a tyre manufacturer that lists the weigth of teh tyre.
Quote from: "SteveJ"(mind you that's not as bad as the 1.0 second he lost by using the decat pipe s:oops: :oops: s:oops: )
I can just see mark sitting on a decat pipe trying to get to 60... still, a second slower than him in a car aint bad at all! s:wink: :wink: s:wink: s:lol: :lol: s:lol:
Well we drive like girls anyway, and now we have a sillycar we will not be racing around as if we had a 2. YEAH RIGHT!.
Oh, I will not go into the fact that I raced a 03 roadster yesterday.
s:lol: :lol: s:lol: s:lol: :lol: s:lol: s:lol: :lol: s:lol: s:lol: :lol: s:lol: s:lol: :lol: s:lol:
that woke you all up s:wink: :wink: s:wink:
Applied mathematics, cold fusion or quantum physics s:wink: :wink: s:wink: aside I have yet to notice any performance loss when upsizing from 15" to 17" or 16" to 18"
likewise all this talk of weigh reduction you hear in regards to batteries and exhausts etc? My 190 celica performed identically like for like against an identical car with a driver a good 3 stone heavier than me?
I'm sure these various theories are correct, however........ in the 'real world' where we are not competing in top level motorsport where every performance issue is measured at almost molecular/atomic level :-) :-) :-) then it makes sod all noticable difference unless the differences are major IMHO
If you bought a standard 190 celica whn it was new in 2001 it came with 16" wheels and tyres and had a quoted 0-60 by toyota
If however you bought it with a sports pack it came with 17" wheels and tyres yet toyota still quoted the same 0-60 time and top speed?
So do the 'toyota know best, so dont change it' gang dissagree with toyota on this one? s:roll: :roll: s:roll:
I definitely noticed a beneficial difference downsizing from 17s to 15, though I didn't notice the difference when I upsized.
Empirical evidence from comparing straight line acceleration on an airfield between my car (which then had the Unichip fitted, ~159bhp and 17" wheels) and pmdye's Roadster (stock with 15s) illustrated no comparable difference. Of course there could be 1001 other reasons why the extra power wasn't being demonstrated, however I put it down, rightly or wrongly, to the additional rotational inertia of my not-so-light 17s.
Quote from: "perry190":lol: s:lol: :lol: s:lol: s:lol: :lol: s:lol: s:lol: :lol: s:lol: s:lol: :lol: s:lol:
that woke you all up s:wink: :wink: s:wink:
Applied mathematics, cold fusion or quantum physics s:wink: :wink: s:wink: aside I have yet to notice any performance loss when upsizing from 15" to 17" or 16" to 18"
likewise all this talk of weigh reduction you hear in regards to batteries and exhausts etc? My 190 celica performed identically like for like against an identical car with a driver a good 3 stone heavier than me?
I'm sure these various theories are correct, however........ in the 'real world' where we are not competing in top level motorsport where every performance issue is measured at almost molecular/atomic level :-) :-) :-) then it makes sod all noticable difference unless the differences are major IMHO
If you bought a standard 190 celica whn it was new in 2001 it came with 16" wheels and tyres and had a quoted 0-60 by toyota
If however you bought it with a sports pack it came with 17" wheels and tyres yet toyota still quoted the same 0-60 time and top speed?
So do the 'toyota know best, so dont change it' gang dissagree with toyota on this one? s:roll: :roll: s:roll:
I somehow doubt Toyota actually measured it with the options on.
s:lol: :lol: s:lol: s:lol: :lol: s:lol: s:lol: :lol: s:lol:
If you mean
1.does it look like I give a f##k. Then I couldnt agree more s:wink: :wink: s:wink:
However if you mean
2.does it look like I've got any friends. I honestly wouldnt know Mark have you ? (apart from here) s:lol: :lol: s:lol: s:lol: :lol: s:lol:
edited due to missing text.
ah ha
surely not! s:shock: :shock: s:shock:
Mmmmm I wonder if TRD or TTE actually measure the performance of their mods or not Mmmmmm interesting.
How can life go on as we know it if the Roadster isnt perfect as it is after all s:shock: :shock: s:shock: , or 'god forbid' but do you guys think it could be at all possible that it can be improved on s:shock: :shock: s:shock: s:shock: :shock: s:shock: not possible surely! s:wink: :wink: s:wink: s:D :D s:D
I agree it can be improved.
but lets face it TRD quote 15bhp for a cacbox and inlet duct.
no way did they they get that figure by testing
I'm sure Toyota checked the times for the car as it was intended to be sold. Do I think they re-tested after some marketing/design bod decided on the bolt ons for the option pack? not really.
Bluudy hell, and I thought I was going to look silly asking Mr T. Look at you all - GEEEEEEEEEKS! s:lol: :lol: s:lol: s:lol: :lol: s:lol: s:lol: :lol: s:lol:
oh yes s:wink: :wink: s:wink:
Quote from: "markiii"but lets face it TRD quote 15bhp for a cacbox and inlet duct.
Wasn't that for the duct, manifold and muffler...?
Well Slacey is moving down from 17" to 15" - I wonder what his view is re. acceleration?
Or is he staying away to dodge the incoming fire (can't say I blame him really! s:D :D s:D )
Sundance s8) 8) s8)
Quote from: "Sundance"Well Slacey is moving down from 17" to 15" - I wonder what his view is re. acceleration?
Or is he staying away to dodge the incoming fire (can't say I blame him really! s:D :D s:D )
Sundance s8) 8) s8)
I dodge nothing! s:lol: :lol: s:lol:
I'll be honest, the car is sooo much nicer to drive on the 15's... the 'alertness' is back acceleration wise, the ride smoother, the turn in sharper and less understeery. I love the look of my 17's and will be keeping them, but for everyday thrashing, the stock wheels win it for me.
Quote from: "Slacey"I'll be honest, the car is sooo much nicer to drive on the 15's... the 'alertness' is back acceleration wise
That'll be less rotational inertia then
Quote from: "Slacey"the ride smoother
That'll be less unsprung weight then
Quote from: "Slacey"the turn in sharper and less understeery.
That'll be less gyroscopic effect then.
s:twisted: :twisted: s:twisted: The prosecution rests s:twisted: :twisted: s:twisted:
what size wheels are on the back of yours :-) :-) :-)
16's by any chance? surely not s:lol: :lol: s:lol:
Quote from: "markiii"what size wheels are on the back of yours :-) :-) :-)
s:oops: :oops: s:oops: Ok - I'll admit I have post face-lift car with 16" rears, but of the 3 points I have raised against fitting larger wheels :-
1) Rotational inertia.
Slightly worse than 15's, but nowhere near as bad as 17's
2) Gyroscopic effect.
See 1) except it doesn't apply to the rear wheels (unless the back-end is going sideways and then I really couldn't give a s**t) as they don't change direction in the same manner that the front's do
3) Unsprung Weight
IIRC, no increase in total mass so no effect.
Why do you think Toyota left the front wheels alone when they face-lifted the car s:?: :?: s:?:
I agree, but either the engineers increased the rears so they could go bigger width, to tame the oversteer (unlikely as you can get 7" wide 15" wheels) or it was the designers because the rear wheel arch gap always looked silly compared to teh front..
how I'd love to get inside teh designers head, then I could ask, why did we get this sh*te engine as well :-) :-) :-)
The 'official' reason was to 'make it look more sporty'.
Quote from: "Slacey"Quote from: "Sundance"Or is he staying away to dodge the incoming fire (can't say I blame him really! s:D :D s:D )
I dodge nothing! s:lol: :lol: s:lol:
For his wings are like a shield of steel! s;) ;) s;)
I did ponder changing to the '03 setup (15" front, 16" rear) as part of my '03ifying'.. but only if I can find a stock set for cheap..
Then again, might have to get mine refurbed anyway as guess what? Yup - all the laquer & paint is starting to flake off on the edges of the spokes..
Ok so 17's depending on make & tyre combination might be slightly heavier so the initial force required is more but in the real world it makes bugger all real difference.
The overal radius is pretty much the same so gyro effect pha do you see touring cars running on little wheels I don't think so. Do they have big handeling problems well NO. Yes I know they have very light wheels but they still have a heavy bit of rubber attached to the outside.
Ask yoursel some questions.
1. Do you want the lightest fastest road car ?
Yes - you have bought the wrong Car.
No - you have made a good choice.
2. Do you want to live in the real world and have a car that looks nice handels well goes quite quick ?
You can have this but everything is a compramise. My intension is to have a quick car that looks nice and handels well. I have modded it to achieve these results as I see fit and am happy with it.
IMO the 2 looks much better with 17's but just make your choice....... its your car no one else's.
s:twisted: :twisted: s:twisted: s:D :D s:D s:twisted: :twisted: s:twisted: s:D :D s:D
agreed it's all individual choice. but remember touring cars or any other that runs large wheels as they come from the factory will have had the suspension, final drive, gear ratios e.t.c chosen with the whole package in mind.
Touring cars also run huge wop off brakes, which need big wheels to house them
oh and unless you choose superlight (read expensive wheels) they will be more than a little heavier.
by way of example. stock front wheel are under 14lbs in weigth. most MOMO 17" for example are 28Lb or higer
thats doubleing teh unsprung weight before you add tyres.
quite apart from the effect on handling unsprung weight normally counts 4 times as much as sprung weight, so thats 14lb per wheel 14 x 4 x 4 = 112lb of ballast you've effectively added to teh car.
thats nearly as much as a passenger, and I certainly notice the difference when there is 2 of us in teh car.
Quote from: "DAZ400"do you see touring cars running on little wheels I don't think so. Do they have big handeling problems well NO.
Don't think of one thing at a time. Yes touring cars have large~ish wheels (16" OR 17"), however, you must not forget that there is a hell of a lot of other changes that stop them having big handling problems. Suspension, steering turn ratio, angle of wheels are just a few of the changes. Then these are set up for each circuit. A set up for Brands Indy would be no good for Brands Int.
If I chose 17"ers and had an BTCC team and equiptment to work on my 2, then I would expect it to handle well.
Don't forget they are using huge brakes...those simply won't fit inside a 13" wheel s8) 8) s8)
Ever noticed how WRC cars use huge brakes (and wheels) on tarmac rallies, but smaller ones with less grippy surfaces..? There's no need for huge brakes on gravel/snow, so they can use smaller wheels as well. On tarmac, the smaller brakes just won't do it...
Like I said it is a compramise I like the look of the 17's and IMO there is no real loss of performance to make me compramise the looks for a bit less weight. Hey I got a turbo and loads of other good bits .......
to be fair MOMO's have got to be one of the heaviest wheels going if used as a comparrison, good quality...but heavy as hell
I think your right they are
and soft too, they bend easy
just happened to be a weight I had to hand.
In fairness I think light enough wheels with the appropriate profile would probably be ok.
but your talking mucho dosh to get them and the tyre profiles are so thin, IF you can get them that the ride quality is hopeless.
especially with teh sportivo, thats why I sold, my kidneys were hurting.