mylesofsmyles
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| posted on 24/3/07 at 05:00 AM |
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17" Wheels Too Big?
I want to throw a set of RS-Watanabe F817 wheels on my future Locost7 build. How big is too big and how wide can I go? I intend to run cycle
fenders, 12" rears and and 8-9" front fenders.
I am thinking about a gray/gunmetal face with polish lip; my car will be lotus chrome orange!
[Edited on 24/3/07 by mylesofsmyles]
[Edited on 24/3/07 by mylesofsmyles]
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zetec
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| posted on 24/3/07 at 08:50 AM |
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If you are building a show car only and not too interested in the handling then you can fit what ever you like, it will fit one way or another. But if
you are interested in getting it to drive as it should I would say that 15" with, max 7" width 195 or 205 tyres is as big as you want to
go. Most cars of this type end up being less than 700KG so the size of the contact patch and the weight of the tyre need to be correct or the car will
never handle as it should.
" I only registered to look at the pictures, now I'm stuck with this username for the rest of my life!"
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graememk
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| posted on 24/3/07 at 10:12 AM |
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i have 16" 205s and to be honest there to big
when i change the tyres i'm going to go 15" 195's
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Danozeman
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| posted on 24/3/07 at 11:53 AM |
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I wouldnt go bigger than 15's unless i had a Big wide viento. I saw a westy at a show with 18's on. It looked ridiculous... The
wheels were higher that the body. They were chrome aswell.
Dan
Built the purple peril!! Let the modifications begin!!
http://www.eastangliankitcars.co.uk
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Angel Acevedo
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| posted on 24/3/07 at 03:52 PM |
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There`s another thread where it`s discussed...
There are ride height and roll center issues if you change tire size.
Beware of what you wish.. for it may come true....
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Simon
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| posted on 24/3/07 at 04:04 PM |
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I have 17's on mine and it's fine.
But, it is a slightly heavier locost
ATB
Simon
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mylesofsmyles
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| posted on 25/3/07 at 05:13 AM |
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I am clearly missing something here...how would having a larger wheel be a detrament to the vehicle's handling. Excuse my ignorance, I come
from a household with much heavier, high-power, high-performance German and Italian cars; most of these come standard with 17", some with
optional 18" and 19"...from my primative knowledge, larger diameter usually aids to the handling.
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martyn_16v
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| posted on 25/3/07 at 09:30 AM |
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New cars these days were designed from the start to have big bling wheels with little compliance in the tyres though, seven types generally
aren't.
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C10CoryM
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| posted on 25/3/07 at 04:12 PM |
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larger wheels are not detrimental to handling...... in theory. In reality most wheels get much heavier as the rims get bigger. Especially OEM
wheels as they need to be designed to handle more abuse. Bigger rims are needed because of bigger brakes. There is no other reason to upsize your
rims. Unless the upsize makes for a lighter wheel of course.
"Our watchword evermore shall be: The Maple Leaf Forever!"
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RK
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| posted on 25/3/07 at 05:41 PM |
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http://www.deman-motorsport.com/
These are 17" and they look hideous.
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ChrisGamlin
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| posted on 25/3/07 at 08:56 PM |
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Although any wheels will fundamentally work and if driven in isolation you would probably think they were OK, but there's several reasons why
large wheels are a disadvantage on a light car.
As C10CoryM mentioned, when comparing a light weight 13" rim and a light weight 17" rim and you'll probably find the latter will
weigh nearly double with no significant tyre weight advantage. Most 17" rim / tyre combinations weigh nearly 20kgs each, compared to maybe
12-13kgs for a 13" rim / tyre.
Larger wheels/tyre combinations also have more of their weight towards the very outer circumference, plus they weigh more to start with so
there's far more gyroscopic effect. This means the wheels will be less inclined to change direction quickly, so adversely affecting handling
particularly on a light car.
Another thing to take into consideration is that 17"/18"/19" tyres specifically designed for light cars is severely limited / non
existant, the vast majority are designed for cars weighing maybe 1200-1600kgs, 2-3 times the kit car's weight. This means the compounds will
never work as well as readily available 13/15" tyres (A048s / ACB10s etc) designed more for light cars, and the sidewalls will also be far too
stiff.
cheers
Chris
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mylesofsmyles
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| posted on 26/3/07 at 12:54 AM |
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I think I like the look of the 17"
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chockymonster
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| posted on 26/3/07 at 08:07 AM |
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quote:
Originally posted by mylesofsmyles
I think I like the look of the 17"
If you like the look then go for 17s.
Get the car on a track and then swap for 13s and realise how much your bling wheels have altered the handling. On cars of this size and weight you
really need the lightest wheels you can find/afford. I've learnt in the past how a poor choice of wheels that look good can destroy the handling
of a car.
PLEASE NOTE - Responses on Forum Threads may contain Sarcasm and may not be suitable for the hard of Thinking.
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ChrisGamlin
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| posted on 26/3/07 at 10:30 AM |
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quote:
Originally posted by mylesofsmyles
I think I like the look of the 17"
Yep, at the end of the day if thats more important for you than ultimate performance then they will still keep your brake discs from rubbing on the
ground and you'll still think the car handles / accelerates very well, just be sure before you buy that you won't have that nagging
feeling afterwards of what if.....
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mylesofsmyles
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| posted on 26/3/07 at 04:43 PM |
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I suppose you are all right; this just isn't the car for 17". I will opt for the 15"
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PaulBuz
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| posted on 26/3/07 at 05:58 PM |
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quote:
Originally posted by RK
http://www.deman-motorsport.com/
These are 17" and they look hideous.
You're kidding, right?!!
Amazing looking car!
ATB
Paul
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RK
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| posted on 26/3/07 at 08:52 PM |
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All in the eye of the beholder I guess. I prefer the retro look of the 13". Also, it seems most racing people use 13". Must be a reason
for it and that would be weight I would guess.
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blueshift
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| posted on 26/3/07 at 10:03 PM |
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I was happy today to find out that my sierra alloys are 14", not 15" as I'd thought. I think I'll get them refurbed in black
and use them for keeps on the locost.
I'm not into big wheels on locosts, 17" and above looks horrible I think, and with really thin rubber you get a very flimsy-looking wheel.
just looks out of proportion and your brakes look really dinky unless you have some kind of monster overbraked setup, not to mention the weight and
your screwed handling from the low profiles..
still some people think it's all about inches and the more the better
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soggy 3
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| posted on 26/3/07 at 11:37 PM |
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It makes me laugh when people say ooh if you fit big wheels it wont go as fast as it will add an extra 20 kg, what the weight worriers forget is that
even with 19 inch rims and a 1.3 crossflow these type of cars are quick and will always put a smile on your face,so go on fit your 17,s they look nice
but not as nice as my 17,s 
[Edited on 26/3/07 by soggy 3]
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mylesofsmyles
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| posted on 27/3/07 at 02:42 AM |
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quote:
Originally posted by soggy 3
It makes me laugh when people say ooh if you fit big wheels it wont go as fast as it will add an extra 20 kg, what the weight worriers forget is that
even with 19 inch rims and a 1.3 crossflow these type of cars are quick and will always put a smile on your face,so go on fit your 17,s they look nice
but not as nice as my 17,s
I intend to build this car for performance; I live in Northern California an d intend to take advantage of the great windy roads around here, there
are no track events in the future of this Locost. I am of the rare few that favor the look of a bigger rim; not for the fact that it adds inches, I
just find larger wheels, with low profile tires more appealing. My major concern wasn't in whether or not I could fit the 17" or if the
ride will be compromised; the answers to this, I know. I am more concerned as to whether or not having bigger wheels with low profile tires will be a
detrament to the handling of this little car. I am getting such mixed feedback, I think I will simply opt for my 17"...how bad can it be?
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blueshift
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| posted on 27/3/07 at 07:37 AM |
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myles, you seem to have quite selective reading or I've missed something.
All comments on the subject that I've ever heard are to the effect that small wheels are best for handling on a seven, not just because they are
lighter but because of.. err.. things to do with sidewalls that other people can explain better than me
All racers and experienced car setup type folks I've ever heard comment on the subject agree.
The ONLY people I've ever heard promoting something as big as 17"s on a seven are people who like the way they look and say "I have
them on my car and it handles fine".
I suggest to you that you may be happy enough with the way it drives on 17"s but if you are really into pushing the limits, if you switched to
13"s you would notice a great improvement.
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NS Dev
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| posted on 27/3/07 at 12:41 PM |
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quote:
Originally posted by blueshift
myles, you seem to have quite selective reading or I've missed something.
All comments on the subject that I've ever heard are to the effect that small wheels are best for handling on a seven, not just because they are
lighter but because of.. err.. things to do with sidewalls that other people can explain better than me
All racers and experienced car setup type folks I've ever heard comment on the subject agree.
The ONLY people I've ever heard promoting something as big as 17"s on a seven are people who like the way they look and say "I have
them on my car and it handles fine".
I suggest to you that you may be happy enough with the way it drives on 17"s but if you are really into pushing the limits, if you switched to
13"s you would notice a great improvement.
Hit the nail on the head perfectly.
What people are failing to realise is that the tyres on a light car actually carry out a great deal of the springing.
With the cheap (i.e. sub £250 apiece) dampers that we all use, their damping and springing in the very small movement range is extremely poor. Here
the high profile tyres help, by acting as springs and dampers neatly combined in a rubber ring.
If you drove a car fitted with steel rings for tyres you would not be surprised if it wheelspun and handled badly.......................
Effectively this is what you are doing by fitting low profile stiff-sidewall tyres to a light Locost. Before you say that is rubbish, think about
something like a tank or other extremely heavy vehicle. Fitting this with steel wheels would not be a big problem as the weight would distort both
road surface and "tyre" in much the same way as a car distorts a rubber tyre. Remember that both the tyre and the road under it distort,
they need to in order for any traction to be effected (and is why road surfaces break up over time)
Now go back to the locost, we need to fit high profile tyres to maintain tyre flexibility and thus correct contact patch and traction.
Next consider unsprung weight....................or more correctly, and never quoted by many other than me "SPRUNG TO UNSPRUNG WEIGHT
RATIO"
Again make it simple to visualise, picture a 2 tonne wheel attached via a spring to a 1tonne car. You go over a pothole and what bounces? The car of
course, not the wheel! Now bring it back to normal situation. A 25kg unsprung weight at one corner of a 1200kg family car is 48:1 ratio. The same
assembly fitted to a 500kg locost is 20:1 ratio, making the wheel effectively 2.4 times harder to control over bumps.
Over unsprung kg saved makes the life of your cheapo Avo, Gaz etc dampers much easier, and you handling much better.
Hope this helps
Nat
Retro RWD is the way forward...........automotive fabrication, car restoration, sheetmetal work, engine conversion
retro car restoration and tuning
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ChrisGamlin
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| posted on 27/3/07 at 05:50 PM |
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quote:
Originally posted by soggy 3
It makes me laugh when people say ooh if you fit big wheels it wont go as fast as it will add an extra 20 kg, what the weight worriers forget is that
even with 19 inch rims and a 1.3 crossflow these type of cars are quick and will always put a smile on your face,so go on fit your 17,s they look nice
but not as nice as my 17,s
Errm, us "weight worriers" aren't forgetting anything, nobody has said it wouldnt be quick and wouldnt handle OK with 17"
wheels but it will be even quicker and handle even better if it weighs 20kgs less and has 13" wheels!
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