Wheel Question

[AndyD]

Hey guys i currently have a set of 18's on my car which are in poor condition and was thinking of replacing them. However most of the rims i like are all 17x7/7.5 my current set up is running 18's with 235/40 profile tyres i like how the tyres sit in relation to the guard so what im wanting to know is what set up would have the same overall diameter so they sit and look the same as my current set up (obviously the profile of the tyre will be greater). Also what is the best width to run on s2 stags im not sure how wide my current one's are or what offset they are. Also if i change to 17's would i need to do any speedo corrections?

[M I K E]

your post confuses me.. had to read it like 3 times lol

so your'e saying you are going to change to 17's or you want to stay with 18's?

either way, i personally wouldn't run less than an 8.5" wide wheel on a stag, the guards can take it and they are big,heavy, fast cars

[KiwiRS4T]

1. if you want 17s with the same overall diameter 235/45 will do it - best on 8in but 7.5 will do.

2. If you have the same overall diameter your speedo reading will not change.

3. Take a wheel off and look inside for the actual size and offset (e.g. 8J or 7 1/2 JJ offset 30)

4. Because the front track is narrower than the rear you need a smaller offset number on the front or alternatively use a 25mm spacer on the front.

[AndyD]

Sorry for the confusion

-currently have 18's with 235/40 tyres on them

-Want 17's in same overall diameter as not to interfere with speedo

-Need best offset and width to suit stagea

[M I K E]

17x9+30 seems to keep most people satisfied (ie r33gtr wheel) and you can run a 235/45 on them

[AndyD]

also do all 4 wheels have to be exactly the same as in width and tyre profile cos of the 4wd system soz for the noob questions.

[_Ryan_]

rolling diameter must stay the same eg http://www.miata.net/garage/tirecalc.html

[66yostagea]

This is interesting as atm I am looking at a new set of tyres. Currently running 225/50R/17 as supplied with the car.

Was looking at the compliancing papers and original specs for a 1996 RSFour.

Documentation states vehicle is an RS FOUR S. Specs detail tyre size front and rear as 205/60R/15. (Yes fifteen). Sticker on door and DOTARS inspection certificate lists size as 225/50R/17 on 7 JJ 17 +40 rims. Yet the rims are 8 JJ 17.

Now the rolling diameter of the 17s must be larger than the 15s. Right?

If Nissan supply car with 17s instead of 15s, do they adjust the speedo to suit? If they dont then it could be the reason I appear to be getting poor economy.

[AndyD]

rolling diameter must stay the same eg http://www.miata.net/garage/tirecalc.html

Ok so assuming im completely noob the diameter is the crucial part so width of rims has no bearing and cannot do any damage to 4wd system or transfer case?. So i can run two diff widths front and rear without fear of damage say 8" front 9" rear is this correct?.And in using this theory why the hell would any 4wd car running 16 or 17" rims be fitted with a tiny ass space saver tyre?

[QWK32]

Now the rolling diameter of the 17s must be larger than the 15s. Right?

shouldn't be, the tire profile is adjusted to accommodate the larger rim and still have the same rolling diameter.

[pintaline]

ok to help you all with speedo issues, standard tyres fitted to stageas are:

16inch - 205/55/16

17inch - 215/55/17 (rs4s)

these are the factory tyre sizes, there may be some 15s on some cars (possibly non turbo?) but i haven't seen any so i dont know. some stags will have different sizes on their compliance tyre placard but this is only because the tyres were that size at the time of compliance (mine has 225/45/17s, speedo reads 9km/h over what i'm actually doing))

im pretty sure nissan would not have adjusted the speedo to suit the 17s on the manuals so they would just be out from factory.

you need to match the rolling height of the 205/55/16 to make your speedo as accurate as you can, ill check the rolling height and any close matches tomorrow at work and get back to you all.

the other thing you can do is go to jaycar and buy their electronic speedo correction kit. it's just a little circut that intercepts the signal from the speedo and allows you to adjust it. cost about $45 from memory... i'm yet to fit mine but ill let people know how it goes when i do.

as for the attesa question, you must have the same rolling height on the front AND back of your car. there are allowances in the system for tyre wear etc. but from what i've found, they're very small. best to keep same heights all round to prevent any damage to the system or get the closest match you can. ie. i wouldn't allow a difference greater than about 3mm in rolling height.

space savers, allows for bigger fuel tank and more boot space, they are the worst thing ever invented and i hate them. they would match the rolling height of the factory 16s.

you can put different size tyres on them, i haven't looked into that yet but i've been told not to bother by a few of the reps from companies that make them. the prices are insainly high and it's basically not worth it.

D.

[KiwiRS4T]

Hugh I have 17in 235/45 (seems a popular size) and the diameter is slightly bigger than stock but that just seems to make the speedo more, not less accurate - most cars you will notice have speedos that are slightly or sometimes very "optomistic" and the stock Stagea is no exception.

[KiwiRS4T]

ok to help you all with speedo issues, standard tyres fitted to stageas are:

16inch - 205/55/16

17inch - 215/55/17 (rs4s)

these are the factory tyre sizes, there may be some 15s on some cars (possibly non turbo?) but i haven't seen any so i dont know. some stags will have different sizes on their compliance tyre placard but this is only because the tyres were that size at the time of compliance (mine has 225/45/17s, speedo reads 9km/h over what i'm actually doing))

im pretty sure nissan would not have adjusted the speedo to suit the 17s on the manuals so they would just be out from factory.

you need to match the rolling height of the 205/55/16 to make your speedo as accurate as you can, ill check the rolling height and any close matches tomorrow at work and get back to you all.

the other thing you can do is go to jaycar and buy their electronic speedo correction kit. it's just a little circut that intercepts the signal from the speedo and allows you to adjust it. cost about $45 from memory... i'm yet to fit mine but ill let people know how it goes when i do.

as for the attesa question, you must have the same rolling height on the front AND back of your car. there are allowances in the system for tyre wear etc. but from what i've found, they're very small. best to keep same heights all round to prevent any damage to the system or get the closest match you can. ie. i wouldn't allow a difference greater than about 3mm in rolling height.

space savers, allows for bigger fuel tank and more boot space, they are the worst thing ever invented and i hate them. they would match the rolling height of the factory 16s.

you can put different size tyres on them, i haven't looked into that yet but i've been told not to bother by a few of the reps from companies that make them. the prices are insainly high and it's basically not worth it.

D.

Dave I am very interested in the jaycar speedo correcter. They are supposed to have a large range of correction and I think it could be the basis for our 320km/hr speedo - i.e the jaycar unit plus a new scale printed on sticky paper to stick on the stock speedo face??!! (Of course you could do 300 or 280 etc but there would be economy of scale in printing just one and 320 should suit everybody).

[66yostagea]

Was surprised. Put an R30 wheel, 205/60/15 against the 225/50/17 and there is SFA difference in dia.

[pintaline]

Dave I am very interested in the jaycar speedo correcter. They are supposed to have a large range of correction and I think it could be the basis for our 320km/hr speedo - i.e the jaycar unit plus a new scale printed on sticky paper to stick on the stock speedo face??!! (Of course you could do 300 or 280 etc but there would be economy of scale in printing just one and 320 should suit everybody).

yeh it could be used for that i spose... i'm not sure if it works by adjusting the signal at set points/speeds that you set (like 80, 100km/h etc.) or weather it just adjusts it all the way thru the speed curve which is what you'd want if you were changing the dials. if it does, sweet, problem solved! if not then i guess you'd have to set corrections at say 5 or 10km/h incriments to make it accurate but even then it would be slightly off unless you were sitting on one of your set speeds. i'd also be worried about it not correcting the speed until you were doing on of the set correction speeds... say you set it to correct at 80km/h and your speedo was normally over reading by 5km/h. if you were sitting on 79 on your speedo, you'd really be doing 84... so would it start correcting only when you hit 80? if that's how it works then that could be a problem... i hope that all makes sense....

Was surprised. Put an R30 wheel, 205/60/15 against the 225/50/17 and there is SFA difference in dia.

visually, yes. they would look about the same. technically, no. they are about an inch different in diametre. use the link above to check the difference. another thing to consider is that different sizes of tyres will sit differently when under the weight of the car. if i remember tomorrow ill bring home my tyre bible from work and if anyone wants to know rolling heights or anything, i should be able to help.

D.

[32TAXI]

I've got 225/40r18 on 18x7.5 rims which look small on a stagea and NOT recommended!

Fitting 18x9 Volk GT-N with 235/40R18 very soon!