Wheels/tyres 13'' vs 15' opinions.... please

Guys (and Gals). Opinions welcome.

Working towards getting my phase 2 back on the road soon. Its been off the road for nearly 3 years in thattime my selection of tyres have been gently ageing (read, going from hard to rock-hard)they were already all pushing 8 plus years or more anyway!

Money depending I'll splash out on a new set soon, here's the dilemma....

I'm stuck between (new) 13's probably 185/60/13 or (new) 15's 195/45/15no track-day specials just good all round safe quality makes. At the moment I have..

A set of 15' wheels.. with out-of-date195/45/15 Falkens.

Nearly 2 full sets of original 13 phase 2 wheels with a selection of195/55/13's two Uniroyals are less than 8 years old... all the others, ancient rock hard death traps!! Some terrifyinglift-off oversteer moments still hunt me.

My thoughts are:

13's look more original, all-up have lighter unspring weight and weresize renault designed suspension around too... But tyre choice limited, can't get195/55's. Do 185/60/13 work as well on 13'' rims ok? Any views welcome.

15's more choice, more grip, better more modern looks... ultimately probably safer too. But heavy!.. Try the weight difference between 15's & 13's and they raise gearinga bit too.

Sorry for long post... Look forward too all your thoughts..

15's you have a much better choice of tyres.

Quote:

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Originally Posted by RussellT

15's you have a much better choice of tyres.

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agreed Russel,

whats your thoughs over weight (of tyre and wheel combination). have you ever ran 13s in competition?

i remember from my mini days smaller wheels were often considered better

Did you check 185 60 13 Nankang ns-2r? Dont have them but its what I will buy as my next tire...

185/60/13 look horrible, they increase the tyre side-wall height and they alter the gearing a bit too in comparison to the original tyre:

Specification Sidewall Radius Diameter Circumference Revs/Mile Difference
195/55-13 ......4.2in ...10.7in ..21.4in ......67.4in .........940 .......0.0%
185/60-13 ......4.4in ...10.9in ..21.7in ......68.3in .........928 .......1.4%


195/45/15 alter the gearing slightly more than 185/60/13's but the side-walls are smaller in comparison to the OE tyre and they look much better:


Specification Sidewall Radius Diameter Circumference Revs/Mile Difference
195/55-13 ......4.2in ...10.7in ..21.4in .......67.4in ........940 .......0.0%
195/45-15 ......3.5in ...11.0in ..21.9in .......68.8in ........921 .......2.2%

Calculator: http://www.miata.net/garage/tirecalc.html

On the issue of wheel weight, what are the figures, anyone know? I'm sure the OE wheel weights are on the site somewhere and IIRC the Ph1's are lighter than the Ph2. Anyway, then it depends on which 15" wheels are available as some are as light as the 13's (not Renault ones obviously).

Theres very little visual difference using 185/60's and the gearing is hardly effected at all as Trev mentioned. I have Nangang NS2-R's on my Cup wheels and while I haven't used them yet they look ace and I'm yet to hear a bad word about them.

Re 15's, I've run them too and overall I would say it's down to personal choice. I have both! :D

The original 195 55 on 13's Michelin's squash about 5mm more that the 195 45 on 15", so that means it's not just about circumference but about radius from hub to floor. So there's a bigger difference in speed reading as the 45's are nearer their actual radius. 15" wheels with 194 45 were 6% more than the speedo shows, IIRC.

15" will give a bumpier ride. I also got more precise turn in with better 'bite'. But less progressive, that might be about tyres as much as very low profile vs. taller softer side wall.

I think Renault put those very soft side walled OE 'baloons' on to give a softer ride. My car's cornering and behaviour was terrible with them. But with Yokohama AO32r 185 60 it's seemed OK. I only had two of them for the Pod so didn't really use them on the road but the grip was a lot better than my 15" tyres and there was no wheel spin on the warm dry road, even with some deliberate provoking.

I have Nankang AS-1 on the Fiat 13" 5j5 wheels now as I didn't know much about the NS2 six months ago and now I see they are B rated for wet braking instead of C for the AS-1, looks like 50% more money though. A lot better cornering than the Pirelli's at both low and higher speed, lighter steering too but more precise feel. They are 175 50 I think. But it says on the side was they are meant for 5j5.

Alex, does it say anything like that on your NS2-R's?

R would be the 120 tread wear?

I've not looked in depth to be honest Ian. The 120 your refer to is the compound. I have the 180 compound which is the hardest.

I was wondering that if Nankang are stating that 175 is correct for a 5j5 then shouldn't 185 go on a 6 inch wheel?

I think those Michelin 195's on the OE 5j5 wheels were a thing of their own specially made for Renault for this car to give a smooth ride as the side walls really do squash a lot over bumps and Renault used a hard bump setting on the shocks.


Regarding the original post; for a road car in the UK I'd be most keen to have tyres that are A rated for wet braking. Provided they also had sufficient traction to put down all that torque a modified 5GTT can have. That probably means having 15 inch wheels or maybe 14 inch. Or 16's. The best tyres seem to be only in the larger diameter.

In my experience the 185/60's have a pronounced visual difference over the 195/55's, certainly on the OE alloys. They look balloon-like, odd. It may be that on the cup wheels this is not so noticeable. Are they wider than the Ph2 alloy wheels?

I think the cup wheels are 5j5. Their outward offset is more.

Quote:

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Originally Posted by 1312_Tom

what's your thoughts over weight (of tyre and wheel combination).

i remember from my mini days smaller wheels were often considered better

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Paddy Lowe was in the news last year saying they wanted to stay with 13" wheels in F1 as the performance was better than they would get from larger wheels with lower tyres.

Whilst a greater overall diameter will climb bumps better, stall less when hitting into them, so maintaining forward velocity better, if it's all wheel and no tyre, a trade off would be the increased unsprung mass and the extra flywheel mass that needs to be spun up, and that the tyre don't squash and so does stall the forward velocity by giving more kinetic energy to the obstruction instead of more easily going over it.

The push for ever larger wheels is likely to be just a money making scam from the car makers to keep some people constantly spending money 'upgrading' when it could be more of an expensive downgrade in performance and comfort.

A pal with a brand new sporty small car, Suzuki swift 1.4, has just had Suzuki take off the 15" or 16" wheels and no profile tyres and fit some smaller wheels and taller thinner tyres as he was no longer willing to tolerate the punishing hard ride (some of these no tyres cars feel like every bit of gravel on the road seems shudder the car). He's very happy now not just with the comfort but the turn in, traction and braking are also improved and the quietness. He fitted the new Goodyear Vector all seasons tyres with a rated 67dB, as well as comfort he particularly wanted quiet, also best wet braking. The rest is a bonus.

What looks the best should be what performs the best. But the car industry now has people under a delusion that a 20 inch wheel running on it's rim is what looks best!

The issue of comfort is due more to the state of British roads than the wheel/tyre combinations discussed here. Certainly for comfort you'd go for 185/60 on a 13" rim. You could choose to go 195/50/15 as another option. That used to work for many here.

As with everything though, it's a trade off. Most people ascribe some value to how things look, in addition to handling, traction, comfort, price and originality. Since each wheel/tyre combination will return a different set of overall values, it's down to the personal choice as to the priority of each. :agree:

Quote:

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Originally Posted by Trevhib

In my experience the 185/60's have a pronounced visual difference over the 195/55's, certainly on the OE alloys. They look balloon-like, odd. It may be that on the cup wheels this is not so noticeable. Are they wider than the Ph2 alloy wheels?

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Thats some eyes you've got there Trev, theres less tahn 4 mm difference in the sidewall between the 2 sizes! :D :agree:

I think it's 0.2" per side, so 0.4" in total, so actually that's a full 1cm extra side-wall when looking at a wheel. I know what you're saying mate but it's one of those things, the eye picks it up quite easily. I tried to find some pics to do a side-by-side but couldn't find any. :agree:

It's 3.75 MM. Here's my cup wheels with 185/60/13's on

http://i1076.photobucket.com/albums/...0B59544E03.jpg

I was considering the same thing.

It seems that from a value point of view keeping a car or returning a car to its original look is the way to go; original cars appear to have much higher sales values and surely this trend will continue? I am not considering selling my car but I do see it as a fun investment and anything that increases value is a bonus.

I like the old school original look however my car has a set of 15 alloys with low profile tyres (I bought it like this) and whilst the ride is harsh (probably the lowered suspension is a big contributor) it does handle very well and if this was reduced by changing to 13's it would be disappointing and feel like a step backwards.

My car has been tweaked by previous owners (bigger turbo, boast increased, uprated intercooler etc) and I am sure it is quicker than a standard set up and whilst I like the idea of a "original" car I think if I returned it to standard I'm sure the driving fun would be greatly reduced. My R5 is a weekend car so the pleasure of owning and the driving fun is what it is all about. I have a passion for fast cars and my desire for a GT turbo and its cult status back in the 90's when I was young is the reason that I finally bought the car having turned 40....:cry: I also love the reaction of like minded people who remember these cars and that returning to an original look must add to this.

Basically I want the best of both worlds..... an original looking car but with the best performance and safety possible. Clearly there will always be a compromise which is annoying.

How do those running 13's feel about the way the car handles and stops? How big is the compromise between performance/safety and original looks?

I've run both sizes on the road and on track and there's little difference to be honest. The main thing is the quality of tyres you use I would say. If you have 15's I would probably stick to them as you'll have a far better choice of tyres to choose from and if you've got larger brakes you can't get smaller wheels on.

Quote:

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Originally Posted by Alex

It's 3.75 MM

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No it isn't :wasntme:

They look fine on the cup wheels :agree:

You know, maybe I was thinking of 195/60s? :confused:

185mm + 60% = 111mm
195mm + 55% = 107.25mm
111mm - 107.25mm = 3.75mm

:agree:

Yep, per side of the rim :agree: Your side-wall isn't 111m in total across the diameter of the wheel (like 55mm per side), it's 222m in total. As you look at the wheel, it's 111m from the top of the rim to the top of the tyre and 111m from the bottom of the rim to the bottom of the tyre. So visually it's an extra 7.5mm of tyre to look at within the total height of the wheel/tyre combo.

Miata calc must round up as they use inches and have 0.2" per side. If it really is 3.75mm then that's only 0.147", which is just over the required 0.145" to round up. So it's misleading. What I thought was 10.1mm, is 7.5mm. Fair enough.


Edit - It would also be true to say that not all 185/60's are equal. The ones you have, have nicely squared edges, which helps. In the past I've seen people fit budget 185/60's that have rounded edges, which exacerbates the issue.

What about going 175/50/13? :D Showing here vs 185/60/13's:

http://65833.forumromanum.com/member...al_1145524.jpg

I my opinion it's performance that is number one consideration.

So finding the best tyre for the rim is the tricky part. If the best performing tyre has bulbous side walls and is large looking then why would anyone say that's not the best looking and prefer the look of something that is terrible performing instead :confused:

Form has to follow function.

Probably my quickest run to my sisters, up 10 miles of bumpy county lanes, was on the old original 13" 5J5 wheels shod in some old type Nankangs, not sure any more which, they did leave some black lines here and there, tramlined badly, but did have a progressive and controllable feel.

The several 195 45's on 15 inch 6j5 and 7j wheels in general had more turn in grip, but less, or no, progression so I was not confident in attacking corners as once understeer set in there was no coming back from it.

For turn in bite and precise control, by far the best of those was the 15 inch 7j wheels. But it's not all that clear as by then I also had 250lb springs and the roll was less, so tyres remained flatter with the road and so the grip was more and the understeer was less. When I years later fitted the standard fare lowered springs the understeer returned as the care rolled around. I basically had to drive slower.

As Alex says, it may be more about what tyres that anything else. I drove a 5 with the standard fare lowering springs, 15" 7j wheels, but Yoko AVS tyres and that was about the most fun drive I've ever had in a 5. I could push really hard into every corner and bend yet retain steering control when in understeer and so turn in some more in needed. Was probably going slower than in my own car though with it's 250lb springs at the time. I couldn't afford to bin my newish tyres to and buy a new set of those Yokos just as an experiment.

Over the years there don't seem to have been many people here in this club who really new how to best set up a 5 for changing direction. The work has been on drag racing. The few track people seem happy enough with anything and not all that bothered about lap times apart from a few who compete in sprinting and did very well. They used 15 inch wheels I think. But what works at 80mph on a smooth track may not the same as at 20 to 50 mph in town and small and large roundabouts or a bit more than that on very bumpy lanes.

Slight thread hijack here but I managed to get my wheels on today. I'm very pleased with them and I think the ride hight is spot on after the axle refurb.

http://i1076.photobucket.com/albums/...976B8E9ED1.jpg

Does look a little high at the rear but could just be angle of pic:D

Another angle of the dangle

http://i1076.photobucket.com/albums/...0479FE6E81.jpg

Looks great ;):agree:

https://www.tacomaworld.com/tirecalc...5r13-185-60r13

Handy site :agree:

Oh look :wasntme:

Thanks all for comments/opinions.

I’m probably leaning towards 13’s more to do with the poor state of our roads,than outright performance. That said, if I lived somewhere with smooth decent roads 45/15s would be 1^st choice.

Let you know the outcome..