Changing wheels size : from 17 to 13 : which tyres

[kitkat]

Hello,

My Westfield is equipped with big wheels and I want to change them in order to get the smallest non-suspended weight.

My tyres are now 205/40 R17

After some reading on this forum, it appears that I have two choices : 13 or 15. I think I am going to choose 13 but then I need expert's advices on the tyres : in order to stay in the same diameter range, it seems that 185/70 R13 or 205/60 R13 are possible.

The car will be exclusively used on roads (I live in a rainy area : North of France, so wet roads are frequent), someone advised me on Yoko A021R.

Thank you for your ideas on the tyres : brand and size.

Regards

Kitkat

[stewart pickles]

why do you need to stay in the same diameter range? depending on what speedo you have you should be able to re programme it.then that would open up the choice for tyres.the ao21r is a wet track tyre and would cost twice the price of say a maragoni zeta linea that would be just as good for road use

[blankczechbook]

some registration documents show the size of tyres - for homologation purposes.

any other size can be an MOT fail.

dunno about in france, but here it is like that. (czech rep)

what's wrong with 14s ?

i weighed my 14 rim/tyres and came in pretty light - bigger sidewalls than 15s so supple ride is nice and tyres aren't too dear!

now where's that thread with the rim weights gone...

[kitkat]

why do you need to stay in the same diameter range? depending on what speedo you have you should be able to re programme it.then that would open up the choice for tyres.the ao21r is a wet track tyre and would cost twice the price of say a maragoni zeta linea that would be just as good for road use

Good advise for the size but our roads (North of France and Belgium) are quite different from the ones in UK : "bumps" on the road to slow down vehicles, holes and nests in the roads, ... so the height is important. I fear that with smaller tyres, I will touch more often than necessary...

Marangoni has also a nice profile and are quite cheap, but they don't exist in 13" (at least for Camskill : http://www.camskill.co.uk/products.php?plid=m4b580s0p0). Should I go to 15 to get more freedomfor choosing ?

[pistonbroke]

I would say go 15 they seem to be the popular choice and wider options available  

[stephenh]

I think the 13" diameter wheels tend to be used mostly by owners who use their cars for racing or hillclimbs. I doubt that you would notice the difference for road use.

15" wheels will be the most common size, as it is what Westfield supply. At the moment there is a good range of tyres for that size. Mine are 205/50x15" tyres, but for most road cars that is unnecessarily wide. 195/55x15" or 185/55 or 60x15" might suit you.

[kitkat]

OK,

So 15 inches seems a more reasonable compromise. Well, I need to change my plans then.

Thank you for the help.

[combatsapph]

QUOTE

Good advise for the size but our roads (North of France and Belgium) are quite different from the ones in UK : "bumps" on the road to slow down vehicles, holes and nests in the roads,

Actually - that sounds just like our roads!

[chappers]

13" or 15" would be fine IMO. 13" compomotive CXRs or the new 13" team dynamics pro race 1.2 will be lighter than 15" wheels, and A021Rs in e.g. 185x70x13 will be great in the wet. If you want lowest unsprung weight I'd go for 13" wheels which are fine on the road and will be way better than the 17" wheels and 40 profile tyres you have now.

I run 15" wheels at the moment, mainly for aesthetic reasons, but lots of people have changed from 15" to 13" wheels are are very happy about it. I wouldn't go for 14" wheels as there is less tyre choice, plus they are more expensive than tyres for 13" wheels.

[kitkat]

I run 15" wheels at the moment, mainly for aesthetic reasons, but lots of people have changed from 15" to 13" wheels are are very happy about it.

You are right, I am also wondering about aesthetic !

It would be great to see two similar cars side by side on the same picture, one with 195/50R15 and the other with 185/70 (or 60)R13

Pffff, it's not that simple... but I think that I am aiming to 15 inches now with Marangoni tyres. I have always liked these wheels : https://www.caterhamparts.co.uk/product....id=3683

Does someone know if they will match a Westfield SEIW factory built from 1998 ?

[h4muf]

Hi there.

I`ve just gone from 16" 225/40 back/205/45`s front

To

13"pro races with 888`s and just cannot belive the difference!

All tramlining has stopped, the front ends so light and more pointy.

I wished i`d done it last year!  

ETA.

I`ve lost 7 stone with the weight saving(including the spare)

[adam1330]

You are right, I am also wondering about aesthetic !

It would be great to see two similar cars side by side on the same picture, one with 195/50R15 and the other with 185/70 (or 60)R13

Here you go, Top with 205/50/15, second with 185/60/13.

There is a good wheel size calculator here.

[fatbaldbloke]

If you go for 13" it's pretty common to have 6" rims on the front with 185x60's and 7" rims on the rear with 205x60's.

[Martin Keene]

A few points to consider from somebody who used to run 14" wheels with 195/60 Yokohama A520 tyres and switched to 13" with 185/60 A048R tyres.

1) 13" vs 15"

Stick to 13" or 15". 13" will offer you by far the biggest range of cheap sticky tyres and 15" will offer by far the biggest range of cheap road tyres. And by cheap I don't mean some obscure brand you've never heard of, I mean sizes made in massive quantites and there for attract volume discounts.

2) Weight

I would only go for one of the lighter sizes of 15", i.e. Team Dymanics Pro Race, OZ Super Leggera, etc. I saved 18kgs of upsrung weight by swapping the 14" for the 13" and the difference was simply unbelievable and very noticeable. Believe me, you *will* notice the difference between 13" and heavy 15" on the road. The whole car will feel lighter on it's feet, more 'pointy' and generally more alive. Oddly, the lightest wheels will also improve your ride comfort the most, which is a big factor for road use. The difference between a 13" and a lightweight 15" will not be as noticeable.

3) Tyres

I am firmly of the opinion that normal road tyres are not suited for Westfields, etc. I had some quite interesting moments on 'normal' tyres in the wet and very low speeds. I firmly beleive that a lightweight car like a Caterfield simply does not have the weight to make a normal tyre work properly in the wet. Unless there is standing water, and by that I mean puddles, my car has far more grip in the damp/wet with the A048R's than it ever had on the A520. The A021R you mentioned in your original post is an excellent tyre, and has many great things said about, and one I'd like to try myself one day. It is also the closest I'd get to a normal tyre on a Se7en anymore. Another great tyre to consider is Avon CR500.

4) Sizes

Your current wheels have a rolling diameter 596mm, to match this you are going to need a 185/70x13 (589mm dia) or a 195/55x15 (596mm dia). For the 13" this is an interesting option because it is a standard size in the UK for stock car racing and the control tyre is an A021R, so they are seriously cheap in this size. FWIW, I wouldn't worry about this too much pick the right tyre size, which unless you are running lots of power, 200bhp+, for me would be a 185/60x13 or a 195/50x15, then get the speedo recalibrated to suit.

I fear this may have confused you even more, but if I had know more at the time I would never have sold my original 13" wheels to replace them with 14" and go back to 13" a few years later!

[kitkat]

Thank you for this interesting post, really complete.

Wet road performance is really an issue for me.

185/70R13 looks odd (old style) but interesting

185/60R13 looks better but I loose 18mm of height and I am afraid to touch more often.

195/50R15 is a compromise with lightweight wheels

I will take my final decision in April, so I still have a few nights to think about :-)

Thank you