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Tyre choices - calculators out!

Terry Field

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I'm looking for new tyres (at last) to replace the Michelins on my 1.6 XFlow (flares).


Current tyres are 185/70 on 13" rims. I mainly need a road tyre as I only do one or two track days a year, and can't afford to change every 5k or so, which is my annual mileage 😬 so very soft compounds are out. Can't justify new wheels either.


By reading the many good threads here, the current favourites are either the yoko 021's, the Bridgestone Re720's or the new Yoko A539 which sounds ideal. Trouble is the size.


The nearest A539 size is 185/60R13 which, by my calculation changes the rolling radius from 1851.02mm to 1734.79mm, a reduction of 116.23.


The 021-R's are available in 185/70/R13, but does anyone know how well they last?


I can't find out about Re720 sizes, so would appreciate any advice.


If I went from a 70 profile to a 60 profile, (A539's) would that be too much. I know it would increase consumption *eek*,the speedo would overread, and it would also reduce ground clearance.


Would appreciate any thoughts on:


-Choice of tyre

-Effect of profile change

-Cost of choice of tyres





Trying to get out of the garage

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Don't forget that as you wear a tyre out from 8mm to 2 mm you lose 12mm on diameter. The difference in diameter between a 185/70 and a 60 is 2 x 18.5mm, 37mm, ie only 3x as much. When was the last time you noticed a difference, however slight, in speedo reading/revs per mph, across the life of a tyre?


You can always use a bike computer to get an accurate reading.


I have just bought 4 185:60:13s in RE720. They are less sticky than A032 but the 032s wore out at a scary rate, I lost over 1mm in 1000 miles. Apparently the 720s get better with age (like me). Whether they ever approach 032s I dunno, the grip you get with them is incredible but oh boy do they wear out. Poor in standing water too, I hear. Look at the tread and see why. 21s are bettter in this regard. Remember the Yokos only come with 5 or 6 mm as new.


Dunno if you can get 720s in 70 profile, app. 70s give a more predictable feel at the limit, albeit this may be slightly lower.

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I'm in the process of replacing my Michelins with RE720s for my 14" wheels. I believe they are 185/60

Currently running around on 13" mags with 032Rs and the rear tyre is actually a greater circumference than the 14" Michelin. Traction is fantastic, though rears are only just about legal. Michelins are hopeless but the RE720s are supposed to be the best all rounder according to Bentley Boy who's used them all.


Don't be too deceived by the apparent lack of tread on the 032Rs, they still have surprising grip in the damp (though haven't driven them on standing water).

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Terry, can help you on some of the questions. Not on others.

I run a x-flow live axle, non adjustable suspension. ONly had it for 7 months.


Size - have tried 185x70 on 13's and also 185x60's. (70's were CR322's and 021's, and the 60 profile were 032's).

Although I didn't bottom too much on the 60 profile tyres I did have to take it steady getting out of the drive. I had to increase setting on shocks to harden the ride up a bit to stop bottom ing out on a bump about 1/2 mile from home. 032's were sticky as hell - though many have said that they are TOO STICKY for ital axles (on track at least).

DOn't know about cost of 032's.

You can pick up 70 profile 021's for about £45+vat + delivery (see other threads for preferred source. Initials GP will come up frequently and I can also recommend these guys). CR322's can often be found second hand from racing guys and generally have lots of trread left. Expect to pay less £20 / corner down to "please take them away". CR322's don't really wear out according to popular myth. In fact they do - but don't check tread depth weekly. They don't wear out - cos they don't leave much rubber on the road. As a result they don't stick anything like as well as 032's. The other yoko's mentioned above (021's) ARe quite sticky and are definitely my tyre of choice at present. (Many others are of the same opinion). Having had the last 5 days back on 322's after losing a rim I was really glad to get back onto sticky rubber for a quick drive today.

I've never tried the Bridgestones so can't comment.


Take the above with a pinch of salt - I've only had a seven for 7 months,


(sorry for the length of the ravings above - I needed the typing practice)



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I have run RE720's and 32R's but not 21R's ( yet ) .

The RE720's are a *normal* road tyre , the grip level from these is no way near that of the 32R's , even when they wear down to the softer compound at 4 mm depth . The difference should not be underestimated ! .Anyone that tells you different isnt trying hard enough !!!


The 32R's are a track / race tyre and as such have a far softer ( grippier) compound . I would expect these to usually wear down ( with soft compound ) with your power on the road in about 6K miles on the front and 4K- 5K on the rear . The Re720's will probably last upwards of twice that mileage .


But the downside is that not only is the rear traction far less but of course the braking power before lock up is far less for the 720's .....


I have never run the 21R's , but they are designed as a wet race tyre , I intend getting a set fro wet track use this year . They will get slaughtered on track in the dry on my car . But I imagine they would suit you well on the road . I would expect to see about 6K - 7K miles from a set on your car - based upon what I have seen from friends similar cars . If you rotate them around .


Of course this all depends how you drive on the road *tongue*


The 32R's give surprising grip in the wet , but aquaplaning can occur sooner than 720's . In my experience .


What would I choose if I were in your shoes ???

Well the difference a decent set of tyres can make to our cars is such that I would go for 21R's in your situation , road work 95% / track 5% - soft tyre , good grip , good water clearing properties , and live with the cost of £200 every 6-7K miles or more if you drive *normally* , after all you will get far more enjoyment during those 6-7K miles than you will from 720's , and it will be safer as you can stop sooner in emergency .


George polley motorsport is the place to get the tyres - whatever you choose .






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i've got 21r's on ours. i'm replacing the rears next week after 5.5K with several track days, and a grueling 4000 miles across in europe in a rallye.


the fronts still look new at 5.5K and have only lost 1.5mm in that time.



210Bhp Sinister Version-VHPD here

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Another one from the Yoko 21r 185/70 camp. Excellent tyre for road and the occasional foray onto the track *thumbup* Prices are very cheap compared to many of the other choices. I reckon on about 6,000 miles from mine including 3 trackdays a year and I wouldn't say I was 'light' on the loud pedal.


Chris Alston

C7CAT.com *cool* 1800 Supersprint

Drive it like you stole it! 😬 *thumbup*


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I have 4 yoko A359'rs 185/60's R13 which are brand new, 0miles, which I bought to get through an MOT. I'm now going to stick my ACB10's back on, so I can really wear them out, so the Yoko's are for sale. Two of them have been put on rims but will be taken off again straight away. I paid £200 for them, so if you want them make me an offer!
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