Avon Replacement

[KnifeySpoony]

1 hour ago, Croc said:

I understand it to be the R888.  They will be my new set for next week’s events.  
 

 

That would give us some good data on pace compared to ZZR and the Avon slick, as we can compare historical laptimes.

[Slonie]

On 5/12/2024 at 3:15 PM, Vovchandr said:

For what it's worth, I've had this setup and the front to back size difference in side wall and width combo makes the car looks a bit stupid. Rear wheel is too small compare to front

 

60/R13 vs 45/R13

 

13x6	Track	DOT	Toyo	R888 185/60R13	Medium	21.8	551	7.3	185
13x8	Track	DOT	Toyo	R888 225/45R13	Medium	21.0	532	8.9	225

 

Oh, thanks! Somehow I had overlooked the existence of the 225/45R13 size when shopping for my current set of tires. I've got the 205/60 and the diameter is large enough to cause tire rub on my driver's side rear fender. Thinking the 225 might actually do the trick even with the slight aesthetic hit due to the overall smaller diameter.

 

Of course the other solution that would work is a wheel with less negative offset (or a fender that doesn't come back so far at the outer edge?). When I bought the car it had Kumho slicks on it with a lower profile and it wasn't an issue.

 

Also, apologies for the post spam. The page didn't refresh after hitting "reply" and... well, I posted about ten times. Hopefully the mods can clean it up and hide my shame.

 

 

Edited May 14 by Slonie
Added photo

[Cueball1]

Has anyone tried the toyo RR?  It's a substantially lighter carcass than the r888.  It is being replaced by the new R model with an updated compound.  The turbo Miata guys seem to like the RR tires and praise their consistency and longevity.  Hopefully the new R is better still.  

[KnifeySpoony]

RR and R don't come in 13" sizes. Might work for those running 15s. In fact I think I know someone running RRs on his CSR on 15s. 

[Cueball1]

Newb mistake! Sorry. I'll be running 15s to start since I have lots of 15" wheels already.  Will see how that goes and consider the move to 13s in the future.  Hopefully you smart folks and the tire mfg's have a good 13" solution then.  

 

Not in the same class as hoosier by a long shot but well liked for track days on heavier cars is the Nankang AR1.  Available in 13s.  Have folks here tried them on our cars?

Edited May 16 by Cueball1

[JohnCh]

If you are ok running a square setup, Toyo's site shows the RR comes in 205/60-13.   https://www.toyotires.com/product/proxes-rr/

[Cueball1]

These folks show the 13" RR for sale.  I don't see the 13 on other race tire sites.

 

https://rcomptires.com/proxes-rr/

 

Not entirely sure about running a square set up on my car.  The car should be in the 360-370bhp/ton range.  Will likely run square this first season and see how it goes. 

 

(Welcome to thead drift 😉)

[KnifeySpoony]

5 hours ago, JohnCh said:

If you are ok running a square setup, Toyo's site shows the RR comes in 205/60-13.   https://www.toyotires.com/product/proxes-rr/

That's odd - I must've been on some defunct Toyo site because it didn't show the 13.  Too bad no wider sizes for rear. Also, I've according to grassroots motorsports, the RR is similar pace to a AR-1, which comes in same 13" sizes as 888s. 

[Cueball1]

The grassroots tire tests are interesting and hugely informative. I do wonder if the substantially lighter carcass of the RR vs the AR1 and R888 will make it a better tire for our featherweight cars. Was really hoping for an opinion from someone here who had tried the RR before I pull the trigger on them.

[Croc]

15 hours ago, Cueball1 said:

The grassroots tire tests are interesting and hugely informative. I do wonder if the substantially lighter carcass of the RR vs the AR1 and R888 will make it a better tire for our featherweight cars. Was really hoping for an opinion from someone here who had tried the RR before I pull the trigger on them.

 

Try them out.  If you are driving with some energy they will not last long if they are the wrong choice!

[MV8]

I assume you guys running sticky tires don't locate the upper balljoint with the anti-roll bar. Does Bean still sell the bolt-on kits?

[Cueball1]

And now that I had pretty much decided the Toyo RR was the tire to try (lightweight, soft sidewall, durable for lots of heat cycles) toyo just announced it's being replaced by the Toyo R.  Lots of hoopla over the new compound and carcass being improved.  Of course it's heavier and has a stiffer sidewall.  They seem to have mainstreamed it for heavier cars.  😑🤬

[sf4018]

11 hours ago, Cueball1 said:

And now that I had pretty much decided the Toyo RR was the tire to try (lightweight, soft sidewall, durable for lots of heat cycles) toyo just announced it's being replaced by the Toyo R.  Lots of hoopla over the new compound and carcass being improved.  Of course it's heavier and has a stiffer sidewall.  They seem to have mainstreamed it for heavier cars.  😑🤬

I've raced the Toyo RR and Hoosier R7 on the same weekend in a SpecE46 (2850'). The RRs were just not very good, happy to see them make a better tire.

[Croc]

 

I used 3 sets of tires this week on track in France. 

 

1) Avon ZZR extreme compound - the last runs of my last set of these

2) Avon ZZS - I use these as my intermediate/wet

3) Toyo R888R - my first time using these.

 

I am going to focus on the Toyo R888R with points of comparison to each of the ZZR and ZZS as these tires are no longer readily available.

 

The Caterham for this exercise was a 2018 420R SV.  The Toyo R888R were 205/60/13 used on all four corners. 

 

 

 

Interestingly, I have a stagger wheel set up - 6x13 on the front and 8x13 on the rear.  The same Toyo tire size was used on both wheels.   The end width result looks like this.

 

 

 

I was running at cold pressures of 17psi with the objective of 22-23psi hot.  I did not get the opportunity to experiment much with pressures to see if they responded better with variations.  I strongly suspect (when you read my impressions below) that a lower front pressure will work better.   

 

I don't have a set of final suspension set up numbers.  I was running the traditional ZZR set up with a little more neg camber than what Caterham publish in their build manuals.  I think that is too much when it comes to the Avon ZZS use and for the Toyos as well.  I have asked for my car to have its suspension reset to standard Caterham manual track use when it gets back to the UK from France. 

 

My impressions:

• Very little scrub in needed on the Toyos compared with both Avons.  The Toyos feel fairly grippy out of the box whereas the Avons used to have a greasy feel until you scrubbing them in somewhat.
• For the first 1 hour on track the Toyos feel almost as good as the ZZRs - within a second a lap.
• They are close to equal the ZZR on lateral grip - not quite as good but not that far off.  Where they are some off on the ZZR is in-line grip - braking distances are not as short - I was surprised as to the difference.  Its not as if the wheels are locking - I am ensuring that does not happen - but you have to be thinking braking slightly earlier, particularly downhill braking.  This change is what accounts for 90% of the slower lap time by the R888 versus the ZZR. 
• The R888 transition from braking to cornering is not as adept as the ZZR - you have to be far more precise in your driving whereas the ZZR is more forgiving of hard driving.  I think that is driven by the tread pattern difference between the two.  
• After the first 1 hour on track the R888R goes off.  There is plenty of tread.  The tire looks fine.  But it is a very different tire in grip feel.  Loses a modest amount of lateral grip and a really noticeable amount of in-line grip.  Stopping distances increase slightly on the level and a noticeable amount on the downhill braking - felt like 1-2 car lengths over the ZZR and ZZS. 
• Turn in grip is noticeably weaker in this second phase of the R888.  I would have liked more time to see if dropping front pressures more helped the situation - I suspect it would have assisted somewhat but not a lot. 
• The Avon ZZR and ZZS are great for grip consistency over their entire life.  The Toyo is not like that.  You get an hour and then the grip degrades a notch down.  I have not driven on a track tire like that since the late 80s/early 90s when tires going off was a fairly normal part of car racing.  Since then a lot of work has been put into tire compounds to make them more reliably consistent for grip over the full life - however, the R888R does not do that.  Its a remarkably quick transition too - I felt it happening over 1-2 laps
• My experience with the R888 matches what the race guys are doing.  They are using fresh Toyos for qualifying and then going to fresh Toyos for the race.  This way they get the best grip phase of the tire for their competition but then throw the virtually unused R888s away afterwards.  This explains why the race support guys have a huge store of 1 hour old tires lurking. 
• Fortunately the R888 are half the price of the ZZR (when it was available - UK retail) but this is an expensive exercise for us just having some track day fun. 
• To get the best out of the R888 then a precise driving style is required.  Both the ZZR and ZZS were very forgiving of driving styles on the edge when things could be pressured or sloppy.  For the pro driver this is not an issue but its a major issue for those on this thread as I bet none of us are driving with that level of precision lap in and lap out.  
• If I had to rank the tires - clearly the ZZR are at the top with high consistent grip levels.  In teh first hour then the R888 is a second place to ZZR, a clear notch below.  The ZZS would be in third place at this point but its not by much.  After the first hour then the R888 is worse than the ZZS - a clear big notch below.  If the ZZR was ignored, then the R888 vs ZZS clear choice would easily be ZZS for me - consistency of grip over time, better stopping distances and roughly equivalent lateral grip plus its tread pattern makes it a good intermediate/light wet whereas the R888 suffers like the ZZR did in the wet. 

 

For my next set of dry track tires the plan is to follow the Roger Krause suggestion (USA - take a Formula Continental slick) which in the UK will be an Avon Motorsport slick and then hand groove a ZZR tread pattern into them.  The slicks are still available from Avon in the UK only the ZZR/ZZS have supply issues. 

 

For intermediate/moderate wets, I have one set left of the ZZS so will continue on them for now.  No ZZS alternative has emerged in the UK yet as there are enough ZZS stocks at TFL Racing to continue using them.  If you can get them in the USA then this is my second suggestion instead of a ZZR if the preferred hand grooved dry slick option does not appeal. 

 

 

 

 

 

[CBuff]

I’m surprised the 205 fit both the 6” and 8” wheels. Do you see any advantage to running this square on staggered setup?. Or would the 185 on the 6” be better?  Assuming these can be sourced. 

[Croc]

7 minutes ago, CBuff said:

I’m surprised the 205 fit both the 6” and 8” wheels. Do you see any advantage to running this square on staggered setup?. Or would the 185 on the 6” be better?  Assuming these can be sourced. 

 

I don't think it changes the end result to be honest.  The size choice on front might improve the sidewall flex which is a clearly something to be considered for front end grip but it would have zero impact on the grip degradation over time as that is a rubber compound issue. 

 

The fact that everyone is doing the same thing for the race series in the UK tells me that it is likely the best option.  TFL are supporting 40 something Caterhams in race and track days and the do talk with the other support outfits, McMillian being the next biggest.   What I was given is the best consensus in UK Caterhams right now.  Not really a great answer for you tbh but I did not have unlimited time to experiment. 

 

 

[Vovchandr]

21 minutes ago, CBuff said:

I’m surprised the 205 fit both the 6” and 8” wheels. Do you see any advantage to running this square on staggered setup?. Or would the 185 on the 6” be better?  Assuming these can be sourced. 

 

6.5" can fit up to 245 I believe. Definitely 225.

[Cueball1]

The fast knowledgeable turbo Miata guys running time attack and super Miata racing really stress the idea that wheel width needs to match tire width for a racing tire to work optimally.  I imagine that 205 on a 6" rim may have impacted the front tires ability to do their job. 

[Croc]

3 hours ago, Cueball1 said:

I imagine that 205 on a 6" rim may have impacted the front tires ability to do their job. 

 

Yet the entire fields of Caterham UK race series competitors are doing exactly that when running this tire. A lot of people are wrong - its not going to be you or I to say which ones are. 

 

Logic to me says go down a size but then I see some very fast drivers who I am on track with say its not the right way.  A conundrum eh?

 

But it misses the point - the correct decision is to choose a different tire

[Cueball1]

Definitely a different tire.  R888 is old tech.  Hoping the new toyo R is a good option.  Not likely the same pace the new soft avons were but they are a lighter tire than most, like avon, which seems to be helpful in our featherweight cars.  

 

Doesn't seem like it should be this hard to find a really good tire but light cars on track aren't exactly a massive market to sell to. Guess folks were spoiled having avon available all these years.