Caterham 16 inch wheel/tire questions

[athens7]

I'm due for new tires before autocross season starts. I want to fit tires that are streetable, but as aggressive as possible. My choice was a set of Toyo R1Rs, which are one of the very few types available in 205/45R16 like the original Avon ZZ3s. When I went to have them installed, I found they were too wide, and rubbed against the wing stays (I had been warned that this was a likely possibility). Another choice is the Bridgestone RE-11, but I fear the same problem will exist with them. I am told most of these types of tires are bigger/softer than sized as a way to shade competition rules. A 5 mm spacer would allow the tires to clear the wing stays, but it looks like they will then contact the outer lip of the cycle wing. I would prefer to avoid the extra expense of new wheels, and I cannot use a tire with a UTQG less than 140 (R comps) without making a number of other modifications to the car to remain legal, so Advan A08s or Toyo R888s are out. Can anyone recommend a tire/size to fit my wheels? If I must go to a 15" wheel, what are some good choices for light weight? Is the Caterham 15" wheel any good, or am I better off with an Enkei or other aftermarket wheel?

[Guest speedcraft]

Brad...you probably already know this but the wing stays are 'adjustable', ie just bend them as the assembly manual indicates within reason. take the wing off of course so you dont crack it and try to get everything aligned including the holes to reinstall the wing.

 

on a side note, i have run R888's [13"] and find them heavy and too stiff a sidewall for the 7...on the road they bounce somewhat over bumps. they wear like nails though. the CR500's are an incredible tire for the car...but UTQG 20.

[pksurveyor]

The Hankook Rs2 205/45-16 with treadwear of 200 works on my SV. I have been thinking go to 195/50-16. The Yoko factory rep told me that their tires are oversized.

[Croc]

Hi Brad

 

What did you end up with as your final decision? I am up for a set of new tires (after 7000 miles....). I am definitely not putting another set of Sumitomo's back on the car (a little too sudden to break away and useless in the wet). I would be interested in hearing about your final choice.

 

Cheers

[athens7]

I installed a set of Toyo R1Rs. We bent the wing stays very slightly to accommodate the tires, something I found to be a simple matter, as noted earlier in this thread. The tires are UTQG 140 AA A, so street legal and not requiring race mods to run in D Modified (prop shroud, external cut off, etc.). I have been warned that the tires will wear fairly quickly for street use on most cars, but most cars are a lot heavier than 1420 lbs. I drive about 4000 miles per year, plus about 15 autocross events. If I have to put on a new set each year, it seems a fair price to pay in terms of cost to compete. I have put a couple of hundred miles on the tires and run one autocross so far, and the tires are great! They ride softer than the Avons on the highway, with a slightly higher tendency to react to road crown as well as a little more jiggle in the wheel on uneven road surfaces. These traits are only noticable with hands off the wheel, and they do not cause the car to react uncomfortably in normal driving. As an autocross tire, they transform the car: turn in is dramatically sharper, and the back end just sticks. Previously, the car was very easy to overdrive, oversteering on throttle and brake, but also capable of plowing as the front end lost grip. Now you just point and the car goes there, and lateral grip is very high. In my first event on these tires, with no practice, I won my class by almost 3 seconds against a CRX running 255 series DOT slicks, and was fast modified in any class (including beating an E Mod Cobra with a 500 hp turbo V8 and Ecsta V710s). On a 60 degree day, the tires never got above 90 degrees F, and the pyrometer I used showed a 5 degree spread from edge to edge at 21 psi (I run 18 psi on the road), with sidewall roll over just barely on the vertical side of the tread edge. I don't know that these would be the best choice as a road only tire due to the softness of the compund, but for my purposes I am very pleased.

[Croc]

Thanks Brad - this is great feedback. I think I might give these a try for my next set. The CR500s were great but oh so quick to wear. The Sumitomos wore fine but not the best for roadholding when pushing along.

 

Congratulations on the class win first time out on these tires - that is a powerful recommendation.

[athens7]

I find the Toyo R1R to be a very good wet weather tire, based on the VERY wet SoloPro school I attended today. Very good grip, both off the line with 2000 rpm standing starts (needs 3000 rpm in the dry), and in transient maneuvers. Breaks away progressively, and easy to catch. The tires also handled standing water on course without hydroplaning or snatching the wheel out of my hand.

[pksurveyor]

Good information. It looks like R1R is a good compromise street/track tire for 16 inch wheels.

[pmarie]

Yes Toyo R1R come in the 205/45-16 size.

But while the stickier Toyo R888 and even stickier Yoko A048 don't come in that size, they do come in the 195/50-16 size which will fit within the front cycle wings as they are only 4 mm larger in radius.

 

On the rear, these tires come in the 225/45-16 size which will fit on the 7" rim and they are only 7 mm larger in radius.