Jump to content
SAU Community

Recommended Posts

Currently have 235/40/18 all round, running 8.5" wide front and 9.5" wide rear. Looking at getting some more grip down and was thinking of putting 255/35/18 on the front but was seeing if anyone else had done this using the same rim width and if there was any bulge creating more of a disadvantage then an advantage etc? If I can run the 255 on the front I'll go 275/35/18 on the rear. If not I'll just stick with the 235/40/18 on the front and upgrade the rear to 255/35/18.

Any opinion/experiences would be appreciated!

Link to comment
https://www.sau.com.au/forums/topic/364941-r888-tyre-size-vs-rim-size/
Share on other sites

Hey Ryan,

Check this

http://www.toyor888.net/racing/index.htm

8.5inch is the smallest recommended for a 255 and you might find it moves around a touch which will result in quicker warm up temps and possibly higher peak temps.

This is just my understanding though, some of the gurus will likely drop in and correct me.

Yeah checked that link, 8.5"-10". Hmmm quicker warm up would be good as the car is time attack not circuit so only 3/4 of a lap then into one timed lap straight away. Just don't want the front to feel squirmy and un predictable.

It's hard to say how it will respond as each R compound has slightly different widths for a given tyre size. Obviously the best way is to test but then you've forked out the bucks already.

As an aside, When looking at the R888s I was advised slightly away from them by some other circuit guys on here stating that they are in the same ball park grip wise as a KU36, which isn't even an proper Semi.

Can you use your contacts to get some cheap AO50s or RE55s? What are you currently using?

I'm in the process of shopping myself and might just grab another set of second hand RE55s as mine have been good.

yeah using R888 now and rate them pretty highly.....not saying there the best semi out there and I'am definetly open to trying other brands etc. Have also tried KU36 and didn't rate them to well, took a long time to come up to temp (not ideal for time attack) BUT the KU36 are def good value for $$.

Ahh OK well if you're already on them and are comfortable then all good.

Anyone you know running the same sizes you want that you could borrow from? Chuck on their wheels and go?

Is this on an S chassis?

Edited by ActionDan

Ahh OK well if you're already on them and are comfortable then all good.

Anyone you know running the same sizes you want that you could borrow from? Chuck on their wheels and go?

Is this on an S chassis?

unfortunately not :-(

I wouldn't run 255 semis on a 8.5. 235 is ideal. you could probably get away with 245 if you want though.

I would buy a pair of 255s. try them on the front rims. see what you think. if you don't like it, put them on the rear 9 inch rims, and then buy 235 or 245 for the fronts.

I think you'll get more out of a better tyre @ the same sizes as it doesn't seem the R888 is much chop compared to other choices around, which is probably more important for Time Attack in terms of grip rather than a club sprint type/general track day where you are cutting many laps/sessions

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now


  • Similar Content

  • Latest Posts

    • After my last update, I went ahead with cleaning and restoring the entire fuel system. This included removing the tank and cleaning it with the Beyond Balistics solution, power washing it multiple times, drying it thoroughly, rinsing with IPA, drying again with heat gun and compressed air. Also, cleaning out the lines, fuel rail, and replacing the fuel pump with an OEM-style one. During the cleaning process, I replaced several hoses - including the breather hose on the fuel tank, which turned out to be the cause of the earlier fuel leak. This is what the old fuel filter looked like: Fuel tank before cleaning: Dirty Fuel Tank.mp4   Fuel tank after cleaning (some staining remains): Clean Fuel Tank.mp4 Both the OEM 270cc and new DeatschWerks 550cc injectors were cleaned professionally by a shop. Before reassembling everything, I tested the fuel flow by running the pump output into a container at the fuel filter location - flow looked good. I then fitted the new fuel filter and reassembled the rest of the system. Fuel Flow Test.mp4 Test 1 - 550cc injectors Ran the new fuel pump with its supplied diagonal strainer (different from OEM’s flat strainer) and my 550cc injectors using the same resized-injector map I had successfully used before. At first, it idled roughly and stalled when I applied throttle. Checked the spark plugs and found that they were fouled with carbon (likely from the earlier overly rich running when the injectors were clogged). After cleaning the plugs, the car started fine. However, it would only idle for 30–60 seconds before stalling, and while driving it would feel like a “fuel cut” after a few seconds - though it wouldn’t fully stall. Test 2 – Strainer swap Suspecting the diagonal strainer might not be reaching the tank bottom, I swapped it for the original flat strainer and filled the tank with ~45L of fuel. The issue persisted exactly the same. Test 3 – OEM injectors To eliminate tuning variables, I reinstalled the OEM 270cc injectors and reverted to the original map. Cleaned the spark plugs again just in-case. The stalling and “fuel cut” still remained.   At this stage, I suspect an intermittent power or connection fault at the fuel pump hanger, caused during the cleaning process. This has led me to look into getting Frenchy’s fuel hanger and replacing the unit entirely. TL;DR: Cleaned and restored the fuel system (tank, lines, rail, pump). Tested 550cc injectors with the same resized-injector map as before, but the car stalls at idle and experiences what feels like “fuel cut” after a few seconds of driving. Swapped back to OEM injectors with original map to rule out tuning, but the issue persists. Now suspecting an intermittent power or connection fault at the fuel pump hanger, possibly cause by the cleaning process.  
    • For race cars, this is one part where I find having the roll cage bar having gone through a hole in the floor better than the build it up on a ledge inside... The Merc I help on, the main hoop ends are marked on the car, and the jack is marked... Jack goes under a few inches and lifts one whole side of the car up... Removes that fight for long slim jacks for race car duties!   My biggest issue for the daily drivers I work on, is my jacks don't go high enough. The jacks start out on a few blocks, jack it up, then start a second jack under it on more blocks, and then I can get an axle stand under it. My axle stands are presently in use, and are nearly fully extended. The car is sitting with barely more than a cm of clearance to get the wheel off the studs! Sarah's Kluger is the same, as it has an ungodly amount of droop available in the suspension and a distinct lack of good jacking points!
    • Happy? Yep, my to do list is getting shorter and shorter. Either this light approaching is the end of the tunnel, or I'm about to be hit by a train... Ha ha ha   Also, Duncan isn't that far out of town that you need to make a multi day drive out of it. 😛
    • Sorry I meant that we are building the EH for a client.
    • LOL, when one "money pit" is never enough Noice, and excellent work mate
×
×
  • Create New...