wheels and dynamics

[twobone]

Coming from the Porsche community, there was a love affair with bigger tires. I was running 245 on the rear and 205 on the front of my 911. It had so much grip that slippage was never found unless on the track.

 

What is the norm for 7s?

 

Is the approach to keep the standard wheel and tire set ups to maintain the toss-ability of the cars and promote a bit of tail out fun?

 

I just want to make sure I don't do anything stupid in terms of upgrade fever and end up losing some of that critical feel and delicacy I'm expecting from my 7

 

P.S. sorry for all the questions...I'm just so excited about getting my hands on a 7!

[WestTexasS2K]

I run 225/40/17 in front 275/35/17 in back.

[Kitcat]

Your 1600 cc Kent engine will do fine on 185-205 tread width. Your car is so lite it will be hard to warm them up if they are much bigger. I have Toyo R1s 205 15's all around. Plenty of grip. I run abt 18 lbs pressure in rear, 16 up front, on street and at the track. Adding lightness to the wheel/tire combo pays handling dividends.

 

The big horsepower cars do better on wider wheels than our Kent power 7's but I think even the new 260 hp Caterhams use 195 fronts.

[slngsht]

also, don't forget big wheels and tires add weight in the worst possible place... you have to accelerate them linearly, rotationally and control their bounce. I have big wheels and suffer from this...

[JohnCh]

Rule of thumb on the UK Westfield and Caterham forums is 185's all around if you have less than 200hp, and 205's out back if you have more than that.

 

-John

[Kitcat]

Anyone going to the trackday at LOG 30 on 185's ? I will be there on 205's and we can test the tire width theory there at the track.

 

Mike

[Guest speedcraft]

another consideration is to be aware of actual tire dimensions rather than just sidewall or catalog numbers...lots of examples where sidewall doesnt tell the whole story.

 

ive tried a number of combinations and seems that caterham's original sizing is a pretty good balance between grip and handling. its pretty tweaky from that point and may be more suspension setup than tire....

[WestTexasS2K]

Ultralites usually run 205 and 235. For a stock 240 hp car it works pretty well. It just wasn't enough tire for us. The wider tires are a little harder to get warmed up though. To really get best lap times we switch to 15 x 10 wheels with Hoosier slicks for reduced ride height lower wheel mass and weight. I personally don't want this look for street driving.

[KiwiBirkin]

My Birkin runs 205s all around on 15" rims but im moving back to 195s all around as I feel they will be a better combo on my light weight car, if it helps my mate had 175s on his Birkin and he had no trouble keeping with me on the track and on spirited drives through some of the more fun roads here in NZ. Dont go too big my advice you dont need too.