Wheel/Tyre Widths

cammmy · Post by **cammmy** » Thu Mar 07, 2013 1:34 pm

Hi Guys

Just wondering, what width wheels/tyres should I be looking at for up to 400bhp (i'm leaving room for improvement). I believe the maximum width wheel I can get under the rear arches without major flaring is about 8" - 8.5". I was thinking about 225/50/15 on the back; haven't thought much about the front.

I'm looking for fast road use and the car weighs ~1200kg

On another forum I've been told to stick to 185 or 195 but that seems a little skinny?

ian.stewart · Post by **ian.stewart** » Thu Mar 07, 2013 1:46 pm

Similar size to what I had on my cortina, 225/50/15, on 8" compomotive MLs, I used Toyo 888Rs, superb tire, and surprisinly good in the wet too.

kiwicar · Post by **kiwicar** » Thu Mar 07, 2013 2:43 pm

Hi
With a semi trailing arm set up as on the back of the Triumph I would be very carefull of low tyre height tyres. I would also probably not go above 235 at the rear and think that a narrower higher profile tyre might work better than low and wide. A 215/ 60X15 on the back would be better if you can get them to fit otherwise I think when it lets go it will be rather quicker than is ideal

I would have the rim up to an inch narrower than the tread width at the back rather than wider as is fasionable at the moment. I would go about 10 to 20 mm narrower on the front with maybe a rim the same width as the tread or even 1/2 inch wider ie probably the same width rims front and rear!
You want to keep the tyre relativly hghly loaded at the back so it is nice and warm across it's width, you don't want to go into a corner on a nice hot part of the tyre only to roll onto a relativly cold bit as you feed in the power, in that aim a narrower tyre with a higher profile will warm more evenly as it will comply to the road and changes in camber more easily.
Best regards
Mike

cammmy · Post by **cammmy** » Thu Mar 07, 2013 3:15 pm

Great, thanks for that. I'll have a look at the options. Do you recommend having the rim narrower than the tread at the back to make it a bit more progressive before it lets go?

kiwicar · Post by **kiwicar** » Thu Mar 07, 2013 4:10 pm

Hi
Yes to give you some warning before it lets go and to also give the tyre more of a chance to slightly change shape as the camber changes at the rear all of which should give a more progressive transition to loss of traction.
Best regards
Mike

stevieturbo · Post by **stevieturbo** » Thu Mar 07, 2013 11:56 pm

width is far less important than the actual rubber.

Yes a little wider will be more rubber, but the difference in grip between a trackday tyre and normal road tyre is night and day.

And the difference if it's for drag racing between a trackday tyre and a drag radial...again, is like night and day.

dbv8 · Post by **dbv8** » Fri Mar 08, 2013 8:50 am

As already suggested the Toyo 888's are a fantastic tyre. Excellent grip in the dry and damp and not too dangerous in standing water. They aint cheap but you get what you pay for.

I fitted a 'budget' alternative to my TVR. Federal RSR's. They are about 2/3rd thr price of 888s and i think give 80%+ the performance. A 225 in godd rubber as these will serve you well i think. Maybe a 205 on the front would be a good balance.

Other alternatives that come recommended are Kuhmo Ecsta V70A

cammmy · Post by **cammmy** » Fri Mar 08, 2013 9:19 am

Cool, thanks guys.

I wanted Potenza RE002's but they don't think they do anything over a 205/15.

I'll have a look at track day tyres but I will be doing long trips in the car, so may need to stick to performance road tyres as opposed to a semi-slick.

stevieturbo · Post by **stevieturbo** » Fri Mar 08, 2013 5:43 pm

How far is a long road trip ?

The likes of 888's wont wear out that quickly. If all you ever did was drive normally, they'd still do 4-5k.

The last set I had lasted about 3k at the rear and a little longer up front before they were illegal ( ie sub 1.6mm over 3/4 tread width )

Some trackday tyres like the Kumho dont have a full tread depth over the entire width, so will become illegal sooner.

cammmy · Post by **cammmy** » Sun Mar 10, 2013 8:23 pm

Would cover at least 900km on a decent trip, NZ is quite a long country and tyres are more expensive there.

Might start with performance road tyres and go from there. Either that or Silverstone FTZ-RR semi's. Have those on the Pug and they grip very well and are a lot less than the 888's.

stevieturbo · Post by **stevieturbo** » Sun Mar 10, 2013 9:33 pm

I think it's just a case of getting more wheels.

Then you can have tyres for the road trip, and then tyres for sporty usage.

Although 400hp with good quality road tyres shouldnt be too bad. And I'm sure 95% of the time you'd just be driving normally on the road anyway.

Ive used some Marangoni tyres before and they were pretty good for normal road tyres.

Toyo R1R's or the Federal RSR595's might be another option. They arent as soft so might last a lot longer than 888's and have decent tread to get rid of water
I think Hankook do a similar type of tyre too, RS2 or RS4 or something.

cammmy · Post by **cammmy** » Mon Mar 11, 2013 1:12 pm

Yeah the only issue is that on the trips I want to be able to really enjoy any good roads we come across (we keep a map book with all the good B roads in it) so need something that will do normal duty and still be good for enjoying the twisties. Either performance road tyres or reasonably priced semi's I think.

Could start with road tyres and move up if necessary.

Post by **Rossco** » Mon Mar 11, 2013 6:16 pm

stevieturbo wrote:width is far less important than the actual rubber.

Yes a little wider will be more rubber, but the difference in grip between a trackday tyre and normal road tyre is night and day.

And the difference if it's for drag racing between a trackday tyre and a drag radial...again, is like night and day.

I'm confused....thought the clocks went forward at the end of the month.....too much night and day for my tiny brain

stevieturbo · Post by **stevieturbo** » Mon Mar 11, 2013 6:24 pm

Rossco wrote:
stevieturbo wrote:width is far less important than the actual rubber.

Yes a little wider will be more rubber, but the difference in grip between a trackday tyre and normal road tyre is night and day.

And the difference if it's for drag racing between a trackday tyre and a drag radial...again, is like night and day.
I'm confused....thought the clocks went forward at the end of the month.....too much night and day for my tiny brain

just buy decent tyres at mid-day on a Wednesday and it's all good

Ian Anderson · Post by **Ian Anderson** » Mon Mar 11, 2013 6:49 pm

The GT40 guys are getting great results with the Avon cr66 range

good grip wet and dry and do reasonable miles on a set.

That said the 400 hp would be put through wider tyre than 225

Ian