PDA

View Full Version : Tyre sizes



kevchard
27-03-06, 10:25 AM
Hi
Can anyone suggest the max size tyres i can get on a CORTINA based DMS/Cobretti Viper.
We already have the 15" rims (7.5 width i think). I want as high a profile as poss (to allow height for SVA), and max width (for looks).
I would like 60 profile, but not sure if this will be high enough.
It is a fine line between filling up the arches and everything rubbing, weighed up against small tyres/too low for SVA/stupid looking empty arches.
I don't understand the 3 o'clock / 9 o'clock SVA rule for wheel clearance of body.
Also do DVLA / SVA take your word for speed ratings on engine/gearbox/diff combo. Or do they test it / you have to prove it etc.
I have an engine that was good for 145mph, but not with our g/box or diff. So proving speed is not straight forward.
We are having electronic speedo before anyone comments measuring speed etc :).
Cheers

kevchard
28-03-06, 08:35 PM
No offers or opinions? :(

steamyrotter
28-03-06, 09:11 PM
No offers or opinions? :(

Too big won't fit

Too small look silly.


:D


Other than that how the heck have you got to that stage!??!?!??!?!?!!?!?!?


:eek:

kevchard
29-03-06, 08:29 AM
Well thankyou Jeremy Clarkson!!!!!!!!!! What size tyres you gonna fit? (except correct sized ones).
Cheers

kevchard
29-03-06, 08:42 AM
I've got to that stage by missing all the menial parts out (eg body fitting properly, engine not fitted, no exhausts). Oh yes and by employing 3,000 people to do it all for me :).
No seriously, I am still doing all the work, but have some money that is burning a hole in my pocket, so tyres seem to be the choice for the cash.

To do list:-

The doors, bonnet and boot still need fettling
Body needs prepping for paint (Helen is undercoating for SVA, proper paint post SVA)
Door cards need modifying (eg door handles fitted and 'plumbed in')
Seats need upholstering
Carpets need to be made and fitted (I am paying someone to do this)
Dashboard needs finishing (cutouts for speedo, gauges etc)
Speedo needs buying
Seatbelts need buying / fitting
Sidepipes need to arrive / be fitted (arrive no later than 24/04/2006 according to grannysspeedshop)
Few odds and sods to do tidying engine bay pipes / wires etc
Alarm needs to be finished installing
Windscreen, wipers, heater are all to be done post SVA.
Ar*e, forgot roll bar, bit of a git to fit aswel now, what with parcel shelf being grafted into car :(

steamyrotter
29-03-06, 04:21 PM
Well thankyou Jeremy Clarkson!!!!!!!!!! What size tyres you gonna fit? (except correct sized ones).
Cheers

tricycle ones me thinks!!!!!!!!
can't afford anything else..
:(

tony
29-03-06, 05:03 PM
Kev.

You declare your maximum speed on the sva application form, the tester will then check tyre ratings to make sure they can cope with the declared speed. You don`t have to prove or diss-prove the figures, he`s just interested in the speed rating of your tyres.

9 0.clock rule, if you look at your wheel full on from the side , imagine the 9 and 3 o.clock positions on the rim itself.The examiner will take a vertical line ie. plumb bob from the top of your wheel arches in line with these points , so long as your wheel rims don`t protrude outside the line your ok. Hope that makes sense :) .

slogger
29-03-06, 08:01 PM
Kev.

You declare your maximum speed on the sva application form, the tester will then check tyre ratings to make sure they can cope with the declared speed. You don`t have to prove or diss-prove the figures, he`s just interested in the speed rating of your tyres.

9 0.clock rule, if you look at your wheel full on from the side , imagine the 9 and 3 o.clock positions on the rim itself.The examiner will take a vertical line ie. plumb bob from the top of your wheel arches in line with these points , so long as your wheel rims don`t protrude outside the line your ok. Hope that makes sense :) .

Tony,

Is that the wheel rim or the sidewall of the tyre? I don't know and haven't been through that SVA bit. I run 275-60-15 on rear and 225-60-15 on the front of my cob. The side wall balloons out quite alot at these sizes.

tony
30-03-06, 05:12 PM
Tony,

Is that the wheel rim or the sidewall of the tyre? I don't know and haven't been through that SVA bit. I run 275-60-15 on rear and 225-60-15 on the front of my cob. The side wall balloons out quite alot at these sizes.

It`s the wheel rim itself, tyre walls are exempt. I just put maximum toe-in on the front for the test and re-set afterwards :) .

When he did mine at L. Buzzard he held a spirit level in the vertical postion about an inch from the wheel at 3 and 9 oclock positions.He then measured back to the rim at both points and compared them to the measurements taken at the wheel arch.

kevchard
23-09-06, 10:04 PM
Has anyone with a Corty based setup have trouble with 205 x 55 x 15 front tyres?
I have tried 225 x 60 x 15 but they too big. They rub on the rear of the front wheel arch, so drastic times call for drastic measures (smaller tyres).
Cheers

cobrageoff
23-09-06, 11:43 PM
i have a pilgrim sumo mk2 with v8, cortina based

I have 195 x 60 x 15 on front and 235 x 60 x 15 on the rears.

cooper cobra tyres.

Hope that helps :cool:

kevchard
24-09-06, 10:24 AM
Thanks Cobrageoff
I can get away with 225 x 60 x 15 on the rear. The diameter of the fromt tyres are the prob, i need small enough to allow them to fit in the arches, but tall enough to bump up headlights far enough for SVA.
Cheers
Kevin

steamyrotter
24-09-06, 09:23 PM
Kev.

Cant remember if you are using standard front springs?
If so you could try fitting some spring assisters as per caravan towing usage??
They are like split doughnuts that slip in between 2 coils and give better load handling.
Advantage here is since the front end is lighter than a standard car rear when towing,
it should raise the front a little to get it through but not so much that it will alter the geometry.

Will give a slightly harder drive but for the short term should / could do it.

Cheers

kevchard
25-09-06, 08:35 AM
Hi Dean
Thanks for the idea. i am using standard suspension setup (eg separate springs and dampers). Any idea where i can get these 'assistors' from?
Trouble is the springs are well lame, they might aswel be made of elastic.
I have been advised by corty club to go for 2.3 v6 corty springs.
How's yours going?
Cheers
Kevin

lutman
25-09-06, 11:37 AM
If you go to the TOYO tyres web site they have a very easy to read chart that details the actual diameter of the tyres and equivalents dependant on wheel rim size. That is - if you currently run a 15inch rim with 235x60 and want to put on 18inch rims what tyre size will be the same or close in diameter, or what is the max tyre size a rim can take.
So for your application you could measure the space available under the arches and see what will be max diameter size you can install and max width tyre the rim will safely hold.

Good luck
Chris L

CeeJay
25-09-06, 11:48 AM
Has anyone with a Corty based setup have trouble with 205 x 55 x 15 front tyres?
I have tried 225 x 60 x 15 but they too big. They rub on the rear of the front wheel arch, so drastic times call for drastic measures (smaller tyres).
Cheers

Kev

I think my coby has 225's fitted (Well when I say fitted, they are currently sitting in the shed). From what I can recall (The wheels and body have been off the chassis for a while now) they looked 'right' - what I mean is is that they suited the look of the car - I'll check what they are 2nite and get back to you!

CeeJay.

steamyrotter
25-09-06, 08:52 PM
Kev

Try here:-
http://www.towsure.com/default.asp?t=6462


Now 1/3 way through the wiring loom. All scratch built and definitely NOT standard as you'd expect from me!!

Cheers

D.

Iain
26-09-06, 08:50 AM
Tyre sizes (remember that mine is a Jag Kit Classic Replicas)

Front - 225/45/ZR17
Rear - 255/45/ZR17

Cheers...

kevchard
10-10-06, 03:53 PM
I have now got it sorted.
For Cortina based kits only mind you:-
225x60x15 rear
205x55x15 front.
Any bigger on the front and the tyres hit the front or rear of the wheel arch when you turn steering wheel.
HTH
Cheers

steamyrotter
10-10-06, 11:53 PM
Won't rub on mine!!!!!!!
:D :D :D :D :D :D :D