This tyre question will stump you lot

[thinfourth]

Whats the best road tyre for taking a 7 offroad

 

I am entering a production car trial and the following reg is causing me a few headaches

 

All vehicles will be fitted with standard road tyres, no exceptions! No Mud and snow, winter, rally, block tread, hand cut, off road, forestry, or agricultural tyres allowed.

 

I'm thinking the old stalwart of the CR322 might work BUT would the big treads of a 48R give grip on muddy stuff

 

 

Oh and for those that don't know a production car trial is getting up a reasonably smooth course but it is offroad in this case it is going to be run in a farmers field

 

I would enter my normal road car but 4wd and mud tyres are out so i'm not going to able to use the landy

 

 

Autotesting in Scotland tires provided by Skip motorsport services

(Well we pull them out of skips)

 

[rj]

Just disconnect the front propshaft and fit un-decent tyres and the Landy is in

 

 

- How about rain tyres for the Seven?

[CageyH]

A021's?

 

I think 48's being semi slick won't help.

 

Only dead fish go with the flow....!

[Bricol]

I used to use a very tuned westie for PCTing - although the MSA has redesignated them as "car trials" . . . Used to use 145/80/13 remoulds in Michelin MX type pattern.

 

If it's dry (ha!) then nearly any road tyre will do.

If it's new, virgin, untouched, juicy grass, or even slightly damp through to mud bog proportions, you want as narrow as possible.

 

So if they are following the rules exactly, look up the narrowest tyres fitted to a seven of your vintage, and visit the local scrappers for some steel wheels and maybe even tyres. If you got for some new cheapo tyres, use them on the road first to buff them up and remove any moulding agent etc. Drive there, and then fit RHS rear wheel to LHS and vice versa. The worn edge will bit better You want blocky tyres with as few lines around the tyres as possible.

 

Lift you suspension a touch, fill the tank, find a passenger of similar weight to you, carry (well wrapped) your usual 3 ton trolley jack, brace, tool box, spare wheel etc etc. Want weight over the driving wheels. A mate of mine has been known to fill the spare tyre with water, a la tractors (you can get special valves to do so).

 

If they follow the usual rules, tin-tops will be letting their tyres down, and you will be blowing them up to the minimum in the regs for your class.

 

And use torque - not revs - start off slow and build momentum without wheelspin. Take the smoothest line, not necessarily the shortests, or a racing type line - minimise the gradients you have to attack and avoid as much as possible any form of cross-axling - any lifting of the drive wheels, or the loads on them will stop you. Maybe turn early around one marker to get onto shallower slopes to attack the next. Steering adds resistance to motion - so if you can steer before any steeper bits, do so. Going over humps straight might just get you over, whereas with some lock on, the extra resistance will stop you. Maintain momentum, keep throttle constant and gentle if you need to alter it. Think of where you need to be on the next set of markers - usually amusing watching even experienced triallers get caught out by not leaving enough room by being on the wrong line to get around the next marker.

 

Beginners mistake is to floor it - you only floor it, right to the floor, if trickling, low, constant revs doesn't work - and if that doesn't work, give up. Sitting there on high revs, one wheel smoking will annoy everyone else, and wreck, eventually, your diff. Although usually the only technique for mud is full welly!

 

LSD is not necessarily a good thing as it will stick you in a higher class if they ask or test for it, and makes steering less effective.

 

Not that I know anything about trialling . . . 😬 here here and a bit gentler here

 

I really don't know how the westie driver does it on those wide tyres - but note the engine note . . . constant!

 

Check for course changes between rounds - follow the markers, not the tyre tracks! And walk the course - watch others. Steer around sheep/cow/horse do dar - not only does it smell when it lands in the car, it's pretty frictionless and you tend to come to a very quick stop when one driven wheel lands on it - but you do get bonus points for getting it to flick off a front wheel onto any area of your passenger

 

Above all - have fun! And if you already know all this, at least a load of others didn't . . .

 

And for all you others - it's a great way to teach car awareness, control sensitivity and even skid control to new and experienced drivers.

 

Bri

(yeller dutton)

[thinfourth]

visit the local scrappers for some steel wheels and maybe even tyres

 

What spend money 😬

 

As a founder member of skip motorsport i can't possibly do that

 

But many thanks for the advice 😬 i didn't think there was anyone that would even know what a PCT was

 

 

 

 

Autotesting in Scotland tires provided by Skip motorsport services

(Well we pull them out of skips)

 

[Jason Plato]

I believe there is a list of permitted tyres in the Blue book for PCT

 

here is C7 TOP

Taffia rear gunner

 

[Neil_K]

How about some ZV1's. the tread pattern is pretty blocky, and the blocks are quite deep. Should be dead easy to get hold of as well.

 

Where am I?

[Bricol]

Too wide. Good in the dry. Crap any other time - in the field of course. I find them fine on the road, but the odd time the Caterham has ventured up a trials section, I found it lost grip pretty quickly.

 

Problem with a Caterham is the lack of front suspension travel when in road mode - that lifts and tilts the chassis, removing much needed weight on the rear corner and the grip goes immediately.

 

If not LSD, you spin the wheel. If you've got an LSD, then both wheels spin and you slip sideways down the hill - normally into the marker you've just passed, so getting a higher score than if you's stopped slightly sooner and no slid into it - lowest score wins.

 

Been not very amusing in the yeller Dutton in the vid, a very much modded for classic trials rather than car trials (- it'll pop wheelies in first!), to do a full club event and not drop any points at all - and still not win against tin-tops in a better supported class that dropped 40, 60, 100 points - all to do with index of performance and how much you beat your competitors in class by - and as my mate double drives, we normally end up with pretty similar scores - unless brain fade takes over and one or other of us drives out early on in a section.

 

Bri

[nickh7]

A539's 🤔

 

Fuel your Addiction here

[Bricol]

Kingpin remoulds - KM / KML / KZX or KM7 / KMT here

 

Fantastic grip (relatively) when down to around 5psi - although you need the power/torque to be able to drive them through soft, deep, leaf mould - and to be able to consider tyres as an expendable component.

 

Narrow and tall - give you a bit more ground clearance. Although if you have a tall first gear and no torque, then lower profile might be better.

 

I just happen to have a couple of car sets, Ford fit - but N.Yorks might be a long way to come to borrow a set.

 

For anyone in the Colne/Skipton/Keighley/Bradford/Halifax/Ilkley etc area, my local motor club is running a car trial on a fantastic bit of land on the 23rd October (if that's a Sunday) - blatmail me if anyone wants any details, even if only to come and watch for a few minutes.

 

Bri

[MADMALC]

I used to use remoulds on my 1968 Mini Cooper. I chose the Goodyear G800 pattern and then selected the ones with the most moulding spikes left sticking out of the tread pattern. Very effective, with some pots to prove it.

Are remoulds still around?

These were only fitted once on the grass so as not to lose any of the bobbles.

Must get some serious weight over the back wheels and it might be worth raising the ride height.

Not the ideal car for the sport but you should have fun. Watch the top performers for some education!

 

S7MAD

[thinfourth]

Spare wheels aren't even vaguely a problem 😬 i have a reasonable supply I had 16 rims at last count and i'm always looking for more, but that said i am a supplier of autotesting rims to anyone that wants them up here

 

I'm morally against spending money on new tyres so i shall go around a few tyre places to see what they can supply. Is tread depth an important factor?

 

So give the choice between a newish tyre with a 185 profile or a worn tyre with a 135 profile what would you go for?

 

Autotesting in Scotland tires provided by Skip motorsport services

(Well we pull them out of skips)

 

[Bricol]

Depends - if they are sticking to the letter of the rules in the Blue Book, you'll probably have to run with the 185s - or find that special run of Caterhams fitted with 135s . . . producing proof of it too ...

 

Narrow is good - but watch the profile or you'll run out of ground clearance.

 

Tread depth is very important if it's wet - deeper is better. In mud you ned to beon the limiter instantly to get wheel speed to throw the mud out of the tyre so it can attempt to bite again - no fannying about with a bit of revs - once grip goes you've got one chance - floor it!. Sometimes works - I've got out of a deep mud sections on classics on the limiter in after a crash change into second but only doing 1mph . . . not something you want to be doing to anything delicate! And on that occasion I think the rears were down to something really silly in an attempt to get further than all the competitors who had attempted the section before us and failed - dropped down to 3 or 4 psi - as I said, tyres become disposable.

 

PCTs will have pressure limits tho - and as I mentioned before, probably higher than you would run on the road! Try some carefull running of your tyres at lower pressures somewhere - get the sideways nice and pliable - makes a difference too - but as before, put the RHS on the left and viki-verki. Get the newly worn sharp edges digging in.

 

Wide tyres on the front in mud will of course add rolling resistance and impede progress. I have run different sections front and rear - you win on that theory and lose on the steering grip - so now I mainly stick to same section front and rear - swopping between 165 and 175 - it does make a difference!

 

Becareful jacking the suspension up - if you get any/too much preload on the setup, you'll lift wheels on the opposite corner.

 

 

All this and then you can't get off the line. . . or drive out at between the start and 12 . . . or go 4 wheels out . . . (take a line between outer markers - you can't put all four wheels past that line. I once really upset a CofC over that rule - he laid a section out that you couldn't get round without going 4 wheels out - so he allowed it on that section - so I drove out, up the field, turned round and took a run at the next bit . . .organisers weren't chuffed - spend the rest of the day attempting to find a way in the Blue Book to throw me out . .. took the CofC 6 yrs to talk to me again! Serious stuff is this PCTing 😬 )

 

Bri

[thinfourth]

First in class

 

hanks for the advice

 

Autotesting in Scotland tires provided by Skip motorsport services

(Well we pull them out of skips)

 

[Graham Perry]

You need to tell us a bit more than that What tyres did you go for ? What techniques worked ?

[ALEVS7]

I dont think General Grabber's come in 13"... 😬

 

Al Evs.

 

PurpleGtiEater....here