Jump to content

TR4 Tyre choice and neg camber advice


Recommended Posts

1 hour ago, mike ellis said:

What would happen if one had an accident and it was shown that the car was running tyre pressures far removed from manufacturers' recommendations.  In my 55 or so years of driving mostly rear wheel drive cars and my daily drivers still are I have never come across one where the pressures recommended were not higher at the rear.  Presumably there is a reason for that as intuition might suggest higher pressure at the front due to weight etc.

How many of those cars didn't have an anti roll bar fitted at the front Mike ?, the Tr4 doesn't. The roll of the front suspension in standard trim changes the tyre footprint reducing it and causing less grip, the lesser grip cause the car to run wide at the front (understeer). The increased front tyre pressures helps reduce the tyre deformation and retain it's footprint reducing understeer making it a more neutral handling car.

If you had an accident with the tyres inflated as suggested.

Regulation 27 section b states “if the tyre is not so inflated as to make it fit for the use to which the motor vehicle or trailer is put”.

As regards the tyre pressures being different from the manufactures  recommendations, that's all they are, recommendations,  and for an offence to be committed it would have to be shown the applied pressures "do not make it fit for the use" and caused a problem with the tyres application which they do not, in fact improving the overall handling of the car and reducing the likelihood of having an accident.

Also as Drew points out above 2modifying suspension systems by changing geometry, spring rates, dampers 2 etc will have more of an affect upon your cars handling and braking performance than a couple of lbs difference in tyre pressure (10%).

If you prefer you may run the pressures suggested by the manufacture, but upon another subject I'd suggest that a forum which regularly suggests that a spare wheel is used which doesn't comply with whole vehicle type approval or with UK Construction and use regulations regarding size, profile and different tyre pressure completely for that wheel alone never mind having a tyre pressure slightly altered from a recommendation, may decide it not overly decisive.

Mick Richards

Link to post
Share on other sites

As the tyre walls on my T-Trac tyres are taller (and possibly softer) than the previous Avon 175/65 R15 tyres, would refitting my ARB (5/8") have a positive effect? I am not looking for track type handling, just general road driving without causing rapid tyre wear

Andy

Link to post
Share on other sites
18 minutes ago, Ocheye said:

As the tyre walls on my T-Trac tyres are taller (and possibly softer) than the previous Avon 175/65 R15 tyres, would refitting my ARB (5/8") have a positive effect? I am not looking for track type handling, just general road driving without causing rapid tyre wear

Andy

No.

Anti roll bars act as they are described. The cornering forces without an anti roll bar act independently at the front (separate springs), with the compressed spring being forced up and the unladen spring pushing the suspension down. By linking the two separate suspensions together with an anti roll bar you introduce across car stiffness...but only upon the front. That changes the factory setting of understeer and makes it UNDERSTEER as the tyre footprints are deformed and you get less grip making you take armfuls of lock trying to get the car to turn into the corner.  

The other way to neutralise it without having tyre scrub is with...power, when the car understeers feed in bootfulls of throttle which will loosen the rear end by removing grip as the tyre profile squirms trying to transmit it to the road reducing the tyre footprint and reducing grip allowing the rear end to come around and balancing the car (as long as you don't overdo it). You may not feel comfortable doing that on public roads.

Kas Kastner never had a front anti roll bar on his TR4s, he said they don't need it, I agree with him.

If you fit an anti roll bar to the front only it will maybe make cornering feels nicer because the car will not roll as much (there's that description again), but actual tyre grip will be reduced unless you make other changes to compensate (like slowing down). As said above more tyre pressure in the front will allow the tyre to be presented to the road surface in a better manner and increase it's grip. Ultimately it's about how you drive the car and what you feel comfortable with, I would only fit anti roll bars to front and rear together...as a package, then you can vary the grip delivered between the two and gets the best compromise. Remember if you talk with anybody who says their car handles like it's on rails...they are not driving fast enough.

Mick Richards   

Link to post
Share on other sites

Agree with above, fitting a front ARB helped with roll, but increased understeer.

Adding a rear ARB gives more neutral handling, changing to oversteer with large amounts of welly.

I like this setup a lot :)

Bob.

Link to post
Share on other sites
  • 3 weeks later...

Because of gigging commitments over the festive period (I still work as a musician) and appalling weather, yesterday provided the first opportunity to have a decent blast in the TR4 with its' new Vredestein T-Trac 2s. We decided to visit my brother near Lockerbie and stuck to country roads and covered about 70 miles. It was wonderful. The steering is lighter and the ride much more comfortable in spite of the appalling road surfaces in the Scottish Borders. I am very well pleased with the tyres.

I feel there is no need to replace the anti roll bar.

The car gets better every time I drive it. Needs a good wash now. She will have to wait until 'Brendan' has passed, though!

Link to post
Share on other sites
  • 1 month later...

Hello all, quick question on topic. Tyre size, not pressures. On my 2 OGB800 I used to fit 165s and never had a problem. Back end you could slide front was fine. But it has been strongly suggested to me to go for 185s for the new 3.

It was a long time ago. Has consensus shifted to 185s?

When I test-drove the car, the steering felt really heavy. So until you move off it is very heavy. Parking must be murder? And what about extra pressure on steering joints? I have read favourable remarks on Vredesteins, but for an all year round tyre, winter tyre, was thinking of Goodyear Performance or other such, 165s. But would appreciate some advice from you Experts.

Link to post
Share on other sites
On 9/19/2019 at 8:28 PM, iain said:

Back to Tyres I used a set of TTrac2 for the Liege  Brescia Liege rally in July.

They were excellent, good in wet and dry, great fuel economy, nice feel.

Best deal at the time was Demon Tweeks. Currently £43 incl Vat including delivery on 4. No association just a very satisfied customer.

Iain

 

Yes, but 165s?

Link to post
Share on other sites
5 hours ago, RogerH said:

Hi David,

 

my 4A is on 165/80  Vredstein classic sprint and they are excellent.

What tyre pressure do you run on in the front tyres.  I tend to be higher than standard. and it is not heavy to park.

 

Roger

Thanks Andy, Iain and Roger, good question about pressure! The car is getting new tyres early next week. As far as I can remember, I had higher pressure in front and higher as a rule. But can't say exactly what it was.

Then I'll be driving it over from Manchester asap; in a couple of weeks or so. And no, try as I might, I just can't remember what pressures I had on the 2.

The thing is that I don't like the feel of 185s, way too heavy. In a panic, I also asked my friend Mike. I was getting worried. Should I reconsider? He wrote back:

"Tyres can be controversial, but for me, 165s is what I will run. With stock geometry.
    185s are just too wide for daily driving, in my opinion, fine for racing. And, yes, this car handles well kicking the ass end out.
    The geometry is not right in these cars for radial tyres, so having better traction makes it hard to steer when sitting still. For those reasons, I stay with 165s.
    Oh, one more thing. You will have a chance getting the spare in its spot in the back. No chance with a 185."

So, after much pondering, here is where I'm at:

185s
PROs greater stability. Very suitable for track.
CONs heavy steering from stationary. Parking.

165s
PROs Easier to steer. Parking not an issue. Back end can make TR steer better around bends in rally competition, so more manoueverable, more competitive.
CONs Narrower tread, so less grip.

WHICH TYRE CHOICE? SOLUTION

All-weather. Increased grip with winter tyres. So you counter-balance.
The consensus here seems to be Vredesteins. They're summer tyres, I think. Winter tyres should compensate providing more grip than standard summer 165s people tend to choose. Myself, I'm considering: 165/80 r15 Goodyear Efficient Grip Performance and don't know what the pressure should be.

Edited by David Brancaleone
Improving punctuation, flow, literacy, and accuracy.
Link to post
Share on other sites

Are you running standard size wheels (4") or wider David ?

Reason for asking is I am going to try some 5½" wheels on my '3 & was intending to use 185 tyres, but above answers are making me re-consider.

I would have thought 165 was too narrow for 5½" rims, & 185 too wide for 4" rims .

Bob

Bob.

Edited by Lebro
Link to post
Share on other sites
19 minutes ago, Lebro said:

Are you running standard size wheels (4") or wider David ?

Reason for asking is I am going to try some 5½" wheels on my '3 & was intending to use 185 tyres, but above answers are making me re-consider.

I would have thought 165 was too narrow for 5½" rims, & 185 too wide for 4" rims .

Bob

Bob.

165 on 5 1/2" rim was standard on UK TR6.  Works fine for me.

Have had 185/70 on 5 1/2" TR 6 rims on TR3. Inner face Touched the  arb on full lock.

Peter W

Link to post
Share on other sites

165 work just fine and the side walls stiffen up when fitted to the 5 1/2 inch rims, this give you the best handling compromise. As Bob says the 185 is too wide for the 4" rims but will work on the 5 1/2 inch rims, the more camber that exists on the car (negative or positive) the more the wider 185-195 tyres are compromised on their tread presentation to the road.

The 165 continue to offer drivers what the cars were designed with...handling, swooping curvy roads make you smile using it, and when you park the car you don't need muscles like Popeye to get it into spaces.

The wider 185/195 tyre fitments offer more grip, making it more point and squirt and the squarer profile makes it more exciting when the limits of grip are exceeded, which we normally reach only on the race track.

I use 165 /80 tyres for this reason, choices are made by drivers for different circumstances, if you like the squarer profile wider tyres the 195 give you that, no big deal, drivers fit what they want. 

Mick Richards

Link to post
Share on other sites

Thanks so Mick, Bob, John, Peter!

This is very helpful. I guessed 185s would be best suited to track. And my own driving experience on road was based only on 165s. Maybe Pirellis, not sure. 

Next question last (I promise!): if you had to choose a make of tyre based on its performance on the wet, and on ice, with good weather spells rare enough (like in UK), which makes would be the contenders?

Personally speaking, I am considering winter tyres 165/80 r15, rather than with a summer bias. What are the options?

So more grip without the heavy steering, better at not skidding in the wet or ice, not noisy, long-lasting, not soft...

Link to post
Share on other sites

Hi Dave,

For ice I wouldn't use anything but a genuine, purpose-designed winter tyre - assuming you can find one in that size (they are not common here in Canada). These would also be good in wet weather, but that's true of several tyres; ice is a different matter. 

I would also recommend changing them once the ice has definitely gone in spring, because normal usage in warmer weather on dry tarmac will tend to wear off the sharp corners of all the sipes that grip on ice - this will make them much less effective the next time you need them. 

I've used snow tyres on my TR which are great on snow and gravel, but less good on ice. When i've used true winter tyres on other vehicles, the difference is huge. 

Just my experience - others will no doubt have their own to share. 

Cheers,

Tim

Link to post
Share on other sites

I used Toyo 330s for a while. When new they seemed fine but at about 4 years they lost grip which manifested on the exit of a roundabout. It was interesting and from then on I couldn’t really trust them. Probably my driving but the Yokohama C drives that followed them have been excellent. 

Edited by peejay4A
Link to post
Share on other sites

Given your driving condition wants in one tyre you may have to look at the modern Mitchelin cross climate. 
 

but compromise in the profile

165/65x15

175/65x15

or as suggested above go for summer and winter tyres that are designed for the job. 
 

maxsport do some very good winter tyres that aren’t too expensive. And I know Neil revington rates them highly.
but you may have to go to a larger profile.

(not what you want I know but I have been using the very soft tarmac ones for motorsport and really good for a few seasons now.)

 

Link to post
Share on other sites

When I rebuilt my 4A all those years ago, I fitted 185/80x15 Michelin XAS on 6" Minator wheels. They seemed to suit the car very well with their old style rounded profile. About 9 years ago, an alignment problem in the rear suspension led to needing new tyres. The quote for Michelin XAS was about $A1800 (or 900 pounds)! I fitted Hankook 185/80x15 Optimo for about a quarter of that. I realised that the 185s raised the gearing by about 7% but as the car had a rebuilt engine with 87mm liners, it pulled the higher gearing easily. 

I decided to try going back to the original gearing and fitted 195/65x15 Michelins. They gave better acceleration with a slightly harder ride. I did have a major spin on the race track when the wider profile tucked under at the rear. 165/65 tyres are almost unobtainable here in Australia and very expensive although I do have one on a 4"rim as a spare to retain the flat floor in the boot.

I put the Hankooks back on for our recent trip from Melbourne to Perth across the Nullarbor Plain and back. We did 8400km in 3 weeks. The higher gearing made the trip more pleasant. Going from 165/80 to 185/80 is the equivalent of fitting a 3.45 TR6 diff. The 165 and 175/65s suggested by Hamish would cause a major change in gearing. Interestingly, the 185/80 weighs the same as a 195/65 so no change in unsprung weight.

Link to post
Share on other sites

Thanks again, pals!

Curioser and curioser(it's getting).

You are introducing new parameters that I hadn't considered at all. Profile and gearing.

I agree that if there are several "wants" -- what a nice old-fashioned, perfectly serviceable word -- one will have to choose which one is most important.

Me, what with mixed use in mind, everyday car and occasional events, hopefully, I'd have to exclude a track tyre size 185 Yokohama, which, I can imagine, must be great fun. (I did a few track days so long ago, and never seriously, in 165s that I can hardly remember).

There is yet another variable, regrettably or not. Piston size: I suspect, 189mm, or at least 187mm. The engine was prepared by someone called Mark Mason who did it for himself, not to sell. Whatever I can see of his work points to serious and very skilful prep., resulting in 150bhp at the wheel. So maybe that's the reason for the insistence to opt for 185s?

I test drove Mason's former TR but couldn't open up to really work the engine. It just all feels bloody good and miles better than my old 2, OGB 800, ever did. And yet torque already comes in, way down the revs. So he must have installed a mid-range cam, certainly nothing overly wild.

This is hoe far I got. To wonder if the power off the rear wheels on acceleration would tend to make the rear wheels spin. Ergo the reason for others suggesting that I stick to 185s. I just don't know.

So I concluded that all-year round use, rain or shine, normal and possibly competitive driving, town, track or road rally, tyres would have to be my compromise. A compound with more grip, but not soft. Back when, I used Michelins and Pirellis. That's all I knew or know. But nowadays there seem to be more options, thanks to more research.

Part of me loves the look of Vredestein Classics. They really look the part. But I'm not sure if they'd be flexible enough. Comfy ride and wee bit soft, but smashing looks! Only a guess.

I do know what I really want to avoid, having tried the 185s: heavy steering. I know it soon lets up, but cannot imagine street parking in busy traffic. 

So now the problem is narrowing down further: down to Hamish's suggestion to compromise on the profile. 165/65x15 or 175/65x15.

Yes indeed, would that one could try those two options. It would be a very interesting test comparison, the kind of "scientific" approach that would appeal to Roger or Peter W? 

The OR sounds feasible though. All weather, summer and winter tyres with a bias for the wet, hence more grip, to handle potential spin when pulling away, with very gentle handling.

Well, look here, at the very least, all your helpful suggestions are forcing me to think about this more carefully. I'm fine about changing my mind.

But how do you know 175s will be very much lighter? What happens to gearing if you go from 80 profile to 65 or so? Truth be told, I haven't the foggiest.

What I will say is that this Forum is ace! I have a mind to write a long piece waxing lyrical and extolling its virtues.

I just hope there'll be a chance to return the kindness. If I didn't live in Ireland (the Republic) I would be volunteering to do some of the Register Office filing backlog, I mean it.

 

Edited by David Brancaleone
Inceeasing light humour side and correcting typos
Link to post
Share on other sites

David

you have the power to cope with a wider section tyre and enjoy the driving. 
 

On my 3a I have 185/70x15 vredestiens sprint classics for the road along with a steering box and the steering is only heavy if you try steering without moving. I think that changing the steering orientation whilst stationary causes undue stresses and rarely needed.

they are great in the dry and the wet. 
this is a video of castle Combe in the wet that I thoroughly enjoyed the sprint classics

this site will allow you to see the size and profile difference radius etc and the effect it has on the speedo.

 https://tiresize.com/comparison/

 

this site allows you to change all the gear, diff ratios as well as tyres sizes for speed and revs etc (just make sure you have all the aspects correct if you change anything. I think the diff can default easily from memory. )
http://www.mintylamb.co.uk/gearspeed/

And this is with the 185/55x15 sticky tyres. But nowhere near the power you quote tho !!!!

Tyre width changes the aspect ratio automatically as it’s a percentage of the width. 
so I have a massive gearing difference between the tyres I use.

i would consider 2 sets if budget allows summer and winter .

H

Link to post
Share on other sites

Well, Hamish, I am left speechless (not a bad thing, I know).

I'll go away and do my homework and try to get my head round all this. It is really helping me a lot. You are. I'm a fan of specifics.

And exhilarating to watch you in action. To see a TR being used like that. What a glowing example. Makes me sad to hear of cars under wraps for decades or in a museum. Though when they sometimes come out of the woodwork they might just be used differently.

I do know not to steer from standstill; it's an effective way to scrub tyre treads and strain steering joints prematurely.

But even from pulling away, while at the same time steering (I could, but what an effort), the 185 Yokohamas felt heavy. Maybe I'm exaggerating.

I tend to agree with you about having two sets, one for summer, the other for winter, and hope that the day will come when I can. 

Makes very good sense to me.

Right now, digging up a space for a levelled out hardstanding, setting down concrete over gravel and erecting a Meccano set type carport with a door and hefty chain, without overstepping mark with darling wife, will be as far as I can stretch the pounds. I know steering gets lighter as soon as you set off. And on my one test drive, I did appreciate the stability of the fat tyres, but, truth be told, I also love TR controlled sliding which, if my memory serves me well, is a necessity in autotests and rallies. Maybe 165s with 70 profile is going to be the best compromise and, at a later date, a set of 185s only for the other stuff (she knows, she knows).

Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Restore formatting

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Loading...
×
×
  • Create New...

Important Information

Please familiarise yourself with our Terms and Conditions. By using this site, you agree to the following: Terms of Use.