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Triumph TR6 - 'Nother Tire Question

Greetings All,

New to this forum. Just bought a '71 for a driver. Last owned a '72 TR6 in 1979. I'm sure this has been brought up before, but what is the most common tire size to use on a driver since the original size is nla. Not looking for Redlines, but rather a mainstream tire with good performance. I will be adding a tube shock conversion.

Thanks,
Howard
'71 TR6
Howard

If you want a tire that looks right i.e. fills out the wheel wells and has the same diameter as the original 185R15 then your choice is:
195/75 R15 or 205/70 R15; I would go for the latter as the choices in performance levels are much better as you can get several models in a HR rating and 1 in a VR rating (Pirelli). The 195/75 would be an SR or less and have an all season wimpy tread pattern and look better on a Tempo or Minivan.

While many people put on a 195/60 R 15 or even a lower profile, it looks odd on the TR with its big fenders.

I myself run a 205/70R15 HR Yokohama that I have been really pleased with in handling. Any wider that 205, you may get some rubbing in the rear from the bump stop flange. While Redlines look great they have terible handling and are notorious in the wet as the rubber is as hard as hockey pucks
steven

Ha Howard
Welcome to this BBS and congratulations in getting back into the seat of a neat car. I also have a '71 and last May completed 3 yr. body off restore. With the TR6 tube shock conversion it is stated to go no wider than 185/70 or 195/60. I agree with Steven, an aspect ratio of 60 is low and you will have a big air gap to look at. aspect ratio of 70 is less than 1% larger overall diameter than original red lines so the spedo will be very close to accurate. The tube shock conversion appears to limit your tyre choice as you could go up to P215/70SR-15 without the conversion (215 is 1.17" wider than 185). Howard are you aware that you can buy brand new red lines using modern technology to make them? Steven I agree with what u say about ORIGINAL Michelin red lines. I am not sure if that holds true with modern versions of the red line. In any event Howard, hope this helps. Most of all, enjoy your new toy and again welcome.
Rick
Rick Crawford

About 10 years ago, I saw something really neat at Triumphest in Ventura, Calif. (No I didn't have my TR out there that time). There is a man who goes to all the car shows out there with his grinding machine and offers to put red lines or wide whitewalls etc. on your own tires right there at the show. He jacks up one corner at a time, grinds in the groove, fills it with some kind of rubber of the colo(u)r you want and then, I believe, he vulcanizes it somehow. As far as I know he is still around. What I saw him do is very high quality.

Don Elliott
Don Elliott

Unless you need the perormance, I would stick with the proper size. Coker makes a 185/15 redline house brand that is a lot cheaper than the Michelin's and is a modern tire. Universal Tire also makes their Sport tire that looks like the G800 that was original on some TR6's and they also carry the Vredestien SP. I had the Vredesteins on my first TR many years ago and they were a great tire, but they have large sidewall letters & graphics and look to modern. The Universals have a much more period look and I will probably order a set to replace my original(!) Redlines. I'd go w/the Redlines but I think there are better modern tires out there that have 1970's looks (Universal)and I can't stand redwalls on a magenta car...you'd have to see to understand.
Wayne

to figure out the diameter of the tire which mixes metric and imperial together for some strange reason ( it is best to calculate in cm as it is easier):

Formula:
(width x aspect ratio x 2(top and bottom of the tire) ) / 10 + wheel height x metric conversion to cm which is 2.54

eg Original redlines were 185 R 15 and 78% aspect ratio so :
(185 x .78 x 2) /10 + 15 x 2.54 = 66.96cm


for a 205/70 15 it would be:
(205 x .70 x2) /10 + 15 x 2.54 = 66.8cm


as you can see that a 195/60 R 15 would be way too small:
195x.60x2/10+15x2.54=61.5cm a full 5.4 cm smaller in diameter which is over 2 inches


It is best to keep the original diameter for speedo, odo and final driver ratios. The only way to get the same diameter while going lower in aspect ratio is to go + 1 in wheel size ie going to a 16" Thus a 215 / 60 R 16 would yield the same diameter as original

steven

I have a set of 195/75 15's on a TR5 and while they fit well and look reasonable I'm troubled by the grip. They are branded 'classic radials' and are manufactured, I believe, by Cooper (or Tyre and Battery). I'm looking for a replacement set and would welcome advice on modern alternatives - Michelin, Bridgestone, Yokohama etc - rather than new 'redlines'.

Guidance appreciated.
Jim

Hi Howard,
Here is my 2 cents, Get the Victoria British shock
conversion kit not the Moss. The VB kit will allow you to change to different strengths of springs if you ever
want to.
I just bought 215/65 15's for my TR6 They are suppose
to be 7mm shorter than 205/70 15's but I put mounted
tire/wheels next to one another and there was no difference in height. The 215/65 15's are 10mm wider
which equals better grip in all aspects of driving.
However my springs are new and as they settle I my see
some rubbing but I can't see how as there is all kinds
of space between inside of tire and bump stop flange.
Good luck.
Christopher Trace

Howard
A correction to my comment re limited tyre size. It is true that the MOSS conversion kit says limited tyre size but opened my mouth before seeing that VBL offers one also and says nothing about limited tyre size. The choice of which will limit or open up your tyre size selection. I have heard that going to big is a problem in the front with the tyre rubbing on the wheel well in tight turns. Steven gets the brownie points for the facts...205/70 15 is best choice for accurate spedo. The 215/70 is only 1/2" greater in diameter.....error in the spedo...well, I will let someone else figure that out ( another subject I did not get an A in).
Don E. it would be interesting to ask this chap, if still around, what he charges per tyre. Fred at BAS mentioned a guy in Toronto a few years back that USE to do it. The issue of new and old redlines (Michelin) would go away. Anyone else got some info on this subject?
Rick
Rick Crawford

Jim,

Pirelli's is the way to go for a good tire. When properly installed they give good handling and reliability. My TR6 has 205-70x15 P600 HR for 3 years and a lot better than previous Yoko.. P600 are not avaliable anymore but I believe that P3000 is a good replacement.
Cheers. JGC.
Jean G. Catford

Thanks for the nice welcome back into the fold. Back in the mid 70's to early '80's, I owned a '67 Spitfire, '72 TR6, '76 TR7. Glad to have another TR6.

Wow, lots of wonderfull advice. The shock kit I was looking at is made by John Horton (ad on VTR site), he says it is a copy of the VB kit. Anyone familier with his kit and tire limitations it may or may not impose?

Considering the 205/70 tire option, although I am tempted by the "classic" tire options.

Thanks again...
Howard

I just upgraded from a Midget to a 74 TR6, and will have a ton of questions, so please bear with me.

On this tire question, I have Pirelli P66 195/60 R15's. From Steven in Toronto's post, it looks like this is small, so this means my actually speed is slower that what my speedo says, right? (I have not had my coffee yet this morning)

Are there any other issues to think about, i.e. how does this affect my suspension, wheel bearings, handling?

Thanks,

Ignatius
Ignatius Rigor

Hi Ignatius
You got it right..even without the coffee....slower by about 5MPH! Go to the following WEB page and click on technical information. Here u will have your question answerded. http://www.sctoa.org/ Read the entire thing for the cautions at the end. On the handling suspension beerings..I do not think what u have will be a problem.
I use to own a midget also. Great little car..hard to be seen in traffic though.
Rick
Rick Crawford

Interesting issue. We presumably picked the TR6 because we like the appearance including the way the wheels fill the wheel arches.

If performance was the main criteria, then there are any number of newer vehicles that could blow it into the weeds. If we want performance in an older vehicle, then the TR5/TR250 is lighter with the pretty much the same engine.

Where is the interference point with the tires, the top end of the tires, or the sidewall?

One of the items overlooked in the discussion is the impact of the lower profile tires. Yes, the wider tires will give you a wider contact patch (same amount of area, just wider). The shorter sidewalls result in a more firm ride (tires provide some of the springing), and a faster turn in. When you turn the steering wheel, it eventually moves the wheel rim, which then moves the sidewall, and transfers the movement to the tread. If we get the wheel/tire combination the same height (using same rim diameter), as stock, then we can expect to miss some of the advantages the sharper turn-in.

One of the compromises one must make.

Regards,

Len
LG Middleton

This thread was discussed between 11/02/2002 and 02/04/2002

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