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Triumph TR6 - New tyres air pressure.

Just to change the subject, I have installed 4 new tyres on my baby. General Altimax RT 205/70 15.
I think the car is going to handle very differently from the red lines. They HAD TO GO.

With this size in mind, what is the going rate for front and rear tyre pressures?

Thanks
Rick
Rick Crawford

32?

Ah, that be American lbs.
Your Canadian air might be heavier!
DON KELLY

I'm liking 20 psi/24 psi in front & back.
Brent B

20...24 in a 205/70X15 ....maybe if you like sidewall wobble. 30 to 32 would be more like it IMHO.
JT White

At 25/29 psi the ride was too harsh for me, and when I rotated the tires the 29 had tread wear of over inflation.
Brent B

20/25 sounds like easy numbers for this old f@*% to remember.

Thought I had them a little to hard.

Thanks guys.

Rick Crawford

Treadwear from "over inflation" at 25 to 29 lbs...highly unlikly even on a car with the TR6's weight...even my 71 Midget I ran pressure at around 30 wit no center tread wear...plus you would have to either put daily use car miles on it or drive it under LBC hobby car use for 10 years without rotating them.....I think there's more at play then just inflation....it would come down to a combination ofcamber/caster, alignment, toe, rotation, compound, road condition, milage etc but not just 25/29 lbs air.
JT White

JT - Several things, but I don't think it's an arguing point.

1) Took an hour long drive & measured tire. Up 2 psi, so I don't think I'm under inflated.

2) Comparing the max tire load rating with max corresponding pressure, 1420 lbs @ 32 psi (original 185's) vs 1499 psi @ 35 psi (the 205's) with recommended pressure shows the 20/24 is spot on with "normal" loads.

3) Comfort factor - higher pressures in the tires are too jarring. Sure - If I autocross or slalom, boost 'em up. But I don't.

Actually, thanks for your input, but that's exactly the sort of stuff that made go to higher air pressure, which I didn't like. To each his own, eh?
Brent B

Rick , nothin against the PSI mentioned ,but..., I wouldn't go that low.

Unless you plan on drivin like an old lady
DON KELLY

And you back that up with what, Gramps?
Brent B

Take you back behind the wood shed and Tan your hide!
DON KELLY


Here is a link to the Toyo website where they have posted the TRA (Tire and Rim Association) recommended standard for car and light truck tire load and inflation tables. I think you'll find this very useful.

http://www.toyotires.ca/sites/default/files/loadinflationtable.pdf

SID
Sid Turner

My "Point" wasn't as to personal driving preferance but as to the fact that 29 psi isn't going to in an of itself cause "over inflation" wear on the tires.
JT White

Rick,
I've been running Michelin Harmony 205/70R15, 29 lb frt, 27 in rear. With the long distance driving we do, this has worked well. I'm on my second set, the first set lasted 30k, could have gone another 5k, but I picked up a deck screw near the sidewall, non-repairable. On back roads the car ususally gets a good workout, so I was happy with the mileage I got outta that set.
Rod
Rod Nichols

Rod, you like the tire pressures that low eh, maybe I'll try that on the Wedge to rid it of the buckboard wagon syndrome
DON KELLY

Wow, did not think I would get it this heated. A spred of opinions.

Rod, are your numbers reversed or do prefer higher pressure in the front?

Rick
Rick Crawford

I would think you would want the front higher, that's where the weight is
Unless you got a mother in law in the boot
DON KELLY

If you check the TR6 Repair & Op Manual it lists the recommended pressures for both 165 x 15 and 185 X 15 tires. The pressures are 22psi/26psi & 20psi/24 psi. Notice a trend? Wonder where 205 X 15 tires would fall?

Rick, I suggest you just try some pressures yourself and see what you like from a handling & comfort perspective.
Brent B

Guys...
Those are correct front and rear. Don saw the logic, and my old autocrossing days tell me to inflate the fronts a little higher to pevent pushing. If it's harder for the tire to roll, it gives a little more stability, right? IF I was autocrossing, the pressures would be higher all the way around, but I don't go there anymore. Age of the car and me both eliminate that scenario. Mostly the car...... ;)

Be it right, or wrong...it is my humble opinion!

And now, I'll let Brent blow a few holes in my theory!

Rod
Rod Nichols

Oh come on, Rod. My opinion is to run the pressures wherever you want so long as not below vehicle recommended and above the tire maximum. I've been playing with the pressures on mine to give decent comfort while minimizing oversteer. Never said it was the proper pressure and your mileage and driving tastes will vary.

I never "drive like I stole it", more like "drive like I'm the one to fix it". You can drive these cars aggressively without being too dangerous.
Brent B

Oh, I never did say: The tires are Michelin X, about 7-1/2 years old with 24k miles on them. They still look pretty good - probably a 40k mile tire, maybe more.

The previous set was Pirelli (P200's?). They were shot after 20k miles.
Brent B

Brent
You got it man!

I am going to experiment.
So call me stupid but I am seeing tire pressure being said as XX/XX and meaning front/rear and the first number being lower than the second ( front tire pressure lower than the rear). This is why I asked if you where saying it correctly Rod.
The official manual says the original 185SR15s under ALL CONDITIONS where 20/24 ( front/rear). As I have heard, the 205/70 15 is the closest match to the original size.

I am not saying one is correct and the other is wrong..just trying to understand the whys and the reasoning.

Rick

Rick Crawford

Hello,

My two cents advice agrees with diamond back tyres:

Modern p-metric radials are designed for higher air pressure. This reduces rolling resistance, reduces heat build-up, and improves your car’s steering response. It also helps prevent damage to your whitewalls. Because of so many applications, specific air pressures cannot be recommended. A good setting for most applications is 35 psi COLD


This topic is for hot rod, but for my TR6, I use Fr/R= 28/30 and with Pirelli P4000 215/65x15 it performs fine..

Cheers,

Jean G.
J. G. Catford

Brent,
I figured for a response....I didn't intend to p*** you off! Sorry 'bout that. I do like "I never "drive like I stole it", more like "drive like I'm the one to fix it". You can drive these cars aggressively without being too dangerous. "
I agree heartily. I was hoping for an explanation on having the rears higher than the fronts. Shoulda just asked?!?!?
Now...let's retire to the pub and enjoy a pint......

Rod
Rod Nichols

May be hard to believe, but I wasn't upset at all. I'm pretty sure the reason the vehicle recommended pressure (as well as mine) is to stiffen up the back end to counter over steer.

Tire pressures is one of those no single correct answer topics, and I was curious about why you ran with the front higher than the rear as well. Good to know.

Brent
Brent B

I shall head for the middle and have the rears a little harder.

Sorry guys but my style of driving has changed over the past 2 years. I tend to drive her like I stole her with a little "you gotta fix it if you break it" in the back of my mind. You have to be carefull these days. If you get caught squeeling the tires it is considered racing and they have the right to seize and crush your car.

Thanks for all the input guys. Put the collision back on effective Saturday morning and go pick up my tranny oil Saturday morning. Looking forward to a nice drive.

Rick
Rick Crawford

Well talk about having an issue with air pressure. With the air at a starting point of 24/26 I had extreme difficulty keeping the car in a straight line. Talk about MUSH!

I am now up to 34/34 and I still seem to have a very little bit of "wonder". Still, seems to ride OK. Will try a little more. Maybe these tires just need a higher air pressure than my old ones.

A bad point is that when I read 100 KPH I am actually doing 95KPH.
The ride is so smooth that 100 seems like a very good speed (for 80 KPH zones that I mostly travel in).

What a difference in handling. I take corners at twice the speed I use to. It kinda feels like I have power steering and just a slight turn of the wheel is responded to.
Should have done this sooner.

Rick
Rick Crawford

Uh, Rick...that's called Rack & Pinion steering!! A singular attribute to our beloved LBC's.
db
Doug Baker

For sure Doug. The new tyres are helping me enjoy it.

Rick
Rick Crawford

Rick,
Did you say 100???? Nyuk, Nyuk!
Rod



Rod Nichols

That's a real 100
none of this KPH nonsense
DON KELLY

Sorry Don but that would be a (real) metric number.
HAY I never wanted to go metric, I still think Imperial and always will........don't get me going Don.




You guys are just jealious...I can say 100 and you have to admit to a miniscule 60!

NYUK NYUK NYUK

Rick
Rick Crawford

Wish my 6 could even go 10
DON KELLY

So do we all.........
Rod Nichols

Thinking of selling it
DON KELLY

....And so this guy walks into a bar, and says "I'm thinking of selling my TR6!"


We give up Don....what's the punchline?????
Rod Nichols

Depends on upcoming situations
DON KELLY

Now where are you moving to?
Rick Crawford

Still trying to get to SC.
Daughter starts school in Savannah in Sept
DON KELLY

Don is she going to SCAD?
JT White

Yes!
DON KELLY

This thread was discussed between 24/04/2011 and 14/05/2011

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