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Tyre Pressures

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REPLIC8
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Tyre Pressures

Postby REPLIC8 » 28 Mar 2014 16:25

The steering on my TR7 seems rather heavy, I was wondering if upping the tyre pressures would improve things. I'm using 195/65 14 tyres on 6" rims. At present they are 28lbs rear & 24lbs front.
This seems quite low compared to modern cars, any suggestions based on experience please.

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dursleyman
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Postby dursleyman » 28 Mar 2014 17:36

I run at least 28psi in the fronts.

Russ

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FI Spyder
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Postby FI Spyder » 28 Mar 2014 18:42

I run 32 psi on highway (we've basically only got one Highway #1, the Trans Canada), I may go down to 30 psi when trundling down 60 kph side roads (which are all the other roads being on an island). That gives me even tire wear, good handling and road feel. No doubt lightens the steering which is important around town as the Spider has the 13" TR8 wheel with no power steering.

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Postby Hasbeen » 28 Mar 2014 21:58

Steering effort can be really effected by the make & type of tyre you have fitted.

I did a post on this recently, [New tyres, on 20 Jan this year] when I replaced my aging, but only slightly worn Pirellis on the front of the 7 with a set of Kumho tyres.

The steering is so much lighter that it is like I fitted power steering. I was quite worried about getting something worth fitting, as all the top makers no longer supply their good tyres in 13 inch, or even 15 today.

Not only is the steering lighter, but there is less road noise, & the ride is better, & the cornering every bit as good.

Not only that, but instead of the $180 each for the 15" Bridgestones on the 8, & $265 each for the 16" in the S2000, they cost just $103 each. Perhaps there is such a thing as a free lunch after all.

Still, before you run off to the tyre shop, Try a little more pressure. The tyre shop had put 35 PSI in my new tyres. I dropped them to 28 PSI without any extra effort being noticeable.

When did you last grease your steering box? It is supposed to get 6 strokes of a hand grease gun, every 6000 miles. They do get much heaver if that is not done. I always give 4 strokes with the wheels straight ahead, & one stroke with the wheels on 2/3 lock either side.

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Postby silverseven » 28 Mar 2014 22:51

A lot of the new cars are running very high tires pressure no a days for less rolling resistance and better fuel economy. Most of the GM's we have in the shop are running 35 psi and higher depending on the model.

On my seven (205-60-r13) I run 34 psi frt and rear without any noticeable centre wear. I'll prolly replace my tires this summer as they are starting to crak from age (roughly 8years) and have become feathered on the interior edges due to the lowering and what I think was possibly a poor alingment with too much toe-out.

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Postby Hasbeen » 29 Mar 2014 01:33

Yes Ron, I can see that happening now. I have had new tyres on the S2000, Ford Capri, & the 7 recently, & each time the tyre shop has pumped them up to 35/38 PSI.

As an old reactionary I have let them down somewhat, but not to the original recommendation by both Ford & Triumph.

I have been wondering if it is due to a change in tyre construction that has led to the higher pressures, or could it be due to the very low profile being used on some moderns. The number of tyres & rims destroyed on pot holes was rapidly growing here, so perhaps the higher pressure could be to try to avoid sidewall & rim damage.

Unfortunately I don't have contact today with any tyre people I could ask.

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Postby john 215 » 29 Mar 2014 04:49

Hi,

On my 14 inch tyres on the DHC, I run 28psi and 30 psi on the rear, have done for several years with no adverse effect on tyre wear.

Cheers John

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Postby busheytrader » 29 Mar 2014 05:56

195 x 60 14's with 28psi all round is a good compromise between handling and comfort for me. (rear spax on no.4 setting IIRC)

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Postby REPLIC8 » 29 Mar 2014 06:13

Cheers everyone, I'll up them to 28 psi and see how we go from there. I have greased the steering rack. Next winters project is revamping the front end, new bushes, inserts, ball joints etc so that should help no end as well. [:)]

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Postby Workshop Help » 29 Mar 2014 11:19

30 PSI all around.

Mildred Hargis

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Postby DNK » 29 Mar 2014 12:06

<blockquote id="quote"><font size="1" face="Century Gothic, Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote"><i>Originally posted by Mildred</i>

30 PSI all around.

Mildred Hargis
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Postby Beans » 30 Mar 2014 14:31

2,0 to 2,2 bar all round depending on tyres, payload and sort of driving.

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