Tyers for a Bristol 407
 

I am in the market for tyers for my 407. any advice re suitabilty or availability would be welcome
Mick

If you like to go fast put Vredestein 185 x 16 from Longstone or Vintage tyres or you can try Taxi tyres for about a quarter of the price 175 x 16.

Avon Turbospeed 600 x 16 are correct but you wander all over :-)

Tyres for a 407
 

Hi Mick,
After spending ages pontificating about the fact that a 407 ought to have crossply tyres, as that what they were designed to take, I ended up, after 9 years of arm twisting the Avon Turbospeeds as per the handbook, changing to Michelin X.
These have been fantastic, no more tramlineing, a far better ride, better fuel consumption and quieter. I have felt a right chump!.
They were available when the car was new and so in my mind are acceptable as the period is correct.
The size is, 185 R 16, they are H rated ie OK for a Max of 210km/h or 130mph.It is also wise to fit inner tubes.
You must get the right speed rating, as you will not be covered by insurance if you have tyres rated at a lower speed than your car is capable of doing.
They are readily obtainable in the UK from Longstone or Vintage tyres, you will not get a discount even in the trade, you might get carriage thrown in.

NickC 407 6028.

Tyres for a 407
 

If you put on Taxi tyres you will be illegal!
Nick

Tyers for a Bristol 407
 

I agree with Greg.

http://www.stefanopasini.it/Bristol_409-Vredestein.htm

My car arrived with 'Austone' tyres usually fitted on cabs. Cheap, sturdy,
the car drove straight but they are not legal (speed rating is very low.)
The 6.00x16 Avons I fitted to replace them were quiet and looked perfect,
but the 409 developed a sudden, unexplainable 'pull' to the right that no
swapping of tires or adjustment of the front suspensions could cure. I
fitted four 185x16 Vredesteins and the 409 now drives straight and has a
better handling, though you might feel a bit more road noise. They look
correct, too.

Perhaps the Pirelli Cinturato and Michelin X would be as good as the
Vredesteins, but I have no proof of that they are much more expensive....so
I recommend the Vredestein 'Classic Sprint'

Ciao

Stefano

The speed rating is 90 mph for Taxi tyres. I have been told it's not illegal to use them. I also have a London cab and I think they are closer to the original cross plye with a better ride.

Up to you.

Tyers for a Bristol 407
 

I use Vredenstein 185 x 15 on my 408 - no problem - good price, good loocking.Best Hans

Tyers for a Bristol 407
 

Greg, I think you will find that to be legal, tyres need to have a speed
rating that exceeds the maximum speed of the vehicle to which they are
fitted, regardless of the speed at which you intend to drive.
Surely a 407 is capable of more than 90 mph?

Tyers for a Bristol 407
 

I have had Vredenstein's on my 410 for a number of years now, they are good tyres not too expensive, look right for the car and are the correct speed rating.

Taken from a UK tyre web site showing a Taxi tyre is LEGAL up to 99MPH --

TYRE SPEED SYMBOLS & CATEGORIES
back to Technical Information Index Page
Most car and van tyres used in the UK have both a load and speed rating after the tyre size, e.g. 195/65R15 is usually followed by 91V. This means the tyres can carry their rated load upto a maximum non-stop speed of 240 kph. When replacing tyres it is important to ensure the new tyres, even if a different size, have the same or a higher speed rating. However, in the UK, with a national speed limit of 70 mph, it is quite safe and not illegal to fit a tyre with a lower speed rating, provided you do not exceed this reduced rating. The table below shows the maximum speeds applicable to each speed letter.
Max Speed
(sustained)
Kilometres/hr Speed Rating Max Speed
(sustained)
Miles/hr
N P Q R S T U H V W Y Z
300 Kph 190 Mph
290 Kph
280 Kph
270 Kph 170 Mph
260 Kph
250 Kph
240 Kph 150 Mph
230 Kph
220 Kph
210 Kph 130 Mph
200 Kph 125 Mph
190 Kph 119 Mph
180 Kph 113 Mph
170 Kph 106 Mph
160 Kph 100 Mph
150 Kph 94 Mph
140 Kph 88 Mph
130 Kph 81 Mph
120 Kph 75 Mph
Max Speed
(sustained)
Kilometres/hr N P Q R S T U H V W Y Z Max Speed
(sustained)
Miles/hr
Speed Rating

Marking Charactistics
Speed Symbol "N" For vehicles with a speed capability not exceeding 140 Km/h (88 Mph)
Speed Symbol "P" For vehicles with a speed capability not exceeding 150 Km/h (94 Mph)
Speed Symbol "Q" For vehicles with a speed capability not exceeding 160 Km/h (100 Mph)
Speed Symbol "R" For vehicles with a speed capability not exceeding 170 Km/h (106 Mph)
Speed Symbol "S" For vehicles with a speed capability not exceeding 180 Km/h (113 Mph)
Speed Symbol "T" For vehicles with a speed capability not exceeding 190 Km/h (119 Mph)
Speed Symbol "U" For vehicles with a speed capability not exceeding 200 Km/h (125 Mph)
Speed Symbol "H" For vehicles with a speed capability not exceeding 210 Km/h (130 Mph)
Speed Symbol "V" For vehicles with a speed capability not exceeding 240 Km/h (e.g. 225/55 R 15 91V)
Speed Symbol "W" For vehicles having speed capability not exceeding 270 Km/h (e.g. 225/60 R 15 96W)
Speed Symbol "Y" For vehicles having speed capability not exceeding 300 Km/h (e.g. 275/40 R 18 94Y)
Speed Category "VR" For vehicles having speed capability over 210 Km/h (e.g. 195/50 VR 15)
Speed Category "ZR" For vehicles with a speed capability over 240 Km/h (e.g. 205/40 ZR 17)
ZR+ Speed Symbol "W" Tyres marked with both designations for vehicles with speed capability over 240 Km/h but not exceeding 270 Km/h
ZR+ Speed Symbol "Y" Tyres marked with both designations for vehicles with speed capability over 240 Km/h but not exceeding 300 Km/h

Other Technical links:
Tyre Load Tables || Tyre Size Calculator || Vehicle Wheel Fitment

to Technical Information Index Page || to Top of Page || to First Page || Site Index & Enquiries

Tyers for a Bristol 407
 

Hello Greg,


the 'taxi' tires fitted on my 409 when I bought it were marked 'C' (as for
'Cargo', I suppose, i.e. vans etc; later I found on the Austone web site
that they are widely used on cabs) and the speed rating for these tires is
very low. Even if they are good tires and probably safe up to 99 mph, a 409
has a declared top speed of 132 mph and weighs nearly 2 tons, so the MoT
would never pass it with 99mph tires; even more important, in case of an
accident the insurance company would not pay any damage.

BTW, what tire pressures are you using on your V8 Bristols?

Cheers

Stefano

Hi Stefano,

I thought that the statement lifted from a U.K. tyre company would finally dispel the myth that Taxi tyres are illegal in the U.K. !! I should have known better.

The Bristol will still pass an MOT with Taxi tyres -- lots of them do. Just to be safe you can inform your insurance company what tyres you have fitted. Does anyone think cross ply tyres are safer than Taxi tyres ?

Taxi tyres are essentially a van tyre (and we all know how fast white vans go ) with a stiffer wall and can easily handle the weight of a Bristol. How much do you think a London cab weighs ? especially with 7 people and luggage.

As Stefano says, his car was purchased with Taxi tyres on and had probably passed the MOT with them on.

I run the tyres on my Taxi at 30 psi, the same as my Bristols.

It's up to you......

Hi Greg
They might be legal in the UK but surely Stefano has to comply with Italian legislation.

quote Hi Greg
They might be legal in the UK but unfortunately Stefano has to comply with Italian legislation.
Today 08:29 AM

First prize for stating the bleeding obvious!

I know Stefano uses Vreds now ( the best in my opinion )

I was answering the original question.

Tyers for a Bristol 407
 

Hello Greg,
out of curiosity, I rang my insurance broker and asked about the matter.
They would not accept a low speed rated tire on a car insured by them. I
fully agree that cross-ply tires are not safer than those 'taxi' tires but
the law requirements in Italy are extremely strict about tires and in case
of an accident there would be trouble if I had fitted taxi tires with a low
speed rating.

During the long and exceedingly tiresome process of registering the 409 in
Italy, the MoT inspector confirmed that they require tires of a speed rating
exceeding the declared top speed of the car (this applies to vans too,
incidentally, so those fast Mercdes-Benz 'Sprinters' use special tires) and
thus the Austone tires were not approved, even if I pointed out that they
were good enought to pass the British MoT. I passed the inspection with the
Avons.

I am using 38-39 psi now on my 409....maybe too hard, but this summer is
very hot and I have been always told that when temperatures go near 40°C it
is better to keep the tires a bit overinflated. Or is wrong? Surely the ride
is a bit hard....

Cheers

Stefano

I was only commenting on the UK

39 does sound high and I thought hot air expanded.

Let me know if you find out any more on if it's correct to over inflate in high temperatures. I would of thought that it's the other way round if anything.

The "C" is not for cargo. It's a load rating.

Hi Stefano,

This doesn't make sense to me for normal everyday use. My understanding is that tyre pressure increases with heat. If your tyre pressure is 39 when cold, add in the heat of a summer's day and some friction from driving and your pressures may end up at 45 psi.

That's probably not a safety issue but it would definitely make for a hard ride.

The only time I have ever run with tyre pressures at around 40 psi is on a track or a road rally. Makes a big difference to handling.

Personally I think you should experiment with the tyre pressures of your V8 Bristol in the 28-32 psi range, see what feels right/best.

Cheers,
Kevin

Tyers for a Bristol 407
 

Dear Greg, Stefano,
Isn't the EU wonderful?
I keep trying to avoid getting into discussions on subjects about which I
don't know enough.
As a general rule I would say it's wise to stick to the manufacturer's
recommendations on tyre sizes and pressures, but obviously choosing tyres
gets trickier if the manufacturer was unaware of the advent of radials when
the car was designed.
Recommended tyre pressures are based on achieving the correct footprint on
the road surface. So if the weather gets hotter, you would need to let out
some air to get back to the recommended pressures. Radial tyres should never
be driven underinflated, but because of their better shape retention, a
certain degree of over inflation is quite acceptable. It doesn't change the
area in contact with the road anything like as much as it does with crossply
tyres. So you should actually be more careful with tyre pressures when the
weather turns colder. With crossply tyres, correct pressure is not only
important for grip, but also for tread wear.
Regarding the insurance issue and legality. I would call someone else's
insurance company and say you are just "considering" fitting taxi tyres....
And in the UK, I wouldn't start a discussion with the MOT examiner if you
already have....

tyres for 407
 

Thanks to you all for your very helpfull coments re the tyres for my 407. After reading them and contacting other Bristol owners I know I have ordered a set of Vredestein sprint classics. I did however have just a little difficulty finding a dealer who had them in stock as they seem to have dissapeared from the manufacturers list of products in 16" rim size. I eventualy ordered them from Vintage tyres who gave me an all in price of £701. All I have to do now is get them fitted.
Thanks once again for your help

Mick

Yes, I think the Vreds are probably the best choice all round :-)

My only gripe is the price for the 185 x 16 that the dealers charge. As far as I know only Vintage Tyres and Longstone Tyres sell them and they seem artificially high and maybe a Cartel. When I had my 408 I was tempted to get the wheels banded to enable the fitting of a more popular / cheaper tyre -- maybe 205x16. The other option was to fit the steel wheels from the full size spare of a modern Mercedes E class ( same pcd up to 410 - I think )

I think at around £200 for five,I would definitely put Taxi tyres on a 6 cylinder and maybe a V8. Depends on how you drive it.

Fit for purpose - is the UK MOT criteria

Glad we could help

barry cooper
 

The "C" on a tyre is for commercial as is "LT'" for light truck < its marked with one or the other..
As for the tyre pressure the benefit of running the high pressure is to keep the actual vessel cooler therefore not increasing the internal temperature as much. The friction of the tyre on the road causes the vessel to get hot , the lower the pressure the harder the tyre is working hence the hotter it gets then heats the air inside the tyre. An example, try pushing a carof a car with 10 psi in the tyres then push it with 40 psi in it, neither the pusher or the tyre is working as hard at the higher pressure. 40 psi is fine in the hot weather but if the roads are wet drop them back down 32 or 34psi. I run my 400 with 34psi on 165r16 Avons & find the grip amazing in the wet if a little harsh on the rougher roads
My regards Barry.

Tyers for a Bristol 407
 

Thank you Kevin,


in fact the ride is a bit too hard with the tires inflated to 39. I'll try
30psi, as you and Greg suggests, and ride will surely improve.

Speaking of tyres and wheels, my 5 wheels (rims) are not looking good, they
all are a bit 'warped'. It would be nice to hear from someone who knows
where I could find 4-5 wheels in better condition, or if any other Marque
used the same pattern as the Bristol. I know that LJKS used Minilites on his
409, but I'm not sure if I like their looks on a classic Bristol.

Cheers

Stefano

Tyers for a Bristol 407
 

Greg,
With vintage tyres the moulds are often no longer owned by the original
manufacturer (in this case Vredestein) but by another company who is either
retailing or distributing the tyres. They will typically have a run of say
1000 or 2000 tyres produced which may take several years to sell. So they
are not really expensive.
They may also choose to sell on tyres to other retailers. Is that a bad
thing if it keeps the tyres available?

Stefano,

You could get in touch with the bloke I gave you details of that is breaking a 409. If his wheels are in good condition you could do a deal to swap them so he can still roll it.

Or find a scrap yard with Mercedes steel wheels

cooper_bm
 

[quote=pasini s;3247]Thank you Kevin,

Stefan
A good wheelworks can reroll your steel wheels, buying other used ones may still have the same issue. I had mine rerolled, two of them had to have the centres removed & refitted to ensure correct centreing once this was done they needed minimal weight to rebalance and improved the smooth running noticeable on good roads.
My regards Barry

barry cooper
 

Actually tyres generate most heat not due to friction but due to a curious
phenomenon called "Hysterysis". The Stress-Strain curve for rubber compounds
curiously doesn't follow the same path back when the stress is removed. A
quite significant amount of the stored energy (represented by the area
between the two curves) is released as heat. By increasing tyre pressure,
the tyre sidewall and tread will flex less when rolling, hence lower heat
build up.
I still wouldn't recommend playing around with the tyre pressures. The big
tyre companies continue to spend an awful lot of money on R&D.

tyres
 

1) I would love to hear from someone who went to Bristol Cars and bought a new set of steel (or better) wheels for their vintage Bristol that looks the same but has the diameter and offset of the more affordable and available modern wheels, and is certified by the factory as an acceptable replacement.

2) On the taxi tyre issue, this is where the Club or new Club should step in, go to Bristol Cars and ask them to issue an official factory statement to the effect that they are acceptable for Bristols that do not exceed 99 mph.

Ckaude

tyres
 

... Whatever questions you ask, you need to clear it with your insurers, as without their acceptance, If involved in a prang, the vehicle examiner will be checking tyre codes as well as tread depth etc.. I know this from personal experience (I was OK with my tyres, but had a chat about codes, dates of manuf. etc.with him at the time). This is very important when you have a car which does limited miles, & still has plenty of tread. eg signs of cracking in walls?
.
........ Batmanbruce

There would have to be a market for these, albeit limited to secondhand Bristol owners. Sounds like a job for BODA!

Which Bristols cannot exceed 99 MPH? Given their famous numberplate (100 MPH) used in marketing shots for many years, I would have thought it would be hard for them to make this statement.

Furthermore, there is Bristol's reputation for rigorously testing components
used on their cars. This testing could be done, but it would be expensive to do it properly, having a car of each type in perfect original condition would be a challenge for starters.

But why would Bristol do this? I can't see that it would benefit them in any way. Making 15" wheels would be a much more sensible.

I'm tired of the tiresome tirade about tyres.

tyres for 407
 

At the risk of starting yet more controversy does anyone know if the standard 407 wheels are suitable for tubeless tyres or do I have to run them with tubes as my previous crossply.

cheers
Mick

tyres for 407
 

It is safer to run them with tubes, there is no guarantee that after 48
years your wheels are air tight and
as Bristol specified Avon Turbo speeds and Dunlop RS5's the wheels were not
designed for tubless tyres.
Better safe than sorry.

32lbs pressure seems ideal by the way.

Nick 407 6028.

tyres for 407
 

Thanks Nick I thought this would be the case. Have now ordered the relevant tubes.

regards
Mick

Tyers for a Bristol 407
 

Bristol cars already offer wider wheels to take advantage of wider modern tyres, If you look in the upgrades section of their site they list these for all models back to and including the 400.

Tyers for a Bristol 407
 

Tyre pressures increase with heat and the heat increases the harder the tyre is worked. On my race car, I look to set pressures cold (before the sun gets on them) and achieve a 5 lb lift in pressure at the end of a track session. If the pressure rise is less, the tyres have not come up to working pressure which means the pressure has been set too high for the conditions - I reduce the pressure to get more heat into the tyre. If the pressure comes up more than 5 lbs, the tyre is under-inflated for the conditions and, somewhat counter-intuitively, the pressure must be increased to stop the tyre overheating.

My race car is an Alfasud, a small front wheel drive saloon, on treaded race tyres (Yokohama A048s). I will commonly start with 26 lbs in the front and 17 lbs in the rear. The rear end sees little weight and does relatively little work so the low pressure is essential to get them up to working temperature. Ordinary road tyres do not have such stiff sidewalls and need more pressure on the track to stiffen them up and stop them overheating.

I run about 30 lbs all round on my 411.


Chris Browne
Auckland, New Zealand
irie@orcon.net.nz
Cellular: +64-21-617007

Tyres for 407
 

The sole reason for running at 32 lbs per sq in was, that unlike your 411, the 407 has no power steering and the soft side walls of the Michelin X's make low speed parking and maneuvering very hard and puts a great strain on both driver and car. The soft walls also contribute to a far better ride.
I experimented with several tyre pressures for everyday running and found that 32 lbs sq in to be the best compromise.
I am so happy with the tyres after struggling when parking with the Avon Turbo speeds. The lock on the 407 is not good and parking a car 16ft 7inches
long with a turning circle of 39ft, weighing, empty of occupants and fuel, some 32 cwt in old money, was a great strain.
Also the 411 has the engine moved back from the front axle and has an aluminium gearbox.
Just thought I would mention it as the car is used for day to day practical work and not track days or racing. The odd circuit of Le Mans and Silverstone excepted that is!
Happy Bristoling,
Nick 407 6028