Tyre profiles and ride height issues
Discussion
I've been offered a set of 205 50 VR15 Toyo Proxes at a very reasonable price. However, from the Chim forum:
The wedge bible says 350i 1983 on uses 205 50 VR15, but my car came with 205 60 15 S02pp's on the front and 215 55 15 bridgestones on the back.
Comments please.
19560 said:
These tyres are spot on for 280i/Tasmin owners who want to swap to 15" wheels from 14" (195/60/14 www.toyo.co.uk/index.php?fuseaction=tyreconverter.table8a&pId=1 ) but are a little small for the 350i/SE which began life with a 205/60/15 (same as the Chimp.)
Jonathan
The wedge bible says 350i 1983 on uses 205 50 VR15, but my car came with 205 60 15 S02pp's on the front and 215 55 15 bridgestones on the back.
Comments please.
tallbloke said:
The wedge bible says 350i 1983 on uses 205 50 VR15, but my car came with 205 60 15 S02pp's on the front and 215 55 15 bridgestones on the back.
It's another misprint.
Remember this:-
19560 said:
All 350s left the factory with 205/60VR15 tyres, mostly Goodyear Eagles because this was one of the best tyre sizes and models at the time. I do not know which maintenance manual that you are looking at but it is wrong - a missprint perhaps?
The 390s and 400s nearly all came with 225/50ZR15s (a few of the early ones came with 225/50ZorVR15s for some odd reason). Neither of these tyre sizes will fit under the front wheel arch of your 350.
The 420s, 430s and 450s all came with 225/50ZR15s all round except for one motor show SEAC model that came with outragously wide wheels and tyres and which is still around.
One of the problems for 350 owners is that although 205/60s are still available they are not available in modern rubber. No manufacturer makes sports car tyres in 60 profiles. 205/55ZR15 as fitted to the Griffith at the front is a good alternative which also sharpens up the front end. The V rating is also OK because you will never exceed 150mph.
and Steve talking about tyre sizes in his books:-
shpub said:
As for misprints/changes, happened all the time.
Steve
www.tvrbooks.co.uk
215/55/15 is novel and not a bad idea IMHO.
I hope that this helps. Jonathan
shpub said:
The 50 profile is a misprint and it should be 60.
the 205/50 will cause a drop of around 3/4 inch to the ride height but the lower profile will sharpen up the handling a bit.
Ahaaa!
Thanks Steve. I think the drop in ride height won't be a problem with my series 1 wedge, as the front spoiler sits quite high anyway. I'll check and see that my trolley jack will still clear the skirts though.
tallbloke said:
The 50 profile is a misprint and it should be 60.
the 205/50 will cause a drop of around 3/4 inch to the ride height but the lower profile will sharpen up the handling a bit.
Ahaaa!
Thanks Steve. I think the drop in ride height won't be a problem with my series 1 wedge, as the front spoiler sits quite high anyway.
Apart from, in the words of John Ravenscroft, the change in diameter is "too big and the suspension angles won't work properly."
19560 said:
Thanks Steve. I think the drop in ride height won't be a problem with my series 1 wedge, as the front spoiler sits quite high anyway.
Apart from, in the words of John Ravenscroft, the change in diameter is "too big and the suspension angles won't work properly."
Fortunately, I'm not sufficiently expert in 4 wheel matters to have an opinion on this. I'll just try the lower profile tyres and stiffen the lateral tendencies of my series 1 trailing arms, and report back to describe the shape of the broken bits.
19560 said:
Apart from, in the words of John Ravenscroft, the change in diameter is "too big and the suspension angles won't work properly."
They don't work probably anyway as the whole design is pretty agricultural and while you think there is nice correct wishbone movement... there isn't. It basically uses rubber stiction to control the movement so as the wheel moves vertically all the settings can change quite considerably.
Instead of the shocks/springs doing the work, the rubber bushes start acting like they were springs and shocks.
Considering it came from a 1970s saloon it is amazing that it works at all!
Also take into account the 14 inch wheel cars... significantly smaller but with the same setup. There is no adjustment apart from castor that can be made and they were just bolted on.
Just ditched the whole design and came up with new design that just bolts in and provides a complete rose jointed insitu adjustable wishbone which controls the movement more consistently. Fully adjustable for camber castor etc in situ.
It has transformed the car as it no longer bounces off bumps. This is also running with 650 lb springs.
shpub said:
Just ditched the whole design and came up with new design that just bolts in and provides a complete rose jointed insitu adjustable wishbone which controls the movement more consistently. Fully adjustable for camber castor etc in situ.
It has transformed the car as it no longer bounces off bumps. This is also running with 650 lb springs.
Corr! Thats impressive. Jpeg!I'll see what I can do... but I am waiting for the alloy uprights and hubs to arrive to complete the final spec. These will fit the original design as well.
Tested it at Silverstone with the normal uprights and hubs and it really did improve the car. It was noticeable just driving the car to the track. The great thing was that adjustments could be made in seconds. It only takes about 5-10 minutes to change the shock without any special tools.
Looks like it will take about 3-4 kg weight off each side with the alloy bits as well.
Anyone else interested?
>> Edited by shpub on Wednesday 19th January 10:06
Tested it at Silverstone with the normal uprights and hubs and it really did improve the car. It was noticeable just driving the car to the track. The great thing was that adjustments could be made in seconds. It only takes about 5-10 minutes to change the shock without any special tools.
Looks like it will take about 3-4 kg weight off each side with the alloy bits as well.
Anyone else interested?
>> Edited by shpub on Wednesday 19th January 10:06
shpub said:
I'll see what I can do... but I am waiting for the alloy uprights and hubs to arrive to complete the final spec. These will fit the original design as well.
Looks like it will take about 3-4 kg weight off each side with the alloy bits as well.
Anyone else interested?
Could you email me with some idea of costs Steve. Sounds like the way forward.The ride height is controlled by a coil over shock so that can be adjusted within the parameters defined by the open/closed length of the shock and how stiff the spring is. So you could lower it several inches or turn it into a four by four.
The original non adjustable shocks and big cortina style springs are not used. It uses standard off the shelf springs.
In my setup, the only thing I have reused is the roll bar and the front tie rod mounts. Looking at making it a bit more modular so that you can pick and choose at which level you want to come in at.
The original non adjustable shocks and big cortina style springs are not used. It uses standard off the shelf springs.
In my setup, the only thing I have reused is the roll bar and the front tie rod mounts. Looking at making it a bit more modular so that you can pick and choose at which level you want to come in at.
Steve, thanks for the info. Sounds good especially using off the shelf shocks and springs. Looking at some of the threads around at the moment on ride height etc this could be the solution. I did spend a long time trying to work out what springs to use to give the correct ride height on the front and it's not easy getting this right especially when you have a non standard car with an engine that weighs something different to any other car. Could you give me any idea of price?
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