Do you think tyre profile is too wide?
Discussion
I was having a chat to a mechanic yesterday and he said "why don't you get bigger wheels eg: 17 or 18 inches and get lower profile tyres? it will be better for a high performance car like this" The front tyre on a 1998 Griff is 55, which when looking at it, it does look quite wide.
I've been on a tyre site and you can put 18 inch wheels on with a 35 profile without messing up the speedo.
Is there any reason why TVR put a fairly wide profile tyre on? particularly on the front.
Grouch.
I've been on a tyre site and you can put 18 inch wheels on with a 35 profile without messing up the speedo.
Is there any reason why TVR put a fairly wide profile tyre on? particularly on the front.
Grouch.
The main drawback is suspension compliance is generally not great with lower profile tyres as the lower sidewall will remove the cushioning effects of the tyre. This can result in a choppy ride (but probably not much more than standard and still within the bounds of acceptability).
I am looking at wheel upgrades and have been told that TSW in the UK are expanding their range to incorporate some of the USA models (if you are interested look at the Catalunya or the Kylami and think how they would look on a Chim or a Griff). Check out www.tswnet.com/new/productline_passenger.php
Accepted methodology seems to be 17" front 18" rear.
Richard
>> Edited by BigGriff on Wednesday 8th December 16:37
I am looking at wheel upgrades and have been told that TSW in the UK are expanding their range to incorporate some of the USA models (if you are interested look at the Catalunya or the Kylami and think how they would look on a Chim or a Griff). Check out www.tswnet.com/new/productline_passenger.php
Accepted methodology seems to be 17" front 18" rear.
Richard
>> Edited by BigGriff on Wednesday 8th December 16:37
Lower-profile tyres are less able to tolerate camber changes as the suspension moves. If you ran the car exclusively on race tracks you could fit short, stiff springs to limit the suspension movement. On a real road you can't do that because you need the suspension travel to deal with bumps without the tyres leaving the road.
The bottom line is the suspension needs to be tuned to the tyres and if it isn't you'll get a car which may not generate as much grip as before, nor feel very pleasant on a bumpy road.
The bottom line is the suspension needs to be tuned to the tyres and if it isn't you'll get a car which may not generate as much grip as before, nor feel very pleasant on a bumpy road.
groucho said:
I've been on a tyre site and you can put 18 inch wheels on with a 35 profile without messing up the speedo.
Is there any reason why TVR put a fairly wide profile tyre on? particularly on the front.
Grouch.
G, there's loads of stuff in the archives about wheels especially 17" & 18" conversions and tyre profiles etc. do a search. One reason TVR put 15" / 16" wheels on is that they were pretty much it back in 1989/90 when the car was designed and I guess another consideration was cost. Rich...
>> Edited by RichB on Wednesday 8th December 17:19
JonRB
You are not quite correct, a lower profile tyre of the same width will actaully put more rubber on the road (bigger contact area) as there is less flex in the sidewalls.
davidy
PS my recommendation with the Griff would be to stick with 15/16 as you are likely to destroy the ride with bigger wheels, its not like the car is soft to start with!
You are not quite correct, a lower profile tyre of the same width will actaully put more rubber on the road (bigger contact area) as there is less flex in the sidewalls.
davidy
PS my recommendation with the Griff would be to stick with 15/16 as you are likely to destroy the ride with bigger wheels, its not like the car is soft to start with!
JonRB said:
Sorry to be picky, but lower profile tyres are not wider, they're just, er, lower profile.
The width is how wide they are. The profile is how thick they are (in the sense of how much of the diameter of the circle is rubber and how much is wheel).
I thought that but didn't want to be pedantic, good job!
Jon is right in what he says. width is the 205, 225, 245 bit, profie is the 40, 45, 55, bit. and that relates to the height of the sidewall of the tyre as a percentage of the width. Rich... >> Edited by RichB on Thursday 9th December 11:06
Others have changed to 17/18" wheels and report no significant ride difference. (cue RichB... 
)
Another point to bear in mind is that the lower profile will give you more grip (assuming a fairly smooth road/track) but when they let go they'll go very quickly. Less warning so harder to retrieve. No doubt a good thing if your senses are highly tuned but if not then may ultimately be less fun.
) Another point to bear in mind is that the lower profile will give you more grip (assuming a fairly smooth road/track) but when they let go they'll go very quickly. Less warning so harder to retrieve. No doubt a good thing if your senses are highly tuned but if not then may ultimately be less fun.
groucho said:
The front tyre on a 1998 Griff is 55
Which matches your
RichB said:
profie is the 40, 45, 55, bit. and that relates to the height of the sidewall of the tyre as a percentage of the width. Rich...
I can't see any confusion here, I have not mentioned 205, 225 or 245.
Grouch.
RichB said:
Is there any reason why TVR put a fairly wide profile tyre on? particularly on the front.
G, there's loads of stuff in the archives about wheels especially 17" & 18" conversions and tyre profiles etc. do a search. One reason TVR put 15" / 16" wheels on is that they were pretty much it back in 1989/90 when the car was designed and I guess another consideration was cost. Rich...
Yep, and
Andrew Noakes said:
Lower-profile tyres are less able to tolerate camber changes as the suspension moves. If you ran the car exclusively on race tracks you could fit short, stiff springs to limit the suspension movement. On a real road you can't do that because you need the suspension travel to deal with bumps without the tyres leaving the road.
The bottom line is the suspension needs to be tuned to the tyres and if it isn't you'll get a car which may not generate as much grip as before, nor feel very pleasant on a bumpy road.
To jump 3" to 18" at the front is asking too much of the suspension which struggled to cope with the power to weight ratio in the first place.
One major consideration is: are you thinking of two different pairs of wheels or four the same. The originals have different dia.s, widths and offsets.
There are a few other points:-
Assuming that you keep the rolling radius the same then larger wheels will: Downside:- cost more, have more expensive tyres, perform worse in the wet, perform worse on bumpy roads, be more susceptible to tram lining, increase the weight of the car, increase the un-sprung weight, produce a harsher ride, increase the rotating un-sprung weight (second moment of inertia) and be more liable to scuffing on kerbs when parking. On the plus side they should:- prevent the tyre from distorting thus giving greater cornering grip in the dry and on smooth roads, be more direct giving greater steering feel, produce less heat and be better for long high speed journeys, and effectively increase the spring rates being an easy way to fine tune your springing rates from summer to winter if you swap back to the smaller wheels for winter and they should look good.
Also note that fitting lower section tyres with less sidewall flex can make the car more sensitive to suspension geometry changes. Lowering the car can adversely affect the handling by throwing the static geometry out, and giving you too much camber correction and bump steer.
The optimum is probably 215/40/17 front and 245/40/17 (or 255/40/17) at the rear.
I had no adverse affects of fitting 265/35x18rear 235/40x17 front before suspension upgrades.
One thing to be aware of,standard 500 fronts, 225widths in 17's x40 profile in goodyear gd3 and so2/so3 are'nt available,therefore offsets are critical if you go for the larger size.
Obviously being grippier,you'll be putting more stress on your drive train etc.
One thing to be aware of,standard 500 fronts, 225widths in 17's x40 profile in goodyear gd3 and so2/so3 are'nt available,therefore offsets are critical if you go for the larger size.
Obviously being grippier,you'll be putting more stress on your drive train etc.
groucho said:
Lordy, there's a minefield of information to take into account.
Grouch.
Groucho, I've gone up to 17's on mine and the only real difference is that the ride becomes a lot bumpier, and that the car tram lines a little.
The trade off is however i can do things like this
my words of warning are however, watch out for the tyre size on the front as there is not a lot of room to play with, and also re offsets, i've used a 28mm offset, which i'm told is the peugeot setting, (advice from pennisula & speedline corse)
if you do go for wide tyres on the back, just remember to get a correct width wheel, i.e 8 or 8.5j else only the tyre will be squeezed in to far at the bead & in effect only a small preportion of the tyre will be in contact with the road & the centres of the tyres will wear quicker.
Also wider tyres IMHO do not always offer greater grip, as the load through the footprint area of the tyre is reduced. (ducks and runs)
>> Edited by k77-widow maker on Thursday 9th December 09:20
groucho said:They were just examples
I can't see any confusion here, I have not mentioned 205, 225 or 245. Grouch.
Grouch - I don't want to pick an argument with you because believe it or not I was actually trying to help, and if you are interested I have done exactly what you are talking about and have given advice to others which they did find helpful. That’s why I’m a bit pissed off with your attitude! The title of your post is quite clearly ambiguous, that or you don't really understand what the profile of a tyre is, and judging by the rest of your comments you do. So to reiterate... 205, 215, 225 (just examples) are the width in cm. 45,50,55 etc. are the height of the tyre wall expressed as a percentage of the width, and 16,17,18 etc. is the diameter of the bead in inches. So there will be no significant difference between tyres of the same width but different profiles. Your title says “Do you think tyre profile is too wide” That’s ambiguous! 
Rich…
Well that's why we all ask / answer questions on here!
for info Groucho, it's all about aspect ratio's
for example 205/55/15
The tyre's tread is 205mm wide, it's sidewall height is 55 % of the tyres width, and the rim size is 15"
check out this site if you want to work things out.
www.chris-longhurst.com/carbibles/index.html?menu.html&tyre_bible.html
>> Edited by k77-widow maker on Thursday 9th December 09:45
for info Groucho, it's all about aspect ratio's
for example 205/55/15
The tyre's tread is 205mm wide, it's sidewall height is 55 % of the tyres width, and the rim size is 15"
check out this site if you want to work things out.
www.chris-longhurst.com/carbibles/index.html?menu.html&tyre_bible.html
>> Edited by k77-widow maker on Thursday 9th December 09:45
Gassing Station | Griffith | Top of Page | What's New | My Stuff