[gemithomas]

I've always wanted to know what the Tyre profile has to do with Ride quality and F.E. Also what would be its effect on Handling of the vehicle.

Is it like Tyre profile in directly proportional to ride quality and inversely proportional to F.E and Handling?!!.

Another question would be would changing the tyre profile affect the suspension in the long run.

[hydrashok]

Lesser profile = better handling, harsher ride, better looks.

I don't think tyre-profile as such has anything to do with FE.

The lower profile tyres have stronger sidewalls that don't flex during hard cornering. This translates into better handling. The difference is really perceptible.

I don't think lower-profile tyres will affect the suspension, if the tyre-upsizing is done as per formula, keeping the rolling radius the same. However, the slightly increased stress put on the suspension (due to the harsher ride-conditions) may speed-up wear and tear somewhat. Just a common-sense assessment. Don't know this for a fact

[aah78]

lower profile tyres are also more susceptible to aquaplane in the wet - a larger contact patch with the road.

the wider contact patch, however, increases your traction which leads to a drop in fuel efficiency.

as hydrashok says, lower profile tyres will translate to better handling but bad roads lead to a harsh ride which has an adverse effect on suspension in the long run.

they're great for showing off! mega rims and low profile tyres is a popular bling-factor combination.

the tyres your car comes with from the factory are generally selected after extensive tests to attain that "perfect" balance of handling, economy, ride comfort, etc.

[gemithomas]

Originally Posted by aah78

lower profile tyres are also more susceptible to aquaplane in the wet - a larger contact patch with the road.
.

what does that really mean. what is aquaplane

[Vid6639]

aqua planing occurs when your driving on wet roads. If the road has a lot of water and the tyre is not capable of displacing the water then a thin film of water is formed between the tyre and the road. When this happens you lose grip as the tyre is not in contact with the road. this is extremely dangerous and a wider tyre is more susceptible to this.

[gemithomas]

ok. The Ford fusion has got 195/60 R15 tyres. I think that is one of the major factors that is spoiling its ride comfort expecially at low speeds. Will there be any difference if i change ot 155/75 R15. If not what would be the appropriate size without affecting the speedometer

[rohan_fonseca]

Wouldn't low profile tires would lead to a decrease in pickup due to higher weight of the rim and greater contact patch? Broader tyres on a light car would increase the chances of auaplaning as well?

[razor4077]

Originally Posted by gemithomas

ok. The Ford fusion has got 195/60 R15 tyres. I think that is one of the major factors that is spoiling its ride comfort expecially at low speeds. Will there be any difference if i change ot 155/75 R15. If not what would be the appropriate size without affecting the speedometer

Speedo will not be affected much by the change in size... BUT...

I would seriously suggest that you do not consider downsizing to 155 from 195!
155 is the width of a stock Santro tyre. Apart from the fact that it will look quite ridiculous on your Fusion, your handling (wet/dry/whatever) and braking will go for a toss too! Furthermore, this would require you to change your rims from the stock ones to thinner ones to accomodate the new tyres.
A Ford Fusion was not designed for tyres that thin. Period.
Haven't come across a case of downsizing from OE before this

To improve your ride, I would suggest you invest in some quality rubber which are designed keeping road comfort in mind. An example would be the Michelin Engery XM1, a tyre that is quite popular on this forum. You'll be surprised at the difference a better tyre can make to the ride (and handling).
You could also consider getting yourself alloy wheels (dunno if you already have them). The reduced unsprung weight (alloys are much lighter than the steel rims) helps the ride factor.

[vina]

Pure technical question:


How does the sidewall height of a tyre help/hurt performance, comfort ....



I'm asking because at Ford workshop today I saw that Endeavour tyres had pretty high sidewalls (I don't know about other vehicles in its class - nor do I want a comparison for Endeavour vs. Fortuner vs. .... or anything like that - let's keep it pure technical)


PS: I searched on the internet as well as TBHP and went through general tyre threads also. Nothing specific turned up regarding tyre sidewall height - though people do talk about tyre width.

Hence the question. If Moderators feel this has been answered elsewhere - please delete the thread and PM me the search terms to use.

[Ricky_63]

The wall height especially in a SUV goes to help in more ways than one. As you may be aware the tyre wall height is the percentage of the tread width hence 265/70/15 would mean 265 = tread width, 70% of 265 = tyre side wall height, and 15 = rim dia

The taller the tyre wall height the more comfortable the ride because of better absorption of shocks on a bad road etc, lesser the chance of damage to the rim. But a tyre that is not riding on correct tyre pressure will have a bulging side wall, which would be suseptible to cuts / damage from pot holes...

Hope this helps




Cheers

[VCheng]

The sidewall is only one component of the overall suspension design in a vehicle.

To make it overly simple, taller sidewalls allow for a softer ride at the expense of squirming in turns, whereas shorter sidewalls make for sharper turn-ins at the expense of a fussier ride.

However, adequate design of other components and the type of vehicle and its use play a big role too.

[vina]

Originally Posted by Ricky_63

The wall height especially in a SUV goes to help in more ways than one. As you may be aware the tyre wall height is the percentage of the tread width hence 265/70/15 would mean 265 = tread width, 70% of 265 = tyre side wall height, and 15 = rim dia

The taller the tyre wall height the more comfortable the ride because of better absorption of shocks on a bad road etc, lesser the chance of damage to the rim. But a tyre that is not riding on correct tyre pressure will have a bulging side wall, which would be suseptible to cuts / damage from pot holes...

Hope this helps




Cheers

I knew about the calculation of the sidewall height part, and was aware of most of the other part too.

The thing is, several people go for upsized rim too for a given vehicle - I'm pretty sure that doesn't help the ride comfort (and probably the suspension doesn't like it either) but what is the advantage of doing that?


Also in SUV context how would more sidewall height help - your first sentence gives a taste and then you take away the platter by not telling anything specific to SUV (or may be I am missing it)?

[Ricky_63]

Originally Posted by vina

I knew about the calculation of the sidewall height part, and was aware of most of the other part too.

Thought you would.

The thing is, several people go for upsized rim too for a given vehicle - I'm pretty sure that doesn't help the ride comfort (and probably the suspension doesn't like it either) but what is the advantage of doing that?

Upsize is mainly for cosmetic reasons. My Octy runs 17" alloys looks great, handles brilliantly, but leads to pre-mature tyre / suspension wear. Ride quality also compromised. But on an Octy it is perfectly acceptable, it still rides & drives great. Braking improves for sure.

Also in SUV context how would more sidewall height help - your first sentence gives a taste and then you take away the platter by not telling anything specific to SUV (or may be I am missing it)?

SUV's are supposed to take the rough roads with aplomb. My Pajero does. I am running stock size on it. You can take it just anywhere without a thought, whereas one does think if one is running 18" wheels. Case in point - my friend's Q7 - it is running 19" rims, but one needs to be careful on bad roads or else you either cut your tyre or get a busted rim.

Hope THIS helps

Cheers

Note from Support: Please DO NOT posts responses within quotes. Use multi-quote instead.

[kpzen]

Off-road SUV tires have higher sidewalls
1. For extra reinforcement to absorb the vehicle's huge gross weight.
2. Highly stiff sidewall to absorb the shocks.
3. For High ground clearance.
4. To make it over loose sand, mud or rocks.

[vina]

Originally Posted by Ricky_63

...
Hope THIS helps


Cheers

It does.

More questions now:

How does sidewall help in cornering? I would think higher sidewall will flex more = poor performance. OTOH lower sidewall may generate so much force, the tread may "peel off" - again poor performance.