Rally Guanajuato Mexico 2013

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Originally Posted by Mirek

I started what I didn't even want :) No matter the situation on the photo it's fact VW has longer travel. What are the benefits and disadvantages is an interesting question for me and I don't care if we continue about that. But I would surely not overestimated one particular photo, that was just a random thing I found particularly interesting going through photos of André - in the end it might be like the discussion in Swedish topic about Ogier/JML in the same corner. Just remember ;)



It is important because the traction of an axle depends on the wheel with lesser load. Limited slip differential can't lock completely and therefore one wheel in the air must reduce the torque on the other as well. If You make the same with normal car without LSD You would just spin the inner wheel in the air and You would not accelerate at all.

The other thing is that there is some limit for lateral forces the tyres are able to cope with. If You have a wheel in the air it means the lateral force on those on the ground is higher - You have either smaller cornering speed or You loose time sliding sideways. The situation is the worse that car kicked in the air has higher center of gravity and the load on outer wheels is therefore further increased.

Just thinking loud here, feel free to tell me if it's BS :)

But there was sure a good point from Bluuford about the vulnerability of long struts. That sure is more risky. I also remember when they first brought Fiesta S2000 here in CZ. That time it was the only car with extremely long suspension travel (who would think VW will go even further). On our extremely bumpy asphalt they had huge problems to make a suitable setup. The asphalt suspension settings of M-Sport were useless because especially in braking the car was very hard to control sliding over the sumpguard. The problem was that when they made the ground clearance higher the suspension became very soft and unstable for competing on asphalt. I don't know how it was later solved with Prokop/Tarabus but I clearly remember the initial issues resulting in many hot moments.

By the way even last year Flodin with PS Engineering Fiesta touched ground very frequently in Barum rally...

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Very good points, but not perfect perhaps - how come a car with higher center of gravity will put more pressure on the other wheels, it will just slide it imo. I still don't get it for the great danger long suspension travel might become. Perhaps the tyres are stronger these days in every direction.

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Originally Posted by dimviii

Mirek just a correction here....plated lsd diffs can transfer plenty of torque even when you have one wheel of the ground.Some other type lsd diffs like torsen yes they cant transfer torque when we have one wheel in the air.

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I know but "plenty" is still less than if both wheels have similar traction ;)

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Originally Posted by stefanvv

Very good points, but not perfect perhaps - how come a car with higher center of gravity will put more pressure on the other wheels, it will just slide it imo. I still don't get it for the great danger long suspension travel might become. Perhaps the tyres are stronger these days in every direction.

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I think this was referring to the Latvala retirement. One could guess that the track control arm is more exposed to bigger rocks if the suspension travel is longer? So a rock that the DS3 might hit with the front bumper could presumably get past this on the VW and hit the TCA? I'm sure VW will look into that. Trust Latvala to find the right sized rock to just go under, yet be big enough to break the TCA :D

I remember from Finland and Sardinia last year, that despite the shorter travel, the DS3 seemed to have better traction than the Fiesta. The Citroëns looked even slightly understeered (mostly Loeb and Neuville, Hirvonen less, perhaps due to his driving style)... http://rally-image.be/foto/0311/images/047.jpg - on this photo from Finland you could think the suspension is doing a bad job, but in fact Loeb was extremely fast there, faster than all others, and the car didn't even go sideways... Spring travel is one thing, dampers characteristics another thing... I think the dampers were the main difference between Citroën and Ford last year, especially in Finland, the cornering speed of Citroën was much higher before they started to go sideways. And that's something we certainly can't judge from one photo. A few years ago Loix was testing several sets of new dampers (think 3 sets) for the Ypres Rally, with Skoda. All looked exactly the same from the outside and had the same dimensions of course. What's in the inside is unfortunately hidden and kept secret for us, but when he got back in the service area after testing another set of dampers, a smile on his face revealed there was a noticable difference... :) Just to say, don't judge the whole suspension on just the travel regarding photos from one particular situation...

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Originally Posted by Sprocket

I think this was referring to the Latvala retirement. One could guess that the track control arm is more exposed to bigger rocks if the suspension travel is longer? So a rock that the DS3 might hit with the front bumper could presumably get past this on the VW and hit the TCA? I'm sure VW will look into that. Trust Latvala to find the right sized rock to just go under, yet be big enough to break the TCA :D

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I don't think the suspension travel is variable here, just bad luck

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Originally Posted by stefanvv

Very good points, but not perfect perhaps - how come a car with higher center of gravity will put more pressure on the other wheels, it will just slide it imo.

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That's what I meant. If the apex speed is same the car with higher center of gravity will start sliding because the load on outer wheels would be too high. In extreme situation on dry asphalt it can end by rollover :)

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Originally Posted by stefanvv

I still don't get it for the great danger long suspension travel might become. Perhaps the tyres are stronger these days in every direction.

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Any construction made of long narrow components is rather fragile or better to say can't be so strong like similar construction made of shorter elements. That's natural thing.

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Originally Posted by tommeke_B

I remember from Finland and Sardinia last year, that despite the shorter travel, the DS3 seemed to have better traction than the Fiesta. The Citroëns looked even slightly understeered (mostly Loeb and Neuville, Hirvonen less, perhaps due to his driving style)... http://rally-image.be/foto/0311/images/047.jpg - on this photo from Finland you could think the suspension is doing a bad job, but in fact Loeb was extremely fast there, faster than all others, and the car didn't even go sideways... Spring travel is one thing, dampers characteristics another thing... I think the dampers were the main difference between Citroën and Ford last year, especially in Finland, the cornering speed of Citroën was much higher before they started to go sideways. And that's something we certainly can't judge from one photo. A few years ago Loix was testing several sets of new dampers (think 3 sets) for the Ypres Rally, with Skoda. All looked exactly the same from the outside and had the same dimensions of course. What's in the inside is unfortunately hidden and kept secret for us, but when he got back in the service area after testing another set of dampers, a smile on his face revealed there was a noticable difference... :) Just to say, don't judge the whole suspension on just the travel regarding photos from one particular situation...

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In my opinion the difference You speak about (Fiesta/DS3) was more in differential settings but that's just my feeling ;)

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Originally Posted by Mirek

Any construction made of long narrow components is rather fragile or better to say can't be so strong like similar construction made of shorter elements. That's natural thing.

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It depends of the construction I think, it might appear even stronger

EDIT:
http://data21.gallery.ru/albums/gall...740-u7379c.jpg

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Originally Posted by stefanvv

It depends of the construction I think, it might appear even stronger

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The longer your suspension travel is, the more fragile it is, without any doubt. If you have an impact, if the distance towards the top mount is 1,5x as much as with another car, the torque on the top mount will be 1,5x as much too. And if the wheel drops deeper, the chance of hitting some edge/stone/whatever is multiple times higher too.

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Originally Posted by Mirek

In my opinion the difference You speak about (Fiesta/DS3) was more in differential settings but that's just my feeling ;)

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Of course it's likely some set-up thing, but still, my point is that there is more on a rally-car than just suspension-travel. :) Some people here are almost translating time differences between Ogier and Hirvonen to the difference in suspension travel, and that's not so smart...