I'm posting a new thread on this because it’s a specific issue I'm looking for advice on.
My project van is (sort of) well documented on this thread http://www.expeditionportal.com/forum/threads/78237-Pre-birth-of-a-camper-No-laughing
It's now largely finished but I'm having a handling problem that I can't figure out.
The Symptom:
If you make moderate steering adjustments at speed (>60kph) the tail feels like it's coming around and causing the van to overseer which then has to be corrected quite quickly. It feels like the tail would easily come around and a bit scary. Interesting thing is though, if you're on a twisty road and having to make significant steering adjustments then the problem is not really noticeable even at dizzy speeds up to 80+kph.
This has been brought to a head because the guy who's doing the engine re-mapping made similar (more colourful) comments.
The Facts:
The base van is a Mercedes 814DA 4x4 chassis. It recently went through a reasonably comprehensive DoE test so suspension joints, bushes, ball joints etc. are in good shape although I do think the shocks are tired.
It originally came with 17.5" wheels with Michelin 9.5 R17.5 XZT tyres and dual wheel set-up on the back. I've since fitted 19.5" "Super Single" wheels from Aspect fitted with 285/70 R 19.5 Continental HDR tyres. I believe its fitted with the heavy duty version of the anti-roll bar - but I need to check this.
Wheelbase is 3.7m, rear overhang is 2.1m and its 3.5m high and 2.3m wide, overall length is about 7m. Distance between the outer walls of the rear wheels is 2200mm. Box construction is fairly standard 2mm GRP, 4mm ply, 50mm dense foam and 2mm GRP. There are 2 baffled water tanks of about 250L each mounted in the box (effectively on top of the chassis rails) and just behind the rear axle line. Most tests were done with these full or nearly full.
The axle loads are 2500kg on the front (max is 2800kg) and 3300kg at the back (max is 5500kg). So loaded weight is 5800kg on a 7500kg rated chassis. There is comfortably 100mm of travel left in the rear suspension before it even begins to touch the bump stops and the stops have a lot of give in them. The front it much closer with only about 45mm travel left. But I've checked this and any other 814DA I've looked at has similar limited front end travel. It does easily bottom out at the front when on bad roads - but the "symptom" is most evident on smooth roads.
I've had a friend who's a trained car mechanic followed me while I navigated some roundabouts and other corners and he felt it was not leaning much - no more than other commercial vehicles.
I think I'll get the shocks replaced anyway. Any suggestions on what to upgrade them to or who I should talk to in UK, Ireland or Northern EU?
I'm wondering if the single tyre on the back has more tyre wall movement than the original setup? Although the walls in the HDR tyres are shorter and much heavier than the XZTs.
Thoughts, Suggestions?
My project van is (sort of) well documented on this thread http://www.expeditionportal.com/forum/threads/78237-Pre-birth-of-a-camper-No-laughing
It's now largely finished but I'm having a handling problem that I can't figure out.
The Symptom:
If you make moderate steering adjustments at speed (>60kph) the tail feels like it's coming around and causing the van to overseer which then has to be corrected quite quickly. It feels like the tail would easily come around and a bit scary. Interesting thing is though, if you're on a twisty road and having to make significant steering adjustments then the problem is not really noticeable even at dizzy speeds up to 80+kph.
This has been brought to a head because the guy who's doing the engine re-mapping made similar (more colourful) comments.
The Facts:
The base van is a Mercedes 814DA 4x4 chassis. It recently went through a reasonably comprehensive DoE test so suspension joints, bushes, ball joints etc. are in good shape although I do think the shocks are tired.
It originally came with 17.5" wheels with Michelin 9.5 R17.5 XZT tyres and dual wheel set-up on the back. I've since fitted 19.5" "Super Single" wheels from Aspect fitted with 285/70 R 19.5 Continental HDR tyres. I believe its fitted with the heavy duty version of the anti-roll bar - but I need to check this.
Wheelbase is 3.7m, rear overhang is 2.1m and its 3.5m high and 2.3m wide, overall length is about 7m. Distance between the outer walls of the rear wheels is 2200mm. Box construction is fairly standard 2mm GRP, 4mm ply, 50mm dense foam and 2mm GRP. There are 2 baffled water tanks of about 250L each mounted in the box (effectively on top of the chassis rails) and just behind the rear axle line. Most tests were done with these full or nearly full.
The axle loads are 2500kg on the front (max is 2800kg) and 3300kg at the back (max is 5500kg). So loaded weight is 5800kg on a 7500kg rated chassis. There is comfortably 100mm of travel left in the rear suspension before it even begins to touch the bump stops and the stops have a lot of give in them. The front it much closer with only about 45mm travel left. But I've checked this and any other 814DA I've looked at has similar limited front end travel. It does easily bottom out at the front when on bad roads - but the "symptom" is most evident on smooth roads.
I've had a friend who's a trained car mechanic followed me while I navigated some roundabouts and other corners and he felt it was not leaning much - no more than other commercial vehicles.
I think I'll get the shocks replaced anyway. Any suggestions on what to upgrade them to or who I should talk to in UK, Ireland or Northern EU?
I'm wondering if the single tyre on the back has more tyre wall movement than the original setup? Although the walls in the HDR tyres are shorter and much heavier than the XZTs.
Thoughts, Suggestions?
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