BIG tyres under stock kombi guards (photos on page 2)

KruizinKombi · 2004-03-24T04:28:56+00:00

Ok, I have to repost this since the forum went down.... Finally, I've managed to fit some rear tyres that I'm happy with. The wheels are from a BA Falcon one-tonner, machined by Ian (aka Desert Bug) to suit the kombi 112mm stud pattern (Falcon PCD=114.3mm). The tyres are Pirelli Scorpion 235/85-16 LT's with an All-Terrain tread. Results? I have about 12mm clearance to the inside lip of the rear guards, and 8mm clearance between the tyre and the spring plate. The rolling radius is now 384mm (compared to my previous 291mm!!!). Theoretically this works out to around 4240rpm @ 100kmh in 3rd, and approx (in practice) 2900rpm @ 100kmh in 4th. In other words, I can rev to peak power (4200rpm) in third and then change into fourth and find myself at close to peak torque (2800rpm). I don't know if anyone had noticed, but stock kombis work this way anyway. The difference is, I'm now doing it at around 100kmh! 😀 The purpose behind this is to gain footprint area (and hence flotation) when I'm on the beach this coming Xmas. I've done it on stock-sized tyres before, but they were less than ideal, requiring me to lower my tyre pressures radically (7psi) which resulted in two tyres coming off the bead. Hopefully I should be able to run these new tyres at around 12-15psi. I'm also hoping to gain some fuel economy on the longer trips while I'm loping along at about 3000rpm instead of screaming along at about 4000rpm as I have been. Mileage tests are underway, I'll post results when I have some. The downside of all this is that taller gears effect my take-off. The bus is noticably slower getting off the line, but still quite ok for around town. Fourth gear is now basically an overdrive; pretty useless for going up big hills, but I can also change down to third and maintain 110kmh, which I couldn't before. The new drive ratio will be a problem for steep bush-work, where I have found the kombi's major limitation to be gearing (even with stock-sized tyres). I'm not really going to let this bother me, as I'd decided a year or so ago not to try to out-do 4x4's as I was suffering too much body damage anyway, and I don't think it will be a problem on the sand. I did take the family out for a drive in the bush around Walhalla on the weekend, but not on anything really steep. I found the larger tyres ride considerably better over bumps and holes, and the additional 90mm clearance gives me some peace of mind also. Hopefully I won't be losing my tailpipe once I've replaced it! 🙂 Next on the wish list is some new front tyres, to be mounted on the other 3 wheels that are waiting for cashflow, followed by a custom rear bar with twin, swing-away wheel carriers and some better shockers to try to counteract some of the extra body roll I'm encountering. I have to keep reminding myself though, there's nothing wrong with having goals!! [Edited on 14-5-2004 by KruizinKombi] [ Edited on 2-11-2006 by KruizinKombi ]

kombi_kid Moderator Good Kid too many projects

124 posts · joined Aug 2002 · 21 Jul 2004, 5:19 pm

#205717

sorry for hijacking this colin but what PSI should i set the tyres at you reacon??? they put them at 34PSI at the tyre joint but i noticed it jumpin around at the back was thinkin maybe 24 for the back 22 for the front or vice versa?
cheers
rhys

[Edited on 21-7-2004 by kombi_kid]

it aint just cool its aircool'd

Desert Bug Wolfsburg Wizard

687 posts · joined Aug 2002 · 21 Jul 2004, 10:46 pm

#205987

Rhys, I would try around 28-30 at back, and 24-26 at front then roadtest and adjust pressure up and down a little and roadtest on the same section of road till you're happy with it, remember to increase the pressure if you are carrying a full load. You should always have more pressure at the back, likewise in a Beetle.
Cheers, Ian.

KruizinKombi Seriously Obsessed Cyber Dubber

3,493 posts · joined Aug 2002 · 12 Oct 2004, 3:39 pm

#245027

My rears are good for 80 psi, so I set them to 60 after finding that 30, 40 or 50 just allowed the thing to wander all over the place in corners. I can't remember my fronts, but from memory they are within 10psi of maximum.

Kruizin Kol