Fork pressure / pump
 

We just had a Dirt Jumper 3 (DJ3) installed on our tandem by the lbs. There is no guideline in the factory manual regarding pressure for weights after 220lbs. I was curious as to what pressure other teams were running in this series of fork. Also I can't find a pump that reads accurately in the low pressure range in which this shock operates. The maximum pressure per leg is 15psi. My printed manual does not mention a recommended pump for any of their models. I emailed Marzocchi and they are out of stock of their pump. What brands or models work well?

Send an Email to: Alex@MTBTandems.com

He helped Marzocchi "tune" its DJ forks for tandem use and knows them inside and out.

With all due respect to Alex, I thought it would be unfair to ask him a technical question about a product that I did not purchase through him.

I doubt he'd care... He's a very active member of our off-road tandem enthusiasts' forum who is always willing to help out fellow tandem folk who have questions about their equipment, regardless of how them came to have it installed on their tandems. If somewhere down the road they choose to do business with him, well that's part of being a great tandem dealer.

A standard suspension pump will work fine. These are available at every shop. You must pump until the desired pressure, then release the pump and reattach it. Then read how much pressure you've lost when releasing the pump. Add this loss to the desired pressure and pump until that limit.
We also have a DJ on our tandem. We run it at something like 0.4 bar (or barely 6 psi). At first I pumped it to the recommended pressure for a 130 kg rider and then ..... it became almost rigid. By steadily lowering the pressure I found the optimum for us as a 285 lbs team (tandem not included). The great thing about DJs is you can even ride them without any pressure at all because of the steel springs inside. Things get a bit "springy" then, but in case of an emergency (= blown air chamber) it is possible.

DJ3 fork update
 

We finally ran the new Marzocchi shock under a somewhat loaded condition . The total weight including the bike was 360lbs. The pressure in each leg was 7.5lbs. The ride contained a large amount of washboard pavement sections and several quick dips in the pavement of approximately 3 or 4 inches. Moving from the rigid fork to this suspension fork created a major improvement in the handling. I didn't have to fight the bike when we were leaning in the rough corners. The shock was supple and didn't complain about the drops. We didn't observe the usual tire and chassis oscillation that occurs on this route. So far, we're both impressed.