Tandems.co.uk

Hello,
My wife and I live in Australia and purchased a KHS Milano a few months ago. This is a “entry” level tandem and comes with a 9 speed Tiagra transmission, Shimano hubs, Weinmann rims and a assortment of generic Taiwanese bits and pieces. While I have ridden for 30 years, my wife is new to cycling, but is quite strong and fit. After the initial tandem wobbles when starting and stopping and a few communication issues, we are now working more or less in sync. We take our 4 year old daughter on a child seat on the rear. This adds about 19 Kg (40 lbs) to the bike, but I am used to taking her on my single and sometimes ride solo on the tandem with the child.
What is very apparent is our speed or lack of, even on the flat. I am used to riding my old Klein Manta mountain bike with slicks for commuting and find the tandem cannot match the pace of the single. Even though my wife puts in, I find that just 20Km on the tandem feels like 80+ Km on the single. I realise the uphill are always going to be harder, but was under the impression that with the extra power and an aerodynamic advantage over separate bikes, we would be able to maintain high average speed on the flat.
The tyres that came fitted were Kenda Kwest which blew out after a few hundred Kms. I fitted Vittoria Randonneur 700 x 28c tyres which handle more predictably, are smoother but don’t seem any faster.
I have checked for brake drag, the hubs feel OK and are cool after a ride and the tyres are always inflated to the recommended pressure.
My questions are:
Why would it be so hard for us to maintain even 25 Kph (15 1/2 Mph) on the flat when I can easily average 30 Kph on the Mtn bike, and 28-29 Kph when solo on the tandem? (before anyone suggests my stoker, I can feel her input and dare not go down that path
Our combined weight would be ~ 160Kg (350lbs). Would larger tyres like 32c or 35c be a better choice for this weight?
Do relatively low end hubs slow a heavy bike?
Could imperfect sync be an issue?
Am I just wrong about my expectations?
Also I am new to road bars and feel somewhat restricted in my handling with the narrow bars. My breathing could be a little restricted compared to my position on the mtn bike, so I am considering changing to a flat bar setup.
Could this make a difference?
I look forward to your suggestions.

We have sold KHS Milano tandems and have found them to be really good, particularly for the money.  I’m not sure why you are finding the going so slow.  You mention about having the tyres upto recommended pressures, but they need to be at 100psi region.  Continental have brought out some new extra puncture proof duraskins or gator skins as they are often known.  What psi are the tyres you are running rated to?

Size nothing wrong with 28c for your weights, you could go wider but they wouldn’t be any quicker, just more comfortable.

Come back to me on this and we can explore more possibilities.

Regards
Ruth

Hi Ruth,
Both the exploding Kenda and the new Vittoria Randonneur tyres have a max 85 psi rating. By your recommendation and some other articles I have come across on the web, it looks like at least 100 and maybe as much as 120 psi is required. I might have to keep the Vittoria’s as back up and get some Cont Ultra Gators.

Regards

Simon