Donnie Johnson

Good Morning BikeForum,

I have recently acquired a second hand flat bar tandem. I think it is about a 2002/4 model and it appears not a lot of maintenance has been undertaken during its life. The frame is in excellent condition and the wheels will be in good working order after a service however the drive line is excessively worn and much of the original gear needs to be replaced. This leaves a world of opportunity to rebuild an excellent machine. I’m less concerned about the weight of components relative to functionality and lifespan of replaced parts. The bike will be used mostly as a commuter and comfortable weekend ride with occasional touring and holidaying. It regularly will tow a trailer with my 3 year old daughter.

Considering the need the need to replace much of the driveline and most of the bearings, are there any recommendations or suggestions regarding good combinations for gears ratios, chains and other tandem specifics.
The bike currently runs 8 speed, 11-30 and has Tracer Cranks with 30, 42, 52 (30 chainring needs replacing and the rest are close) on the drive side and 42 teeth on the syncro side. The bottom bracket is square type, probably the sealed cartridge. The syncro chainrings are worn however I will probably reverse them (front to rear and vice verca) if I don’t upgrade the entire crankset.

In my spare parts box I have a touring crank arm (same length) with 26, 36 48 chainrings and new 9 speed shifters and 11-34 cassette. Will this combination suffice? Or is it likely the gearing will be too low. (I don’t imagine we will often use top top gears very often). Considering the current condition (almost everything needing to be replaced) is there any specific new tandem cranksets and drivelines that I should consider?

Any recommendation or suggestions are greatly appreciated.

Kind Regards

Donnie

nfmisso

Hi Donnie;

I would suggest just going with the parts you have in your box for now, you can always change to something different in the future.

On our Trek T50, we have 54-44-28 and a 11-34 9 speed cassette with a SRAM X.9 RD with 38-622 tires.

Tandems are heavy and need lower gearing for going up hills than singles, but conversely, they are more aerodynamic than singles, so on the level and downhill they can be very fast, using much higher gearing than singles.

Leisesturm

It sounds kind of shocking that a bike from 2002/4 should need such extensive re-working. Are you sure it isn't much older? What make/model is it? I only know of two flat-bar road tandems (700C) and they were the Fuji Absolute and the Raleigh Coupe. Our 2005 Coupe had a 30/42/52 and 12-27 9sp. I left the 52 alone but dropped the granny to 24 and the middle ring to 39. Haven't done anything with the cassette. It is a club racer it won't pull trailers ever. The tandem that will (Trek T900) has an 11-32 8sp and 28/38/48 as stock gearing. So far so good but I am eyeing that granny with a jaundiced eye and at the slightest provocation it gets axed for a 24T. If you get from that that I don't think gears commonly available go low enough you would be correct.

42T syncro rings are a nice touch, often they are 39. Bigger is better here I am told. I am uneasy about your swapping just the right hand crank arm even if the lengths match. I don't know why. Is the 11-34 a 9sp like the shifters? The tandem triples on both the Raleigh and Trek are by Truvativ. Their Elita is a tandem road set and I don't know what the MTB/Hybrid models call themselves. I don't believe they are terribly expensive but they do represent a significant outlay.

Donnie Johnson

Thanks for you replies,

The bike is a KHS Tandemonia Comp. Judging from the color and info sourced from the web it seems to be from around 2002-4. It could very well be older. The main wearing appears to have come from chains that have worn past their replacement point and have damaged the gears. The captain must have been a strong rider considering the wear patterns on the syncro chainrings and I think the previous owners toured on it with loaded panners and whatnot. There was also quite a bit of rust on the chains and a lot of dirt and grim build up. Its no biggie, just making the necessary maintenance changes so it will serve us well into the future. I initially intended on reusing most of the components that is existing on the bike with a few modifications to match some of the general components on my other bikes. I thought its is worth asking people with proper experience before purchasing a whole bunch new gear first.

JanMM

Our first tandem was a 2000 Tandemania Comp. Cromo frame, flat bars, 26 inch wheels. In order to climb hills better, I did end up replacing all three rings with smaller ones - I think the final big ring was 50t. High enough gearing for our needs. Low enough, too, on the other end. Can't recall the size of the small ring. (May have left the middle ring alone.) The wheels were sturdy with Rhinolyte rims. Our KHS 'starter' tandem served our needs for a decade until we moved up to a RANS recumbent tandem.

tandembethesda

How do you like your Rans Screamer?

I am thinking of going the recumbent route. How easy is it to climb hills? I don't live in a big hill area, but some of the hills are challenging with my Trek T900

ksisler

I have seen Truvativ cranks and crank parts on ebay rather often and at very low prices. They aren't quite as spit and polish as more expensive sets, but seem plenty functional and strong.

From my world view, within reason, tandem gearing should shade toward lower being better than higher. My favorite loading touring tandem is 12-34 7-speed with 22-40-50 crank. Crossover rings are 38 or 40. Finding them on sale, I had bought a fancy complete Deore tandem setup with longer arms and fancy bottom brackets under the assumption that the stock setup would wear out or would be unsatisfactory for whatever reason. But after years on the original setup with no issues I just continue to ride it with a smile.