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Tandem Cycling A bicycle built for two. Want to find out more about this wonderful world of tandems? Check out this forum to talk with other tandem enthusiasts. Captains and stokers welcome!

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Old 09-13-17, 03:46 PM   #26
pdlpsher
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I'm running 90psi on a 25mm rear tire on my solo bike, and 110psi on a 25mm rear tandem tire.

I've yet to learn the exact weight distribution of a tandem, but I've heard that the front vs. rear bias is not as extreme as it is on a single bike. I'm sure the weight distribution is highly dependent upon the team. If the captain is heavy, a higher percentage of weight would be shifted to the front. It would be interesting to find out what my tandem's weight distribution is. I might run that experiment. Has anyone run a similar experiment?
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Old 09-13-17, 04:09 PM   #27
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Quote:
Originally Posted by pdlpsher View Post
I'm running 90psi on a 25mm rear tire on my solo bike, and 110psi on a 25mm rear tandem tire.

I've yet to learn the exact weight distribution of a tandem, but I've heard that the front vs. rear bias is not as extreme as it is on a single bike. I'm sure the weight distribution is highly dependent upon the team. If the captain is heavy, a higher percentage of weight would be shifted to the front. It would be interesting to find out what my tandem's weight distribution is. I might run that experiment. Has anyone run a similar experiment?
Of course it depends on the riders, but take a look at picture of two on a tandem. The captain's center of gravity is slightly forward of midway, but the stoker's CoG is much closer to the rear axle. I roughly estimate that if the riders weighed the same, the distribution could be in the 35/65 range or even worse. Of course, most (sexist?) recreational teams have lighter stokers, so it's not as bad as it might be.

Easy enough to check with a bathroom scale, a phone book, and a friend. Set the bike up near a wall, on the scale and phone book, adding height where needed so it's level. Have both mount using the wall to keep from falling. Settle into normal riding position, and have the friend read the weight. Turn the bike around for the other axle weight, or simply subtract from the total weight if known.

Divide the axle weights by the total for the percentages.
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Old 09-13-17, 10:46 PM   #28
Chancy
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Quote:
Originally Posted by pdlpsher View Post
I'm running 90psi on a 25mm rear tire on my solo bike, and 110psi on a 25mm rear tandem tire.

I've yet to learn the exact weight distribution of a tandem, but I've heard that the front vs. rear bias is not as extreme as it is on a single bike. I'm sure the weight distribution is highly dependent upon the team. If the captain is heavy, a higher percentage of weight would be shifted to the front. It would be interesting to find out what my tandem's weight distribution is. I might run that experiment. Has anyone run a similar experiment?
I checked this many years ago on our previous tandem (older Santana Arriva) with us ready to ride. We had 2-3 water bottles, rear rack with trunk bag (rain jackets, cable lock, and a few other things, 5-6 lbs total), and a small triangle frame bag with tool kit, CO2 pumps, spare tubes and patch kit, and phone). We checked it just as FBinNY described (except we didn't need a 3rd person- I read the scale when it was under the front wheel and Nancy read it under the rear wheel). Our distribution was 46% in front, 54% in the rear...and I out weigh my wife by ~70 lbs!

Tailwinds,
Charlie
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Old 09-16-17, 05:30 AM   #29
marciero
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As was said, 120 psi is WAY too high for a 32 tire. Our Commotion has 700x32 and we run them at around 60psi front 65psi rear max, typically a little lower. We are about 280 lb team and that is plenty for us, even on gravel. We got a pinch flat once or twice but it was pilot error riding straight into a pothole or something. The ride is sublime with high quality tires. The Berto chart should be considered as a rough guideline. Does not make sense to double the pressure of single bike.
Our Cannondale with wider tires has even lower pressures. Our lower limit on that bike is determined by the handling. No pinch flats on that bike as it is tubeless. That is, we could probably go even lower but the handling gets mushy. I've also never heard of high quality tires failing due to flexing of the casings. This is what they are designed to do! It's certainly never happened to me on single or tandem in many tens of thousands of miles.

Last edited by marciero; 09-16-17 at 05:35 AM.
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Old 09-20-17, 05:33 AM   #30
merzcm
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I looked at several of the online tire pressure calculators. Some of them came up with very high pressures indeed.

Tire Pressure Calculator ? Bike Tinker

I used 400 lbs total for tandem team bike and gear and 32MM tire. Front (psi) 109 Rear (psi) 135

If you drop to 300, the pressure requirements drop to Front (psi) 80, Rear (psi) 99.

I switched to Continental Gatorskins which fit the Araya VX300 rims much tighter than the other tires I had been using. No problems yet.
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